Quantitative CT monitoring of extracorporeal photopheresis response in chronic lung allograft dysfunction: A retrospective case series.

Purpose: To explore the feasibility and preliminary behavior of the Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) tool in detecting radiologic differences in lung parenchyma of lung transplant recipients undergoing extracorporeal photopheresis (ECP) for chronic lung allograft dysfunction (CLAD). Methods: We performed a retrospective case review on a series of adult lung transplant recipients at Mayo Clinic who had a baseline CT following transplant, underwent ECP for CLAD, and had follow-up CT imaging. Our primary outcome was temporal change in lung parenchymal morphology exemplars assessed by CALIPER. Secondary outcomes included changes in distribution of vascular-related structures, calculated lung volumes, and spirometric indices. Data was analyzed using a linear mixed effects model. Findings: Of 91 eligible recipients with CLAD, 15 were treated with ECP. Following ECP we observed an increase in normal lung tissue (p = 0.038) and a decrease in interstitial lung abnormalities (p = 0.003). There was no significant difference in hyperlucent areas, distribution of pulmonary vascular-related structures, or calculated lung volumes. There was a slight increase in FVC (p < 0.001) after initiation of ECP, but no significant change in FEV Conclusions: Initiation of ECP was associated with favorable parenchymal changes as calculated by CALIPER in this sample of patients.