[Evaluation of left ventricular function using 99mTc-diethylenetriamine-pentaacetic acid-human serum albumin (DTPA-HSA)].

A newly developed blood pool agent 99mTc-DTPA-HSA (Japan Mediphysics, Inc.) was used for ECG gated blood pool scintigraphy. The radiopharmaceutical remained in the blood pool with disappearance half time of 420 min in a healthy subject. The gated blood pool study in the same subject clearly demonstrated contracting left ventricle and right ventricle both with planar and SPECT images. Three healthy volunteers and 14 patients were included in the study, in that gated blood pool images were successfully obtained. The left ventricular ejection fraction (LVEF) calculated by the analysis of LV volume curves correlated well with those obtained by echocardiography (US). In 11 patients with implanted pacemaker for complete atrioventricular block and sick sinus syndrome changes of LVEF were evaluated in relation to pacing rates. The mean LVEF at pacing rate of 60/min was 58.5%, which decreased to 54.4% at 100/min pacing rate. However, changes of LVEF in individual patient did not show same pattern. We conclude that 99mTc-DTPA-HSA is a convenient blood pool scanning agent which does not require time consuming labeling preparations. Stable labeling and slow blood clearance allows its use for repeat measurements of LVEF in different conditions in a patient such as with pacemaker.