Comparison Between Computerised Lung SPECT-CT and Noncontrast Thoracic HRCT for Quantitative Analysis of Post-Acute COVID-19 Pulmonary Vascular Pruning

We read with great interest the study recently published in the European Respiratory Journal from Claudia Ravaglia et al . entitled “Clinical, radiological and pathological findings in patients with persistent lung disease following SARS-CoV-2 infection” [1]. As this study and other point out, lung endothelium [2], from proximal to distal parts, is a well-known target of SARS-CoV-2 virus during the acute phase of the infection [3] and leads to a persisting vascular remodeling [1, 4]. Exploring lung vascular remodeling in post-acute COVID-19 patients using noninvasive tools is one of the post epidemic challenges that physicians have to face. Contrast CT scan and lung perfusion 99mTc-MAA scintigraphy (SPECT-CT) are routine tools used to explore the lung vascular compartment, and are primarily used to rule out chronic or distal pulmonary embolism in suspected pulmonary hypertension [5]. However, the large number of patients infected, the need to inject either a contrast agent or a radionuclide and the cost of these exams, limit their application to investigate post-acute COVID-19 lung vascular remodeling. Recently, we have developed computerized image processing from routine high-resolution non-contrast computed tomography (HRCT-scan) for the identification and characterization of vascular pruning via small branch pruning of pulmonary arteries under various conditions [6]. Therefore, we question whether such a computational analysis on a routinely performed HRCT-scan would allow the study of a possible vascular remodeling after COVID-19 infection. In this preliminary study, we established a method for computerizing SPECT-CT to obtain quantitative data and compared them with those obtained from HRCT-scan in the same patients. Footnotes This manuscript has recently been accepted for publication in the ERJ Open Research . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article. Conflict of interest: This study was funded by Fondation du Souffle (COVID2021) and ANR Silicovilung (ANR-20-COV4-0004). The authors have no personal conflict of interest to disclose.