CINE MRI OF MITRAL REGURGITATION IN PLANES ANGLED ALONG THE INTRINSICCARDIAC AXES

Objective: This prospective study was designed to evaluate the mechani sm and severity of mitral regurgitation (MRG) by means of cine MRI usi ng planes angled along the intrinsic cardiac axes. Materials and Metho ds: In 25 patients with MRG, analysis of the direction, extent, and di stribution of left atrial signal void area was performed on both two c hamber and four chamber cine MRI views. Cine MRI features including qu alitative grading, maximal length of regurgitant jet, and ratio of reg urgitant jet area to left atrial area were compared with the results o f color flow Doppler (CFD) mapping (n = 25), angiography (n = 20), and regurgitant fraction as determined at catheterization (n = 15). Resul ts: In the four chamber view, cine MRI demonstrated central extension of regurgitant jet (n = 8) in cases with dilatation of valve annulus o r retraction of both mitral valve leaflets, anterior extension (n = 8) in cases with prolapse of the posterior leaflet, and posterior extens ion (n = 7) in cases with prolapse of the anterior leaflet or retracti on of the posterior leaflet. In two cases of mild MRG with small signa l 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 correlate d 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 < 0.0 001, respectively). In 15 patients the maximal length of regurgitant j et was correctly correlated with regurgitant fraction determined at ca theterization (r = 0.76, p < 0.001). Conclusion: Cine MRI by means of planes angled along the intrinsic cardiac axes allows assessment of bo th the mechanism and the severity of MRG.