Planimetry of mitral valve stenosis in rheumatic heart disease by magnetic resonance imaging.

BACKGROUND AND AIM OF THE STUDY: To date, no investigations have been made on the role of magnetic resonance imaging (MRI) in evaluating mitral stenosis (MS) in Asian countries such as India, where rheumatic MS is more common. An accurate assessment of the mitral valve area (MVA) is particularly important when managing patients with valvular stenosis. Current standard techniques to assess the severity of MS include echocardiography and cardiac catheterization, the former of which represents the most practical approach. The study aim was to evaluate the accuracy and clinical utility of planimetry of the MVA and peak gradient, assessed by MRI in comparison with echocardiography, in rheumatic heart disease (RHD) patients with MS.

METHODS: Among a group of 30 patients with suspected or known MS, planimetry of the MVA and mitral valve gradient (MVG) was performed with a 1.5 Tesla MRI scanner, using a breath-hold balanced gradient echo sequence (true FISP) and velocity-encoded MRI, respectively. The data obtained were compared with the echocardiographically determined MVA (ECHO-MVA).

RESULTS: The correlation between the MRI-MVA and ECHO-MVA was 0.81 (p < 0.0001), and between the MRI-MVG and ECHO-MVG was 0.81 (p < 0.0001). The MRI-MVA slightly overestimated the ECHO-MVA by 8.1% (1.61 +/- 0.42 cm2 versus 1.48 +/- 0.42 cm2; p < 0.05).

CONCLUSION: To the present authors' knowledge, this study is the first in which MRI has been used to evaluate MVA by planimetry, particularly in RHD. MRI is capable of adequately evaluating patients with rheumatic MS with respect to the peak gradient and MVA by planimetry. Thus, MRI planimetry of the mitral valve orifice in MS offers a reliable and safe method for the quantification of MS. Further studies are required to standardize the procedure in those patients with atrial fibrillation, or who are more symptomatic.