CEUS of the Lung Reveals Multiple Areas of Microthrombi in a COVID-19 Patient

A case of a 61-year-old woman (see Fig.  1) with severe COVID-19 and a negative CTPA study. We were able show that these areas of irregularity, labelled as subpleural consolidation by Peng et  al. were avascular and therefore most likely to represent 3–5 mm microinfarcts. Conversely, non-thrombotic consolidation would be seen to have some enhancement; a process not appreciated using other imaging modalities due to the superior spatial resolution of ultrasound. Anecdotally, we have also seen these areas resolve with clinical improvement. It is becoming apparent that severe cases of COVID-19 are characterised by hyperinfammation and a thrombotic phenomenon.

The theory of an underlying thrombotic process also corresponds with studies identifying admission D-dimer, prothrombin time and thrombocytopenia as prognostic markers [3]. Immuno-thrombosis is used to describe the interaction between platelets, coagulation factors and innate immune effector systems that, during an infection, results in secondary thrombus formation. This is not the first time CEUS has been used to evaluate the presence of emboli. Trenker et  al. found that, despite the lack of definite confirmation of PE on CT, peripheral subpleural consolidations with no or inhomogenous enhancement on CEUS to be highly suggestive of embolic consolidations [4].

A follow-up study by the same team used histological examination of six cases, and pulmonary infarction was found in all of them [5].