Heterogeneity of myocardial wall motion and thickening in the left ventricle evaluated with quantitative gated SPECT

Background. Global and regional ventricular function may be evaluated by us ing gated myocardial perfusion single photon emission computed tomography ( SPECT), This study investigated two parameters of regional contraction of t he left ventricle, segmental wall motion (WM) and wall thickening (WT), to determine their similarity and disparity in each myocardial segment in pati ents with normal myocardial perfusion. Methods and Results. Thirty-five patients with normal myocardial perfusion and cardiac function (mean left ventricular ejection fraction, 62.6% +/- 8. 8%) were included in this study. A I-day stress/rest protocol was used as a means of acquiring technetium 99m (Tc-99m) sestamibi gated SPECT protocol for each patient. A commercially available software package for quantitativ e gated SPECT (QGS) was used to generate cine loop three-dimensional surfac e display and SPECT images. The left ventricle was divided into 9 segments to score WM and WT ton a scale of 0 to 4, with 0 being normal and 4 being s everely reduced) by 6 independent observers. The WM score was significantly higher than the WT score in the septum, wher eas the WM score was lower than the WT score in the inferior segment. Simil ar WM and WT scores were observed in the remaining segments. Conclusions. Heterogeneous myocardial WM and WT were observed by using QGS software. These findings suggest that different criteria are required in ea ch segment to evaluate segmental WM and WT by means of gated myocardial per fusion SPECT.