HIGHLY AUTOMATED ANALYSIS AND VISUALIZATION OF CORONARY ALLOGRAFT VASCULOPATHY PROGRESSION IN HEART-TRANSPLANT FACILITATES LONGITUDINAL STUDIES OF CAV PROGRESSION: A SERIAL OCT IMAGING STUDY

Quantitative assessment of intimal thickness changes in months and years after heart transplantation (HTx) is the only objective indicator of vascular wall changes that may lead to Coronary Allograft Vasculopathy (CAV), a frequent complication of HTx. We have developed a method for segmenting the intimal layer in registered baseline and follow-up OCT pullback datasets to yield complete location-specific maps of intimal thickness (IT) progression over time. The resulting analyses of intimal thickness and associated progression maps are needed for objective patient-specific analysis of CAV development risk.

In each 3D pullback (baseline, follow-up), lumen surface, intimal and media layers are identified by automated multi-surface graph-based optimization, approved by expert observer, and adjusted if needed using our Just-Enough-Interaction (JEI) approach. Intimal and medial layer thicknesses are determined for each image frame and each circumferential location of the 3D pullback. After expert-guided highly automated 3D registration (both axial location and orientation), layer thickness values are compared at each wall location and layer thickness changes computed in a location-specific manner.

49 baseline (1 month post HTx) and follow-up (12 month) OCT pullback pairs from 49 HTx patients (407±70 overlapped image frames each, 19,938 frames total) were segmented and mutually registered. IT progression was determined and visualized as open-artery maps. The chart below gives patient-specific IT changes in the analyzed cohort, showing that the average IT thickening ranged from -0.01 to +0.16 mm. Furthermore, two IT progression maps are given, one for a patient with virtually no IT progression, the other exhibiting noticeable IT progression.

The presented approach facilitates precision-medicine management of HTx patients.