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 thi ckening (WT) using gated myocardial perfusion single photon emission comput ed tomography (SPECT) and to determine their similarity and disparity in pa tients with coronary artery disease. A total of 44 patients underwent 1 day stress/rest (MIBI) gated SPECT. Commercially available quantitative analys is of gated SPECT (QGS) software was used to generate 3D surface display an d 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 i ndependent 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 \ less than or equal to 1) was 85%. A large difference between W M and WT (WM - WT greater than or equal to 2) was observed in 15 segments, including 12 segments with greater WM abnormalities and 3 segments with gre ater WT abnormalities (lateral and inferior walls). Greater WM abnormalitie s were most commonly observed in anteroseptal segments especially in post c oronary artery bypass grafting patients. In conclusion, WM and WT showed si milarity on QGS studies. However, these two parameters may be determined se parately 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.