Impact of combined supine and prone myocardial perfusion imaging using an ultrafast cardiac gamma camera for detection of inferolateral coronary artery disease

Background: Although combined supine and prone acquisitions improve the detection of inferolateral obstructive coronary artery disease (CAD), the predictors of inaccurate detection of inferolateral ischemia have not been reported by using cadmium zinc telluride (CZT) myocardial perfusion imaging (MPI).

Methods and results: Vasodilator stress (99m)Tc tetrofosmin MPI using CZT camera and coronary angiography was performed in 322 patients within an interval of 2 months. Prone MPI was performed immediately after supine MPI. Narrowing of the luminal diameter ≥ 75% was considered significant. The presence of an abnormality on both supine and prone images was considered significant. Combined supine and prone imaging, compared with supine-only quantification, was more specific (93% vs. 72%, respectively, p<0.0001) and accurate (88% vs. 74%, p<0.0001) without compromising sensitivity (82% vs. 68%, p=0.10). The area under the curve for detecting inferolateral ischemia was 0.769 (95% CI 0.705-0.833) for supine imaging and 0.802 (95% CI 0.730-0.875) for combined supine and prone imaging (p<0.05). Multivariable analysis revealed that previous inferolateral myocardial infarction was an independent predictor of a false diagnosis (odds ratio=3.45, 95% confidence interval [CI] 1.62-7.37, p<0.001).

Conclusions: Combined supine and prone quantitative CZT MPI enhances the detection of inferolateral CAD without adversely affecting its sensitivity. However, we recommend inferolateral ischemia be monitored in patients with a history of previous inferolateral MI because previous inferolateral MI is a predictor of inaccurate diagnosis.