Optical Coherence Tomography: Optical Biopsy with a Short

Photonic Needle?

I.K. Jang, MDMassachusetts General Hospital

Harvard Medical School

The 3rd Vulnerable Plaque SymposiumAtlanta, March 16, 2002

Optical Coherence Tomography

• Optical analog of ultrasound

• Cross-sectional imaging

• 10 µm resolution

• 2 mm penetration depth

Low signal High signal

MGH OCT System Technical Data

Optical wavelength :

Image acquisition rate :

Catheter:

Axial Resolution :

Transverse Resolution :

Data storage :

1300 nm

4-8 images / sec

3.0 F

10 m

25 m

Digital

Ex Vivo StudyAim

Establish OCT criteria for plaque characterization

Materials and Methods• 357 arterial segments from 90 cadavers

– 78 Coronary; 86 Carotid; 143 Aorta• training set, n=50

validation set, n = 307

• Specimen registration• OCT imaging• Histology processing• Correlation of OCT with histology

Ex Vivo Study

Type NumberFibrous 11 (22%)Calcific 27 (54%)Lipid pool 12 (24%)

Type NumberFibrous 67 (22%)Calcific 167 (54%)

Lipid pool 73 (24%)

Validation Set (n = 307)Training Set (n = 50)

Histologic Diagnoses

OCT Characteristics

lp

lp

Homogeneous,Signal-rich

Fibrous Lipid

Echolucent, Diffuse Borders

Echolucent, Sharp Borders

Calcific500 µm

Intimal Hyperplasia

Low signal High signal

Fibrous Plaque

F

IMA

F

EELIEL

lp

n

lp

Lipid-Rich Plaque(with neovascularization)

Calcific Plaque

C C

Ex Vivo Study Results

SENS .87 PPV .88SPEC .97 NPV .96

SENS .95 PPV 1.0SPEC 1.0 NPV .95

SENS .92 PPV .81SPEC .94 NPV .97

Accuracy Statistics

Fibrous

Calcific

Lipid pool

Interobserver = 0.88, Intraobserver = 0.91

Clinical Study 1

Feasibility and Safety:Pre and Post PCI

Pilot Human Study

Aim: Test feasibility and safety of OCT in patients

Methods• 10 patients (average age 59, 8M/2F)• Coronary angiogrpahy• IVUS + OCT imaging (3.2 F catheter)• PCI• Repeat IVUS + OCT Imaging

Fibrous Plaque

Fibrous Plaque

Lipid-rich Plaque

Lipid Rich Plaque

g

lplp

f

g

2x

ma

i

iel eel

f

OCT IVUS

Fibrous Plaque with Calcium

Fibrous Plaque with Calcium

Post balloon Dissection

Cutting balloon

Stent

Stent

Stent

Pilot Human Study Results No OCT related complications

Variety of pathology imaged and compared with IVUS• 10 patients with 28 plaque segments• 8 dissections• 13 stent locations

Problems• Obstruction by blood• Motion artifacts

Acknowledgements

Massachusetts General HospitalCardiology DivisionH. Yabushita, B. MacNeill, H. Lowe, M. Hayashi, S. Clarke, E. Pomerantsev, D. DeJoseph, I.K. Jang

Wellman Laboratories of Photomedicine B.E. Bouma, M. Shishkov, C. Kauffman, N. Iftima, G.J. Tearney

Dept. of PathologyS. Houser, H.T. Aretz

CIMITJ. Muller, T. Brady, J. Rosen

Guidant CorporationD. Kilpatrick, J. Ellis, R. Jones, T. Linnemeier