Reproducibility and accuracy of left ventricular ejection fraction and wall motion determinations using gold-195m: a new ultrashort-lived radionuclide for cardiac studies.

Gold-195m has a halflife of 30.5 sec. Its ultrashort halflife and low radiation exposure (240 mrads to the kidney from a 20-mCi injection) make it an ideal agent for sequential first-transit studies of cardiac function. The reproducibility of ejection fraction and wall motion determinations were assessed from two gold-195m first-pass angiograms performed 3 min apart in 38 subjects. The accuracy of these evaluations was assessed by performing another first-transit study using technetium-99m. The correlation of the ejection fraction between the two gold-195m angiograms was 0.95 (standard error of the estimate (SEE) = 0.049) over an ejection fraction range of 20-78. The correlation of the ejection fraction using technetium-99m versus gold-195m was 0.95; SEE = 0.050. Only six minor discrepancies were noted when wall motion was evaluated in the gold-195m angiograms and compared with the technetium-99m study. We conclude that gold-195m can provide repeated, accurate, and reproducible ejection fraction and wall motion determinations with conventional imaging equipment at a substantially lower radiation exposure than with technetium-99m.