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Most clinical cardiac events due toatherosclerosis occur suddenly (e.g.AMI, UAP).Typically caused by a disrupted or

ruptured atherosclerotic plaque withoverlying thrombus.Neither fluoro x-ray nor IVUS can

identify the features of coronaryplaques that are vulnerable to rupturefrom more stable plaques.Evolution of therapeutic modalities

has increased the need to identifyvulnerable plaque.

DF Kacher, E Larose , M Aikawa ,E Rabkin *, S Kinlay , P Ganz , AP Selwyn ,

P Libby , EK Yucel

Brigham and Womens Hospital Dept. of Radiology * Dept. of Pathology

Div. Cardiovascular Medicine, Dept. of Medicine

Pitfalls of PlaqueIdentification Chemical Shift

Vessel wall motionCoil susceptibilityPartial Voluming

In-vivo IV MR Imaging ofHuman Atherosclerosis

REFERENCES Black et al.,.Neurosurgery,

41:831-842, 1997 (1998).Ferrant M. et.al.,. IEEE

Transactions on MedicalImaging, 20:1384-1397(2001).

A. Balakrishnan et al. Proc.ASME (2003).

Miller, K. et al.,. J Biomech,33:1369-1376 (2000).

ACKNOWLEDGEMENTS:

NAC grant RR013218-06.

Correlation Between IV MRI and Histology

Force

MRI offers contrast of structureswithin the vessel.SNR of MRI surface coils and volume

coils is limited for deep vessels.IV MRI coils are better volume

matched to the sample and can thusachieve higher SNR.Loopless coil is a flexible, scalable

design that can eventually fit into the

coronary arteries, unlike other IV coildesigns that offer higher SNR.

Proximal Shaft

Overall length (100 cm)

Imaging coil anddistal spring (9cm)

Silicon coating

Matching and isolationcircuit attachment site

a

IV Coil

Loopless antenna (Surgi-Vision)Outer diameter 0.032 FDA approved

1.5T CV/i scanner (GEMS)

1. Correlate ex-vivo IV MR imagingof human atherosclerosis withmatched histopathologic sections.2. Show feasibility for in-vivo IV MR

imaging in rabbit model of aorticatherosclerosis.3. Show feasibility and safety for in-

vivoIV MR imaging of human iliac andaorta atherosclerosis, before

proceeding to coronary arteries.4. Demonstrate difficulties of plaque

identification and imaging techniques.

Oil-red-O(lipid)

Picosirius(collagen)

Surfacecoil

.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.5 1 1.5

Sensitivity SpecificityMRI score 1.4

(Fibrous)83% 81%

1.4>MRI score0.5

(Lipid)73% 85%

MRI score