Interactive drawing of the left ventricular borders from cine magnetic resonance images

Abstract

The calculation of the left ventricular (LV) function requires the endocardial and epicardial contours of the cavity to be accurately defined beforehand. This identification is generally achieved by manual tracing of the LV borders. Such manual methods are tedious and time-consuming, limiting their clinical usefulness for cardiac quantitative analysis. The purpose of this study was to evaluate an efficient method for drawing the LV borders from magnetic resonance (MR) images. This technique, based on the use of cubic B-spline curves to modelize the shape of the cavity, allows an interactive and real-time remodeling of the contours. The variability and the accuracy of this contour tracing tool have been evaluated on standard cine-MR images obtained in 10 healthy volunteers in a short-axis view. Theendocardial and epicardial areas and themean local error between the contours were compared through interobserver and intraobserver analyses. A good correlation was observed between the enclosed areas in both studies (r>0.98 for endocardium,r=0.99 for epicardium). The mean local error between the contours was less than 2.8% for the endocardial borders and less than 1.4% for the epicardial borders. This method has a high degree of flexibility for the interactive trace and deformation of contours. Although further validation is needed, this method may prove useful in clinical application to permit the measurement of LV function from MR imaging.