Background: A 17-segment model has become the standard for interpreting myocardial perfusion single-photon emission computed tomography (SPECT). Methods for converting pre-existing databases from 12-segment models to the 17-segment model are needed for ongoing prognostic studies.
Methods and results: To develop the conversion algorithm, 150 consecutive SPECT studies (82 abnormal) were read by both a 12-segment and the standard 17-segment models. Summed stress scores (SSSs) were calculated from a 17-segment model derived from the 12-segment data and compared to those of the standard 17-segment model. The effect of the conversion algorithm on prognostic data derived from the 12-segment model was evaluated in 25,876 patients from the Duke Nuclear Cardiology Database, including a sample of 3,205 patients with known covariates for adjusted analysis. The derived 17-segment SSS from the 12-segment model was highly correlated (R = 0.99) to the SSS from the standard 17-segment model. In both unadjusted and adjusted analysis, there was no difference in the prognostic information.
Conclusions: An algorithm for conversion of 12-segment perfusion scores to 17-segment scores has been developed which is highly correlated to visual interpretation by the 17-segment model with nearly identical prognostic information.