Usefulness of superb microvascular imaging for differential diagnosis of malignant cardiac tumours: a case series

Superb microvascular imaging (SMI) can visualize low-velocity blood flow vividly without contrast agents. Superb microvascular imaging could be used to evaluate blood flow in the myocardium or cardiac tumours, which have never been assessed using a conventional echocardiographic probe. Evaluating intratumoural blood flow using SMI may provide supportive haemodynamic characterization for the differential diagnosis of cardiac tumours.

This report describes three cases in which SMI was useful for detecting intratumoural blood flow signals and differential diagnosis of cardiac tumours. Intratumoural blood flow signals were detected in Case 1 (pulmonary artery intimal sarcoma) but not in Case 2 (malignant lymphoma). The patient described in Case 3 had a large intracardiac tumour and was too old and frail to undergo surgery; therefore, based on the SMI findings of abundant intratumoural blood flow signals, cardiac sarcoma was presumed, and best supportive care was selected without performing invasive tests or treatment.

Rapid differential diagnosis between cardiac sarcoma and malignant lymphoma is important for determining the treatment strategy. Cardiac sarcoma has a poor prognosis and progresses rapidly, whereas cardiac malignant lymphoma can potentially be cured by chemotherapy. Intratumoural blood flow is abundant in patients with cardiac sarcoma but poor in those with malignant lymphoma. Superb microvascular imaging can assist whether blood flow is abundant or poor in a cardiac tumour. Evaluation of intratumoural blood flow using SMI provides supportive haemodynamic characterization for the differential diagnosis of cardiac tumours and may shorten the time to treatment.