MRI EVALUATION OF LEFT-VENTRICULAR MASS BY AUTOMATIC BORDER DETECTIONOF THE ENDOCARDIUM AND EPICARDIUM

This study describes a method of automatic border detection of the lef t ventricular endocardium and epicardium associating three methods of segmentation (increase of region, border detection and adaptive thresh old), applicable to the evaluation of ventricular mass and volume by m agnetic resonance imaging. Despite slight underestimation, the spin-ec ho sequence used in 9 small pigs provided a value of left ventricular mass close to that observed ex vivo (r = 0.97, SEE = 6.05 g). Clinical validation using a rapid gradient-echo sequence was undertaken and co mpared with manual border detection carried out by three independent, trained operators. The study population included healthy subjects and patients with global or segmental left ventricular dysfunction with or without ventricular deformation. The correlations between automatic a nd manual detection were satisfactory both for calculation of left ven tricular mass (r = 0.93, SEE = 13 g) and measurement of surfaces (r = 0.91, SEE = 1.4 cm(2)). The concordance of the two methods was confirm ed by the Bland and Altman test, Cardiac magnetic resonance imaging ma y provide accurate and reproducible measurements of left ventricular m ass within acceptable acquisition and image processing times for routi ne use. Although the clinical value of such a method is accepted both for establishing the prognosis and guiding management, studies of the cost/efficacy ratio should be undertaken to situate magnetic resonance imaging with respect to other non-invasive techniques of investigatio n of left ventricular function.