R-WAVE SYNCHRONIZED BLOOD-POOL IMAGING - COMPARISON OF THE ACCURACY AND REPRODUCIBILITY OF FIXED AND COMPUTER-AUTOMATED VARYING REGIONS-OF-INTEREST FOR DETERMINING THE LEFT-VENTRICULAR EJECTION FRACTION

Three methods for determining the left ventricular ejection fraction (EF) from R-wave synchronized blood-pool images were compared to contrast angiography; the reproducibility of these methods was established in 51 patients. The EF was systematically underestimated by the fixed region-of-interest (ROI) method compared to the two methods that used varying ROI's which track the left ventricular boundary. All methods correlated reasonably well with angiography and were highly reproducible. Use of varying ROI's resulted in EF values that were essentially identical to those determined by angiography. Resolution-recovery image processing appeared to improve reproducibility when varying ROI's were used.