Lung and Kidney Perfusion Deficits Diagnosed by Dual-Energy Computed Tomography in COVID–19 Patients: Evidence Supporting Systemic Microangiopathy

Abstract

Objectives: There is increasing evidence of thrombotic events occurring in patients with coronavirus disease (COVID-19). We evaluated dual-energy computed tomography (DECT) findings, particularly lung and kidney perfusion, in non-intubated COVID-19 patients. Methods: Thirty-one COVID-19 patients who underwent pulmonary DECT angiography between March 15 and April 30, 2020, and were suspected of having pulmonary thromboembolism were included. Pulmonary and kidney images were reviewed. Qualitative and quantitative analyses of the perfused blood volume and iodine maps were performed. Results: DECT images showed perfusion deficits (PDs) in eight patients (25.8%), which were not overlapping with areas of ground-glass opacity or consolidation. Two patients had pulmonary thromboembolism confirmed by CT angiography. Five of 10 patients who had been infected for more than 5 days had PDs documented. Patients with PDs had a longer hospital stay (12.25 ± 8.81 vs 6.83 ± 5.04 days, p= 0.14), higher intensive care unit admission rates (37.5% vs 4.3%, p=0.02), higher CT scores (13.3 ± 8.2 vs 5 ± 5.4, p= 0.02) and more severe disease (50% vs 4.3%, p=0.01). In the PD group, serum ferritin, aspartate aminotransferase (AST), fibrinogen, D-dimer, C-reactive protein (CRP), and troponin levels were significantly higher, whereas albumin level was lower (p<0.05). D-dimer levels ≥ 0.485 ug/L predicted PD with 100% specificity and 87% sensitivity (AUROC: 0.957). Renal iodine maps showed heterogeneous enhancement consistent with perfusion abnormality in 13 patients (50%). Sodium levels were significantly lower in this group (p=0.03). Conclusions: Pulmonary perfusion abnormalities in COVID 19 patients is associated with more severe disease and in most of the patients can occur without macroscopic pulmonary thromboembolism. High rate of kidney perfusion abnormalities suggests subclinical systemic microvascular obstruction.