ABSTRACT
Background: Patients suffering from Post-Acute Sequelae of SARS CoV-2 (PASC) infection may benefit from a pulmonary rehabilitation program (PRP). However, patients respond differently to the protocols. Treatment selection based on sensitive endpoints remains arbitrary. Can quantitative CT play a role in providing a safe, effective PRP? Methods: Two patients admitted for PRP were tested. A low dose quantitative CT scan was taken. Functional respiratory imaging (FRI) was performed on the scans. FRI, Lung function and blood vessel analysis were used for clinical decision making in treatment protocol. Result(s): At visit 1, patient 1 showed a significant decrease in small blood vessel volume and increased volume for the larger vessels (fig 1). This vascular redistribution resulted in cardiac disturbances. Therefore, patient 1 was treated with corticosteroids. Patient 2 showed no deviations on the proportion of blood volume in vessels with a cross-sectional area between 1.25 and 5mm2 (BV5%) and enrolled in the PRP. Patients were re-evaluated after 3 months. Patient 1 improved significantly, recovered, and showed normalized results in BV5%. In Patient 2 V02max changed from 1728 to 2738 ml/min from 52% to 84% predicted. Conclusion(s): Vascular density endpoints as BV5% can be considered as identifier for selection of patient for a PRP in long-COVID, and potentially other pathologies. Once normalized, patients can safely enroll in a PRP.