FIRST-PASS RADIONUCLIDE ANGIOGRAPHY USING I-123 MYOCARDIAL TRACERS AND A MULTICRYSTAL GAMMA-CAMERA

The purpose of this study was to validate the accuracy of the assessme nt of ventricular function by first-pass radionuclide angiography (FPR NA) with I-123 myocardial tracers and a multicrystal gamma camera. Met hods: Left ventricular ejection fraction (LVEF) and right ventricular ejection fraction were measured in 69 patients by FPRNA using I-123 my ocardial tracers (126 +/- 7 MBq) and Tc-99m tracers (541 +/- 141 MBq) on a multicrystal gamma camera with a high-sensitivity collimator. For 44 patients, ejection fraction values measured by I-123-FPRNA were co mpared to those estimated by equilibrium radionuclide angiography (ERN A). Visual wall-motion analysis was also performed to judge clinical a cceptability of I-123- FPRNA images for identification of wall-motion abnormality, Results: Mean LVEFs (%) estimated by I-123-FPRNA and by T c-99m- FPRNA were 49.6 +/- 13.6 and 49.1 +/- 14.1, respectively (nonsi gnificant p value). An excellent correlation was found between LVEFs e stimated by I-123-FPRNA and Tc-99m-FPRNA (r = 0.96, s.e.e. = 1.9%). Va lues of LVEF measured by I-123-FPRNA also demonstrated excellent corre lation with those measured by ERNA (r 0.95, s.e.e. = 2.2%). A good cor relation was also noted between right ventricular ejection fractions m easured by I-123-FPRNA and Tc-99m-FPRNA (r = 0.72, s.e.e. = 4.0%). The Spearman rank correlation coefficient between I-123-FPRNA and ERNA wa ll-motion scores was 0.87 (n = 135, p < 0.001). Conclusion: Resting ve ntricular function can be reliably measured with I-123-FPRNA in combin ation with a multicrystal gamma camera. This indicates that the assess ment of ventricular function is feasible in conjunction with I-123 myo cardial imaging without an increase in cost or radiation dose to patie nts.