Potential of optical frequency domain imaging for differentiation between early and advanced coronary atherosclerosis

Abstract

Purpose: This study evaluated whether optical frequency domain imaging (OFDI) accurately distinguish between fibroatheroma (FA) and pathological intimal thickening (PIT) compared with histopathology.

Methods: A total of 631 histological cross-sections from 14 autopsy hearts were analyzed for the comparison between OFDI and histological images. Of those, 190 (30%) sections were diagnosed with PIT and 120 (19%) with FA. The OFDI signal attenuation rate was calculated from an exponential. The lipid length was measured longitudinally by detection of sequential OFDI frames within a plaque segment containing lipids. The lipid arc was measured with a protractor centered in the center of the lumen. The fibrous cap thickness was defined as the minimum thickness of the signal rich band overlying PIT and FA.

Results: There was no significant difference in the OFDI signal attenuation rate between FA and PIT (3.09 ± 1.04 versus 2.79 ± 1.20, p = 0.13). However, the lipid length was significantly longer, the maximum lipid arc was significantly larger, and the fibrous cap thickness was significantly thinner in FA than in PIT (7.5 [4.3-10.3] mm versus 4.3 [2.7-5.8] mm, p < 0.0001, 125 [101-174]° versus 96 [74-131]°, p < 0.0001, and 220 [167-280] µm versus 260 [190-332] µm, p = 0.019).

Conclusions: This study revealed OFDI may have the potential capability for discriminating FA from PIT based on the longitudinal and circumferential extent of lipid plaque, although the OFDI signal attenuation rate was similar between FA and PIT.

Keywords: Atherosclerosis; Coronary artery disease; Histopathology; Optical coherence tomography.