ECG-gated Multidetector Computed Tomography (MDCT) is widely used for coronary imaging, including preoperative appraisal of patients with valvular disease. We aimed to evaluate its ability to provide additional valvular information in mitral regurgitation (MR).

Consecutive MDCTs performed for coronary assessment in 29 patients with MR were reviewed. Mitral valves were analyzed in multiphase imaging using a standardized protocol. Four types of multiplanar reconstructions were tested: axial, short-axis slices, and from the three-chamber view slices positioned either parallel or rotating around the centre of the aortic valve. We defined motion as normal, prolapse or restriction, noted the most effective phase and calculated the regurgitant volume as the difference between left and right ventricular ejection volumes. Echocardiography was used as a reference for leaflet motion, functional quantification using effective regurgitant orifice (ERO) and ventricular volumes.

The severity of MR, derived from ERO, was graded 1 for 11 patients, 2 (3 patients), 3 (7) and 4 (8). The motion agreement (Kappa coefficient) for the 174 scallops studied was 0.91 (95% CI 0.83-0.97) for the three-chamber-derived views, 0.88 (0.79-0.96) for the axial slices and 0.60 (0.46-0.74) for the short-axis plane. However, the latter was efficient in prolapsed scallops (Se 0.87, Sp 0.98, PPV 0.87 and NPV 0.98). The MDCT RV differed between grades 1 and 3, 1 and 4 (p=0.001), 2 and 3, 2 and 4 (P<0.03) with a gradual increase. No overlap was observed between mild to moderate (1 and 2) and moderate to severe (3 and 4) groups, with a specific threshold ranging from 44 to 47ml. The most effective phase was 30% in 79% of cases and 20% in the remaining 21%.

MDCT is an accurate tool for evaluating both anatomical and functional parameters of mitral regurgitation. Three-chamber-derived slices and short-axis views allow when combined a reliable interpretation of MR mechanism.