foundations of mri - mcgill university · outline • role of mri in neuroscience! • crash course...
TRANSCRIPT
Foundations of MRI© 1973 Nature Publishing Group
phase of the periodic response at the rota-tion or dilation-contraction frequency, mea-sured with the (complex-valued) Fouriertransform of the response profile over timeat each voxel, is closely related to the polarangle or eccentricity represented at that cor-tical location (13). This technique results inhigh signal-to-noise ratios (because at anyone point in time, approximately one-half ofeach visual field map will be activated) yetprovides fine spatial resolution. Common(for example, retinal) and between-areaphase delays can be removed and examinedby considering clockwise-counterclockwiserotation and expansion-contraction pairs(14, 15).
Figure lA shows a color plot of theresponse to a dilating ring on a medial viewof the cortical surface of the brain of thisparticipant (A.M.D.) (16). The hue of thecolor at each cortical surface point indicatesthe response phase, which is here propor-tional to the eccentricity of the local visualfield representation. In Fig. 1B the corticalsurface was unfolded. This process is similarto inflating a crumpled balloon except thatthe surface has not been stretched. In Fig.iC, the occipital lobe region containing theactivated area has been cut off and theresulting approximately conical surface cutagain along the fundus of the calcarinesulcus to allow it to be flattened completely(17).
There is a systematic increase in eccen-tricity (red to blue to green to yellow to red)moving anteriorly along the medial wall ofthe occipital cortex. Lines of isoeccentricityrun approximately in the coronal plane,cutting across several areas, as shown below.Ventrally, the region showing substantialretinotopy extends almost to the anterior-posterior midpoint of the unfolded ventraltemporal lobe.A parallel treatment of data from the
rotating hemifield stimulus collected a fewminutes later is shown in Fig. 1, D and E.The color again indicates the phase of theperiodic response, which is now proportion-al to the polar angle of the local visual fieldrepresentation. The picture of polar angle ismore complex, alternating between verticaland horizontal meridians both dorsally andventrally. The upper field vertical meridianis red, the horizontal meridian is blue, andthe lower field vertical meridian is green.Several alternations between red and bluestripes are visible ventrally, whereas severalalternations between green and blue stripesare visible dorsally. Mapping experiments inmonkeys suggest that several additional re-representations of the lower visual field ad-join V1 dorsally, including V2 (second vi-sual area) and V3 (third visual area), where-as several rerepresentations of the uppervisual field adjoin V1 ventrally, includingV2, VP (ventroposterior area), and V4v
890
(V4 ventral) (18). In particular, we wouldexpect vertical meridian representations atthe dorsal and ventral V1-V2 border, theventral VP-V4v border, and the dorsal V3-V4 border, and horizontal meridian repre-
sentations near the fundus of the calcarinesulcus in VI, at the dorsal V2-V3 border, atthe ventral V2-VP border, and at the ante-rior border of ventral V4v (4, 6, 7). Can-didates for all of the borders are visible in
Fig. 1. Isoeccentricity and isopolar angle maps of human visual areas. The top row shows isoeccentricitycoded by color [red (fovea) -* blue -> green (parafoveal) -* yellow -> red (periphery)] displayed on theoriginal cortical surface (A), the unfolded cortical surface (B), and the cut and flattened cortical surface (C).The bottom row shows polar angle [red (lower vertical meridian) -> blue (horizontal meridian) -* green(upper vertical meridian)] plotted on the same three surfaces (D), (E), and (F), respectively. Local eccen-tricity and polar angle were determined by considering the phase of the response to a slowly dilating ringor a slowly rotating hemifield at the dilation or rotation frequency. The unfolded representations in (B) and(E) were made by relaxing the curvature while approximately preserving local area and local angles (thesulcal cortex is dark gray and the gyral cortex light gray). The flattened representations in (C) and (F) weremade with the same algorithm after the occipital lobe was cut off and an additional cut in the fundus of thecalcarine sulcus was made.
Fig. 2. Analysis of the data in Fig. 1 byvisual field sign (mirror image versusnon-mirror image visual field represen-tation). Mirror image areas (yellow; forexample, V1), and non-mirror image ar-eas (blue; for example, V2) are shown ina medial view on the folded (A) and un-folded surface (B) and in a ventral view,folded (C) and unfolded (D). The incisionin the fundus of the calcarine is visible in(B). Ventral V1, V2, VP, and V4v (18),comprising four rerepresentations of theupper visual field, are visible below theincision, whereas lower visual field V1and V2 are visible above the incision.The complex folding pattern of the oc-cipital lobe coupled with the weak corre-lation between sulci and areal bound-aries underscores the need for an un-folded representation.
SCIENCE * VOL. 268 * 12 MAY 1995Rick Hoge, Ph.D. McConnell Brain Imaging Centre Montreal Neurological Institute
McGill University
Outline
• Role of MRI in neuroscience
• Crash course on MRI basics
• what is a pulse sequence?
• review of basic pulse sequences and imaging protocols
Structural
T2
PD
T1
DTI
Angiography
Role of MRI in neuroscience
• structure
• cortical anatomy, volumetry
• white matter integrity, vascular burden
• vascular anatomy
• white matter connectivity
Functional
BOLD fMRI
ASL/Perfusion
Spectroscopy
Cardiac
Role of MRI in neuroscience
• function
• localization of processing
• physiological processes (perfusion, metabolism)
• biochemical & molecular information
x-ray
PET
ultrasound
MRI
MRI vs. other modalities
MRI ∼ water imaging
oxygen
hydrogen
hydrogen
Nuclear Magnetization
hydrogen nucleus = proton = “spin”
-
+nuclei aligned
with field
nuclei aligned against field M0
M0 =B0�2�2
4k̄TPD
54°
B0
Different “resonant” nuclei
Nucleus γ [MHz/T]
1H 42.58
13 10.71
19 40.05
31 11.26
Excitation and Relaxation
excite
long delay
BOLDimage
M
*2R
longitudinal magnetization
transverse magnetization
T2*
excite
long delay
BOLDimage
M
*2R
Recovery of longitudinal magnetization
labelprepulse
excite
short delay
perfusionimageM
controlpulse
subtract
What is a pulse sequence?
• a series of radiofrequency (RF) and electromagnetic gradient pulses applied to the body in order to:
• manipulate tissue magnetization to create contrast
• excite tissue magnetization to generate a detectible RF signal
• modulate tissue RF signal to allow generation of cross-sectional images
Exercise: Diffusion Weighting Hands On
B.4$4 IDEA ManualConfidential Draft January 2004
0.0
Figure B.4.1: Sample timing scheme for a diffusion weighted sequence.
GS
GP
GR
ADC
pMrProt->te()[0]
pMrProt->te()[0]/2
lInterDuration
sGSliSel
sGSliSelReph
sGPhasTab
sGPhasTabRew
sSRF01 sSRF02
sGReadDeph
sGBWeightsGBWeight
sGSliSel2
sGradReadout
asGSpoil[Read]sADC01
asGSpoil[Slice]
lInterDuration = Maximum( )'A','B''A' 'B'
lTimeAfterADC
lPERampTime
lAvailableTime = pMrProt->te()[0] - ( sSRF01.getDuration()/2 + sADC01.getDuration()/2 + sGradReadout.getRampUpTime() ) ;
fRTEBFinish()fRTEBInit()
FLASHDiffusion.cpp
Difference between a “sequence” and a “protocol”
• sequence:
• a computer program that generates the specific RF and gradient pulses required to create a particular type of contrast and image geometry
• protocol:
• the set of user parameters that are input to the sequence program
Difference between a “sequence” and a “protocol”
• example of two sequences:
• a T1-weighted anatomic scan (MPRAGE) vs. a T2*-weighted single-shot functional image (EPI)
• example of two protocols:
• a 32-direction DTI scan with 2 mm resolution vs. a 64-direction DTI scan with 3 mm resolution
User control over protocols
User%s Guide Protocol development tools
syngo MR 2004A C.3+37Confidential Draft January 2004
0.0
EXAMPLE:V:/n4/pkg/MrServers/MrImaging/seq/a_ep2d_diff>poetd test.pro /SpuSer /PmuSer
The following window will pop up, if test.pro contains a valid protocol:C.3.
SIEMENS MAGNETOM TrioTim syngo MR B13
\\USER\People\karla\DTI_nogating\mpr_ax111TA: 6:01 PAT: Off Voxel size: 1.0×1.0×1.0 mm Rel. SNR: 1.00 SIEMENS: tfl
PropertiesPrio Recon OffVoice output beforeVoice output afterLoad to viewer OnInline movie OffAuto store images OnLoad to stamp segments OffLoad to graphic segments OffAuto open inline display OffAutoAlign Spine OffStart measurement withoutfurther preparation
On
Wait for user to start OnStart measurements single
RoutineSlab group 1 Slabs 1 Dist. factor 50 % Position R5.5 A13.6 H16.3 Orientation Transversal Phase enc. dir. R >> L Rotation 90.00 degPhase oversampling 0 %Slice oversampling 0 %Slices per slab 192FoV read 192 mmFoV phase 91.7 %Slice thickness 1.00 mmTR 2040 msTE 4.7 msAverages 1Concatenations 1Filter NoneCoil elements HEA;HEP
ContrastMagn. preparation Slice-sel. IRTI 900 msFlip angle 8 degFat suppr. Water excit. normalWater suppr. None
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Averaging mode Long termReconstruction MagnitudeMeasurements 1Multiple series Each measurement
ResolutionBase resolution 192Phase resolution 100 %Slice resolution 75 %Phase partial Fourier OffSlice partial Fourier OffFilter 1 Raw filter OffFilter 2 Distortion Corr. OffFilter 3 Prescan Normalize OffFilter 4 Normalize OffFilter 5 Elliptical filter OffTrajectory Cartesian
Interpolation Off- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
PAT mode NoneMatrix Coil Mode Triple
GeometryMulti-slice mode Single shotSeries Ascending
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SystemBody OffHEP OnHEA On
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Positioning mode REFTable position HTable position 0 mmMSMA S - C - TSagittal R >> LCoronal A >> PTransversal F >> HSave uncombined OffCoil Combine Mode Adaptive Combine
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Shim mode StandardAdjust with body coil OffConfirm freq. adjustment OffAssume Silicone Off Ref. amplitude 1H 111.000 VAdjustment Tolerance AutoAdjust volume Position R5.5 A13.6 H16.3 Orientation Transversal Rotation 90.00 deg A >> P 192 mm R >> L 176 mm F >> H 192 mm
Physio1st Signal/Mode None
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Dark blood Off- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Resp. control OffInline
Subtract OffStd-Dev-Sag OffStd-Dev-Cor OffStd-Dev-Tra OffStd-Dev-Time OffMIP-Sag OffMIP-Cor OffMIP-Tra OffMIP-Time OffSave original images On
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SequenceIntroduction OnDimension 3DElliptical scanning OffAsymmetric echo AllowedBandwidth 130 Hz/PxFlow comp. NoEcho spacing 11.2 ms
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
RF pulse type Fast
6/+
SIEMENS MAGNETOM TrioTim syngo MR B13
\\USER\People\karla\DTI_nogating\mpr_ax111TA: 6:01 PAT: Off Voxel size: 1.0×1.0×1.0 mm Rel. SNR: 1.00 SIEMENS: tfl
PropertiesPrio Recon OffVoice output beforeVoice output afterLoad to viewer OnInline movie OffAuto store images OnLoad to stamp segments OffLoad to graphic segments OffAuto open inline display OffAutoAlign Spine OffStart measurement withoutfurther preparation
On
Wait for user to start OnStart measurements single
RoutineSlab group 1 Slabs 1 Dist. factor 50 % Position R5.5 A13.6 H16.3 Orientation Transversal Phase enc. dir. R >> L Rotation 90.00 degPhase oversampling 0 %Slice oversampling 0 %Slices per slab 192FoV read 192 mmFoV phase 91.7 %Slice thickness 1.00 mmTR 2040 msTE 4.7 msAverages 1Concatenations 1Filter NoneCoil elements HEA;HEP
ContrastMagn. preparation Slice-sel. IRTI 900 msFlip angle 8 degFat suppr. Water excit. normalWater suppr. None
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Averaging mode Long termReconstruction MagnitudeMeasurements 1Multiple series Each measurement
ResolutionBase resolution 192Phase resolution 100 %Slice resolution 75 %Phase partial Fourier OffSlice partial Fourier OffFilter 1 Raw filter OffFilter 2 Distortion Corr. OffFilter 3 Prescan Normalize OffFilter 4 Normalize OffFilter 5 Elliptical filter OffTrajectory Cartesian
Interpolation Off- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
PAT mode NoneMatrix Coil Mode Triple
GeometryMulti-slice mode Single shotSeries Ascending
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SystemBody OffHEP OnHEA On
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Positioning mode REFTable position HTable position 0 mmMSMA S - C - TSagittal R >> LCoronal A >> PTransversal F >> HSave uncombined OffCoil Combine Mode Adaptive Combine
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Shim mode StandardAdjust with body coil OffConfirm freq. adjustment OffAssume Silicone Off Ref. amplitude 1H 111.000 VAdjustment Tolerance AutoAdjust volume Position R5.5 A13.6 H16.3 Orientation Transversal Rotation 90.00 deg A >> P 192 mm R >> L 176 mm F >> H 192 mm
Physio1st Signal/Mode None
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Dark blood Off- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Resp. control OffInline
Subtract OffStd-Dev-Sag OffStd-Dev-Cor OffStd-Dev-Tra OffStd-Dev-Time OffMIP-Sag OffMIP-Cor OffMIP-Tra OffMIP-Time OffSave original images On
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SequenceIntroduction OnDimension 3DElliptical scanning OffAsymmetric echo AllowedBandwidth 130 Hz/PxFlow comp. NoEcho spacing 11.2 ms
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
RF pulse type Fast
6/+
Examples of common pulse sequences
• T1, T2, PD-weighted structural scans
• Diffusion-tensor images
• Blood Oxygenation Level-Dependent (BOLD) imaging
• Fluid-Attenuated Inversion Recovery (FLAIR)
Basic MRI contrasts
T1W T2W T2* W EPIPDW
Diffusion-tensor imaging
ADC FAPrincipal
Eigenvector
Diffusion-tensor imaging
BOLD Functional MRI
Fluid-attenuated inversion recovery (FLAIR)
MS lesions, vascular burden
Other pulse sequences
• Magnetization Transfer (MT) imaging
• Arterial spin-labelling (ASL)
• Magnetic resonance angiography (MRA)
• Susceptibility-weighted imaging (SWI)
Magnetization Transfer
Degeneration of corticospinal tract in ALS
Arterial Spin Labelling: MRI of cerebral blood flow
Image slices
Label plane
Functional
BOLD fMRI
ASL/Perfusion
Spectroscopy
Cardiac
CBF in ml/100g/min
ASL Pulse Sequence
labelprepulse
excite
short delay
perfusionimageM
controlpulse
subtract
Functional
BOLD fMRI
ASL/Perfusion
Spectroscopy
Cardiac
X
Magnetic resonance angiography
Susceptibility-weighted imaging
Other advanced MR methods• Parallel imaging
• allows enhancement of SNR or reduction of scan times
• Magnetic Resonance Spectroscopy (MRS)
• proton (1H)
• phosphorus (31P)
• New contrast agents
• super-paramagnetic iron oxide compounds
The “alphabet soup” of Vendor-specific terminology
2
Vendor MRI Acronyms Siemens GE Philips Hitachi Toshiba
Sequence Type
Spin Echo SE SE SE SE SE
Gradient Echo GRE GRE Fast Field Echo (FFE) GE Field Echo
Spoiled Gradient Echo FLASH SPGR T1-FFE RF Spoiled SARGE, RSSG FastFE
Coherent Gradient Echo FISP GRASS FFE Rephased SARGE SSFP
Steady-State Free Precession PSIF SSFP T2-FFE Time-Reversed SARGE
True FISP TrueFISP FIESTA Balanced FFE Balanced SARGE, BASG True SSFP
True FISP/Dual Excitation CISS FIESTA-C – Phase Balanced SARGE, PBSG –
Double Echo Steady State DESS – – – –
Multi-Echo Data Image Combination MEDIC MERGE M-FFE – –
Ultrafast Gradient Echo TurboFLASH Fast GRE, Fast SPGR TFE RGE Fast FE
Ultrafast Gradient Echo 3D MPRAGE 3D FGRE, 3D Fast SPGR 3D TFE MPRAGE 3D Fast FE
Volume Interpolated GRE VIBE LAVA-XV THRIVE TIGRE
Body Diffusion REVEAL DWIBS Body Vision
Susceptibility-Weighted Imaging SWI (SWAN) (Venous BOLD) –
Dynamic MRA with k-space Manipulation TWIST TRICKS-XV Keyhole (4D-TRAK) –
High-Resolution Bilateral Breast Imaging VIEWS VIBRANT-XV BLISS RADIANCE
Non-contrast MR Angio, TSE-based NATIVE-SPACE – TRANCE VASC FSE FBI, CIA
Non-contrast MR Angio, TrueFISP-based NATIVE-TrueFISP Inhance Inflow IR B-TRANCE VASC ASL Time-SLIP
Parametric Mapping MapIT CartiGram – –
Inversion Recovery IR,Turbo IR (TIR) IR, MPIR, FastIR IR-TSE IR IR
Short Tau IR STIR STIR STIR STIR FastSTIR
Long Tau IR Turbo Dark Fluid FLAIR FLAIR FLAIR FastFLAIR
True IR True IR – Real IR – FastIR
Turbo Spin Echo/Fast Spin Echo TSE (Turbo Spin Echo) FSE (Fast Spin Echo) TSE (Turbo Spin Echo) FSE (Fast Spin Echo) FSE (Fast Spin Echo)
Single-Shot TSE/FSE HASTE Single-Shot FSE Single-Shot TSE Single-Shot FSE FASE
FSE/TSE with 90° Flip-Back Pulse RESTORE Fast Recovery FSE (FRFSE) DRIVE Driven Equillibrium FSE T2 Puls FSE
Hyper Echoes Hyperecho – – – –
3D TSE with Variable Flip Angle SPACE CUBE VISTA – –
Number of Echoes Turbo Factor Echo Train Length (ETL) Turbo Factor Shot Factor Echo Train Length (ETL)
Time Between Echoes Echo Spacing Echo Spacing Echo Spacing Interecho Time (ITE) Echo Spacing
Echo Planar Imaging (EPI) EPI EPI EPI EPI EPI
Number of Echoes EPI Factor ETL EPI Factor Shot Factor Echo Train Length (ETL)
Diffusion-Weighted Imaging DWI DWI DWI DWI DWI
Apparent Diffusion Coefficient Map ADC ADC ADC ADC Map ADC
Diffusion Tensor Imaging DTI Diffusion Tensor Imaging Diffusion Tensor Imaging – DTI
DTI Tractography (Fiber Tracking) DTI Tractography FiberTrak FiberTrak – –
Turbo Gradient Spin Echo (GRASE) TurboGSE, TGSE – GRASE – Hybrid EPI
Motion Correction
1D Navigators for Cardiac Imaging 1D PACE Navigators
2D Navigators for Abdominal Imaging 2D PACE – Navigators – –
3D Prospective Motion Correction for fMRI 3D PACE – – – –
3D Retrospective Motion Correction for fMRI 3D ART – –
Motion Correction with Radial Blades BLADE PROPELLER MultiVane RADAR JET
Soft Tissue Motion Correction BRACE
The “alphabet soup” of Vendor-specific terminology
2
Vendor MRI Acronyms Siemens GE Philips Hitachi Toshiba
Sequence Type
Spin Echo SE SE SE SE SE
Gradient Echo GRE GRE Fast Field Echo (FFE) GE Field Echo
Spoiled Gradient Echo FLASH SPGR T1-FFE RF Spoiled SARGE, RSSG FastFE
Coherent Gradient Echo FISP GRASS FFE Rephased SARGE SSFP
Steady-State Free Precession PSIF SSFP T2-FFE Time-Reversed SARGE
True FISP TrueFISP FIESTA Balanced FFE Balanced SARGE, BASG True SSFP
True FISP/Dual Excitation CISS FIESTA-C – Phase Balanced SARGE, PBSG –
Double Echo Steady State DESS – – – –
Multi-Echo Data Image Combination MEDIC MERGE M-FFE – –
Ultrafast Gradient Echo TurboFLASH Fast GRE, Fast SPGR TFE RGE Fast FE
Ultrafast Gradient Echo 3D MPRAGE 3D FGRE, 3D Fast SPGR 3D TFE MPRAGE 3D Fast FE
Volume Interpolated GRE VIBE LAVA-XV THRIVE TIGRE
Body Diffusion REVEAL DWIBS Body Vision
Susceptibility-Weighted Imaging SWI (SWAN) (Venous BOLD) –
Dynamic MRA with k-space Manipulation TWIST TRICKS-XV Keyhole (4D-TRAK) –
High-Resolution Bilateral Breast Imaging VIEWS VIBRANT-XV BLISS RADIANCE
Non-contrast MR Angio, TSE-based NATIVE-SPACE – TRANCE VASC FSE FBI, CIA
Non-contrast MR Angio, TrueFISP-based NATIVE-TrueFISP Inhance Inflow IR B-TRANCE VASC ASL Time-SLIP
Parametric Mapping MapIT CartiGram – –
Inversion Recovery IR,Turbo IR (TIR) IR, MPIR, FastIR IR-TSE IR IR
Short Tau IR STIR STIR STIR STIR FastSTIR
Long Tau IR Turbo Dark Fluid FLAIR FLAIR FLAIR FastFLAIR
True IR True IR – Real IR – FastIR
Turbo Spin Echo/Fast Spin Echo TSE (Turbo Spin Echo) FSE (Fast Spin Echo) TSE (Turbo Spin Echo) FSE (Fast Spin Echo) FSE (Fast Spin Echo)
Single-Shot TSE/FSE HASTE Single-Shot FSE Single-Shot TSE Single-Shot FSE FASE
FSE/TSE with 90° Flip-Back Pulse RESTORE Fast Recovery FSE (FRFSE) DRIVE Driven Equillibrium FSE T2 Puls FSE
Hyper Echoes Hyperecho – – – –
3D TSE with Variable Flip Angle SPACE CUBE VISTA – –
Number of Echoes Turbo Factor Echo Train Length (ETL) Turbo Factor Shot Factor Echo Train Length (ETL)
Time Between Echoes Echo Spacing Echo Spacing Echo Spacing Interecho Time (ITE) Echo Spacing
Echo Planar Imaging (EPI) EPI EPI EPI EPI EPI
Number of Echoes EPI Factor ETL EPI Factor Shot Factor Echo Train Length (ETL)
Diffusion-Weighted Imaging DWI DWI DWI DWI DWI
Apparent Diffusion Coefficient Map ADC ADC ADC ADC Map ADC
Diffusion Tensor Imaging DTI Diffusion Tensor Imaging Diffusion Tensor Imaging – DTI
DTI Tractography (Fiber Tracking) DTI Tractography FiberTrak FiberTrak – –
Turbo Gradient Spin Echo (GRASE) TurboGSE, TGSE – GRASE – Hybrid EPI
Motion Correction
1D Navigators for Cardiac Imaging 1D PACE Navigators
2D Navigators for Abdominal Imaging 2D PACE – Navigators – –
3D Prospective Motion Correction for fMRI 3D PACE – – – –
3D Retrospective Motion Correction for fMRI 3D ART – –
Motion Correction with Radial Blades BLADE PROPELLER MultiVane RADAR JET
Soft Tissue Motion Correction BRACE
2
Vendor MRI Acronyms Siemens GE Philips Hitachi Toshiba
Sequence Type
Spin Echo SE SE SE SE SE
Gradient Echo GRE GRE Fast Field Echo (FFE) GE Field Echo
Spoiled Gradient Echo FLASH SPGR T1-FFE RF Spoiled SARGE, RSSG FastFE
Coherent Gradient Echo FISP GRASS FFE Rephased SARGE SSFP
Steady-State Free Precession PSIF SSFP T2-FFE Time-Reversed SARGE
True FISP TrueFISP FIESTA Balanced FFE Balanced SARGE, BASG True SSFP
True FISP/Dual Excitation CISS FIESTA-C – Phase Balanced SARGE, PBSG –
Double Echo Steady State DESS – – – –
Multi-Echo Data Image Combination MEDIC MERGE M-FFE – –
Ultrafast Gradient Echo TurboFLASH Fast GRE, Fast SPGR TFE RGE Fast FE
Ultrafast Gradient Echo 3D MPRAGE 3D FGRE, 3D Fast SPGR 3D TFE MPRAGE 3D Fast FE
Volume Interpolated GRE VIBE LAVA-XV THRIVE TIGRE
Body Diffusion REVEAL DWIBS Body Vision
Susceptibility-Weighted Imaging SWI (SWAN) (Venous BOLD) –
Dynamic MRA with k-space Manipulation TWIST TRICKS-XV Keyhole (4D-TRAK) –
High-Resolution Bilateral Breast Imaging VIEWS VIBRANT-XV BLISS RADIANCE
Non-contrast MR Angio, TSE-based NATIVE-SPACE – TRANCE VASC FSE FBI, CIA
Non-contrast MR Angio, TrueFISP-based NATIVE-TrueFISP Inhance Inflow IR B-TRANCE VASC ASL Time-SLIP
Parametric Mapping MapIT CartiGram – –
Inversion Recovery IR,Turbo IR (TIR) IR, MPIR, FastIR IR-TSE IR IR
Short Tau IR STIR STIR STIR STIR FastSTIR
Long Tau IR Turbo Dark Fluid FLAIR FLAIR FLAIR FastFLAIR
True IR True IR – Real IR – FastIR
Turbo Spin Echo/Fast Spin Echo TSE (Turbo Spin Echo) FSE (Fast Spin Echo) TSE (Turbo Spin Echo) FSE (Fast Spin Echo) FSE (Fast Spin Echo)
Single-Shot TSE/FSE HASTE Single-Shot FSE Single-Shot TSE Single-Shot FSE FASE
FSE/TSE with 90° Flip-Back Pulse RESTORE Fast Recovery FSE (FRFSE) DRIVE Driven Equillibrium FSE T2 Puls FSE
Hyper Echoes Hyperecho – – – –
3D TSE with Variable Flip Angle SPACE CUBE VISTA – –
Number of Echoes Turbo Factor Echo Train Length (ETL) Turbo Factor Shot Factor Echo Train Length (ETL)
Time Between Echoes Echo Spacing Echo Spacing Echo Spacing Interecho Time (ITE) Echo Spacing
Echo Planar Imaging (EPI) EPI EPI EPI EPI EPI
Number of Echoes EPI Factor ETL EPI Factor Shot Factor Echo Train Length (ETL)
Diffusion-Weighted Imaging DWI DWI DWI DWI DWI
Apparent Diffusion Coefficient Map ADC ADC ADC ADC Map ADC
Diffusion Tensor Imaging DTI Diffusion Tensor Imaging Diffusion Tensor Imaging – DTI
DTI Tractography (Fiber Tracking) DTI Tractography FiberTrak FiberTrak – –
Turbo Gradient Spin Echo (GRASE) TurboGSE, TGSE – GRASE – Hybrid EPI
Motion Correction
1D Navigators for Cardiac Imaging 1D PACE Navigators
2D Navigators for Abdominal Imaging 2D PACE – Navigators – –
3D Prospective Motion Correction for fMRI 3D PACE – – – –
3D Retrospective Motion Correction for fMRI 3D ART – –
Motion Correction with Radial Blades BLADE PROPELLER MultiVane RADAR JET
Soft Tissue Motion Correction BRACE
Vendor MRI Acronyms Siemens GE Philips Hitachi Toshiba
Sequence Type
Spin Echo SE SE SE SE SE
Gradient Echo GRE GRE Fast Field Echo (FFE) GE Field Echo
Spoiled Gradient Echo FLASH SPGR T1-FFE RF Spoiled SARGE, RSSG FastFE
Coherent Gradient Echo FISP GRASS FFE Rephased SARGE SSFP
Steady-State Free Precession PSIF SSFP T2-FFE Time-Reversed SARGE
True FISP TrueFISP FIESTA Balanced FFE Balanced SARGE, BASG True SSFP
True FISP/Dual Excitation CISS FIESTA-C – Phase Balanced SARGE, PBSG –
Double Echo Steady State DESS – – – –
Multi-Echo Data Image Combination MEDIC MERGE M-FFE – –
Ultrafast Gradient Echo TurboFLASH Fast GRE, Fast SPGR TFE RGE Fast FE
Ultrafast Gradient Echo 3D MPRAGE 3D FGRE, 3D Fast SPGR 3D TFE MPRAGE 3D Fast FE
Volume Interpolated GRE VIBE LAVA-XV THRIVE TIGRE
Body Diffusion REVEAL DWIBS Body Vision
Susceptibility-Weighted Imaging SWI (SWAN) (Venous BOLD) –
Dynamic MRA with k-space Manipulation TWIST TRICKS-XV Keyhole (4D-TRAK) –
High-Resolution Bilateral Breast Imaging VIEWS VIBRANT-XV BLISS RADIANCE
Non-contrast MR Angio, TSE-based NATIVE-SPACE – TRANCE VASC FSE FBI, CIA
Non-contrast MR Angio, TrueFISP-based NATIVE-TrueFISP Inhance Inflow IR B-TRANCE VASC ASL Time-SLIP
Parametric Mapping MapIT CartiGram – –
Inversion Recovery IR,Turbo IR (TIR) IR, MPIR, FastIR IR-TSE IR IR
Short Tau IR STIR STIR STIR STIR FastSTIR
Long Tau IR Turbo Dark Fluid FLAIR FLAIR FLAIR FastFLAIR
True IR True IR – Real IR – FastIR
Turbo Spin Echo/Fast Spin Echo TSE (Turbo Spin Echo) FSE (Fast Spin Echo) TSE (Turbo Spin Echo) FSE (Fast Spin Echo) FSE (Fast Spin Echo)
Single-Shot TSE/FSE HASTE Single-Shot FSE Single-Shot TSE Single-Shot FSE FASE
FSE/TSE with 90° Flip-Back Pulse RESTORE Fast Recovery FSE (FRFSE) DRIVE Driven Equillibrium FSE T2 Puls FSE
Hyper Echoes Hyperecho – – – –
3D TSE with Variable Flip Angle SPACE CUBE VISTA – –
Number of Echoes Turbo Factor Echo Train Length (ETL) Turbo Factor Shot Factor Echo Train Length (ETL)
Time Between Echoes Echo Spacing Echo Spacing Echo Spacing Interecho Time (ITE) Echo Spacing
Echo Planar Imaging (EPI) EPI EPI EPI EPI EPI
Number of Echoes EPI Factor ETL EPI Factor Shot Factor Echo Train Length (ETL)
Diffusion-Weighted Imaging DWI DWI DWI DWI DWI
Apparent Diffusion Coefficient Map ADC ADC ADC ADC Map ADC
Diffusion Tensor Imaging DTI Diffusion Tensor Imaging Diffusion Tensor Imaging – DTI
DTI Tractography (Fiber Tracking) DTI Tractography FiberTrak FiberTrak – –
Turbo Gradient Spin Echo (GRASE) TurboGSE, TGSE – GRASE – Hybrid EPI
Motion Correction
1D Navigators for Cardiac Imaging 1D PACE Navigators
2D Navigators for Abdominal Imaging 2D PACE – Navigators – –
3D Prospective Motion Correction for fMRI 3D PACE – – – –
3D Retrospective Motion Correction for fMRI 3D ART – –
Motion Correction with Radial Blades BLADE PROPELLER MultiVane RADAR JET
Soft Tissue Motion Correction BRACE
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Vendor MRI AcronymsSiemens GE Philips Hitachi Toshiba
Parallel Acquisition Techniques iPAT
PAT: Image-based Algorithm mSENSE ASSET SENSE RAPID SPEEDER
PAT: k-space-based Algorithm GRAPPA ARC – – –
Integrated Calibration Auto-Calibration Self-Calibration (with ARC) – – –
Separate Calibration Turbo-Calibration (Calibration for ASSET) (Calibration for SENSE) / CLEAR (Calibration for RAPID) (Calibration for SPEEDER)
Multiple datasets calibrate each other Self-Calibration, T-PAT – – – –
Spectroscopy
Prostate Spectroscopy 3D CSI PROSE – –
Breast Spectroscopy GRACE BREASE – – –
Comprehensive Cardiac Tool BEAT (2D/3D) – – – –
Patient Orientation Sequence Localizer, Scout Localizer Plan Scan Scanogram Locator
Contrast Bolus Timing/Visualization CARE Bolus Smart Prep; FluoroTriggered MRA BolusTrak FLUTE Visual Prep
Sequence Parameters
Repetition Time, Echo Time (in msec) TR, TE TR, TE TR, TE TR, TE
Inversion Time (in msec) TI TI TI TI TI
Averages Average NEX NSA NSA NSA
Simultaneous Excitation Simultaneous Excitation POMP (Phase Offset Multiplanar) Multi-Slice Dual Slice QuadScan
RF Pulse in Gradient Echo Flip Angle Flip Angle Flip Angle Flip Angle Flip Angle
Scan Measurement Time Acquisition Time, TA Acquisition Time Acquisition Time Scan Time Acquisition Time
Distance Between Slices Distance Factor (% of slice thickness) Gap Gap Slice Interval Gap
Shifting Slices Off Center Off-center Shift Off-center FoV Off-center FoV Off-center FoV Phase & Frequency Shift
Field of View (FoV) FoV [mm] FoV [cm] FoV [mm] FoV FoV
Rectangular FoV FoV Phase/Rectangular FoV Partial FoV (PFoV) Rectangular FoV Rectangular FoV Rectangular FoV
Bandwidth Bandwidth [Hz/Px] Receive Bandwidth [kHz] Fat/Water Shift [pixel] Bandwidth Bandwidth
Variable Bandwidth Optimized bandwidth Variable Bandwidth Optimized Bandwidth Variable Bandwidth Matched Bandwidth
Frequency Oversampling Oversampling Anti-Aliasing Frequency Oversampling Frequency Oversampling Frequency Wrap Suppression
Phase Oversampling Phase Oversampling No Phase Wrap Fold-over Suppression Anti-Wrap Phase Wrap Suppression
Segmented k-Space Lines/Segments Views per segment Views/Segment Segments
Time Delay/Block k-space Time Delay Intersegment Delay TD TD
Half Fourier Imaging Half Fourier 1/2 NEX; fractional NEX Half Scan Half Scan AFI
Partial Echo Asymmetric Echo Partial Echo Partial Echo Half Echo Matched Bandwidth
Gradient Moment Nulling GMR/Flow Comp Flow Comp Flow Comp; Flag GR FC
Ramped RF Pulse TONE Ramped Pulse TONE SSP ISCE
Magnetization Transfer Contrast MTC; MTS MTC MTC MTC SORS-STC
Prep Pulse – Chemically Fat Sat Fat Sat/Chem Sat SPIR Fat Sat MSOFT
Water Excitation Water Excitation – Proset Water Excitation PASTA
Fat-Water separation DIXON IDEAL – FatSep
Prep Pulse - Spatially Presat SAT REST Pre Sat Pre Sat
Moving Sat Pulse Travel Sat; Tracking Sat Walking Sat Travel REST Sequential Pre Sat BFAST
Scan Synchronization with ECG ECG Triggered Cardiac Gated/Triggering ECG Triggered/VCG ECG Triggered Cardiac Gated
Delay after R-Wave Trigger Delay; TD Trigger Delay; TD Trigger Delay; TD Delay Time Trigger Delay; TD
Respiratory Gating Respiratory Gated Respiratory Comp Trigger; PEAR MAR Respiratory Gated
Multi-Channel RF Coil Sensitivity Normalization Prescan Normalize PURE CLEAR NATURAL –
Central k-space Filling Arterial Visualization Elliptical Scanning Elliptic Centric CENTRA PEAKS DRKS
Competition product descriptions, comparison, and specifications contained in this document are based on interpretation of available data at the time this material was being prepared and may require independent verification. Specifications have been obtained from competition brochures, websites, and other independent published sources.
4
Vendor MRI AcronymsSiemens GE Philips Hitachi Toshiba
Parallel Acquisition Techniques iPAT
PAT: Image-based Algorithm mSENSE ASSET SENSE RAPID SPEEDER
PAT: k-space-based Algorithm GRAPPA ARC – – –
Integrated Calibration Auto-Calibration Self-Calibration (with ARC) – – –
Separate Calibration Turbo-Calibration (Calibration for ASSET) (Calibration for SENSE) / CLEAR (Calibration for RAPID) (Calibration for SPEEDER)
Multiple datasets calibrate each other Self-Calibration, T-PAT – – – –
Spectroscopy
Prostate Spectroscopy 3D CSI PROSE – –
Breast Spectroscopy GRACE BREASE – – –
Comprehensive Cardiac Tool BEAT (2D/3D) – – – –
Patient Orientation Sequence Localizer, Scout Localizer Plan Scan Scanogram Locator
Contrast Bolus Timing/Visualization CARE Bolus Smart Prep; FluoroTriggered MRA BolusTrak FLUTE Visual Prep
Sequence Parameters
Repetition Time, Echo Time (in msec) TR, TE TR, TE TR, TE TR, TE
Inversion Time (in msec) TI TI TI TI TI
Averages Average NEX NSA NSA NSA
Simultaneous Excitation Simultaneous Excitation POMP (Phase Offset Multiplanar) Multi-Slice Dual Slice QuadScan
RF Pulse in Gradient Echo Flip Angle Flip Angle Flip Angle Flip Angle Flip Angle
Scan Measurement Time Acquisition Time, TA Acquisition Time Acquisition Time Scan Time Acquisition Time
Distance Between Slices Distance Factor (% of slice thickness) Gap Gap Slice Interval Gap
Shifting Slices Off Center Off-center Shift Off-center FoV Off-center FoV Off-center FoV Phase & Frequency Shift
Field of View (FoV) FoV [mm] FoV [cm] FoV [mm] FoV FoV
Rectangular FoV FoV Phase/Rectangular FoV Partial FoV (PFoV) Rectangular FoV Rectangular FoV Rectangular FoV
Bandwidth Bandwidth [Hz/Px] Receive Bandwidth [kHz] Fat/Water Shift [pixel] Bandwidth Bandwidth
Variable Bandwidth Optimized bandwidth Variable Bandwidth Optimized Bandwidth Variable Bandwidth Matched Bandwidth
Frequency Oversampling Oversampling Anti-Aliasing Frequency Oversampling Frequency Oversampling Frequency Wrap Suppression
Phase Oversampling Phase Oversampling No Phase Wrap Fold-over Suppression Anti-Wrap Phase Wrap Suppression
Segmented k-Space Lines/Segments Views per segment Views/Segment Segments
Time Delay/Block k-space Time Delay Intersegment Delay TD TD
Half Fourier Imaging Half Fourier 1/2 NEX; fractional NEX Half Scan Half Scan AFI
Partial Echo Asymmetric Echo Partial Echo Partial Echo Half Echo Matched Bandwidth
Gradient Moment Nulling GMR/Flow Comp Flow Comp Flow Comp; Flag GR FC
Ramped RF Pulse TONE Ramped Pulse TONE SSP ISCE
Magnetization Transfer Contrast MTC; MTS MTC MTC MTC SORS-STC
Prep Pulse – Chemically Fat Sat Fat Sat/Chem Sat SPIR Fat Sat MSOFT
Water Excitation Water Excitation – Proset Water Excitation PASTA
Fat-Water separation DIXON IDEAL – FatSep
Prep Pulse - Spatially Presat SAT REST Pre Sat Pre Sat
Moving Sat Pulse Travel Sat; Tracking Sat Walking Sat Travel REST Sequential Pre Sat BFAST
Scan Synchronization with ECG ECG Triggered Cardiac Gated/Triggering ECG Triggered/VCG ECG Triggered Cardiac Gated
Delay after R-Wave Trigger Delay; TD Trigger Delay; TD Trigger Delay; TD Delay Time Trigger Delay; TD
Respiratory Gating Respiratory Gated Respiratory Comp Trigger; PEAR MAR Respiratory Gated
Multi-Channel RF Coil Sensitivity Normalization Prescan Normalize PURE CLEAR NATURAL –
Central k-space Filling Arterial Visualization Elliptical Scanning Elliptic Centric CENTRA PEAKS DRKS
Competition product descriptions, comparison, and specifications contained in this document are based on interpretation of available data at the time this material was being prepared and may require independent verification. Specifications have been obtained from competition brochures, websites, and other independent published sources.
Conclusion
• MRI offers a vast array of anatomic and functional contrast mechanisms
• these are made available via an ever expanding array of pulse sequence programs that can be adapted to specific purposes by user edits to the protocol
• these techniques generate image contrast by manipulating nuclear magnetization arising mainly from water