Abstract 212: Cardiac CT Imaging in Embolic Stroke of Undetermined Source (ESUS)

Background Up to 40% of ischemic strokes meet the definition of embolic stroke of undetermined source (ESUS). Although transthoracic echocardiography (TTE) is the conventional method for detecting cardiac structural abnormalities, Cardiac CT Angiography (CCTA) is emerging as a valuable non‐invasive alternative for evaluating intra‐cardiac thrombi, particularly in high‐risk patients. Methods A 42‐year‐old right‐handed male with a history of ischemic strokes, including a left ventricular (LV) thrombus previously managed with warfarin, coronary artery disease, and systolic congestive heart failure (EF 24‐30%), presented to the emergency department with acute aphasia, right facial paralysis, and right hemiparesis. His NIHSS score was 6, with a baseline mRS of 1. Non‐contrast CT of the head (NCCTH) showed multiple chronic strokes in the left frontal and parietal lobes, right frontal and parietal‐occipital regions, left pontine and midbrain areas, and bilateral thalami/internal capsules, as well as probable chronic lacunar infarcts. CTA revealed occlusion of the superior branch of the left M2 MCA and right V1‐V2 segments. CT perfusion (CTP) demonstrated a 39 cc penumbra and 5 cc core in the left MCA territory. Due to concerns about acute‐on‐chronic ischemic strokes with left M2 occlusion and a high risk of hemorrhagic transformation, thrombectomy was not performed. Brain MRI showed acute embolic strokes in the left frontal lobe, insular cortex, and right thalamus. TTE indicated severe left ventricular hypokinesia with an EF of 24% and a markedly dilated left atrium, but no shunt or intra‐cardiac thrombus was detected. Telemetry showed no arrhythmias. Given the suspicion of a cardioembolic source in this young patient with low ejection fraction heart failure, a CCTA was performed, revealing three LV thrombi (measuring 1.3 times 1.1 cm, 0.9 times 0.9 cm, and 0.7 times 0.7 cm) against the distal and apical lateral walls. The patient was subsequently started on Apixaban for LV thrombus treatment and secondary stroke prevention. Conclusion Although earlier retrospective studies have emphasized the value of CCTA in evaluating embolic strokes, the latest AHA guidelines still fall short in providing comprehensive diagnostic recommendations for ESUS. This case highlights the critical role of CCTA in identifying intra‐cardiac thrombi among high‐risk patients with cardioembolic strokes and concurrent heart failure.