Multiple-gated acquisition cardiac blood-pool isotope imaging. Evaluation of left ventricular function correlated with contrast angiography.

Thirty-one patients were assessed by the multiple-gated acquisition cardiac blood-pool isotope-imaging technique using radiolabeled albumin within 24 hours of biplane contrast ventriculography. Data from the imaging method were analyzed by a semiautomatic technique with computer-generated edge detection and background subtraction. An excellent correlation was observed between ejection fractions determined with multiple-gated isotope imaging and those obtained by biplane contrast ventriculography (r = 0.93), and the same was true for average ejection rates (r = 0.80). For assessment of wall motion with this imaging technique, the anterior and the left anterior oblique left ventricular views were divided into nine segments, and a score was assigned to each segment based on the degree of wall motion. The cumulative anterior and left anterior oblique scores correlated well with the score from biplane contrast ventriculography (r = 0.90), and in 94% of segments in the left anterior oblique projection the assessment with multiple-gated isotope imaging was the same as or varied by only one class from the assessment by biplane contrast ventriculography. The multiple-gated acquisition cardiac blood-pool isotope-imaging technique is thus a valuable noninvasive method for assessing left ventricular function as measured by ejection fraction, ejection rates, and wall motion.