Quantitative analysis of regional motion and thickening by gated myocardial perfusion SPECT: Normal heterogeneity and criteria for abnormality

Quantitation of regional myocardial function is valuable in patients with c oronary artery disease. This study assessed normal heterogeneity and develo ped and validated normal limits for quantitative regional motion and thicke ning by gated myocardial perfusion SPECT. Methods: Patients underwent rest (TI)-T-201/exercise Tc-99m-sestamibi gated SPECT. Reference values of motio n and thickening for 20 myocardial segments were obtained in 105 patients w ith <5% likelihood of coronary disease (low-likelihood group). Criteria for abnormality of motion and thickening were defined for each segment, using receiver operator characteristic analysis, in 101 patients with coronary di sease (training group). Semiquantitative visual interpretation was used as the gold standard. These criteria were prospectively validated in 100 patie nts (validation group). Criteria for grading motion and thickening abnormal ities by severity levels were also defined and validated. Results: Normal t hickening decreased substantially along the longitudinal axis of the left v entricle, from 69% +/- 13% at the apex to 25% +/- 11 % at the basal segment s, whereas normal motion varied within the same ventricular plane. Validati on of the criteria for abnormality yielded high accuracy in the detection o f motion abnormalities (sensitivity, 88%; specificity, 92%) and thickening abnormalities (sensitivity, 87%; specificity, 89%). Quantitative motion and thickening segmental scores showed good agreement with visual scores. Conc lusion: Normal regional myocardial contraction by gated myocardial perfusio n SPECT is characterized by a substantial apex-to-base decline in thickenin g and by circumferential heterogeneity in endocardial motion. The assignmen t of segment-specific threshold values for defining motion and thickening a bnormalities provided reasonably accurate identification and grading of reg ional myocardial dysfunction.