962-61 Late Redistribution T1-201/Stress Tc-99m Sestamibi Separate Acquisition Dual Isotope Myocardial Perfusion SPECT: A Feasibility Study

Rest TI201(TI)/stress Tc-sestamibi dual isotope SPECT (DIMPS) is an efficient myocardial perfusion protocol. Patients with rest defects, however, frequently require late TI redistribution imaging the next day. Thus, we recently implemented a modified DIMPS (M-DIMPS), with 3.5 mCi TI injected at rest the night before stress testing. On the day of stress testing, 12–18 hr redistribution TI (late TI) SPECT was performed prior to stress sestamibi study. To assess image quality of late TI, we prospectively studied 107 patients who underwent M-DIMPS. For purposes of comparison between conventional DIMPS and M-DIMPS, a subset (group A, n = 41) also had rest TI(25 sec/stop, 60 stops) the night before M-DIMPS. Late TI used 30 sec/stop. Prereconstruction processing used a 20 Butterworth filter (cut-off: 0.5/order 10 for rest TI, 0.35/order 10 for late TI). Comparisons were made for cardiac counts (counts/pixel) and quantitative heart to background ratio (H/B ratio). Image quality was assessed visually using a 5 point score (0 = unacceptable, 4 = excellent), based on the evaluation of image uniformity, defect clarity, left ventricular border definition and the apparent H/B ratio, Comparisons between rest TI and late TI in 41 group A patients yielded quantitative H/B ratio of 1.63 ± 0.39 and 1.49 ± 0,31 (p = 0.002), and total myocardial counts of 41.4 ± 18.1 and 29.3 ± 11.6 (p l 0.001), respectively. Image quality agreement between rest TI and late TI was 90%, with 31 concordant good to excellent and 6 concordant fair studies. Analysis of the 107 late TI studies by patient weight revealed: l150 Ibs (n = 31) 150–200 Ibs (n = 60) g200 Ibs (n = 16) p cardiac counts 30.4 ± 9.6 28.9 ± 13.8 28.9 ± 7.5 ns H/B ratio 1.49 ± 0.24 1.46 ± 0.32 1.42 ± 0.25 ns quality = 3 or 4 90% 90% 63% l0.05 * * g 200lbs vs. the other two weight categories Conclusion Although quantitatively different, late TI has acceptable count statistics and comparable visual image quality to rest TI, establishing the feasibility of late TI/stress Tc-sestamibi dual isotope SPECT in non-obese (l200 Ibs) patients. The protocol allows for final reporting on the same day as stress testing, potentially decreasing the length of hospitalization.