rochester center for biomedical ultrasound · 2021. 3. 9. · ultrasonic system characterization...

Rochester Center forBiomedical Ultrasound

2004 Annual Report

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Director: Kevin J. Parker, PhD, Associate Director: Deborah J. Rubens, MD | Executive Committee: DianeDalecki, PhD, Morton W. Miller, PhD, Kevin J. Parker, PhD, Deborah J. Rubens, MD, and Karl Q. Schwarz, MD |Provost: Charles E. Phelps | Vice Provost and Dean of The College Faculty: Thomas LeBlanc | Dean, School ofMedicine and Dentistry: David S. Guzick, MD | Annual Report Editor and Designer: Betsy Christiansen

Rochester Center for Biomedical Ultrasound, University of RochesterHopeman Building, Room 203, Rochester, NY 14627-0126Phone: 585.275.9542; Fax: 585.473.4919Email: [email protected] site: www.ece.rochester.edu/users/rcbu

Rochester Center for Biomedical Ultrasound

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Table of Contents

About the Cover ......................................................................................... 4

From the Directors .................................................................................... 5

About the Center ....................................................................................... 6

Selected Publications ................................................................................ 7

Selected Presentations ............................................................................. 8

People, Promotions, and Awards .............................................................. 9

Center Profile: Stephen McAleavey, PhD ................................................ 10

2004 Research.........................................................................................11• Biophysical bases of pulsed ultrasound bioeffects .............................11• Test target design, fabrication, and analysis for C-scan

ultrasonic system characterization ................................................... 12• Ultrasound Imaging Lab at the Rochester Institute of Technology ..... 12• Emergency Department Ultrasound .................................................. 12• Obstetrics and Gynecology Ultrasound Unit ...................................... 13• Pulsatile versus continuous growth in the human fetus .................... 13• Spectral estimation for characterization of acoustic aberration ......... 13• Doppler myography: ultrasonic localization of acoustic

myographic signals ........................................................................... 14• Three-dimensional sonoelastography for in vitro detection of

prostate cancer ................................................................................. 15• Three-dimensional sonoelastography imaging and viscoelastic

modeling of HIFU-induced lesions in bovine livers in vitro ................. 16• Anisotropic elasticity and viscosity deduced from supersonic

shear imaging in muscle ................................................................... 17• Investigations of the response of tissues to underwater sound ......... 18• URI/Field: A Matlab interface between the Siemens Ultrasound

Research Interface and Field II .......................................................... 19• Cardiac stimulation by ultrasound, part I: dependence on

pulse duration .................................................................................... 20• Cardiac stimulation by ultrasound, part II: cavitation detection .......... 21

Education ......................................................................................... 22

Third Tissue Elasticity Conference Sessions .......................................... 23

Patents and Software .............................................................................. 27

Center Members ..................................................................................... 30

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The cover image of the University ofRochester Interfaith Chapel, over-looking the Genesee River, wascaptured one winter morning by JohnYoung, a senior laboratory engineerin the Departments of Biochemistryand Biophysics and BiomedicalEngineering at the University.

The image to the right comes fromthe Massive Change Exhibition andTour, a project by Bruce Mau Designand the Institute without Boundaries,commissioned and organized by theVancouver Art Gallery. Theexhibition’s key themes focus uponthe emergence of design as one ofthe world’s most powerful forces.

The RCBU submitted numerousultrasound images created by BrianPorter for the exhibit’s ImageGallery. This gallery showcasesphotographs made with radio wavesto cosmic rays and everything inbetween, with the idea that newtechnologies are quickly makingvisible the as yet invisible. The exhibitis currently on tour throughoutCanada, the US, and Europe. Formore information and a schedule,visit: www.massivechange.com

About the Cover

Massive Change Image Gallery. Image courtesy of Greg Van Alstyne, IwB Director

Massive Change Image Gallery

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From the Directors

From Director Kevin J. Parker

The Rochester Center for Bio-medical Ultrasound (RCBU) waspleased to co-sponsor the ThirdInternational Conference onUltrasonic Measurement andImaging of Tissue Elasticity, held inCumbria, United Kingdom. Gather-ing investigators from around theworld, this event was organizedjointly with Dr. Jonathan Ophir ofthe Ultrasonic Laboratory at theUniversity of Texas MedicalSchool at Houston, with Professor

Jeff Bamber of The Institute of Cancer Research,Sutton, Surrey, UK, as the local host and organizer.Details of the conference start on page 23.

Elastography imaging is emerging as a promising andexciting new field with numerous approaches and clinicalapplications. Plans are underway for the Fourth Interna-tional Conference, which is being held in Texas in Octo-ber. More details about the upcoming conference can befound at the RCBU Web site:

www.ece.rochester.edu/users/rcbu/conference

The RCBU has, over the years, been a generating sourceof fundamental concepts and innovations. Many oftoday’s developments—contrast agents and nonlineartechniques—have a scientific history that includesbenchmark experiments at the University of Rochester.

This year’s annual report documents continued progressacross broads fronts, from the fundamentals of tissueultrasound interactions to advances in three-dimensionalimaging.

We welcome your comments on any of the enclosedreports.

From Associate Director Deborah J. Rubens andChief Sonographer Nancy Carson

In 2004, the Department of Radiol-ogy Ultrasound continued to grow,increasing exam volume by sixpercent. Early in 2004, thesonographers began to use their newAcuson Sequoias and their new GELogiq9. The machines representstate-of-the-art ultrasound technol-ogy, including compound imaging,speckle reduction, and voicerecognition on the Logiq9, andcadence, spatial compounding, andtissue equalization on the Sequoias.

Partnering with GE, the department acquired an addi-tional Logiq9 this fall to evaluate the latest softwarerelease. The software improves existing features such ascompounding, speckle reduction, and image auto optimi-zation. More importantly, it introduces a new approach tovolume imaging using 3D transducers, including newreal-time multiplaner transducers, termed “4D.” Thistechnology offers the radiologist an opportunity tomanipulate data from a single scan sweep and view theanatomy or pathology from any desired plane, an optionnot widely applied in radiology. These new applicationsallow radiologists to view reconstructed ultrasoundvolumes the same way they view reconstructed CT andMRI data. Information from this reconstructed plane hasalready been shown to be diagnostically advantageous inbreast, gyn, and vascular imaging.

Starting early in 2005, the department will be one ofseveral test sites across the nation to evaluate GE’s cine-loop protocols. The improved cine-loop capabilities let thesonographer acquire data in one or two volumetricsweeps, rather than multiple still images, thus improvingefficiency by decreasing scan time, while actuallycapturing more diagnostic information.

Clinical research continues with our medical centerpartners from pediatric nephrology and pediatric hematol-ogy. Nephrology is studying the intimal thickness of thecarotid artery as it relates to hypertension in a selectgroup of patients. Hematology is evaluating aspirinprophylaxis in sickle cell disease. Ultrasound is used tomonitor flow velocities in the circle of Willis on serialtranscranial Doppler ultrasound studies.

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The Rochester Center for Biomedi-cal Ultrasound at the University ofRochester was created in 1986 tounite professionals from the medical,engineering, and applied sciencecommunities.

The Center started with about 30members and now has around 100members, with several visitingscientists from locations around theworld.

The Center provides a uniqueenvironment where professionals canjoin together to investigate the use ofvery high frequency sound waves inmedical diagnosis along with otherultrasound-related endeavors.

The inside back page of this reportshows the diverse departmentsinvolved in collaborative ultrasoundresearch.

The Center’s objectives include:

ResearchIncludes interaction with joint labora-tories, technical discussion in formalmeetings, and communication througha Center newsletter. In addition,interactions with industry, govern-ment, and foundations provide anassessment of the needs of the fieldand encourage mutually beneficialresearch programs and fellowships.

EducationIncludes graduate-level courses inbiomedical ultrasound and closelyrelated fields, specialized shortcourses open to the internationalcommunity, and post-doctoratecollaborations with bioimaging areaswithin the University.

InnovationThe University of Rochester has along history of leadership and innova-tion in biomedical ultrasound. Formore than two decades, there hasbeen steady progress in the quality ofimages of organs within the bodywhich are reconstructed from theechoes of very short pulses ofultrasound.

In the late 1960s, Center memberRaymond Gramiak led a team thatfirst reported the use of an ultrasoundcontrast agent. At that time, agitated

liquids were injected via a catheterwhile performing an ultrasoundexamination of the heart and greatvessels. A dramatic increase inechoes was produced from the highlyreflective air bubbles containedwithin the injected solution. Work hasprogressed through the years in thisand other areas. Current projects

About the Center

The University of RochesterMedical Center

include: nonlinear acoustics, contrastagents, 3D and 4D sonoelastography,ultrasound and MRI fusion, scatter-ing, bioeffects, therapeutics, ad-vanced imaging systems, and more.

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Selected PublicationsSC Campbell, JA Cullinan, DJRubens. “Slow Flow or No Flow?Color and Power Doppler US Pitfallsin the Abdomen and Pelvis.”Radiographics, 24(2), 497-506,2004.

D Dalecki. “Mechanical Bioeffectsof Ultrasound.” Annual Reviews ofBiomedical Engineering, 6:229-248,2004.

OD Altland, D Dalecki, VNSuchkova, CW Francis. “Low-intensity ultrasound increases endo-thelial cell nitric oxide synthaseactivity and nitric oxide synthesis.” JThrombosis and Haemostasis, 2:637-643, 2004.

N Akashi, J Kushibiki, and F Dunn.“Frequency dependence of acousticproperties of aqueous glucosesolutions in the VHF/UHF range.” JAcous Soc Am, 116(1), 539-544,2004.

MW Miller, RK Miller, LFBattaglia, WC Dewey, MJ Edwards,WL Nyborg, C Cox, JSAbramowicz. “The T thermal doseconcept 1: in vivo teratogenesis.” JThermal Biology, 29, 141-149, 2004.

S Mazza, LF Battaglia, MW Miller,WC Dewey, MJ Edwards, JSAbramowicz. “The T thermal doseconcept 2: in vitro cellular effects.” JThermal Biology, 29, 151-156, 2004.

MW Miller. “Cell size relations forsonolysis.” Ultrasound in Medicineand Biology, 30(10) 1263-1267,2004.

VS Dogra, DJ Rubens, RH Gottlieb,S Bhatt. “Torsion and beyond: newtwists in spectral Doppler evaluationof the scrotum.” J Ultrasound Med,Aug 23(8), 1077-1085, 2004.

F Lei, WS Ng, H Liu, W O’Dell, DJRubens, Y Yu. “Bouquetbrachytherapy: the feasibility andoptimization of conically spacedimplants.” Radiother Oncol, 71 S85-6, 2004. (abstract)

DJ Rubens. “Hepatobiliary imagingand its pitfalls.” Radiol Clin NorthAm., March, 42(2): 257-278, 2004

LS Taylor, BC Porter, G Nadasdy,PA di Sant’Agnese, D Pasternack, ZWu, RB Baggs, DJ Rubens, KJParker. “Three-dimensional registra-tion of prostate images from histol-ogy and ultrasound.” Ultrasound inMedicine and Biology, 30(2), 161-168, 2004.

T Varslot, B Angelsen, RC Waag.“Spectral estimation for characteriza-tion of acoustic aberration.” J AcoustSoc Am, 116(1), 97-108, 2004.

CM Spillmann, E Lomakina, REWaugh. “Neutrophil adhesivecontact dependence on impingementforce.” Biophys J, 87(6): 4237-45,Dec 2004.

EB Lomakina, CM Spillmann, MRKing, RE Waugh. “Rheologicalanalysis and measurement of neutro-phil indentation.” Biophys J, 87(6):4246-58, December 2004.

EB Lomakina, RE Waugh.“Micromechanical tests of adhesiondynamics between neutrophils andimmobilized ICAM-1.” Biophys J,86(2): 1223-33, February 2004.

Z Wu, LS Taylor, DJ Rubens, KJParker. “Sonoelastographic imagingof interference patterns for estimationof the shear velocity of homogeneousbiomaterials.” Physics in Medicineand Biology, 49, 911-922, 2004.

N Yokoyama, KQ Schwarz, SDSteinmetz, X Li, X Chen. “Prognos-tic value of contrast stressechocardiography in patients withimage quality too limited for tradi-tional noncontrast harmonicechocardiography.” J Am SocEchocardiogr, Jan 17(1), 15-20,2004.

PhD students Brian Porter, Maggie Zhang, Clark Wu, and BenjaminCastaneda at the Medical Center with the GE Logiq9.

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Selected PresentationsD Dalecki, SZ Child, CHRaeman. “Effect of exposureduration on lung hemorrhage fromlow frequency underwater sound.”148th Meeting of the AcousticalSociety of America, San Diego, CA,November 2004. J. Acoust. Soc.Am. 116:2560, 2004.

D Dalecki, SZ Child, A Brod, CHRaeman. “Intestinal damage fromexposure to low frequency ultra-sound.” 48th Annual Convention ofthe American Institute of Ultrasoundin Medicine, Phoenix, AZ, June 2004.J. Ultrasound Med. 23:S18, 2004.

SM Gracewski, H Miao, DDalecki, M Miller. “Simulation ofan acoustically excited bubble nearsimulated cells.” 147th Meeting ofthe Acoustical Society of America,New York, NY, May 2004. J.Acoust. Soc. Am. 115:2561, 2004.

M Helguera. “Test target design,fabrication, and analysis for C-scanultrasonic system characterization.”4th International Conference onUltrasonic BiomedicalMicroscanning, September 2004.

S. Levinson, Z Wu, KJ Parker. “AComparison of methods ofsonoelastography in muscle.” ThirdInternational Conference on theUltrasonic Measurement and Imag-ing of Tissue Elasticity, Cumbria, UK,October 2004.

C Rota, CH Raeman, D Dalecki.“Correlation of ultrasound-inducedpremature beats and cavitation invivo.” 148th Meeting of the Acousti-cal Society of America, San Diego,CA, November 2004. J. Acoust.Soc. Am. 116:2508, 2004.

C Rota, CH Raeman, D Dalecki.“Cardiac stimulation by ultrasoundand contrast agents: the role ofbubble dissolution, destruction andbiological damage.” 48th AnnualConvention of AIUM, Phoenix, AZ,June 2004. J. Ultrasound Med.23:S59, 2004.

C Rota, CH Raeman, D Dalecki.“The influence of ultrasound contrastagent dose on the production ofcardiac arrhythmias and biologicaldamage.” 48th Annual Convention ofAIUM, Phoenix, AZ, June 2004. J.Ultrasound Med. 23:S36, 2004.

DJ Rubens. “Interventional ultra-sound head to toe.” SingaporeCancer Center, May 2004.

DJ Rubens. “Ultrasound of acuteabdominal pain.” Tyco Health Care,Japan, May 2004.

DJ Rubens. “Venous doppler of theextremities.” 48th Annual Conventionof AIUM, Phoenix, AZ, June 2004.

DJ Rubens. “Pitfalls in the ultra-sound evaluation of DVT.” Poster,48th Annual Convention of AIUM,Phoenix, AZ, June 2004.

DJ Rubens. “Pseudoaneurysms andthe role of minimally invasive tech-niques in their management,” “Practi-cal tips for distinquishing normal fromabnormal bowel on CT,” and “USevaluation of testicular and peniletrauma.” RSNA November 2004.

KJ Parker, M Zhang. “Color inmedical imaging.” IS&T/SID 12thColor Imaging Conference,Scottsdale, AZ, November 2004.

LS Taylor, KJ Parker, B Porter, ZWu, G Nadasdy, PA diSant’Agnese, D Pasternack, RBaggs, and DJ Rubens. “Detectionof cancer in radical prostatectomyspecimens using sonoelastography.”48th Annual Convention of AIUM,Phoenix, AZ, June 2004.

S Voci, “Ultrasound pitfalls forDVT.” Poster, AIUM May 2004.

Z Wu, DJ Rubens, KJ Parker.“Sonoelastographic imaging ofinterference patterns for estimationof the shear velocity distribution ininhomogeneous biomaterials.” 29thInternational Symposium on Ultra-sonic Imaging and Tissue Character-ization, Arlington, VA, May, 2004.

Z Wu, KJ Parker. “Visualization ofshear wave propagation inbiomaterials with sonoelastography.”Third International Conference onthe Ultrasonic Measurement andImaging of Tissue Elasticity, Cumbria,UK, October 2004.

M Zhang, LS Taylor, DJ Rubens,KJ Parker. “Three-dimensionalsonoelastography imaging of HIFU-induced lesions in bovine livers: Apreliminary study in vitro.” 29thInternational Symposium on Ultra-sonic Imaging and Tissue Character-ization, Arlington, VA, May, 2004.

M Zhang, LS Taylor, DJ Rubens,KJ Parker. “In vitro imaging ofHIFU-induced lesions in bovine liversusing three-dimensional sono-elastography.” Third InternationalConference on the UltrasonicMeasurement and Imaging of TissueElasticity, Cumbria, UK, October2004.

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At the November 2004 Meeting ofthe Acoustical Society of America inSan Diego, the ASA Student Councilmade David Blackstock the firstrecipient of its Student MentoringAward.

David Blackstock and EdwinCarstensen participated in two PilotProject Grant (PPG) meetings onlithotripsy, held by the IndianaUniversity Medical School in India-napolis. They are external advisors tothe grant, which is a consortium ledby Indiana University, with BostonUniversity, California Institute ofTechnology, and the University ofWashington also participating.

Brian Porter successfully defendedhis PhD thesis “Three-DimensionalMedical Ultrasound Acquisition andData Registration and Fusion” onDecember 10, 2004.

Benjamin Castaneda is a new PhDstudent in Electrical and ComputerEngineering at the University ofRochester. Benjamin’s research will

People, Promotions, and Awards

focus on image registration of B-mode ultrasound images, sono-elastography, and 3-D imagesreconstructed from histology slidesapplied to prostate specimens.

An article by Edler and Lindstrom inUltrasound in medicine andbiology recognized the contributionsof the late Raymond Gramiak tothe field of echocardiography. Dr.Gramiak was co-founder of theRCBU, retiring in 1988 as emeritusProfessor of Radiology at the Uni-versity of Rochester. The authorssaid he was “one of the majorcontributors to the development ofechocardiography.” The article, titled“The history of echocardiography,”appeared in Volume 30, Issue 12,December 2004, pages 1565-1644.

Maria Helguera, PhD, AssistantProfessor at RIT, is a co-PI in anNSF-funded grant to develop atextbook and a lab suite. The title ofthe book will be “Imaging in thePhysical Sciences.”

Helguera is also the academiccoordinator of the online MS programin Imaging Science.

Morton Miller was appointed as aNational Council on RadiationProtection and Measurements staffconsultant to its Scientific Committee1-4, to assist in the finalization of theNCRP report “Extrapolation of Risksfrom Nonhuman ExperimentalSystems to Humans” and to its newlyformed Scientific Committee 2-1concerning “Radiation ProtectionRecommendations for First Respond-ers.”

Clark Wu receiving his award at theAIUM Annual Convention.

Deborah Rubens, John Strang,and Susan Voci presented a RSNArefresher course in November 2004,“Venous Doppler Sonography:Visceral and Extremity Applications.”Dr. Rubens also presented “DopplerEvaluation” and “Acute Sonographyof the Painful Scrotum: An Updatewith Special Emphasis on DopplerDiagnosis.”

At AIUM October 2004, DeborahRubens was the Regional CourseDirector for “Vascular Ultrasound.”

John Strang will be the co-directorof the University of Rochester PET/CT center due to open in 2005.

Susan L. Voci was promoted toAssociate Professor of Radiology.She is also a participating member onACR’s Standards and GuidelinesCommittee.

At the AIUM Annual Convention inPhoenix, AZ, Zhe (Clark) Wu, PhDcandidate in Electrical and ComputerEngineering, won the 2004 NewInvestigator Award. He won for hisabstract, “Sonoelastographic Imagingof Interface Patterns for Estimationof the Shear Velocity in HomogenousBiomaterials.”

Brian Porter

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Center Profile: Stephen McAleavey, PhD

Stephen McAleavey recently joinedthe University of Rochester Depart-ment of Biomedical Engineering asan Assistant Professor. Steve is aBS, MS, and PhD graduate of theDepartment of Electrical and Com-puter Engineering at the University.

Kevin Parker served as his advisorfor his PhD thesis, “Butterfly SearchVelocity Estimation: Analysis andVLSI Implementation Issues.” Thiswork provided an understanding ofthe performance of an ultrasoundblood velocity estimator in thepresence of non-uniform flowvelocities from a random processperspective. Expressions predictingthe estimator performance based onthe random process model agreedwith in vitro experiments. He pro-posed and evaluated methods forovercoming artifacts introduced bynon-uniform flow. He made in vivomeasurements of flow using thisestimator with RF echo data col-lected from a GE Logiq 700 scanner.Finally, He described and contrastedtwo alternative realizations of theestimator in silicon.

Since arriving, Steve has beenassembling lab facilities for biomedi-cal ultrasound research. The center-piece of the lab is a Siemens Antaresultrasound scanner. This state-of-the-art clinical instrument provides RFdata acquisition capability that is keyto the development of new imagingtechniques. Other facilities include a60 MHz bandwidth pulser/receiver,digitizing oscilloscope, micron-precision 3-axis stage, and a 75 WRF amplifier.

Novel diagnostic ultrasound imagingmethods are the subject of Steve’slaboratory research. The lab’s goal is

to develop clinically relevant tech-niques to satisfy currently unmetimaging needs. Acoustic RadiationForce Impulse (ARFI) Imaging ishis principle research topic. Thistechnique uses intense, focusedultrasound beams to displace tissuedistal to the transducer. The induceddisplacements are on the order of 1-10 microns, large enough to trackwith ultrasound. The amount ofdisplacement is related to the tissuestiffness; the stiffer the tissue is, theless it moves. This method showsgreat promise in differentiatingtissues whose ultrasound contrast ispoor but whose elastic (stiffness)contrast is marked.

Also in development is a method forimproved imaging of brachytherapyseeds—rice-grain sized radioactivepellets used in prostate cancertreatment. To place the seedsaccurately, the physician often usesultrasound imaging as a guide.However, the seeds can be difficultto see once they leave the needle.Steve’s idea is to vibrate the seeds

with an alternating magnetic field,and detect the micron-level vibrationswith Doppler ultrasound. Preliminaryphantom work on this method hasbeen very promising. While at DukeUniversity, Steve was awarded agrant by the US Army to investigatethis method.

Steve is teaching two classes, Signalsand Measurements in BiomedicalEngineering, an undergraduatecourse, and Advanced BiomedicalUltrasound, a graduate course. TheSignals course is an investigation ofinstrumentation and signal processingtechniques involved in biomedicaldata acquisition.The graduate coursecovers the theoretical basis ofultrasound imaging formation andprovides a close study of the practi-cal implementation of ultrasoundimaging in modern clinical scanners.Topics include linear acoustic sys-tems, spatial impulse responses, thek-space formulation, methods ofacoustic field calculation, dynamicfocusing and apodization, scattering,the statistics of acoustic speckle,speckle correlation, compoundingtechniques, phase aberration correc-tion, velocity estimation, and flowimaging.

When asked what made him decideto return to the University, Steve said,“Rochester is one of a handful ofuniversities in the country with both astrong ultrasound research programand an associated hospital nearby.The combination of outstandingfaculty and students, a long history ofultrasound research, and an excellentteaching hospital made Rochester acompelling choice.”

Steve McAleavey in his lab with theSiemens Antares ultrasound scanner.

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Biophysical bases of pulsedultrasound bioeffects

Morton W. Miller, P.I.NIH sponsorship (R37EB00213-29)

Dr. Miller's NIH-sponsored researchproject focuses on mechanical andthermal aspects of ultrasound-induced bioeffects. For the former,general support was obtained for thehypothesis that cell size is an impor-tant physical factor in ultrasound-induced hemolysis. Erythrocytesfrom a range of mammalian specieswere used. Each species has its owncharacteristic erythrocytic volume,thus facilitating a test of the hypoth-esis. Under a number of differentexperimental ultrasound exposureconditions and cell densities it wasdiscerned that cell volume (i.e., size)is an apparently critical factor in US-induced hemolysis.

Dr. Miller also provided encourage-ment and partial financial support forProfessor Sheryl Gracewski’s recentJASA-submitted paper: “Ultrasonicexcitation of a bubble near a rigid ordeformable sphere: Implications forultrasonically-induced hemolysis.”One- and two-dimensional modelswere developed to investigateinteractions between ultrasonically-excited bubbles and model “cells.”The project’s overall aim is todistinguish between symmetric andasymmetric bubble collapse in cellsystems involving close proximity ofbubbles and cells or surfaces. Thepresence of a rigid or deformablesphere had little effect on bubbleexpansion, but caused an asymmetriccollapse and jetting for tested condi-tions.

ality (e.g., fastest cell doubling time)would be maximal at each cell line’srespective historical physiologicaltemperature (HPT). Two cell lineswere used, one of human origin(HPT = 37.0oC) and the other ofguinea pig derivation (HPT =39.5oC). Both grew best at theirrespective HPT, and both grew lesswell at ± 2.5oC of their respectiveHPT (Figure 1). The hypothesis wassupported. Research is continuing inthis area with a goal of determiningactivation energies for hyperthermia-induced birth defects. The rationalefor this goal is that once the activa-tion energy is determined it canprovide strongly predictive out-comes for any combination oftemperature elevation and duration of

exposure.

2004 Research

Figure 1: Cell doubling times (h) forhuman and guinea pig in vitro

A third project on “Biological andenvironmental factors affectingultrasound-induced hemolysis invitro: 5. Temperature” is nearingcompletion in collaboration with Dr.Charles C. Church, National Centerfor Physical Acoustics (NCPA). The“bioeffects” part of the project hasbeen completed and the NCPA staffis providing calibrations of thetransducers at varying temperatures.The overall results are supportive ofthe hypothesis that cold (i.e., ~ 0oC)erythrocytes will display substan-tially greater amounts of ultrasound-induced hemolysis than the physi-ological (37oC) erythrocytes becauseof a temperature-related transition inmembrane fluidity leading to in-creased fragility.

We have made considerable progressinvestigating ultrasound-inducedthermal effects and mechanisms ofaction. Two papers were publisheddemonstrating the utility of the Tthermal dose concept, the firstrelating to in vivo effects, the secondto in vitro effects. For the former,pregnant rats (day 9.5 of gestation)were exposed to heated waterregimens to raise (i) the pregnantdam’s core temperatures or (ii)surgically-exteriorizedpregnant uteri to 5oC foran equivalent 11.3 minuteexposure period (i.e., athermal dose of t3.5 =11.3 min). Under theseconditions, the yields ofanomalous fetuses werecomparable, thus provid-ing evidence that thethermal dose to themother has little if anyeffect on fetal outcome.For the latter, it was initially hypoth-esized that in vitro cellular function-

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The research at the UltrasoundImaging Lab at the Chester F.Carlson Center for Imaging Sciencehas been concentrating on:

1. Development of resolution testtargets for high frequency ultra-sound C-scanners.

2. Non-contact ultrasound character-ization of polymeric layers ofpowder coated plates and non-contact ultrasound characterizationof paper substrates.

3. High frequency characterization ofskin.

Ultrasound Imaging Lab at theRochester Institute ofTechnology

Maria Helguera

Research

Test target design, fabrication,and analysis for C-scan ultra-sonic system characterization

Maria Helguera

The Ultrasound Imaging Lab at theChester F. Carlson Center forImaging Science at the RochesterInstitute of Technology has beeninvolved in the characterization ofthree different generations of ultra-sound-based C-scanning systems.We are currently developing a set ofquantitative standards for calibration.

Ultrasound is used extensively formedical imaging, nondestructivetesting, and underwater acoustics.Several scanning modalities such asA-scan, B-scan, and C-scan areoften used. Although appropriate testtargets have been developed for B-scan imagers, very little attention hasbeen paid to C-scanners. In order tosuccessfully characterize thesesystems, a quantitative measure mustbe performed. The ModulationTransfer Function (MTF) is one ofthe most commonly used qualitymetrics of any linear shift invariantimaging system, though a test targetmust first be developed.

A direct measurement of MTFnormally requires sinusoidal testpatterns of various different spatialfrequencies. In ultrasound, thisimplies that patterns should have anacoustic impedance mismatch thatvaries in a sinusoidal fashion. This isdifficult if not impossible to achieve.An alternative method is to measurethe system response to line and edgetarget inputs. This project describesthe theory to calculate the MTF fromthe system response to a line or edgeinput. We created polyethyleneterephthalate (PET) film phantoms incollaboration with the Microelectron-ics Department at the Rochester

Institute of Technology. We laseretched a suitable pattern into the filmand acquired images using thescanners.

We wrote a computer routine in IDLto extract information from theimaged resolution targets. We alsoused this same program to compareMTFs calculated from different testtargets presented at different angles.We then compared the resolutioninformation to MTF data calculatedfrom a stand-alone transducer,identical to those used within thesystems, imaging the edge of a glassplate immersed in oil.

Emergency DepartmentUltrasound

Jefferson Svengsouk, MD, RDMS,FACEP, established the emergencymedicine ultrasound program atStrong Memorial Hospital in 2001.

The Emergency Department has twodedicated stand-mounted SonoSite180 Plus ultrasound machines. OneSonoSite is stationed in the trauma/critical care bay; the other isequipped with four probes and ismobile through the department.

The six major applications of emer-gency medicine ultrasound include:trauma (FAST), abdominal aorticaneurism, biliary, limited cardiac,renal, and first trimester pregnancy.Ultrasound guidance of invasiveprocedures is also used in the Emer-gency Department. The use ofultrasound at the bedside allows forrapid diagnosis of life threateningmedical conditions, rapid dispositionto definitive therapies, earlier dis-charge of stable patients in an era ofemergency department overcrowd-ing, and increased success withcomplex invasive procedures.

Dr. Svengsouk is interested indeveloping and expanding the use ofultrasound technology to improve theeducation of residents and medicalstudents, and to enhance EmergencyDepartment patient care.

There are four students working inthe lab: Raj Pai Panandiker andNiranjan Tallapally are graduatestudents working on their PhD, andJeffrey Meade and StephanieShubert are undergraduate students.Stephanie is working on her seniorproject and Jeff is a third yearstudent deeply involved in research.

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Obstetrics and GynecologyUltrasound Unit

Eva Pressman, MD

The OB/GYNUltrasound Unitcontinued to updateits equipment andofferings in 2004.The unit purchased

two new GE Voluson scanners withreal-time three-dimensional capabil-ity. Several staff members completedtraining in nuchal translucencymeasurement and are offering firsttrimester screening for aneuploidy tothe Rochester community.

The unit performed more than 16,700obstetric and gynecologic proce-dures. In addition to diagnosticsonograms, the unit performed 552amniocenteses, 66 chorionic villussamplings, 396 sonohysterograms,and 5 fetal blood transfusions.

Current research projects includeassessment of pulsatile fetal growth(see the abstract on this page) andregion-specific humerus and femurlength for prediction of trisomy 21.

Pulsatile versus continuousgrowth in the human fetus

A.Gordon Fry, Deborah Pittinaro,Shirley Eberly

ObjectiveTo determine if fetal growth occursin a pulsatile rather than continuousfashion.

Study designNon-smoking women of normal bodyhabitus, with medically uncompli-cated, singleton pregnancies, wereenrolled between 26 and 29 weeksgestation. Only data from pregnan-cies delivering normally grown

fetuses at term, in women withnormal weight gain, were included.Sonographic fetal biometric param-eters were measured frequently, witha goal of three times per week, for aminimum of four weeks. For eachfetus, six replicate measurements,obtained by a single examiner, weremade on each of five parameters:• Biparietal diameter (BPD)• Head circumference• Abdominal circumference• Humerus length• Femur length

For each fetus and parameter, asecond degree polynomial regressionon gestational age was generated.Under the assumption of pulsatilegrowth, a cyclical pattern of positiveand negative residuals from a fittedcurve would be expected. We used aruns test to examine the randomnessof the regression residuals. Under theassumption of continuous growth,serial growth increments would beexpected to follow a Gaussiandistribution. For each fetus andparameter, we tested serial growthincrements for normality using theShapiro-Wilk test. P values < .05were considered significant.

Results and conclusionEight subjects meeting inclusioncriteria, with a mean gestational ageat entry of 28.6 weeks, were exam-ined. An average of 15 observationsper subject were obtained. One-eighth BPDs demonstrated a nonran-dom pattern in the residuals(P < .05). We did not observepatterns supporting pulsatile growthfor any other parameters in any fetusstudied.

These findings demonstrate minimalsupport for a pulsatile pattern of fetalgrowth. Increasing the number ofobservations per subject may im-prove the ability to detect a pulsatilepattern.

Spectral estimation for charac-terization of acoustic aberration

By Trond Varslot, Bjorn Angelsen,and Robert C. Waag

In this study, we found parameters ina linear filter model for ultrasonicpropagation using statistical estima-tion. The model employs an inhomo-geneous-medium Green’s functionthat is decomposed into a homoge-neous-transmission term and a path-dependent aberration term. Weestimated power and cross-powerspectra of random-medium scatteringover the frequency band of thetransmit-receive system by usingclosely situated scattering volumes.We obtained the frequency-domainmagnitude of the aberration from anormalization of the power spectrum.The corresponding phase is recon-structed from cross-power spectra ofsubaperture signals at adjacentreceive positions by a recursion. Thesubapertures constrain the receivesensitivity pattern to eliminatemeasurement system phase contribu-tions. The recursion uses aLaplacian-based algorithm to obtainphase from phase differences. Weacquired pulse-echo waveforms froma point reflector and a tissue-likescattering phantom through a tissue-mimicking aberration path fromneighboring volumes having essen-tially the same aberration path.Propagation path aberration param-eters calculated from the measure-ments of random scattering throughthe aberration phantom agree withcorresponding parameters calculatedfor the same aberrator and arrayposition by using echoes from thepoint reflector. The results indicatethe approach describes, in addition totime shifts, waveform amplitude andshape changes produced by propaga-tion through distributed aberrationunder realistic conditions.

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Research

Doppler myography:ultrasonic localization of acousticmyographic signals

Stephen F. Levinson, Hiroshi Kanai,Hideyuki Hasegawa

IntroductionSkeletal muscles generate low-frequency sounds when they con-tract. These sounds originate fromresonant vibrations of muscle fibersand their frequency is related to fiberlength and tension. Although morethan two decades have passed sinceacoustic myography (AMG) was firstdescribed, clinical applications havebeen limited to neuromuscularjunction monitoring during anesthesia.With few exceptions, AMG hasprovided little more information thansurface electromyography (EMG).

Recent improvements in ultrasonicDoppler technology have made itpossible to detect sub-micron dis-placements. Indeed, the measure-ment of heart sounds propagating inmyocardial tissue has been reported.We hypothesize that a similar tech-nique can be used to detect andpossibly image skeletal musclevibrations. This could lead to abiomechanical analog of needle EMGand could provide a noninvasivealternative.

MethodsAs many different terms appear inthe literature, we refer to them as:• AMG—the phenomenon of muscle

fiber vibration• Phonomyography (PMG)—the

recording of AMG signals at theskin surface

• Doppler myography (DMG)—therecording of AMG using Dopplerultrasound

We conducted a single subjectexploration of DMG by placing an

ultrasound transducer over the flexorforearm group. We obtained Dopplersignals during active grasp andadjusted the range gate to be withinthe flexor digitorum superficialis(FDS). Surface EMG and PMGsignals were simultaneously re-corded. We measured the subject’sgrip strength using a grip dynamom-eter (Figure 1).

ResultsWe obtained simultaneous recordingsfor a variety of grip strengths.Vibrations are evident in the DMGrecordings, however, we also ob-served translational motion (Figure2). As with EMG, it is likely thatfilters need to be implemented toremove unwanted components fromthe DMG signal. Additional experi-ments are required to determine theoptimum ultrasound parameters andconfiguration. Still, we believe thatthis is an important first step and that,with additional research, DMG couldbecome a clinically useful test. Theaddition of real-time imaging capabili-ties could lead to a powerful newdiagnostic tool.

Figure 2: Simultaneous recordings ofsurface EMG (top), PMG (middle) andDMG (bottom) signals in the flexordigitorum superficialis during 24 kg ofgrasp.

Figure 1: Apparatus for simultaneous measurement of surface electromyogram(EMG), phonomyogram (PMG) and Doppler myogram (DMG) in the forearmduring grasp. Grip strength is measured using a grip dynamometer.

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PurposeThree-dimensional sonoelastographyimaging was evaluated for in vitroprostate cancer detection. Thestatistical outcomes from lesionswithin whole prostatectomy speci-mens are reported.

MethodsUsing an Institutional Review Board-approved, HIPAA compliant protocolwith informal consent, 19 prostatec-tomy specimens with biopsy provenprostate cancer were scanned in 3Dusing conventional B-scan andsonoelastography using vibrationsabove 100Hz. Step-sectioned whole-mount histology was utilized to createa 3D volume of the prostate andtumors within it. B-scan ultrasoundimages and regions of low vibrationin the sonoelastography images (hardregions) were formatted in 3D.

The lesions in the nineteen caseswere analyzed as two groups: G1)pathology-confirmed tumors of 1.0 ccor greater; and G2) pathology-confirmed tumor size less than 1.0cc. G1 cases were evaluated for B-scan ultrasound and sonoelasto-graphy vs. histology as a referencestandard and were scored as either atrue positive, a false positive, a truenegative, or a false negative. G2cases were evaluated forsonoelastography only. True positivesrequired 3D lesion correlationbetween pathology and imaging data.

Three-dimensionalsonoelastography for in vitrodetection of prostate cancer

Lawrence S. Taylor, Deborah J.Rubens, Brian C. Porter, Zhe Wu,Raymond B. Baggs, P. Anthony diSant’Agnese, Gyongyi Nadasdy,David Pasternack, Edward M.Messing, Priya Nigwekar, Kevin J.Parker

ResultsG1 (7 lesions with tumor volume 1.0cc or greater): Sonoelastography:accuracy of 55%, sensitivity of 71%.B-scan: accuracy of 17%, sensitivityof 29%. Mean tumor size is 3.1cc +/- 2.1cc.

G2 (22 lesions with tumor volumeless than 1.0 cc). Mean tumor size is0.32 cc +/- 0.21 cc.Sonoelastography: accuracy of 34%,sensitivity of 41%, false positives: 6.

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Three-dimensional reconstruction of prostate cancer within the gland surface.The prostate surface (transparent blue) was reconstructed from B-scan data;tumor data from sonoelastography and histology are indicated by arrows. Apex,base, anterior, posterior, right, and left connotations are indicated on the figure.

Conclusion Sonoelastography performed consid-erably better than gray-scalesonography in the detection ofprostate cancer.

Sonoelastography helps improvedetection of tumors over 1 cc. Futureinvestigation may include highervibration frequencies to improvedetection of smaller tumors.

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Research

High intensity focused ultrasound(HIFU) is a promising therapeuticmethod that creates coagulationnecrosis for non-invasively killingmalignant tumors within a well-defined volume in the tissue. In thisstudy, we investigated sono-elastography for the visualization ofHIFU-induced lesions in bovine liversin vitro. Furthermore, we usedmechanical testing and viscoelasticmodeling to clarify the relationship ofthe soft tissue characteristic and thesonoelastography image formation.

We cut the cubic tissue samples(~4 x 4 x 4 cm3) from fresh bovineliver and then degassed them over-night. We used a single-elementconcave HIFU transducer to createHIFU lesions in the tissue sample.We acquired a volumetric series of2D sonoelastography images fromthe liver-embedded agar phantom.Each lesion is displayed as a darkarea surrounded by a bright green

background in the image. We usedIRIS Explorer to reconstruct 3Dlesion images. After, we examinedimaging lesions by gross pathology toverify their shape, dimensions, andvolume. To test the tissue viscoelas-ticity, an MTS machine carried outuniaxial unconfined compression. TheKelvin-Voigt Fractional Derivative(KVFD) model was applied as theviscoelastic model.

The gross pathology results showedthat HIFU lesions were relativelyuniform, palpably harder, and brighterthan the normal tissue. The meanvolumes of three 1 x 2 compoundlesions, three 2 x 2 lesions, and three3 x 3 lesions measured by fluiddisplacement were 1.8 cm3, 2.4 cm3

and 6.0 cm3, respectively. As thesmallest lesion in the test, a singleHIFU lesion with 1.3 cm3 in volumewas also successfully detected by 3Dsonoelastography. The mean sono-elastography volume of the 10 lesions

Three-dimensional sonoelastography imaging and viscoelastic modeling of HIFU-induced lesions inbovine livers in vitro

Man Zhang, Lawrence S. Taylor, Deborah J. Rubens, Kevin J. Parker

was 83% of the volume measured byfluid displacement. Curve fittingresults indicated that the stiffnessratio of the HIFU lesion and normalbovine liver was 8.4:1.

We found a good correlation (R2 =0.9749) between the lesion dimen-sions determined by 3D sono-elastography and gross pathology.The KVFD model may successfullyilluminate tissue viscoelastic effectson sonoelastography imaging. Thisstudy demonstrates that sono-elastography is a potential real-timemethod to accurately monitor theHIFU therapy of cancerous lesions.

A small HIFU lesion with 1.3 cm3 in volume detected by 3D sonoelastography

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Anisotropic elasticity and viscos-ity deduced from supersonicshear imaging in muscle

Stephen F. Levinson, StefanCatheline, Mathias Fink

IntroductionAlthough the role of viscoelasticity inmuscle mechanics is well recognized,methods for measurement in situ arelimited. Recent advances inelastography have made possible theimaging of viscoelastic moduli withinindividual muscles. We have investi-gated a new approach, supersonicshear imaging (SSI), which combineshigh frame-rate (5 kHz) ultrasoundwith acoustic radiation force induc-tion of shear plane waves transients.The elastic moduli can then bededuced from the propagation ofthese waves, and the viscous modulifrom their attenuation.

MethodsWe applied SSI elastography in asingle subject. With the subjectseated comfortably, we obtainedultrasound image sequences from theright (dominant) biceps duringsustained contractions. Holding thesubject’s elbow at 90°, we appliedvarious loads by having the subjecthold known weights. In addition, wecollected data with the forearmsupported (unweighted) and unloaded(limb weight only). We acquiredimage sequences and calculatedtissue displacements using frame-to-frame cross-correlation.

ResultsWe used displacement image se-quences to reconstruct speed ofsound maps (Figure 1) in both thetransverse and axial (longitudinalfiber orientation) directions. Weobtained average shear elastic modulifrom these (Table 1). We could not

observe propagation in the transversedirection for loads greater than 0.8kg. It is evident that the axial elasticmoduli are significantly greater thantheir transverse counterparts, andthat both increase with load.

Although we currently lack a directmeans of calculating viscosity, it isevident from the observed attenua-tion of the induced waves thattransverse viscosity is significantly

Unweighted Unloaded 0.4 kg 0.8 kg 1.2 kg 1.6 kg 2.0 kgAxial 4.0 7.3 47.2 50.8 59.7 82.5 94.6Transverse 1.2 1.3 1.8 4.1 - - -

greater than axial viscosity and thattransverse viscosity increasesdramatically with load to the pointthat propagation is suppressedentirely at greater loads. Whereasthe significance of these results is notclear, we anticipate that knowledgeof anisotropic and dynamic viscositycould have a significant impact onbiomechanics.

Figure 1: Speed of sound images in a for axial and transverse propagation at fourapplied loads. Propagation in the transverse direction did not occur above 0.8 kg.

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Table 1: Axial and transverse shear elastic modulus values (kPa) in the bicepsbrachii as a function of the applied load.

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Research

Investigations of the response oftissues to underwater sound

Yixen Ren, Sally Z. Child, Carol H.Raeman, Sheryl M. Gracewski,Edwin L. Carstensen and DianeDalecki

Investigations are underway in ourlaboratory to study the effects ofunderwater sound on biologicaltissues. These projects are supportedby the US Navy and have relevanceto the safety of divers and marinemammals exposed to sonar fields.Frequencies of interest span the largerange from ~100 Hz to ~200 kHz.These investigations aim to develop agreater understanding of the re-sponse of biological tissues to under-water sound necessary for thedevelopment of guidelines for thesafe use of sonar.

Low frequency acoustic fieldsThrough several different avenues ofinvestigation, we have shown thatmurine lung and intestine can respondto low frequency acoustic fields asresonant structures. Within ourlaboratory, two specialized exposuresystems are available for the genera-tion of low frequency (100-3000 Hz)underwater sound fields. Measure-ments of acoustic scattering nearmurine lung demonstrated a pro-nounced resonance at ~335 Hz foradult mice. Measurements of thedisplacement amplitudes of lung,using a pulse-echo ranging technique,were consistent with observationsmade from acoustic scatteringmeasurements. Exposure to lowfrequency underwater sound at theresonance frequency of the lung canproduce damage to the lung andsurrounding tissues such as the liver.Effects on the liver are an indirecteffect of the oscillation of the lungrather than a direct action of the

sound. The intestine also contains gasand can respond as a resonantstructure in an underwater soundfield. Since the volume of a gas bodyin the murine intestine is less than thelung volume, the resonance frequen-cies of intestinal gas bodies investi-gated were within the frequencyrange of ~700-2500 Hz. Damage tothe gas-filled intestine produced byexposure at the resonance frequency,however, was significantly lesspronounced than that observed withthe lung.

Gas bubble studiesRecent studies in vitro measured theresponse of gas bubbles to lowfrequency sound and compared theresults to analytical and finite elementmodels (FEM). FEM is a numericalmethod for calculating stresses anddeformations in complex geometricalstructures. Balloons of different radii(0.85 cm, 1 cm and 1.25 cm) wereexposed to low frequency soundswept from 100 to 500 Hz at a

pressure of 1000 Pa. We determinedthe resonance frequency of theballoon by measuring the acousticscattering near the balloon and/ordetecting the displacement amplitudeof the balloon surface using a pulseecho ranging technique. The mea-sured resonance frequencies of theballoons were consistently lower thananalytical predictions by about 12%.

To investigate the role of the expo-sure tank on the resonance fre-quency, we built a FEM model tosimulate the frequency response ofan air bubble under our experimentalconditions. The program was writtenin Nastran-Patran and can performfluid-structure analysis for directfrequency responses. The scatteredfield near the balloon and the dis-placement amplitude of the balloonsurface were calculated over thefrequencies of interest. Compared tothe linear analytical theory, the FEMmodel accounts for the limitedvolume of water and restraint of thetank. Resonance frequencies com-puted with the FEM agreed remark-ably well with experiments for allballoon sizes investigated.

Other projectsWork continues on several paths ofinvestigation. Ongoing projectscontinue to focus on determining themechanism of action for lung damagein response to exposure to lowfrequency underwater sound. Com-putational efforts aim to model theresponse of gas bodies exposed tounderwater sound. Studies are alsounderway to characterize the re-sponse of intestine and heart tounderwater sound fields whenmicrobubbles are present in thevasculature. Additional studies arecharacterizing the response of tissuesto underwater sound fields forfrequencies ranging up to ~200 kHz.

USRD type G40 calibrator used for thegenertion of low frequency underwa-ter sound fields in the 100 - 1000 Hzrange.

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Research

A collection of software tools calledURI/Field performs linear acousticsimulations matched to the SiemensAntares scanner. URI/Field simplifiessimulation of a state-of-the-artcommercial scanner. URI/Field is anadjunct to the Siemens UltrasoundResearch Interface (URI) softwareoption on the Siemens Antaresscanner. The URI allows beam-summed RF data and associatedbeamforming parameters (headerdata) to be recorded for off-lineprocessing. URI/Field performsmatched simulations based on thisheader data. URI/Field is imple-mented entirely in Matlab and thusruns on a wide range of computersystems.

URI/Field relies on Jensen’s Field IIsoftware (www.es.oersted.dtu.dk/staff/jaj/field/) to perform the acous-tic simulations by the spatial-impulseresponse method. URI/Field providesa set of Matlab functions that auto-matically configure Field II to simu-late apertures matched to transducerand scanner settings indicated in theURI header. Transmit and receivebeams are specified, which aresteered and walked across theaperture as in the physical system, asopposed to the more commonpractice of simulating scanning byphantom translation. Functions forscan simulation, beam intensityestimation, envelope detection, andscan conversion are included in theURI/Field package and may becalled from the Matlab command lineas desired.

Simulation data is divided into threelogical structures. A probe datastructure contains fixed, transducer-specific information—geometric andimpulse-response data. A beamsetdata structure contains informationrelated to beam formationparameters—beam direction, origin,apodization and focal characteristics.Both of these structures may begenerated automatically from a URIdata file, or may be manually createdto simulate arbitrary systems. Thethird structure, phantom, containspositions and amplitudes of scatterersto be imaged. Commands for creat-ing simple wire target and lesionphantoms are included.

A graphical user interface (GUI)facilitates common tasks. Using theGUI, URI files may be loaded andapertures created automatically.Scans are simulated and beamplots

calculated with simple menu com-mands. Graphical probe, beamset,and phantom editors are included forthe creation or modification of therelated data structure. Using theseeditors, modifications to a baselinescanner configuration may besimulated easily, or completely user-defined systems may be simulated.The GUI allows simulations to belaunched as separate processes onthe local machine, or as batch jobs ona remote machine. The flexible GUIreduces common simulation tasks tosimple point-and-click operations.

Powerful commands make it possibleto describe an ultrasound system at arelatively high level and performcommon simulation tasks easily. GUIeditors simplify the inspection andmodification of URI derived param-eters and allow the specification ofarbitrary scanners.

Figure 1. Screen shot of the URI/Field GUI in operation. Top left: root URI/Fieldwindow. Top right: probe editor, with controls for element number, spacing, kerf,inpulse response. Bottom: beamplotter command window, with slice and vectorselection controls. Bottom right: output of the beamplotter for an apodizedtransmit beam. Center: simulated scan of a set of wire targets.

URI/Field: A Matlab interfacebetween the SiemensUltrasound Research Interfaceand Field II

Stephen A. McAleavey and GreggE. Trahey

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Research

Cardiac stimulation by ultra-sound, part I: dependence onpulse duration

Claudio Rota, Carol H. Raeman,Sally Z. Child, Diane Dalecki

In recent years, experiments in ourlaboratory have demonstrated that,under appropriate exposure condi-tions, ultrasound can produce cardiacarrhythmias. For example, thethreshold for producing a prematureventricular contraction (PVC) in themurine heart with a single 5-ms pulseof 1.2 MHz ultrasound is ~ 2 MPa.The likelihood of producing apremature contraction is dependentupon (1) the acoustic properties ofthe ultrasound pulse (e.g. frequency,pressure amplitude, pulse durationetc.) and (2) the presence of gasnuclei in the heart. The presence ofmicrobubble contrast agents in thevasculature significantly reduces thethreshold for premature cardiaccontractions.

Recent work in our lab has investi-gated the dependence of the thresh-old for ultrasound-induced PVCs onthe duration of the acoustic pulsewhen contrast agents are present inthe blood. Ultrasound exposureswere performed at 200 kHz and pulsedurations ranging from 40 s to 100ms were investigated. Studies in ourlab have shown that exposure ofmurine hearts to ultrasound at 200kHz with 1 ms pulse durations canproduce premature beats withnegative pressure amplitudes as lowas 1 atm (0.1 MPa). Compared todiagnostic frequencies, 200 kHzpulses are significantly more effec-tive stimuli of PVCs. Also, grossvascular damage or compromisedelectrophysiology was not observedwhen the mouse heart was exposed at200 kHz. Thus exposures at 200 kHz

stimulated the heart while minimiz-ing cardiac damage.

Threshold studies were performedwith mice injected with a contrastagent (Optison®). A total of eightpulse durations were investigated(0.04, 0.1, 0.5, 1, 2, 5, 20 and 100ms). Each study consisted of n = 6mice. Each mouse received two bolusinjections (3 L/bolus). The firstbolus was administered prior to thefirst ultrasound pulse and the secondbolus was administered half-waythrough the exposure series. Eachexposure consisted of a single pulseof ultrasound at 200 kHz. Pressureamplitudes tested were 0.05, 0.1,0.15 or 0.2 MPa.

For relatively long pulse durations(i.e., between 0.5 and 100 ms), thethreshold for producing a premature

Figure 1. Strength-duration curve comparison between electrical and ultrasoundstimulation. Electrical stimulation data (in V) was adapted from a study per-formed on a patient at the time of pacing lead implantation (Ellenbogen andWood in Cardiac Pacing and ICDs 3rd ed., Blackwell Science, Figure 2.2; 2002).Ultrasound stimulation data (in MPa) refers to the 50% effectiveness of ultra-sound.

contraction was independent of pulseduration. However, shorter pulsedurations were significantly lesslikely to produce a premature beat.The 50% effectiveness levels (i.e.,the pressure amplitude that produceda 50% probability of triggering apremature beat) were estimated foreach pulse duration. These results aresummarized in Figure 1. Also shownin this figure is a typical strength-duration curve obtained by electricalstimulation. For both ultrasound andelectrical stimulation, the pulseduration dependence is essentiallyflat for durations above 0.5-1 ms butrises rapidly with shorter pulses. Thequalitative agreement between thestrength-duration curves for ultra-sound and electrical stimulationprovides insight on the generaldependence of cardiac stimulation onpulse duration.

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ated with cavitation by the root-mean-square (rms) of the PCDoutput. For a range of exposureconditions, the extent of cavitationactivity was correlated with thelikelihood of producing a prematurecardiac contraction.

In the presence of Optison®, prema-ture beats were produced in all of themice exposed to ultrasound. Mostimportantly, both the number ofpremature beats and the rms of PCDsignal increased with increasingpressure amplitude. On the contrary,none of the animals injected withsaline developed premature beats norwas significant cavitation activitymeasured with the PCD. A directcorrelation between the amplitude ofthe PCD output and the likelihood ofproducing a premature beat (Figure1) supports the hypothesis of cavita-tion as a mechanism for ultrasound-induced premature beats.

Cardiac stimulation by ultra-sound, part II: cavitationdetection

Claudio Rota, Carol H. Raeman,Sally Z. Child, Diane Dalecki

Our laboratory research has activelyfocused on understanding the physi-cal mechanisms responsible forultrasound-induced arrhythmias.Results of several investigations inour lab are consistent with thehypothesis that acoustic cavitation isthe mechanism for the production ofpremature cardiac contractions withultrasound. Acoustic cavitation canbe defined as the interaction of asound field with a gas bubble in aliquid medium. The frequencydependence of the effect is consis-tent with the dependence of thethreshold for inertial cavitation onfrequency. Gas bubbles in vivo arerelatively rare among soft tissuessuch as the heart. However, thepresence of microbubble ultrasoundcontrast agents in the blood signifi-cantly reduces the threshold forultrasound-induced prematurecardiac contractions.

To further test the cavitation hypoth-esis, we measured cavitation activityin the murine heart in vivo with apassive cavitation detector (PCD).We used a 5 MHz focused trans-ducer as a passive listening device ofacoustic signals. We performedexperiments with adult anesthetizedmice. Boluses of either a contrastagent (Optison®) or saline weredelivered via tail vein injections.Pulsed ultrasound exposures wereperformed at 200 kHz with pulsedurations of 1 ms and peak negativepressures ranging between 0.1 and0.25 MPa. Using the PCD, wequantified acoustic emissions associ-

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Figure 1. Correlation between the rms of the PCD output and percentage ofultrasound pulses producing a premature beat. Data were collected from n = 10mice injected with Optison®. Pressure amplitudes of the ultrasound pulseranged between 0.1 and 0.25 MPa.

0 10 20 30 40 50 60 70 80 90

100

<0.01 0.01-0.02 0.02-0.03 0.03-0.04 0.04-0.05 >0.05

rms (V)

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Research

Advanced Biomedical Ultrasound(BME 453). This course investi-gates the imaging techniques appliedin state-of-the-art ultrasound imagingand their theoretical bases. Topicsinclude linear acoustic systems,spatial impulse responses, the k-space formulation, methods ofacoustic field calculation, dynamicfocusing and apodization, scattering,the statistics of acoustic speckle,speckle correlation, compoundingtechniques, phase aberration correc-tion, velocity estimation, and flowimaging.

Biomedical Ultrasound (BME451). The physical basis for the useof high-frequency sound in medicine(diagnosis, therapy, and surgery) andbiology. Acoustic properties oftissues, sound propagation in tissues,including linear processes as well asfinite amplitude sound propagation,and the development of shockwaves; interactions of ultrasoundwith gas bodies, leading to thephenomenon of acoustic cavitation;thermal and non-thermal biologicaleffects of ultrasound ultrasonography,dosimetry, radiation diathermy,thermal surgery, and lithotripsy.

Biosolid Mechanics (BME 483).This course applies engineeringmechanics to biological tissuesincluding muscle, soft tissue, cellmembranes, and bone. Students learnabout realistic modeling of biologicalstructures, including the heart, bloodvessels, and the skeleton. The coursecovers both experimental and compu-tational methods and material models.

Fundamentals of AcousticalWaves (ECE 432). Introduction toacoustic wave propagation. Topicsinclude acoustic wave equation,energy and momentum transmission

Education through infinite fluid media, reflectionand transmission at boundaries,radiation from points spheres, pistons,plane cylindrical and spherical wavepropagation, diffraction and beamforming, and scattering.

Elasticity (ME449). Analysis ofstress and strain, equilibrium, compat-ibility, elastic stress-strain relations,material symmetries, torsion andbending of bars, plane stress andplane strain, and stress functions.Applications to half-plane and half-space problems, wedges, andnotches. 3D problems via potentials.

Finite Elements (BME 486). Thiscourse provides a thorough groundingon the theory and application of linearfinite element analysis in solidmechanics and related disciplines.Topics: structural matrix analysisconcepts and computational proce-dures, shape functions and elementformulation methods, variationalmethods, weighted residual methodsand Galerkin techniques, isopara-metric elements, error estimation andconvergence, and global analysisaspects.

Medical Imaging Systems (ECE452). An introduction to the prin-ciples of X-ray, CT, PET, MRI, andultrasound imaging. The emphasis ison providing linear models of eachmodality, which allows linear systemsand Fourier transform techniques tobe applied to analysis problems.

Microhydrodynamics (BME 466).This course develops insight into themotion of small particles in a viscousfluid. Such problems are encounteredin biology, biotechnology, and com-posite materials processing. Specifictopics include flow past spheres andarbitrary bodies, (thermally driven)motion of bubbles and drops, electro-kinetic flows, and lubrication theory.

Nonlinear Finite Element Analy-sis (BME 487). Theory and appli-cation of nonlinear finite elementanalysis (FEA) with a focus onapplications in fluid mechanics. Quickreview of basic FEA and generaliza-tion to nonlinear situations. Review offluid mechanics (at the undergradu-ate level). Linearization and iterativetechniques. Illustrations from classicfluids problems with extension tomodern problems.

VLSI Signal Processing (ECE492L). Analysis, design, and imple-mentation of signal processingsystems for communications andmultimedia. Using state-of-the-arttools and technologies, the coursesurveys algorithms, architectures, andVLSI implementations of complexsignal processing blocks, payingparticular attention to performance,area, and energy efficiency. Moderndesign flow, from algorithm transfor-mation, automatic (and custom) logicsynthesis and optimization, circuit andphysical design, and timing analysisand verification, for high perfor-mance, small area, and low power.

Biomedical Optics (BME 492).This course introduces students tomajor diagnostic methods in biomedi-cal optics. Currently, the courseemphasizes spectroscopy (absorption,fluorescence, Raman, elastic scatter-ing), photon migration techniques(steady-state and time-resolved), andhigh-resolution subsurface imaging(confocal, multi-photon, opticalcoherence tomography). Essentialmethods of multivariate data analysisare taught in the context of spectros-copy.

All courses are not offered eachsemester. Some courses haveprerequisites. See the officialUniversity of Rochester bulletinfor exact course information.

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Third Tissue Elasticity Conference Sessions

Session TUT: Tutorial: Imaging ofCardiovascular ElasticityChair: F Duck, UK

Cardiovascular Deformation Imaging - PartI: Vascular; Part II: Cardiac. CL de Korte,University Medical Center Radboud,Nijmegen, The Netherlands, and J D’hooge,Catholic University of Leuven, Leuven,Belgium.

Session MMT: Mechanical MeasurementTechniques for TissuesChair: E Mazza, Switzerlan; Co-Chair: SLevinson, USA

The Effects of Deformation on the Young’sModulus Measurement by Two Indentorsof Different Sizes—a Simulation Study.APC Choi, Y Zheng., The Hong KongPolytechnic University, Hong Kong, China.

Ultrasound Critical-Angle Reflectometry:Measuring Velocities In Hard And SoftAnisotropic Tissues. PP Antich, et al.University of Texas Southwestern MedicalCenter, Dallas, TX.

A Device for the Assessment of NonlinearViscoelastic Material Properties of SoftTissues In Vivo. E Tönük, Middle EastTechnical University, Ankara, Turkey.

Assessment Of Nonlinear ViscoelasticMaterial Properties of Soft Tissues ofResidual Limbs of Trans Tibial Amputees.E Tönük, et al. Middle East TechnicalUniversity, Ankara, Turkey.

Session SIP-1: Signal and ImageProcessing - IChair: W Walker, USA; Co-Chair: RMaurice, Canada

Strain Estimation Using Spectral Cross-Correlation: Initial Results Using Paramet-ric Methods. K Hoyt, et al., DrexelUniversity, Philadelphia, PA.

A New Time Delay Estimator for TissueElasticity Imaging. F Viola, WF Walker,University of Virginia, Charlottesville, VA.

2D Strain Estimation Algorithm - InitialResults. E Brusseau, et al., CREATIS,Villeurbanne, France.

Tissue Strain Imaging Using a Wavelet-Based Peak Search Algorithm. H Eskandari,SE Salcudean, University of BritishColumbia, Vancouver, BC, Canada.

Session MIP-1: Methods for ImagingElastic Tissue Properties - IChair: M Fink, France; Co-Chair: TShiina, Japan

The Supersonic Shear Imaging TechniqueApplied to Nonlinear Properties of SoftTissues. S Catheline, et al., LaboratoireOndes et Acoustique, E.S.P.C.I., Paris,France.

Dynamics of Soft Tissue In Response toImpulsive Acoustic Radiation Force withClinical Applications. ML Palmeri, et al.,Duke University, Durham, NC.

Vibration Sonoelastographic Imaging Usinga Phase-Locking Technique. A Iqbal, et al.,University of Dundee, Dundee, Scotland,UK.

Viscoelasticity Imaging Based On Hyster-esis Analysis under Quasi-Static Deforma-tion. N Nitta1, T Shiina2. 1National Instituteof Advanced Industrial Science & Technol-ogy (AIST), Tsukuba, Japan; 2Universityof Tsukuba, Tsukuba, Japan.

Shear Wave Beamforming Using theAcoustic Radiation Force. J Bercoff, et al.,Laboratoire Ondes et Acoustique, E.S.P.C.I,Paris, France.

Visualization of Shear Wave Propagation inBiomaterials with Sonoelastography. ZCWu, KJ Parker, University of Rochester,Rochester, NY.

A Comparison of Methods OfSonoelastography in Muscle. S Levinson, etal., University of Rochester, Rochester, NY.

Session CAA-1: Clinical and AnimalApplications - IChair: WE Svensson, UK; Co-Chair: EEKonofagou, USA

Elasticity Imaging May Improve Local Pre-Treatment Staging of Breast Cancers. WESvensson, et al., Charing Cross HospitalNHS Trust, London, England, UK.

Non-Invasive Vascular Elasticity CanDetect Vascular Disease. WF Weitzel, et al.,University of Michigan, Ann Arbor, MI.

Direct Elasticity Measurement of InferiorVena Cava Thrombi in Rats: Correlationwith Ultrasound Strain Measurements andThrombus Age. JM Rubin, et al., Univer-sity of Michigan, Ann Arbor, MI.

Application of Transient Elastography toIn-Vivo Measurements of Liver Stiffness inPatients with Chronic Hepatitis C. LSandrin, et al., Echosens SA, Paris, France.

Real-Time Monitoring of RadiofrequencyAblation in Liver with Acoustic RadiationForce Impulse Imaging. BJ Fahey, GETrahey, Duke University, Durham, NC.

Hifu Prostate Cancer Treatment Monitor-ing By Elastography. L Curiel1, et al.,INSERM, Lyon, France.

Mechanical Behavior of the Human Cervix:An In Vivo Study. E Mazza, et al., SwissFederal Institute of Technology, Zürich,Switzerland.

Prostate Elastography: Preliminary In VivoResults. SK Alam, et al. (EE Konofagou,presenting) Riverside Research Institute,New York, NY.

The Third International Conferenceon the Ultrasonic Measurement ofTissue Elasticity was once again co-sponsored by the RCBU and theUniversity of Texas. Jeff Bamber, ofThe Institute of Cancer Research,Sutton, Surrey, UK hosted the eventat Lake Windermere, Cumbria, UK.Researchers from all over the worldattended the conference.

24

Session FIP-1: Forward and InverseProblems - IChair: JA Noble, UK

Absolute Modulus Imaging Using Ultra-sonic Freehand Scanning and PressureSensory Data. J Jiang, et al., University ofWisconsin-Madison, Madison, WI.

Elasticity Reconstruction From Displace-ment And Confidence Measures ofUltrasound Image Sequences. J Li, JANoble, University of Oxford, Oxford,England, UK.

Inverse Elasticity Reconstruction Based onan Image Similarity-Measure Approach. JLi, et al., University of Oxford, Oxford,England, UK.

Direct And Interative Algorithms ForInverse Problems In Elastography. E Park,AM Maniatty, Rensselaer PolytechnicInstitute, Troy, NY.

Using Arrival Times to Recover Shear WaveSpeed Parameters in an AnisotropicMedium. D Renzi, J McLaughlin,Rensselaer Polytechnic Institute, Troy, NY.

An Inverse Problem: Localization of Insertsby Correlation Between Finite ElementModels and Elastograms. P Trompette, etal., INSERM, Lyon, France.

Influence of Tissue Viscosity on WavePropagation Characteristics in BoundedRegions. JGG Dobbe, et al., University ofAmsterdam, Amsterdam, The Netherlands.

Plane-Wave Decomposition for an ExactReconstruction of Transversal IsotropicProperties in Steady-State DynamicElastography. R Sinkus, et al.,PhilipsResearch, Hamburg, Germany.

Session CAA-2: Clinical and AnimalApplications - IIChair: WF Weitzel, USA Co Chair: ASarvazyan, USA

A New Animal Model for In VivoElastography. K Hoyt, et al., DrexelUniversity, Philadelphia, PA; ThomasJefferson University, Philadelphia, PA.

Strain Processing of IntraoperativeUltrasound Images of Brain Tumours. JBang, et al., SINTEF Health Research,Trondheim, Norway.

Intra-Operative Ultrasound Elastographyand Registered Magnetic ResonanceImaging of Brain Tumours; A FeasibilityStudy. A Chakraborty, et al., Royal Free &University College Hospital MedicalSchool, London, England, UK.

Preliminary Evaluation of Breast DiseaseDiagnosis Based On Real-Time ElasticityImaging. T Matsumura, et al., HitachiMedical Corporation, Chiba, Japan.

New Elastographic Algorithm for In VivoStudy of Mechanical Behavior of Skin. YMofid, et al., LUSSI, Tours, France.

Session MPT: Mechanical Properties ofTissuesChair: G Cloutier, Canada Co-Chair: RSouchon, France

On the Transverse Anisotropy of Humanand Bovine Calcified Tissues. JL Katz, etal., University of Missouri-Kansas City,Kansas City, MO.

Analysis of Blood Clot Formation UsingTransient Elastography. JL Gennisson, etal., University of Montréal Hospital,Montréal, Québec, Canada.

Intrinsic Limitations in DifferentialDiagnostics Based on QuantitativeElastography. A Sarvazyan, ArtannLaboratories, Lambertville, NJ.

Session SIP-2: Signal and Image Process-ing - IIChair: S Emelianov, USA Co-Chair: MMDoyley, USA

Time Domain Cross Correlation with Prior

Estimates. R Zahiri-Azar, SE Salcudean,University of British Columbia, Vancouver,BC, Canada.

Direct Strain Measurement Based on anAutocorrelation Method. C Sumi, SophiaUniversity, Tokyo, Japan.

Improved Elastographic Signal-to-NoiseRatio Using Coded Excitation. R Souchon,et al., INSERM, Lyon, France.

Systematic Error Can Dominate ImageNoise in Strain Measurements. CX Jia, etal., Boston University, Boston, MA.

Session MIP-2: Methods for ImagingElastic Tissue Properties - IIChair: KJ Parker, USA Co-Chair: NMiller, UK

A Novel Haptic Sensor Actuator Systemfor Palpation Imaging Based on UltrasoundElastography. W Khaled, et al., Ruhr-University, Bochum, Germany.

Mechanism for Human Detection of ElasticLesions in Simulated B-Mode MoviesDuring Palpation. N Miller, J Bamber,Institute of Cancer Research, Sutton,Surrey, England, UK.

Shear Wave Elasticity Imaging with the Useof Time Reversal Acoustics. A Sarvazyan, ASutin, Artann Laboratories, Lambertville,NJ.

Non-contact Ultrasound IndentationSystem for Measuring Tissue MaterialProperties Using Water Beam. M Lu, et al.,The Hong Kong Polytechnic University,Hong Kong, China.

Tissue Elasticity Conference

Jeff Bamber,host, UK;

Jim Greenleaf,USA; Dr. Allan

Chapman, guestspeaker, UK

25

In Vitro Imaging of Hifu-Induced Lesions inBovine Livers Using Three DimensionalSonoelastography. M Zhang, et al.,University of Rochester, Rochester, NY.

Session AA: Alternative ApplicationsChair: JF Greenleaf, USA Co Chair: JD'hooge, Belgium

Sonomyography Analysis of the Morpho-logical Changes of Forearm Muscles inAction. Y Zheng, Xin Chen, The HongKong Polytechnic University, Hong Kong,China.

Thermal Properties ReconstructionTechnique Based on Temperature Measure-ment. C Sumi, Sophia University, Tokyo,Japan.

Thermal Lesion Monitoring UsingMiniaturized Image-Treat Arrays. IRSMakin, et al., Guided Therapy Systems,Mesa, AZ.

Tissue Displacement and Strain PatternsDuring Acupuncture Follow ConnectiveTissue Planes. EE Konofagou, et al.,Columbia University, New York, NY.

Combined Ultrasound, Photoacoustic andElastcity Imaging. S Emelianov, et al., TheUniversity of Texas at Austin, Austin, TX.

Session INS: InstrumentationChair: Y Zheng, China Co Chair: RMSchmitt, USA

Development of High Bandwidth Trans-ducers Using Injection-Molded 1-3 LowPitch Composites: A Numerical Study. RMSchmitt, et al., Winprobe Corporation,North Palm Beach, FL.

Development of an Ultrasound ResearchPlatform. WG Scott, et al., WinProbeCorporation, North Palm Beach, FL.

An Actively Shielded ElectromagneticTransducer for MR-Elastography Dedi-cated to Mammography. H Hörning, et al.,Philips Medical Systems, Hamburg,Germany.

Session CVE: Cardiovascular ElasticityChair: CL de Korte, The Netherlands CoChair: H Kanai, Japan

Transcutaneous Measurement of Myocar-dial Viscoelasticity. H Kanai, TohokuUniversity, Sendai, Japan.

Adapting the Lagrangian Speckle ModelEstimator For Endovascular Elastography:Theory and Validation With SimulatedRadio-Frequency Data. R Maurice, et al.,University of Montréal Hospital ResearchCenter, Montréal, Québec, Canada.

Investigation of “Ring Resonant Fre-quency” for Estimation of ArterialElasticity. X Zhang, JF Greenleaf. MayoClinic College of Medicine, Rochester, MN.

Characterization of Vulnerable CoronaryPlaque by Strain Power Image. T Shiina, etal., University of Tsukuba, Tsukuba, Japan.

Clinical Evaluation of 3D IntravascularUltrasound Palpography for VulnerablePlaque Detection. AFW van der Steen, etal., Erasmus MC, Rotterdam, The Nether-lands.

Robust Assessment of Arterial PlaqueComposition In Vivo Using A ParametricPlaque Model-Based Young's ModulusReconstruction Method. RA Baldewsing,Erasmus MC, Rotterdam, The Netherlands.

A New Method for Two-DimensionalMyocardial Strain Estimation by Ultra-sound: A Comparison withSonomicrometry In Vivo. S Langeland, etal., Catholic University Leuven, Leuven,Belgium.

Two-Dimensional Functional InformationCan Be Used For Automated Left-Ventricular Segmentation. EE Konofagou,TC Pulerwitz, 1Columbia University, NewYork, NY.

Session FIP-2: Forward and InverseProblems - II

Chair: PE Barbone, USA Co Chair: JMcLaughlin, USA

Simulation Study of Reconstruction ofShear Modulus, Density, and Poisson'sRatio Distributions. C Sumi, SophiaUniversity, Tokyo, Japan.

Influence of Viscosity on Shear WavesInduced By the Acoustic Radiation Force. JBercoff, et al.,, Laboratoire Ondes etAcoustique, E.S.P.C.I, Paris, France.

The Inverse Problem of the Shear WavePropagation: Recovering Both ShearModulus and Viscosity Images fromSupersonic Shear Imaging Data. J Bercoff,et al., Laboratoire Ondes et Acoustique,E.S.P.C.I.,Paris, France.

Enhancing the Performance of Modulus

Elastograms. MM Doyley, et al.,Dartmouth Medical School, Hanover, NH.

Transient Elastography: Algorithms andModels. J McLaughlin, et al., RensselaerPolytechnic Institute, Troy, NY.

Session MIP-3: Methods for ImagingElastic Tissue Properties - IIIChair: R Sinkus, Germany Co Chair: EBrusseau, France

Imaging Localized Viscoelastic PropertiesUsing Harmonic Motion Imaging. EEKonofagou, TP Harrigan, ColumbiaUniversity, New York, NY.

Poisson's Ratio Imaging andPoroelastography in Biological Tissues: AFeasibility Study. R Righetti, et al., TheUniversity of Texas Medical School,Houston, TX.

Certificatepresentation

to JeffBamber,

host, UK; byJonathanOphir and

Kevin Parker,conferenceorganizers


26

A Method For Generating PermeabilityElastograms Using Poroelastography. RRighetti, et al., The University of TexasMedical School, Houston, TX.

Towards a Model-Based PoroelasticImaging Method. G Berry, et al., Instituteof Cancer Research, Sutton, Surrey,England, UK.

Monitoring Of Hifu Lesions UsingSupersonic Shear Imaging: A UniqueTherapy and Imaging System. J Bercoff, etal., Laboratoire Ondes et Acoustique,E.S.P.C.I, Paris, France.

Session CET: Complementary ElasticityImaging TechniquesChair: AFW van der Steen, The Nether-lands Co Chair: C Sumi, Japan

3D In Vivo Liver MR-Elastography. RSinkus1, H Hörning2, L ter Beek3, MDargatz1 and B Van Beers4. 1PhilipsResearch, Hamburg, Germany; 2PhilipsMedical Systems, Hamburg, Germany;3Philips Medical Systems, Brussels,Belgium; 4St. Luc, Brussels, Belgium.

Determination of Anisotropic Elasticities ofIn Vivo Skeletal Muscle Using A GeometricAnalysis Of MR-Elastography WavePatterns. S Papazoglou, et al., Institute ofRadiology-Charité, Berlin, Germany.

Measuring The Mechanical Properties ofSmall Biological Tissues Using MicroMagnetic Resonance Elastography(µMRE). SF Othman, et al., University ofIllinois at Chicago, Chicago, IL.

Session PTO: Phantoms and Test ObjectsChair: EL Madsen, USA

Fast Generation of 3d Synthetic RF Data ofNonlinearly Elastic Objects for SpeckleTracking Performance Evaluation. RQErkamp, et al., University of Michigan,Ann Arbor, MI.

Tissue-Mimicking Spherical LesionPhantoms for Elastography with andWithout Ultrasound Refraction Effects. ELMadsen, et al., University of Wisconsin-Madison, Madison, WI.

Tissue-Mimicking AnthropomorphicBreast Phantoms for Ultrasound and MRElastography. EL Madsen, et al., Univer-sity of Wisconsin-Madison, Madison, WI.

Design and Characterisation of a Compliant

Wall Vascular Phantom of Varying Elastic-ity for Ultrasound Investigation of ArterialWall Motion (AWM). J Dineley, PHoskins, University of Edinburgh,Edinburgh, Scotland, UK.

Development of a New Tissue-EquivalentGel for Wall-Less Flow and Wall MotionPhantoms. TL Poepping, et al., Universityof Edinburgh, Edinburgh, Scotland, UK.

Session POS: PostersChair: TA Krouskop, USA

A Study of Vibration Characteristics forUltrasonic Elasticity Imaging. J Park, et al.,Daejin University, Pocheon, Kyeonggi,Korea.

Computer-Based Vibrational ViscoelastocMeasurement of Soft Tissues. EMTimanin, EV Eremin, Institute of AppliedPhysics RAS, Nizhny Novgorod, Russia.

Two-Dimensional Elastic ModulusDistribution Reconstruction Based on aModified Three-Dimensional Finite-Element Model. M Yamakawa, T Shiina,University of Tsukuba, Tsukuba, Japan.

An Arterial Wall Motion Test Tool toAssess Philips AWM Software. SJHammer, et al., The University ofEdinburgh, Edinburgh, Scotland, UK.

Intravascular Ultrasound Palpography forDetermining the Age of a Thrombus: AnAnimal Study In Vivo. JA Schaar, et al.,Erasmus MC, Rotterdam, The Netherlands.

Optical Flow Tissue Tracking Using Real-Time 3D Ultrasound. P Jordan, et al.,Harvard University, Cambridge, MA.

Feasibility of Skin Surface Elastography byTracking Surface Topography. L Coutts, etal., Institute of Cancer Research, Sutton,Surrey, England, UK.

Description of a New Iterative Algorithmfor Scaling Factor Estimation. J Fromageau,et al., CREATIS, Lyon, France.

Gaussian Modeling of Dispersive Media:Application to Calcified Tissues. DHazony, JL Katz, Case Western ReserveUniversity, Cleveland, OH.

Extraction of Modulus from the OsmoticSwelling of Articular Cartilage MeasuredUsing Ultrasound. H Niu, et al., The HongKong Polytechnic University, Hong Kong,China.

Osmotically-Induced Shrinkage andSwelling Behavior of Normal BovinePatellar Articular Cartilage In Situ Moni-tored by Ultrasound. Q Wang, Y Zheng,The Hong Kong Polytechnic University,Hong Kong, China.

Effect of Saline Concentration on SoundSpeed on Articular Cartilage. S Patil, YZheng, The Hong Kong PolytechnicUniversity, Hong Kong, China.

Skin Elasticity Measurement Based on a 20MHz Ultrasound Biomicroscope. Y Huang,Y Zheng, The Hong Kong PolytechnicUniversity, Hong Kong, China.

Ultrasonic Measurement of In-Vivo Strainof Surgically Repaired Achilles TendonUnder Isometric Contraction. J Chan etal.,The Hong Kong Polytechnic University,Hong Kong, China.

Effects of Internal Discontinuities OnStrain Elastograms. TA Krouskop, et al.,Baylor College of Medicine, Houston, TX;The University of Texas Medical School,Houston, TX.

Biomechanical Properties of Corneal TissueDetermined by Applanation and Thin ShellModel. J Liu, C Roberts, The Ohio StateUniversity, Columbus, OH.

Imposing Physical Constraints to YieldAccurate and Unbiased DisplacementEstimates. NH Gokhale, et al., BostonUniversity, Boston, MA.

Analysis of 3D Left Ventricular WallMotion Using Tissue Doppler Imaging. AFKolen et al.,University HospitalMaastricht, Maastricht, The Netherlands.

Session EEX: Equipment ExhibitChair: N Bush, UK

Hitachi Medical Corporation, Kashiwa,Japan

Medison Corporation, Seoul, Korea

Precision Acoustics, LTD, Dorchester,Dorset, England, UK


27

The RCBU is continually working onnovel concepts in ultrasound re-search. A collection of patents andsoftware programs that originated atthe Center are summarized on thenext few pages. For more informa-tion, technology transfer arrange-ments, or licensing agreements for aspecific patent, call the University ofRochester Technology Transferoffice at (585) 275-3998, or asindicated below.

System for Model-Based Com-pression of Speckle Images

Ultrasound images contain speckle.These high-spatial patterns are ill-suited for compression using conven-tional techniques, particularly byJPEG, which is designed for photo-graphic images with regions ofsmooth or negligible intensity varia-tions. Conventional compressiontechniques fail to provide high qualityreproductions with high compressionratios. This combination is desirablefor telemedicine and other applica-tions where the available bandwidthor storage constraints create a needfor high quality and high compressionof ultrasound images. U.S. PatentNo. 5,734,754 issued March 31, 1998,describes a system for compressionof speckle images.

Finite Amplitude Distortion-Based Inhomogeneous PulseEcho Ultrasonic Imaging

A method and system for imaging asample. The method includes thesteps of generating an ultrasonicsignal, directing the signal into asample, determining which signal is

distorted and contains a first orderand higher order component signalsat first and higher frequenciesrespectively. The received distortedsignal is processed, and an image isformed, and then displayed, from oneof the higher order component signalsof the received distorted signal. U.S.Patent No. 6,206,833 was issued toTed Christopher on March 27, 2001.For further information contactEugene Cochran, Research Corpora-tion Technologies, at (520) 748-4461.

Blue Noise Mask

Medical images are sometimesprinted on devices that have limitedoutput states. For example, laserprinters can render black or white butnot shades of gray. Halftone methodsrender gray as patterns of black andwhite dots. The Blue Noise Mask isa halftone screen method for digitalor photographic rendering of images.The Blue Noise Mask produces thefastest possible rendering of medicalimages with an artifact-free halftonepattern. The fax transmission ofmedical images can also be madefaster and with higher quality byutilizing the Blue Noise Mask andnew tonefac algorithm. The BlueNoise Mask invention receivednumerous patents, including: U.S.Patent Nos. 5,708,518; 5,726,772;5,111,310; 5,477,305; and 5,543, 941.This patented technology has beenaccepted by over 15 U.S. companiesand organizations including: Seiko,Epson, Hewlett-Packard, Tektronix,and Research Corporation Technolo-gies. For further information contactEugene Cochran, Research Corpora-tion Technologies, at (520) 748-4461.

Thin-Film Phantoms andPhantom Systems

Phantoms for testing and measuringthe performance of ultrasonicimaging systems have regions ofprecisely controlled scattering orechogenicity that containsubresolvable scatterers. The phan-toms can reveal the combinedinfluences of all the stages in theimaging chain in terms of modula-tions, transfer function, and resolutionlimits as well as other artifacts anddefects in the system, such asaliasing and frequency response,which cannot be evaluated withconventional ultrasound phantoms.Halftone masks may be used toproduce regions of precisely con-trolled subresolvable scatterers to beused for gray-scale evaluation of theimaging system by producing speckleimages of different echogenicity. Thethin-film sheets are thinner than thethickness of the ultrasonic beam andenable propagation of the beam in theplane of the sheets to the patterns,which may be located at differentdepths. The sheets may be made ofpiezoelectric material having elec-trodes across which varying electri-cal signals are applied to displace thesheets, thereby simulating movementof objects for Doppler measure-ments. U.S. Patent No. 5,756,875was granted on May 26, 1998, tocoinventors Daniel B. Phillips andKevin J. Parker.

Patents and Software

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An Inexpensive Wide-BandwidthHydrophone forLithotripsy Research

Probing the acoustic field of extra-corporeal lithotripters places severaldemands upon conventional hydro-phones. “Needle” hydrophones, whilebetter able than “membrane” hydro-phones to withstand the cavitation-related damage inherent in lithotriptermeasurements, nevertheless lacktheir superior high-frequency re-sponse. Even the most popularmembrane hydrophones do not havesufficient sensitivity at high frequen-cies to resolve the rapid rise times (1-20 ns) of waveforms that may occurat a lithotripter focus. To overcomethese limitations, we have developeda membrane-type hydrophone thatcosts hundreds (not thousands) ofdollars and has disposable activeelements that can be replaced easilywhen damaged. These elements, of6 mm PVDF copolymer film, incor-porate an electrode pattern thatassures identical sensitivity from oneelement to the next, obviating theneed for recalibration after replace-ment of the element. On-boardconditioning electronics increase theeffective bandwidth of the hydro-phone to over 125 MHz and provideclipping of the undesirable electro-magnetically induced transients ofspark-discharge lithotripters. Formore information, contact CarrEverbach at (215) 328-8079.

System and Method for 4DReconstruction andVisualization

From raw image data obtainedthrough magnetic resonance imagingor the like, an object is reconstructedand visualized in four dimensions(both space and time). First, the first

image in the sequence is divided intoregions through statistical estimationof the mean value and variance ofthe image data and joining of pictureelements (voxels) that are sufficientlysimilar. Then, the regions are ex-trapolated to the remainder of theimages by using known motioncharacteristics of components of theimage (e.g., spring constants ofmuscles and tendons) to estimate therigid and deformational motion ofeach region from image to image.The object and its regions can berendered and interacted within afour-dimensional virtual realityenvironment. US Patent No.6,169,817 was issued to co-inventorsKevin J. Parker, Saara S. M.Totterman, and Jose Tamez-Pena.

The Acoustic Filter

The acoustic filter is a system forreducing post-cardiopulmonarybypass encephalopathy due tomicroembolization of the brain of apatient with gaseous microbubbles(less than 40 microns in diameter).This invention is recommended foruse during open heart surgery with acardiopulmonary bypass machinebypassing a stream of blood from thepatient through an ultrasonic travelingwave that propagates across thestream without reflection and sweepsthe blood clean of the microbubbleswithout inducing blood cell trauma.The blood passes through a chamberbetween an input port and a filtrateexit port. The microbubbles arecarried by the traveling wave to awaste exit port in the chamberdownstream of the input port. Toprevent establishment of resonanceconditions, reflections, and travelingwaves, the chamber may be sub-merged in a liquid bath and a body ofacoustically absorbed materialdisposed at an end of the chamber

opposite to the end into which theultrasonic beam is projected. U.S.Patent No. 5,334,136 has been issuedto co-inventors Karl Schwarz,Richard Meltzer, and CharlesChurch.

Multiple Function InfantMonitor

Piezoelectric polymer sheets made ofPVDF, placed on the floor of a crib,can output voltage that providesinformation about the heart andbreathing rates of an infant in thecrib. Using external detection andconditioning with the PVDF sheet,we have constructed a low-costPVDF infant health monitor. Themonitor can alert parents, with theaid of a remote alarm, to a decliningheart and/or respiration rate indica-tive of the onset of sudden infantdeath syndrome. US Patent No.5,479, 932 has been issued for thisinvention. For more information,contact Carr Everbach (215) 328-8079.

Apparatus for Bone Surface-Based Registration

A novel technique has been devel-oped that could be used for neurosur-gical and other applications. Thedevice is entitled “Apparatus forBone Surface-Based Registration ofPhysical Space with TomographicImages for Guiding a Probe Relativeto Anatomical Sites on the Image.”The co-inventors of this techniqueare from Vanderbilt University andthe University of Rochester: W. A.Bass, R. L. Galloway, Jr., C. R.Maurer, Jr., and R. J. Maciunas. USPatent No. 6,106,464 was issued onAugust 22, 2000.


29

Sonoelasticity ImagingEstimators

Sonoelasticity imaging is a novelmethod for assessing the stiffness, orelastic constants, of tissues. Thiscombination of externally appliedvibration and new Doppler imagingtechniques was pioneered at theUniversity of Rochester by RobertM. Lerner and Kevin J. Parker in1986, following earlier work by Dr.Lerner on stiffness and compressibil-ity of phantom materials and basicDoppler studies by Dr. Jarle Holenand colleagues. Since sonoelasticityimaging reveals patterns of vibrationswithin tissues, stiff tumors that maynot be accessible to palpation can beimaged regardless of subtle changesin echogenicity. US Patent No.5,086,775, concerning time andfrequency domain estimators forsonoelasticity imaging, has beenissued to co-inventors Ron Huang,Robert Lerner, and Kevin Parker.

Linear and Nonlinear AcousticField Propagation Software

We have developed a computationalmodel for the nonlinear propagationof acoustic beams. The physicaleffects of diffraction, absorption,dispersion, nonlinearity, and planarreflection and refraction are ac-counted for in an accurate andefficient manner. Descriptions of thenovel algorithms accounting for thesephysical effects have been presentedin a series of publications. The modelhas been compared successfully withtheoretical and experimental results.The model has also been used tomake predictions about the in vivoperformance of biomedical ultrasonicimaging devices and lithotripters.Finally, the model is currently being

extended to consider non-axiallysymmetric source propagation inphase-aberrate media. U.S. patentallowed.

Butterfly Search Technique

We have developed a novel, robust,and accurate blood velocity estima-tion technique that is implemented byelementary digital signal processingwithout any transforms, correlationsearches, SAD searches, matchedfilters, or other intensive operations.In this technique, echoes fromrepeated firings of a transducer areresampled along a set of predeter-mined trajectories of constantvelocity. These are called butterflylines because of the intersection andcrossing of the set of differenttrajectories at some reference range.The slope of the trajectory on whichthe sampled signals satisfy a prede-termined criterion appropriate for thetype of signal in question provides anestimate of the velocity of the target.The search for this trajectory iscalled Butterfly Search and is carriedout efficiently in a parallel-processingscheme. The estimation can be basedon the RF echo, its envelope, or itsquadrature components. The Butter-fly Search on quadrature componentshas shown outstanding noise immu-nity, even with relatively few succes-sive scan lines, and was found tooutperform all the common timedomain and Doppler techniques insimulations with strong noise. TheButterfly Search can overcome manydisadvantages faced by present-daytechniques, such as the stringenttrade-off criterion between imagingresolution and velocity resolutionimplicit in Doppler techniques, andthe need for computations. USPatent No. 5,419, 331 has beenissued to co-inventors Kaisar Alamand Kevin Parker.

“Smart” Endotracheal Tube

This invention relates to airwaymanagement devices for use inmedical emergencies and moreparticularly to an endotracheal tubeapparatus that generates a signal toensure proper placement of the tubein a patient’s trachea. A flexible tubeextends from the patient’s oral ornasal cavity to a distal end within thetrachea. An ultrasound transducer isconnected to the tube near its distalend, in contact with the forward innerwall at the midpoint of the patient’strachea. A second ultrasound trans-ducer contacts the forward outer skinsurface of the patient’s neck. Eitherthe first or the second transducer cantransmit an ultrasound signal providedby ultrasound transducer excitation,to which it is electrically connected.The other transducer serves as areceiver, connected to an ultrasounddetector external to the patient.

Also, a process for monitoring theposition of an endotracheal tubeinserted in a patient uses a flexibletube extending from the patient’s oralor nasal cavity to a distal end and thefirst ultrasound transducer connectedto the tube near its distal end. Thefirst transducer contacts the forwardinner wall of the trachea at itsmidpoint, and a second ultrasoundtransducer is contacts the forwardouter skin surface of the patient’sneck at a position at least partiallyoverlying the position of the firsttransmitter. US Patent No. 5,785,051was issued July 29, 1998, to co-inventors Jack Mottley and RandyLipscher for this invention.


30

Center Members

University of Rochester/Strong Memorial Hospital

AnesthesiologyPratima Shah, MDJanine Shapiro, MDDavid Stern, MDJacek Wojtczak, MD

Biomedical EngineeringSally Child, MSDiane Dalecki, PhDAmy Lerner, PhDStephen McAleavey, PhDCarol Raeman, AASYixen Ren, MSClaudio Rota, MSRichard Waugh, PhDMan (Maggie) Zhang, MS

Biophysics/BiochemistryScott D. Kennedy, PhD

BiostatisticsChristopher Cox, PhD

Cardiology UnitXucai Chen, PhDJames Eichelberger, MDKarl Schwarz, MDSherry Steinmetz, RDMSNaoyuki Yokoyama, PhD

DermatologyAlice Pentland, MD

Earth and EnvironmentalSciencesAsish Basu, PhD

Electrical and ComputerEngineeringEdwin Carstensen, PhDBenjamin Castaneda, MSBetsy Christiansen, BA

Jack Mottley, PhDKevin J. Parker, PhDBrian C. Porter, PhDEdward Titlebaum, PhDRobert Waag, PhDZhe (Clark) Wu, MS

Emergency MedicineJefferson S. Svengsouk, MD

Laboratory Animal MedicineRaymond B. Baggs, DVM

Mechanical EngineeringStephen Burns, PhDAlfred Clark, Jr., PhDSheryl Gracewski, PhDRenato Perucchio, PhD

Obstetrics and GynecologyMorton Miller, PhDRichard Miller, MDJames Woods, MD

PathologyP. Anthony di Sant’Agnese, MD

Center for Vaccine Biology andImmunologyMitra Azadniv, PhD

Radiation OncologyYan Yu, PhD

RadiologyMark James Adams, MDNancy Carson, MBA, RDMS, RVTJeanne Cullinan, MDThomas Foster, PhDNina Klionsky, MDLydia Liao, MD, PhDEva Pressman, MDDeborah Rubens, MDJohn G. Strang, MDMichael Violante, PhDSusan Voci, MD

Eric P. Weinberg, MDJianhui Zhong, PhD

Rehabilitation MedicineStephen F. Levinson, MD, PhD

UrologyRobert Davis, MDErdal Erturk, MDIrwin Frank, MDRobert Mayer, MDEdward M. Messing, MD

Vascular MedicineCharles W. Francis, MD

Rochester General HospitalRadiology- Robert M. Lerner, MD

Rochester Institute ofTechnologyCenter for Imaging SciencesMaria Helguera, PhDNavalgund Rao, PhD

Electrical EngineeringDaniel Phillips, PhD

Visiting ScientistsDavid Blackstock, PhDUniversity of Austin

E. Carr Everbach, PhDSwarthmore College

Richard Meltzer, MDLas Cruces, New Mexico

Wesley Nyborg, PhDUniversity of Vermont

Honorary MemberFloyd Dunn, PhDUniversity of Illinois

University of R

ochesterR

ochester Center for B

iomedical U

ltrasoundPO

Box 270126

Rochester, N

Y 14627-0126

Non-Profit O

rg.U

.S. PostagePA

IDPerm

it No. 780

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