Cine MRI of mitral regurgitation in planes angled along the intrinsic cardiac axes

This prospective study was designed to evaluate the mechanism and severity of mitral regurgitation (MRG) by means of cine MRI using planes angled along the intrinsic cardiac axes. In 25 patients with MRG, analysis of the direction, extent, and distribution of left atrial signal void area was performed on both two chamber and four chamber cine MRI views. Cine MRI features including qualitative grading, maximal length of regurgitant jet, and ratio of regurgitant jet area to left atrial area were compared with the results of color flow Doppler (CFD) mapping (n = 25), angiography (n = 20), and regurgitant fraction as determined at catheterization (n = 15). In the four chamber view, cine MRI demonstrated central extension of regurgitant jet (n = 8) in cases with dilatation of valve annulus or retraction of both mitral valve leaflets, anterior extension (n = 8) in cases with prolapse of the posterior leaflet, and posterior extension (n = 7) in cases with prolapse of the anterior leaflet or retraction of the posterior leaflet. In two cases of mild MRG with small signal void area, evaluation of mechanism was not feasible. The results of cine MRI and angiographic qualitative gradings were the same in 19 of the 20 patients and differed by one grade in the other patient. In the 25 patients, maximal length of the regurgitant jet was well correlated with both regurgitant jet area and ratio of the jet area to the left atrial area as determined by CFD mapping (r = 0.91, r = 0.85, p < 0.0001, respectively). In 15 patients the maximal length of regurgitant jet was correctly correlated with regurgitant fraction determined at catheterization (r = 0.76, p < 0.001). Cine MRI by means of planes angled along the intrinsic cardiac axes allows assessment of both the mechanism and the severity of MRG.