Histopathological Differential Diagnosis of Optical Coherence Tomographic Image Interpretation After Stenting

The aim of this study was to identify histological features that correlate with terms commonly used to describe optical coherence tomographic (OCT) and optical frequency-domain imaging (OFDI) images of stented vessels, by means of a histopathological validation study using stented human coronary arteries.

OCT imaging and OFDI are used to evaluate vascular responses to stent implantation. Descriptive terms such as "peristrut low attenuation" and "heterogeneous" have been used to describe neointimal characteristics that may have clinical relevance. However, only limited histopathological correlations are available.

Using the CVPath stent registry, 19 cases were identified in whom implantation duration was >30 days and OCT imaging or OFDI and histological findings were available. Consecutive OCT or OFDI frames (n = 1,063) of stented coronary arteries were categorized according to their predominant imaging features in 1-mm intervals. Coregistration of OCT or OFDI frames and histopathological cross sections was performed in 111 frames.

Seven distinct OCT or OFDI patterns were found: homogenous (45%), layered (15%), high intensity with high attenuation (14%), intraluminal protruding masses (8%), peristrut low attenuation (7%), heterogeneous (2%), and honeycomb (1%). Histopathologically, the homogenous pattern correlated most often with smooth muscle cells within collagenous/proteoglycan matrix and less often with organized thrombus. The layered pattern correlated with healed neointimal rupture or erosion, peristrut neovascularization, or smooth muscle cells within collagen/proteoglycan matrix. High intensity with high attenuation correlated with superficial macrophage accumulation in the majority of cases, but with other histological findings in 30% of cases. The diagnostic accuracy was greater in restenotic lesions. The only OCT or OFDI finding that had a single histological feature was the honeycomb pattern.

This study suggests a lack of correlation between OCT image patterns and distinct histological tissue characteristics.