To assess the clinical utility of incorporating left atrial appendage (LAA) assessment into the CT stroke protocol for thrombus detection.

Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) are frequently used in stroke patients to identify cardiac sources of embolism. TTE is non-invasive but less sensitive for detecting LAA thrombus, while TEE is more sensitive but invasive and requires sedation. This study evaluated whether expanding the standard CT stroke protocol to include LAA assessment could provide helpful information regarding LAA thrombus detection.

616 patients who underwent the updated CT stroke protocol from March 2018 to March 2020 were reviewed. CT scans were reassessed by cardiothoracic radiologists for LAA thrombus. Additional data regarding other imaging performed, comorbidities, and stroke etiology were collected. Patients with confirmed stroke were divided into LAA thrombus (n=10) and no LAA thrombus (n=332) cohorts based on CT findings.

Of 418 acute stroke cases, 342 had scans with adequate opacification for LAA evaluation. CT identified LAA thrombus in 10 patients, 7 of whom also had a TTE performed, all of which were negative for thrombus. In the no LAA thrombus cohort, most echocardiographic studies were negative, with 99.62% of TTEs (265/266) and 94.44% of TEEs (17/18) showing no evidence of thrombus. 2 patients had positive echocardiographic findings despite negative LAA CT results.

Although technically feasible, expanding the CT stroke protocol window to include LAA assessment did not demonstrate a meaningful diagnostic advantage over existing echocardiographic evaluation. The extended field of view increased scan time, radiation exposure, and image review complexity without improving the detection of clinically relevant thrombus. These findings suggest that incorporating routine LAA assessment into standard CT stroke protocols may offer limited value and should not replace established echocardiographic approaches at this time. Future studies are warranted to assess its diagnostic and clinical utility further.