Incremental value of combined perfusion and function over perfusion alone by gated SPECT myocardial perfusion imaging for detection of severe three-vessel coronary artery disease

We hypothesized that combining functional assessment to perfusion enhances the ability of electrocardiographic gating Tc-99m sestamibi single photon emission computed tomography (gated SPECT) myocardial perfusion imaging (MPI) to detect defects in multiple vascular territories in patients with severe three-vessel coronary artery disease (3VD). In patients with 3VD, perfusion defects in multiple vascular territories may not always be evident due to globally reduced perfusion. Gated SPECT MPIs were interpreted sequentially with perfusion first, followed by combined perfusion/function, in 143 patients with angiographic 3VD and a control group of 112 non-3VD patients. All patients underwent coronary arteriography within one month of MPI. In 3VD patients, combined perfusion/function analysis yielded significantly greater numbers of abnormal segments/patient (6.2 ± 4.7 vs. 4.1 ± 2.8, p < 0.001) and more defects in multiple vascular territories (60% vs. 46%, p < 0.05) than perfusion alone. In the control group, there were no differences between the combined perfusion/function and perfusion alone interpretations. Multivariate analysis of 15 different clinical, stress, and scintigraphic variables in all patients revealed age (p < 0.0001) and number of abnormal vascular territories by combined perfusion/function (p < 0.0001) to be the most powerful predictors of 3VD. Addition of functional data to clinical, stress, and perfusion yielded a significant increase in the predictive value of 3VD (global chi-square: 131.7 vs. 89.8, p < 0.00001). Specificity of combined perfusion/function analysis was not lower than perfusion alone (72% vs. 69%, p = NS). Adjunctive assessment of function with perfusion by gated SPECT MPI enhances the detection of defects in multiple vascular territories in patients with severe 3VD, without adversely affecting its specificity.