A comparison of MRI and echocardiography in hypertrophic cardiomyopathy

This study compares MRI and echocardiography as imaging modalities in hyper trophic cardiomyopathy, with particular reference to measurement of left ve ntricular wall thickness and mass. 10 subjects underwent echocardiography a nd MRI. Contiguous 10 mm short asis 35 degrees hip angle cine gradient reca lled echo MR images were acquired from the apex to the base of the left ven tricle at 1.5 tesla. Standard M-mode and cross-sectional echocardiographic views of the left ventricle were obtained. Excellent agreement between meas urements occurred with MRI and M-mode echocardiographic assessment of the t hickness of the anterior interventricular septum (95% Limits of agreement - 1.5 to +1.5 mm). Other comparisons of MRI vs M-mode echocardiographic measu rements had the following limits of agreement: posterior free wall -3.3 to +2.9 mm: end-diastolic dimension -5 to +8 mm, left ventricular mass -291 to +55.5 g. Comparing MRI with cross-sectional echocardiographic measurements , the limits of agreement were: anterior interventricular septum -2.4 to +1 .7 mm, posterior interventricular septum -2.4 to +2.9 nun, posterior free w all -3.4 to +2.5 mm, anterior free wall. -2.4 to +1.7 mm, end-diastolic dim ension -4.1 to +8 mm. MRI estimates of LVM in systole vs diastole showed go od agreement with 95% Limits of agreement of -20 to +17 g, with excellent i nterobserver variability in diastole (-9 to +5 g) and in systole (-7 to +12 g). In conclusion, MRI is superior to echocardiography for the quantificat ion of ventricular mass in the abnormal left ventricle because it does not make invalid geometrical assumptions. Comparisons of wail thickness show gr eater discrepancy with increasing distance from the echocardiographic trans ducer. This study suggests that sequential echocardiography could rationali ze the need for MRI in left ventricular hypertrophy. A change in anterior s eptal thickness of greater than or equal to 3 mm on echocardiography merits a further MRI study.