bjectiveTo use dual source computed tomography (DSCT) for assessment of left atrial appendage volume and function, and to compare the results with those of cardiac cine MR (CMR). MethodsSixty-two patients who received computed tomography angiography (CTA) during March 2008 to Feb. 2009 were included in the present study. The DSCT data sets (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany) and FIESTA (fast imaging employing steady-state acquisition) cines (Signa Excite HD 3T, GE) of the vertical long axis covering the left atrium were obtained on the same day. The images were analyzed to obtain LAAVmax, LAAVmin and LAAEF using Vitrea Heart Function software and Report Card 2.0 software, for DSCT and CMR. Intermodality agreement between DSCT and CMR was tested using linear regression and t test. Interobserver variability was tested by Bland-Altman analyses. ResultsThe DSCT and CMR measurements of the left atrial appendage volume and function were not significantly different, and the measurements of the two methods were well correlated with each other, with the coefficient of LAAVmax, LAAVmin, and LAAEF(%) being 0.85, 0.86, and 0.76, respectively. However, compared with CMR, DSCT showed a tendency of overestimating LAAVmax, LAAVmin and underestimating LAAEF. The interobserver variability of DSCT measurements was lower than that of CMR measurements. ConclusionDSCT is accurate in assessing the left atrial appendage volume and function of patients referred for coronary CT imaging, and the results are reproducible.