MRI-DERIVED VENTRICULAR VOLUME CURVES FOR THE ASSESSMENT OF LEFT-VENTRICULAR FUNCTION

To assess the utility of double oblique, ECG-gated H-1 magnetic resona nce (MR) derived volume curves for assessing LV function, cardiac shor t axis images were acquired with a fast field echo technique. We appli ed this methodology to assess left ventricular function in three group s: normals, patients with left ventricular hypertrophy, and dilated ca rdiomyopathy. Six slices with 16-20 phases per RR interval were analyz ed, representing the initial 75-80% of the cardiac cycle. For each sli ce, the endocardial border of the left ventricular (LV) chamber was ma nually traced. Using Simpson's rule, the total LV volume at a given ph ase was determined considering the traced area, thickness and position in three-dimensional space of each of the six constituent slices. The calculated volumes were plotted against time and the stroke volume, e jection fraction and cardiac output were determined. The volume vs tim e plots for the systolic and diastolic portions of the curve were indi vidually fit to third degree polynomials using a least squares approxi mation. From the fit curves, the following data were extracted: the me an slope (dV/dT) during filling and emptying, and the time to 1/4, 1/3 and 1/2 filling and emptying. These parameters are valuable indices o f the functional status of the myocardium; thus, accurate and useful e stimates of LV function can be obtained using MRI derived volume curve s in normal and abnormal states.