MAGNETIC-RESONANCE-IMAGING COMPARED TO ECHOCARDIOGRAPHY TO ASSESS LEFT-VENTRICULAR MASS IN THE HYPERTENSIVE PATIENT

Echocardiography (ECHO) is useful to document changes in left ventricu lar mass (LVM) in groups of patients, but may be too variable for use in the individual patient. Magnetic resonance imaging (MRI) may be a m ore precise and reliable method to quantify the mass of the left ventr icle. This study reports the accuracy, precision, and reliability of L VM estimates by MRI as compared to data obtained by ECHO in hypertensi ve patients. Accuracy referred to the comparison of LVM by MRI to anat omical LVM determined by autopsy. Precision was examined using 34 dupl icate MRI images and by blindly reading 24 duplicate M-mode strips. Re liability was assessed by MRI in four subjects over 2 months, and by E CHO in 22 hypertensive patients over 2 weeks. Agreement between MRI an d ECHO estimates of LVM was determined in the same 17 hypertensive pat ients using linear regression. MRI LVM estimates were within 17.5 g (9 5% CI) of the true LVM. The linear agreement between MRI and ECHO esti mates of LVM could be described by the equation MRI = 0.61 x ECHO + 49 .57 (r = 0.63, P < 0.1). The precision of LVM by MRI (11 g) was over t wice that observed with ECHO (26 g). The reliability of MRI LVM estima tes was more consistent (+/-8 g) than that for ECHO (+/-49 g). MRI app ears to be a more precise and reliable method for measuring LVM, and w ould be more suitable than ECHO for the clinical evaluation of the ind ividual patient.