RIGHT AND LEFT-VENTRICULAR VOLUME AND EJECTION FRACTION BY TOMOGRAPHIC GATED BLOOD-POOL SCINTIGRAPHY

Tomographic techniques separate overlying structures, permitting measu rements of absolute ventricular volumes. The purpose of this study was to determine absolute right and left ventricular volume and ejection fraction measurements with tomographic gated equilibrium blood-pool sc intigraphy (TMUGA) compared to MRI and conventional planar scintigraph y. Methods: Eighteen patients were studied. Ventricular volumes for TM UGA and MRI were calculated by modified Simpson's rule. TMUGA regions were defined by constraints including phase analysis, intensity thresh old and visual inspection. MRI studies were acquired with a fast gradi ent-echo, ECG-gated, breath-hold technique and boundaries were defined by a semiautomated contour method. Conventional gated first-pass radi onuclide angiography (FP) and planar gated equilibrium blood-pool scin tigraphy (PMUGA) were performed for RV EF and LV EF, respectively. Res ults: TMUGA absolute right ventricular volumes showed excellent correl ation with MRI for both right ventricular volumes (r = 0.91, slope = 0 .90, s.e.e. = 15.7) and left ventricular volumes (r = 0.96, slope = 0. 88, s.e.e. = 18.2). For left ventricular ejection fraction, TMUGA also showed excellent correlation with MRI (r = 0.94, slope = 1.10, s.e.e. = 9.0) and planar MUGA (r = 0.97, slope = 1.23, s.e.e. = 6.2). For ri ght ventricular ejection fraction, TMUGA showed good correlation with both MRI (r = 0.88, slope = 0.79, s.e.e. = 6.0) and first-pass planar scintigraphy (r = 0.86, slope = 1.2, s.e.e. = 7.9). Conclusion: Tomogr aphic gated blood-pool scintigraphy absolute right and left ventricula r volumes and ejection fractions show good correlation with accepted t echniques. Further studies are necessary to define the reproducibility of this method.