MicroCT reveals vulnerable plaque characteristics

For the first time, researchers have used high-resolution microCT to identify microcalcific components of coronary artery vulnerable plaques. Although the technique could help stratify high-risk patients, clinical utility will have to wait until further advances are made in conventional CT image resolution.

Dr. P. Cherukuri and colleagues at the University of Texas Health Science Center in Houston examined specimens of left anterior descending coronary arteries obtained from autopsy of individuals with coronary artery disease. They presented their findings in a poster at the 2004 Transcatheter Cardiovascular Therapeutics conference.

The researchers imaged the arterial specimens ex vivo with a GE RS-9 microCT system (80 kV, 450 µA, 27-µm isometric voxel size). Specimens were decalcified, transversely sectioned every 80 to 90 µm, and stained for histologic correlation.

They found significant correlation between microCT and histology, in particular the distribution of microcalcifications within lipid-rich plaques.

Fibrocalcific plaques were shown to be homogeneous in composition, with a dense focus of calcification. Lipid-rich plaques, however, were variably heterogeneous with ordered distributions of microcalcifications predominantly located deep and lateral to the lipid core.

Histology of these lipid-rich plaques revealed clusters of microcalcifications, many as small as 10 µm in diameter, deep within the arterial wall and peripheral to the lipid core. These microcalcifications were positively identified with the microCT, and the images strongly indicate that the individual deposits are closely spaced.

"Given the abundance of clinical data suggesting that microcalcific lipid-rich plaques are more prone to rupture rather than fibrocalcific plaques, it is highly desirable to characterize the aforementioned plaques to diagnose high-risk patients," the study said.

For more information from the Diagnostic Imaging archives:

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