BACKGROUND Advances in the minimally invasive mitral valve repair techniques increase the demands on accurate and reliable morphologic assessment of the mitral valve using three-dimensional imaging modalities. The present study compared mitral valve geometry measurements obtained by three-dimensional transesophageal echocardiography (TEE) to those obtained with multidetector row computed tomography (MDCT) used as a standard reference. METHODS Clinical preoperative MDCT and intraoperative three-dimensional TEE were performed in 43 patients (mean age 81.0 ± 7.7 years) considered for transcatheter valve implantation procedure. Various measurements of mitral valve geometry were obtained from three-dimensional TEE datasets using mitral valve quantification software, and compared with those obtained from MDCT images using multiplanar reformation planes. RESULTS Moderate and severe mitral regurgitation was present in 48.9% of patients. There was good agreement in mitral valve geometry measurements between three-dimensional TEE and MDCT without significant overestimation or underestimation and tight 95% limits of agreement. For linear dimensions, angles and areas, the 95% limits of agreement were less than 1 cm, less than 15 degrees, and less than 2 cm(2), respectively. In addition, the intraclass correlation coefficients were more than 0.8 for all parameters. Finally, the measurements were highly reproducible, with low intraobserver and interobserver variability (nonsignificant overestimation or underestimation and narrow 95% limits of agreement). CONCLUSIONS The present study demonstrates the accuracy and clinical feasibility of the assessment of the mitral valve geometry with three-dimensional TEE that is comparable to the MDCT measurements. Three-dimensional TEE and MDCT provide accurate and complementary information in the evaluation of patients with mitral valve disease. Its potential incremental clinical value in the field of transcatheter mitral repair procedures needs further assessment in the future studies.