Comparison of volume study by left ventriculography and gated SPECT in endoventricular circular patchplasty

Although quantitative gated SPECT (QGS) is widely used for left ventricular (LV) volume study, its accuracy is not established for those who have a large myocardial infarction scar or who had endoventricular circular patch plasty (EVCPP). Therefore, we compared LV volumes and LVEF calculated by QGS and those calculated by left ventriculography (LVG) before and after EVCPP. Sixteen patients (13 men and 3 women, mean age 67 +/- 9.5 years) were treated with EVCPP for postinfarction LV dyskinetic and/or akinetic scar. All patients were evaluated with both QGS and LVG before and after surgery. QGS was performed using eight frames per cardiac cycle, 1 hour after 740 MBq (99 m)Tc-tetrofosimin was administered. LVG images were acquired at a frame rate of 30 frames per second in the right anterior oblique 30-degree projection. We compared LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) between QGS and LVG. There was an excellent linear correlation between QGS and LVG in LVEDV (preoperative; r = 0.87, postoperative; r = 0.94), LVESV (preoperative; r = 0.95, postoperative; r = 0.89), and LVEF (preoperative; r = 0.73, postoperative; r = 0.81) before and after EVCPP. However, both preoperative LV volumes and postoperative LVEF calculated from QGS gave a smaller value than those calculated from LVG. Postoperative volume data by QGS was much close to LVG. The present study indicated that volume study by QGS is very useful to evaluate the LV function after EVCPP. However, we should pay attention to those facts.