COMPARISON OF ELECTRON-BEAM COMPUTED-TOMOGRAPHY SCANNING AND MAGNETIC-RESONANCE-IMAGING QUANTIFICATION OF RIGHT-VENTRICULAR MASS - VALIDATION WITH AUTOPSY WEIGHTS

Rationale and Objectives. We compared, in the same human hearts, the a bility of magnetic resonance (MR) imaging and electron beam computed t omography (CT) scanning to accurately quantify the free wall and septa l components of right ventricular (RV) mass. Methods. Eleven hearts ex tracted at autopsy were subjected to MR imaging and electron beam CT s canning in short-axis projections. Regression analyses of mass determi nations obtained by manual planimetry MR imaging and electron beam CT scanning and autopsy weights were performed. Results. RV free wall mas s by both MR imaging (53.4 +/- 19.1 g) and electron beam CT scanning ( 53.9 +/- 20.4 g) correlated well with autopsy weight (57.7 +/- 20.2 g) . Regression analysis showed a strong correlation for MR imaging (r = .88, slope = .88, standard error the estimate [SEE] = 7.2 g, p < .001) and electron beam CT scanning (r = .95, slope = .95, SEE = 6.6 g, p < .001). RV septal mass by MR imaging (10.8 +/- 3.5 g) and electron bea m CT scanning (7.1 +/- 2.4 g) correlated less well with the autopsy we ight (12.5 +/- 6.5 g). Regression analysis showed a fair correlation f or MR imaging (r = .45, slope = .83, SEE = 2.05 g, p = .001) and a poo r correlation for electron beam CT scanning (r = .46, slope = .17, SEE = 2.25 g, p = .57). Conclusion. Both MR imaging and electron beam CT scanning accurately predict RV free wall mass but have difficulty pred icting the septal component. Because the septal component constitutes only a small proportion of the total RV mass, determinations of RV mas s should be based solely on the free wall component.