Background In the patient with mitral regurgitation who is being considered for valvular surgery, cardiac catheterization is usually performed to quantify the severity of regurgitation and to determine its influence on left ventricular volumes and systolic function. Magnetic resonance imaging (MRI) potentially provides a rapid, noninvasive method of acquiring these data. Thus, this study was done to determine whether MRI can reliably measure the magnitude of mitral regurgitation and evaluate the effect of regurgitation on left ventricular volumes and systolic function. Methods and Results Twenty-three subjects (14 women and 9 men 15 to 72 years of age) with (n=17) or without (n=6) mitral regurgitation underwent MRI scanning followed immediately by cardiac catheterization. The presence (or absence) of valvular regurgitation was determined, and left ventricular volumes and regurgitant fraction were quantified during each procedure. There was excellent correlation between invasive and MRI assessments of left ventricular end-diastolic ( r =.95) and end-systolic ( r =.95) volumes and regurgitant fraction ( r =.96). All MRI examinations were completed in <28 minutes. Conclusions In the patient with mitral regurgitation, MRI compares favorably with cardiac catheterization for assessment of the magnitude of regurgitation and its influence on left ventricular volumes and systolic function.

Compared with measurements obtained during cardiac catheterization, velocity-encoded, phase-difference MRI measurements of flow in the proximal great vessels can reliably assess the magnitude of intracardiac left-to-right shunting.