DYNAMIC 3-DIMENSIONAL IMAGING OF THE MITRAL-VALVE AND LEFT-VENTRICLE BY RAPID SONOMICROMETRY ARRAY LOCALIZATION

Objectives, The first objective was to develop a quantitative method f or tracking the three-dimensional geometry of the mitral valve, The se cond was to determine the complex interrelationships of various compon ents of the mitral valve in vivo. Methods and results. Sixteen sonomic rometry transducers were placed around the mitral valve anulus, at the tips and bases of both papillary muscles, at the ventricular apex, ac ross the ventricular epicardial short axis, and on the anterior chest wall before and during cardiopulmonary bypass in eight anesthetized sh eep, Animals were studied later on 17 occasions, Reproducibility of de rived chord lengths and three-dimensional coordinates from sonomicrome try array localization, longevity of transducer signals, and the dynam ics of the mitral valve and left ventricle were studied, Reproducibili ty of distance measurements averages 1.6%; Procrustes analysis of thre e-dimensional arrays of coordinate locations predicts an average error of 2.2 mm, Duration of serial sonomicrometry array localization signa ls ranges between 60 and 151 days (mean 114 days), Sonomicrometry arra y localization demonstrates the saddle-shaped mitral anulus, its minim al orifice area immediately before end-diastole, and uneven, apical de scent during systole, Papillary muscles shorten only 3.0 to 3.5 mm, So nomicrometry array localization demonstrates nonuniform torsion of pap illary muscle transducers around a longitudinal axis and shows rotatio n of papillary muscular bases toward each other during systole, Conclu sion. Tagging of ventricular structures in experimental animals by son omicrometry array localization images is highly reproducible and suita ble for serial observations, In sheep the method provides unique, quan titative information regarding the interrelationship of mitral valvula r and left ventricular structures throughout the cardiac cycle.