Blue Lungs in Covid-19 Patients: A Step beyond the Diagnosis of Pulmonary Thromboembolism using MDCT with Iodine Mapping

To evaluate the diagnostic capacity of pulmonary angiography with multidetector computed tomography (MDCT) and iodine mapping in the diagnosis of pulmonary thromboembolism (PTE) in patients with Covid-19 disease. Retrospective observational study of 81 consecutive patients admitted with Covid-19 respiratory infection who underwent MDCT for clinical suspicion of PTE (sudden dyspnea, chest pain, hemoptysis, severe respiratory failure (SRF) not corrected with high O flow) and/or raised D-dimer. Of the 81 patients studied [64 (79.01%) men], acute PTE was identified in 22 (27.16%), bilaterally in 13 (59.09%), and 13 (59,09%) showed areas of hypoperfusion. Of the 59 (72.83%) patients without PTE, hypoperfusion was observed in 41 (69.49%) (attributable in one case to pulmonary emphysema). In 18 (22.2%) of the total number of patients, neither PTE nor hypoperfusion were seen. A crazy paving pattern is a risk factor for developing PTE (OR 1.94; 95% CI 0.28-13.57), as are consolidations (OR 1.44; 95% CI 0.24-8.48) and septal thickening/bronchiectasis (OR 1.47; 95% CI 0.12-17.81). Patients with O -refractory SRF showed a 6.36-fold higher risk for hypoperfusion on the iodine map. By adding the functional image to the anatomical image, pulmonary angiography with MDCT and iodine mapping can demonstrate not only PTE in main, lobar and segmental arteries, but also the presence of hypoperfusion in distal vessels. This makes it a highly useful tool for the accurate diagnosis and therapeutic orientation of patients with Covid-19 lung involvement.