Multicenter clinical trial to evaluate the efficacy of correction for photon attenuation and scatter in SPECT myocardial perfusion imaging

Background-Soft tissue attenuation is a prominent cause of single-photon em ission computed tomography (SPECT) imaging artifacts, which may result in r educed diagnostic accuracy of myocardial perfusion imaging. A method incorp orating simultaneously acquired transmission data permits nonuniform attenu ation correction and when incorporating scatter correction and resolution c ompensation may substantially reduce interpretive errors, Methods and Results-A prospective multicenter trial was performed recruitin g patients with angiographically documented coronary disease (n = 96) and g roup of subjects with a low likelihood of disease (n = 88). The uncorrected and attenuation/scatter corrected images were read independently, without knowledge of the patient's clinical data. The detection of greater than or equal to 50% stenosis was similar using uncorrected perfusion data or with attenuation/scatter correction and resolution compensation (visual or visua l plus quantitative analysis), 76% versus 75% versus 78%, respectively (P=N S). The normalcy rate, however, was significantly improved with this new me thodology, using either the corrected images (86% vs 96%; P=0.011) or with the corrected data and quantitative analysis (86% vs 97%; P=0.007). The rec eiver operator characteristic curves were also found to be marginally but n ot significantly higher with attenuation/scatter correction than with tradi tion SPECT imaging. However, the ability to detect multivessel disease was reduced with attenuation/scatter correction, Regional differences were also noted, with reduced sensitivity but improved specificity for right coronar y lesions using attenuation/scatter correction methodology. Conclusions-This multicenter trial demonstrates the initial clinical result s of a new SPECT perfusion imaging modality incorporating attenuation and s catter correction in conjunction with Tc-99m sestamibi perfusion imaging, S ignificant improvements in the normalcy rate were noted without a decline i n overall sensitivity but with a reduction in detection of extensive corona ry disease.