Assessment of Left Ventricular Thrombus Using Cardiac Computed Tomography

Abstract

Left ventricular thrombus (LVT) can be missed on transthoracic echocardiogram and although cardiac magnetic resonance imaging (cMRI) is the gold standard of assessment, access to cMRI is limited. Cardiac computed tomography (CCT) has been suggested as an alternative. This study prospectively investigated the optimal CT acquisition time to assess for the presence of LVT. Patients admitted to Auckland City Hospital, New Zealand, found to have LVT and no contraindication to CCT were recruited. The CCTs were performed timed at peak contrast enhancement arterial-phase (CTA), 60–70 seconds delay venous-phase (CTV), and delay multi-energy CT (CTD). The study was supported by the Greenlane Cardiovascular Fund. Eleven patients were recruited over a 30-month period. The mean age was 50±13 years and 73% were male. An LVT was confirmed on CCT in 10 patients (91%). One patient with LVT on TTE did not have LVT on CCT and cMRI. Transthoracic echocardiography (TTE) failed to detect 18% of LVT. Amongst the three CT protocols, LVT was best detected on CTV when the thrombus and adjacent myocardium demonstrated good tissue differentiation, allowing for improved thrombus detection. Although CTD was able to detect the presence of an LVT, there was a reduction in image quality. Resolution of LVT was seen in 78% of patients at 3 months and all LVT had resolved by 6 months. The mean radiation dose for CTA was 2.6±2.4 mSv, 1.5±0.9 mSv for CTV, and 3.6±1.8 mSv for CTD. There was improved tissue separation between the adjacent myocardium and LVT and thereby improved LVT detection using venous-phase CT (CTV).