Optical frequency domain imaging (OFDI) can delineate calcified plaque whereas intravascular ultrasound has limited visualization of depth of calcification. The aim of this study was to evaluate the ability of OFDI to quantify and qualify calcification using ex-vivo imaging with autopsy cases.

Eighty nine coronary segments from 11 cadavers received ex-vivo imaging by OFDI. Thirty four matched segments had calcified plaques where the comparison between OFDI images and histology had performed. The thickness of calcification was measured both in OFDI and histology. Additionally, the existence of lipid components (lipid pool or necrotic core) behind or adjacent to calcification were recorded by histological examinations.

There was a good correlation in the thickness of calcification between OFDI and histology (R-square=0.61, p<0.0001), however, this was not true when the lipid components exist behind or adjacent to calcification (R¬-square=0.083953, p=0.4495). The calcification with clear border in outer layer had significantly less lipid components as compared to those with attenuation (35% vs 88%, p<0.0001).

OFDI has a potential ability to detect and characterize coronary arterial calcification, however the extent of calcification could be underestimated when the lipid components exists adjacent to calcification.