Prognostic value of automated quantification of 99mTc-sestamibi myocardial perfusion imaging

Although human interpretation of (99m)Tc-sestamibi SPECT myocardial perfusion imaging has been repeatedly validated in the diagnostic and prognostic assessment of coronary artery disease, it remains unclear if automated computer-derived quantitative indices of perfusion have similar or independent prognostic information.

We studied 718 patients referred for (99m)Tc-sestamibi SPECT myocardial perfusion imaging who were followed for 5.6 +/- 1.1 y (mean +/- SD). The SPECT studies were initially interpreted visually without benefit of computer-based analysis and were then subjected to a blinded reprocessing to extract quantitative indices of perfusion. Follow-up was through the Manitoba Population Health Research Data Repository. Acute myocardial infarction or cardiac death occurred in 79 individuals (11.0% of the cohort).

Visual and quantitative categorization of scan perfusion abnormalities showed similar prognostic value for predicting acute myocardial infarction or cardiac death. Discordance between the visual and quantitative categorizations defined a group at intermediate risk. There was a gradient of risk with increasing severity of the summed stress score (SSS) or summed difference score (SDS). The automated SSS and SDS provided incremental prognostic information over that obtained from visual interpretation.

Automated quantification of (99m)Tc-sestamibi SPECT myocardial perfusion scans provides objective prognostic information and may complement the conventional visual image interpretation.