Early Triage of Cardioembolic Sources Using Chest Spectral Computed Tomography in Acute Ischemic Stroke

Abstract

Objectives: The present study investigated the potential usefulness of delayed-phase, low-dose, non-gated, chest spectral CT scans (DSCT) for the early triage of cardioembolic (CE) sources in patients admitted with acute ischemic stroke (AIS), and for the simultaneous detection of myocardial disease and thrombotic complications. Material and methods: Since July 2020 and promoted by the COVID-19 pandemic, we implemented the use of DSCT after cerebrovascular CT angiography (CTA) among patients with AIS using a dual-layer spectral CT. We explored the presence of CE sources, as well as late myocardium iodine enhancement (LIE) and pulmonary thromboembolism. Among patients further undergoing transesophageal echocardiogram (TEE) or cardiac CTA, we explored the diagnostic performance. Results: Fifty consecutive patients with AIS who underwent DSCT after cerebrovascular CTA comprised the patient population. The confidence degree for excluding cardiac thrombi was significantly higher than for LIE (4.4±0.8 vs. 3.4±1.3, p<0.0001). DSCT identified a CE source in 4 (8%) and LIE in 24 (48%) patients. The iodine ratio of CE sources was significantly lower compared to the left atrial appendage of patients with no CE sources (0.25±0.1 mg/mL vs. 0.91±0.2 mg/mL, p<0.0001). TEE/cardiac CT, performed in 20 (40%) patients, identified a CE source in 5 (25%) cases, whereas DSCT identified 4 (20%), leading to a sensitivity and specificity of 80% (95% CI 28–99%) and 100% (95% CI 78–100%) respectively (kappa 0.86). Conclusions: In this pilot study, we identified DSCT as a potential unsophisticated approach for the early triage of CE sources among patients with AIS undergoing CTA upon admission.