Attenuation and scatter correction in myocardial SPET:: improved diagnostic accuracy in patients with suspected coronary artery disease

Artefacts hamper the accuracy of myocardial single-photon emission tomography (SPET). Systems are now available that may compensate for attenuation and scatter. We evaluated a commercial system for attenuation (AC) and scatter correction (SC) in everyday routine using coronary angiography (CAG) as a reference. A total of 142 consecutive patients referred for myocardial SPET had their studies processed with and without SCAC. Uncorrected and SCAC images were scored by blinded, consensus readings. If readings differed, CAG, if available, was used as a reference. The readings differed in 37% of cases. Among these cases SCAC caused disappearance of irreversible defects (74%), disappearance of reversible defects (14%) and change of irreversible to reversible defects (9%). Two new defects were introduced by SCAC. The defects influenced were located inferiorly (75%), anteriorly (14%), septally (7%), laterally (2%) and apically (2%). CAG, available in 29 of the discrepant cases, supported SCAC and uncorrected image readings in 83% and 7% of cases, respectively. In conclusion, we found a commercial system for AC and SC in myocardial SPET to be of great diagnostic help in a consecutive series of patients. Using CAG as a reference, the SCAC interpretation was confirmed in nearly all cases.