Value of attenuation correction on ECG-gated SPECT myocardial perfusion imaging related to body mass index

Background. Obesity is a growing problem in the United States, and attenuation artifacts are more prevalent in this patient group. This study evaluated the impact of attenuation correction in patients with a high body mass index (BMI). Methods and Results. Three readers interpreted gated attenuation-corrected and non-attenuation-corrected rest/stress technetium 99m sestamibi myocardial perfusion imaging results in 116 patients (BMI < 30, n = 60; BMI >= 30, n = 56) who had coronary angiography no more than 60 days after imaging. Readers were blinded to all clinical information and as to whether myocardial perfusion imaging was attenuation-corrected or non-attenuation-corrected. Sensitivity, specificity, and accuracy for detection of coronary artery disease of 70% or greater for attenuation-corrected versus non-attenuation-corrected single photon emission computed tomography (SPECT) were 86% versus 89%, 79% versus 50%, and 84% versus 79%, respectively. Sensitivity, specificity, and accuracy for attenuation-corrected versus non-attenuation-corrected SPECT for patients with BMI less than 30 were 90% versus 90%, 82% versus 64%, and 88% versus 85%, respectively. For BMI of 30 or greater, the results were 82% versus 87%, 76% versus 41%, and 80% versus 73%, respectively. There was a significant difference in specificity overall (P = .02) and for the category of BMI of 30 or greater (P = .03). Conclusions. This study demonstrates that electrocardiography-gated attenuation-corrected Tc-99m sestamibi SPECT myocardial perfusion imaging improves specificity compared with electrocardiography-gated non-attenuation-corrected SPECT myocardial perfusion imaging, especially in patients with BMI of 30 or greater.