Comparison of attenuation, dual-energy-window, and model-based scatter correction of low-count SPECT to 82Rb PET/CT quantified myocardial perfusion scores

Abstract

BackgroundNew reconstruction algorithms allow reduction in acquisition times or the amount of injected radioactivity. We examined the impact of different corrections on low-count clinical SPECT myocardial perfusion images (MPI) and compared to 82Rb PET/CT. We compared no corrections (NC) to attenuation correction (AC) with and without scatter correction by either a dual-energy-window (AC-DEW) or model-based (AC-ESSE) approach. All reconstructions included resolution recovery. Methods56 Patients were imaged using a standard rest/stress Tc-99m-tetrofosmin MPI SPECT/CT protocol with an additional half-time acquisition. A 82Rb-rest/stress PET/CT MPI was acquired within 4 weeks. Reconstruction methods were compared using summed rest/stress/difference scores from an objective algorithm (SRS/SSS/SDS). ResultsThe SRS and SSS for NC were significantly (P < .01) higher than for AC, but well correlated (r ≥ 0.87). The correlation in SRS/SSS among AC, AC-DEW, and AC-ESSE was excellent (r ≥ 0.98). AC-ESSE and AC-DEW had higher SRS (P ≤ .05) than AC, but the SDS values were not significantly different. Concordance with PET normal/abnormal classification was 76% for NC and ≥85% for the AC methods. ConclusionAC significantly improves the accuracy of low-count myocardial perfusion SPECT half-time imaging for the detection of disease compared to NC. Compared to PET, there was no significant difference among AC, AC-DEW, and AC-ESSE.