In response to the article by M.B. Imran, K. Morita, I. Adachi, M. Konno, N. Kubo, T. Mochizuki, C. Katoh, T. Kohya, A. Kitabatake, E. Tsukamoto & N. Tamaki Comparison between segmental wall motion and wall thickening in patients with coronary artery disease using quantitative gated SPECT software

This study was performed to evaluate regional wall motion (WM) and wall thickening (WT) using gated myocardial perfusion single photon emission computed tomography (SPECT) and to determine their similarity and disparity in patients with coronary artery disease. A total of 44 patients underwent 1 day stress/rest (MIBI) gated SPECT. Commercially available quantitative analysis of gated SPECT (QGS) software was used to generate 3D surface display and cine-mode SPECT display. Left ventricle was divided into nine segments to score WM and WT from 0 (no abnormality) to 4 (severe abnormality) by six independent observers. Finally a mean score was calculated for each segment from the scores of six observers. There was fairly good correlation between WM and WT of individual segments (r = 0.62, p < 0.0001). Concordance rate (|WM − WT| ≤ 1) was 85%. A large difference between WM and WT (WM − WT ≥ 2) was observed in 15 segments, including 12 segments with greater WM abnormalities and 3 segments with greater WT abnormalities (lateral and inferior walls). Greater WM abnormalities were most commonly observed in anteroseptal segments especially in post coronary artery bypass grafting patients. In conclusion, WM and WT showed similarity on QGS studies. However, these two parameters may be determined separately in gated SPECT studies for comprehensive and robust evaluation of the functional status of myocardium. Analyses based on WM assessment alone may lead to erroneous results especially in septal regions.