Courtesy of Department of Radiology, Haaglanden Medical Centre (The Hague, the Netherlands), this image shows chest CT findings from a patient in the early phase of COVID-19, in selected slices (A, D), with perfusion index (B, E) and pulmonary arterial flow (C, F) in corresponding slices. Multiple bilateral perfusion deficits are visible due to microvascular obstruction, with increased blood flow in or adjacent to areas of ground glass opacities.

Recent observations suggest that respiratory failure in COVID-19 is not driven by the development of the acute respiratory distress syndrome (ARDS) alone, but that microvascular thrombotic processes may play a role. As summarised by Prof Edwin van Beek, “COVID-19 is more than a lung infection. It affects the vasculature of the lungs and other organs and has a high thrombosis risk with acute life-threatening events that require adequate treatment with anticoagulants based on laboratory monitoring with appropriate imaging tests as required.”

 

The image below presents a schematic representation of disease progression in COVID-19, based on the results of the Wuhan population. Development of thrombo-inflammation is present in the early phase of COVID-19 in both survivors and non-survivors of the disease, however increasing plasma levels of D-dimer (a degradation product of cross-linked fibrin that reflects blood clot formation) is strongly associated with poor prognosis. CT pulmonary angiography is a recommended imaging investigation for patients with suspected COVID-19 as well as a high clinical suspicion for pulmonary embolism if the D-dimer level is elevated.

 

The images are taken from a recent special report published in Radiology, produced by a group of radiology and vascular medicine experts commissioned by the National Institute for Public Health of the Netherlands to provide guidance for the imaging workup and treatment of thrombotic complications in patients with COVID-19:

Oudkerk M, Büller HR, Kuijpers D, van Es N, …, van Beek EJ. Diagnosis, Prevention, and Treatment of Thromboembolic Complications in COVID-19: Report of the National Institute for Public Health of the Netherlands. Radiology 2020.