Validity of different gated equilibrium blood pool methods for determination of left ventricular ejection fraction.

Left ventricular ejection fractions (EF) were determined in 37 patients by biplane cineventriculography (Angio) and by four modifications of the gated equilibrium blood pool (GBP) method: 1. Region of interest (ROI) in enddiastole (ED), correction by external background, 2. ROI in ED, correction by internal background between ED and endsystole (ES), 3. ROI in ED (maximum) and ES (mimimum); no background correction, 4. ROI in ES, correction by background between ED and ES. EFGBP were determined after injection of 20 mCi 99mTc human albumin (Anger-camera, all-purpose collimator, 16 ECG-segments, 64 x 64 matrix with 1.5 zoom). EF by biplane angiography (EFangio) was calculated by the formula of Dodge. The following correlation between angiographically and scintigraphically determined EF's were found: EFGBP1 = 0.504 EFangio + 8.08, EFGBP2 = 0.847 EFangio + 10.0, EFGBP3 = 0.911 EFangio + 3.75, EFGBP4 = 0.648 EFangio - 3.51 Intraobserver variability of GBP method 2 and 3 was +/- 5%. EFS determined by GBP methods 2 and 3 are as accurate as the EFs determined by cineventriculography.