Comparison of non-attenuation corrected and attenuation corrected myocardial perfusion SPECT

Abstract

To assess the significance of attenuation correction on sensitivity, specificity and diagnostic accuracy of myocardial perfusion SPECT. 102 patients referred for myocardial perfusion imaging (MPI) were divided into two groups: 42 patients (mean age: 54.6 ± 12.6) were enrolled in the group A, who had undergone coronary artery angiography, within six months of the scan. 60 patients (mean age: 49.79 ± 11.3) were placed in the group B who had a <15% pretest likelihood of CAD. Both non-corrected (NC) and attenuation corrected (AC) images were visually analyzed according to 17-segment model of the left ventricular cavity. Visual assessment derived sensitivity, specificity, diagnostic accuracy and normalcy rate of NC and AC sets of images were compared using McNemar test. Sensitivity, specificity and diagnostic accuracy for detection of coronary artery disease were found to be 100%, 11% and 79% respectively for NC images and 66%, 78% and 68% for AC images. The p value was found to be significant in only the RCA territory. Normalcy rates in the group B population were 19% for NC image set and 74% for the AC image set. No significant difference on basis of BMI was observed in attenuation corrected scans. The technique appears to be more valuable in men. This study demonstrates that CT based attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging significantly improved the specificity of the RCA territory compared with non-attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging in both genders irrespective of BMI.