NONINVASIVE DELINEATION OF NORMAL RIGHT-VENTRICULAR CONTRACTILE MOTION WITH MAGNETIC-RESONANCE-IMAGING MYOCARDIAL TAGGING

As the importance of the right ventricle in many diseases and conditio ns has been realized, the need for quantitative assessment of the moti on and contraction of the right ventricular free wall (RVFW) has becom e apparent. This study applied the myocardial tagging magnetic resonan ce imaging (MRI) technique to the normal RVFW to elucidate normal hete rogeneity in RV motion and contractile patterns. The RVFW was divided into three segments (inferior, mid and superior) in each of three slic es (apical, mid and basal) to allow for a detailed analysis of the mot ion and contraction. Percent segmental shortening (PSS) was used to me asure the amount of contraction, and a vector analysis was used to qua ntitate the trajectory of the RVFW through systole. PSS increased mono tonically through time to an average across all segments of 12% in the basal slice, 14% in the mid-ventricular slice, and 16% in the apical slice of the heart. The trajectory of the RVFW was characterized by a wave of motion toward the septum and outflow tract. The data provided in this study provide a better understanding of normal RV kinematics a nd can serve as a comparison for disease states. (C) 1998 Biomedical E ngineering Society. [S0090-6964(98)02005-0].