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Since the start of the epidemic linked to infection with SARS-COV-2, involvement of the pulmonary vascular system has been demonstrated in severe forms of the disease. In this pilot study published in the European Respiratory Journal involvement of the micro-vessels of the lungs was demonstrated by imaging techniques. Two patterns of pulmonary microvascular involvement were found. In the early clinical phase of Covid-19 pneumonia i.e. during the first week since the onset of symptoms, the predominant parenchymal lesions were diffuse bilateral ground glass opacities and were associated with increased lung perfusion in the corresponding lobes on DECT, together with decreased ventilation secondary to viral pneumonia, along with normal or increased perfusion which might be due to the loss of the physiological hypoxic vasoconstriction provoked by inflammatory cytokines. During the late phase of the disease, occuring after two weeks, the predominant parenchymal lesions were bilateral alveolar consolidations combined with decreased lung perfusion in the affected lobes, probably due to the endothelial dysfunction and the release of prothrombotic cytokines, often referred to as « the cytokine storm », and to the formation of microthrombi. The proposed hypothesis involves severe endothelial injury, diffuse vascular thrombosis and new vessel growth through intussusceptive angiogenesis in Covid-19 pneumonia.