Prone imaging allows efficient radiopharmaceutical usage by obviating the necessity of a rest study in Tc-99m-methoxyisobutylisonitrile myocardial perfusion scintigraphy.

ABSTRACT

OBJECTIVE: In myocardial perfusion single-photon emission computed tomography studies, diaphragmatic attenuation of the inferior wall is a common artifact, which can be minimized by prone imaging. The aim of this retrospective study was to validate the impact of stress-prone imaging on the necessity of a rest perfusion study with a final goal of effective radiopharmaceutical usage. METHODS: The findings of 98 patients who had been examined by a combined supine and prone imaging were retrospectively evaluated. Prone acquisition was performed only when reduced perfusion was observed in the inferior wall on the stress supine images. The reconstructed images were evaluated both visually and quantitatively. Rest myocardial single-photon emission computed tomography study was omitted in patients with complete normalization of uptake in the prone images. Results obtained were also compared with the clinical data and follow-up. RESULTS: Prone imaging obviated the necessity of a rest perfusion study in 76 of 98 patients (77.5%). Among normally reported patients (n=89), 76 (85.4%) were saved from a rest study due to the prone study results. Prone study provided improved results in quantitative analysis as well. The difference between the mean summed stress scores of supine and prone studies was statistically significant in normally reported patients (P=0.013). However, no significant difference was observed in scores of ischemic patients (P=0.341). CONCLUSION: Adding prone imaging to a post-stress Tc-99m-methoxyisobutylisonitrile myocardial perfusion study not only minimizes the inferior wall attenuation, but also reduces the need for a rest test, particularly in low-risk or intermediate-risk patients. Thus, prone imaging seems to be both safe and effective.