Lung perfusion assessment in Long-COVID children: a pilot study

ABSTRACT

Aim/Introduction: There is growing interest in the clinical management of children with persisting and debilitating symptoms after Sars-COV-2 infection (Long-COVID). Chronic effects could arise from residual clot burden and small vessel inflammation, both expressing endothelial damage that may lead to lung perfusion impairment. 99mTc-macroaggregated albumin (MAA) SPECT/ CT is a well-established tool to detect lung perfusion defects, even at the small-vessels level. This pilot study aimed at assessing lung perfusion in Long-COVID children with MAA SPECT/CT and at comparing functional patterns with clinical scenarios during acute infection and follow-up. Material(s) and Method(s) Clinical and biochemical data were collected during acute infection and follow-up in 10 children (6 males and 4 females, mean age 13.6 years) fulfilling Long-COVID diagnostic criteria and complaining of chronic fatigue and post-exertional malaise after mild efforts. All patients underwent a cardiopulmonary test and MAA SPECT/CT scan. Dose activities were properly chosen according to the EANM guidelines for lung scintigraphy in children. Intravenous injections were administered to patients in the supine position immediately before the planar scan, which was followed by the lung SPECT/CT acquisition. Reconstructed studies were visually analyzed. Imaging results were compared with clinical scenarios during acute infection and follow-up. Result(s) The severity of acute disease was mild and moderate in 6/10 (60 %) and 2/10 (20 %) children, respectively;there were no significant symptoms in the remaining 2 cases. Persisting symptoms after the acute phase were observed in 7/10 (70%) patients. Five out of 10 (50.0%) children showed perfusion defects on MAA SPECT/CT scan, without morphological alterations on co-registered CT. In particular, 4/5 (80%) children with lung perfusion abnormalities were previously affected by a mild acute infection, whereas a single child (20%) was asymptomatic. However, during the follow-up, persisting symptoms (e.g., headache and dyspnea after the cardiopulmonary test) were detected in 5/5 (100%) patients. Conversely, among the five children without lung perfusion defects, only 2 (40%) showed persisting symptoms (in particular, headache), while 3 (60%) children had dyspnea after the cardiopulmonary test. Conclusion(s) This pilot study showed lung perfusion defects in Long-COVID children. Despite the small patient sample, perfusion abnormalities on MAA SPECT/CT seem to occur more frequently in children with persisting symptoms following the acute infection and dyspnea after the cardiopulmonary test. Larger cohort studies are needed to confirm these preliminary results, providing a better selection among children who can benefit the most from MAA SPECT/CT imaging.