Limited incremental diagnostic values of attenuation-noncorrected gating and ungated attenuation correction to rest/stress myocardial perfusion SPECTin patients with an intermediate likelihood of coronary artery disease

Either gated myocardial perfusion SPECT or attenuation-corrected SPECT can be used to improve specificity in the diagnosis of coronary artery disease (CAD). We investigated whether attenuation-noncorrected gating and ungated attenuation correction could improve the diagnostic performance of rest/str ess perfusion SPECT in patients having an intermediate pretest likelihood o f CAD. Methods: Sixty-eight patients (29 men, 39 women; mean age, 59 +/- 12 y) with coronary artery stenosis greater than or equal to 70% (1 vessel, n = 13; 2 vessels, n = 18; 3 vessels, n = 8; normal, n = 29) underwent rest attenuation-corrected Tl-201 SPECT and dipyridamole stress gated attenuatio n-corrected Tc-99m-methoxyisobutyl isonitrile SPECT with an ADAC vertex cam era. Three physicians graded the post-test likelihood of CAD for each arter ial territory using a 5-point scale (1, normal; 2, possibly normal; 3, equi vocal; 4, possibly abnormal; 5, abnormal). The sensitivity, specificity, an d areas under receiver-operating-characteristic curves were compared for ea ch operator by 3 methods: attenuation-noncorrected rest/stress SPECT, gated poststress SPECT plus attenuation-noncorrected rest/stress SPECT, and atte nuation-corrected rest/stress SPECT plus gated poststress SPECT plus attenu ation-noncorrected rest/stress SPECT Results: When higher than grade 3 was used as the criterion for CAD, no differences in sensitivity and specificit y were found among the 3 methods for each operator, Areas under receiver-op erating-characteristic curves for the diagnosis of CAD and stenosis reveale d no differences for each modality (P > 0.05 for each comparison). Conclusi on: In patients with an intermediate risk of CAD, viewing attenuation-nonco rrected gated poststress SPECT and ungated attenuation-corrected rest/stres s SPECT images did not improve the diagnostic performance for CAD and steno sis.