Left atrial appendage thrombi in stroke patients: detection with two-phase cardiac CT angiography versus transesophageal echocardiography.
OBJECTIVE
To assess the diagnostic accuracy of two-phase 64-section cardiac computed tomographic (CT) angiography for detection of left atrial appendage (LAA) thrombi and differentiation between thrombus and circulatory stasis in patients with stroke, with transesophageal echocardiography (TEE) as the reference standard.


METHODS
This study was institutional review board approved, and all patients gave written informed consent. Fifty-five consecutive patients (36 men, 19 women; mean age, 61 years) who had recently experienced a stroke, had high-risk factors for thrombus formation, and underwent both two-phase 64-section cardiac CT angiography and TEE up to 5 days apart were examined. Agreement between CT and TEE for detection of thrombus was assessed with kappa statistics. For quantitative analysis, the LAA-ascending aorta attenuation ratio (LAA/AA, in Hounsfield units) was measured on early- and late-phase CT images. The significance of differences in CT attenuation measurements were assessed by using the Student t test.


RESULTS
A total of 14 thrombi were detected in the 55 patients at TEE. With TEE as the reference standard, the overall sensitivity, specificity, and positive and negative predictive values of cardiac CT angiography for the detection of thrombus in the LAA were 100% (14 of 14 patients), 98% (40 of 41 patients), 93% (14 of 15 patients), and 100% (40 of 40 patients), respectively. Concordance between cardiac CT angiography and TEE for the detection of thrombus in the LAA was high (overall kappa = 0.953). Mean LAA/AA values were significantly different between thrombus (0.29 HU +/- 0.12 [standard deviation]) and circulatory stasis (0.85 HU +/- 0.12) on late-phase CT images (P < .001).


CONCLUSIONS
Two-phase 64-section cardiac CT angiography is a noninvasive sensitive modality for detecting LAA thrombi and differentiating thrombus from circulatory stasis in stroke patients.
Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, South Korea.
Jin
J
Hur
Young Jin
YJ
Kim
Hye-Jeong
HJ
Lee
Jong-Won
JW
Ha
Ji Hoe
JH
Heo
Eui-Young
EY
Choi
Chi-Young
CY
Shim
Tae Hoon
TH
Kim
Ji Eun
JE
Nam
Kyu Ok
KO
Choe
Byoung Wook
BW
Choi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000000981:diagnostic imaging; D017023:Coronary Angiography / Q000379:methods; D003328:Coronary Thrombosis / Q000150:complications / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020521:Stroke / Q000209:etiology*; D014057:Tomography, X-Ray Computed / Q000379:methods*