Thrombus in the left atrial appendage in stroke patients: detection with cardiac CT angiography--a preliminary report.

PURPOSE: To assess the diagnostic performance of 64-section cardiac computed tomographic (CT) angiography for detection of left atrial appendage (LAA) thrombi in stroke patients by using transesophageal echocardiography (TEE) as the reference standard.
MATERIALS AND METHODS: This study was approved by the institutional review board. Records were reviewed from 101 consecutive patients who had experienced a recent stroke (onset within the previous 1 month) from a suspected cardioembolic source and who had undergone both 64-section cardiac CT angiography and TEE within 1 week. The numbers of thrombi in the LAA detected with cardiac CT angiography and with TEE were recorded, and the agreement between thrombus detection with CT and with TEE was assessed by using kappa statistics.
RESULTS: Eight thrombi in the LAA were detected with TEE, and 12 were detected with cardiac CT angiography. With TEE used as the reference standard, the overall sensitivity, specificity, and accuracy of 64-section cardiac CT angiography for detecting thrombi were 100% (95% confidence interval [CI]): 63%, 100%), 95% (95% CI: 90%, 99%), and 96% (95% CI: 92%, 100%), respectively. The concordance between LAA thrombus detection with 64-section cardiac CT angiography and with TEE was high: 89 patients with no thrombus at CT or TEE; eight patients with thrombus at both CT and TEE; and four patients with thrombus at CT but not at TEE (overall kappa = 0.779 [95% CI: 0.571, 0.987]).
CONCLUSION: Sixty-four-section cardiac CT angiography is a noninvasive and sensitive modality for detecting thrombi in the LAA of stroke patients. Although TEE is currently considered the reference standard modality for detecting LAA thrombi, 64-section cardiac CT angiography has the potential to become a useful modality for detection of intracardiac thrombus. (c) RSNA, 2008.