Evaluation of Scatter Compensation Strategies and their Impact on Human Detection Performance in Tc-99m Myocardial Perfusion Imaging

Human-observer receiver-operating characteristic (ROC) results with clinical patient studies indicate that ordered-subset expectation-maximization (OSEM) reconstructions with a combination of corrections for attenuation, scatter and distance-dependent resolution (DDR) significantly improves perfusion defect detection accuracy over FBP images. A recent Monte-Carlo study has also shown that for scatter correction (SC) in particular, selection of an appropriate strategy can impact cardiac uniformity. The spatial domain based effective source scatter estimation (ESSE) technique was shown to provide more robust performance in improving cardiac uniformity than the triple-energy window (TEW) method which is our current clinical standard for SC. In this work, we investigate if further improvements in observer performance could be obtained by using the ESSE method of SC instead of the currently used TEW SC, in combination with attenuation correction (AC) and resolution compensation (RC). We evaluated the effectiveness of the ESSE method to provide additional improvements in image quality objectively by using human-observer ROC studies on clinically acquired patient acquisitions. Results indicate that both ESSE and TEW SC in combination with AC and RC provide significantly higher detection accuracy than FBP for the overall detection of coronary artery disease (CAD) as well as in localizing perfusion defects in the LAD and LCx territories. Comparing, the two implementations of SC evaluated in this study, we note that ESSE method provides a significant improvement over TEW correction in the LAD territory. ESSE SC also provides small improvements in detection accuracy over the TEW method for the overall detection of CAD as well as in the detection of perfusion defects in the LCx and RCA territories. This indicates that SC implemented with the ESSE method has the potential to further improve the detection accuracy of images corrected for attenuation, scatter and resolution.