Is computed tomography attenuation correction more efficient than gated single photon emission computed tomography analysis in improving the diagnostic performance of myocardial perfusion imaging in patients with low prevalence of ischemic heart disease?

Abstract

The purpose of this study was to compare computed tomography (CT)-based attenuation correction (AC) using a hybrid single photon emission computed tomography (SPECT)-CT system and quantitative analysis of wall thickening using gated SPECT with regard to the diagnostic accuracy of myocardial perfusion imaging. We prospectively included 70 patients with low prevalence of acute coronary artery disease who underwent a myocardial stress-rest SPECT study. Interpretation was based on supine nongated SPECT data with (AC) or without (NC) CT-based attenuation correction, and on gated SPECT data without attenuation correction (GNC). The scintigraphic diagnosis was obtained using standard automated quantitative analysis software and compared with a 23±14 months' clinical follow-up for 57 patients or with the results of a coronary angiography for 13 patients. The sensitivity, specificity, and overall accuracy were, respectively, 77, 60, and 63% for NC SPECT, 67, 81, and 79% for AC SPECT, and 69, 98, and 93% for GNC SPECT. The initial diagnosis was modified in about one-third of the cases for both AC and GNC, this rate being independent of any clinical parameter (including BMI) except sex (two to four times more artifact correction in men). Its widespread availability, cost effectiveness, safety in terms of radiation exposure, and ability to significantly improve myocardial perfusion imaging specificity and accuracy make gated SPECT a self-sufficient modality for coronary artery disease screening and follow-up, whereas CT-AC should be discussed on a case-by-case basis.