Quantitative study of rigid-body and respiratory motion of patients undergoing stress and rest cardiac SPECT imaging

In our previous work we investigated the technique of obtaining patient motion estimates from retro-reflective markers on stretchy bands wrapped around the chest and abdomen of patients undergoing cardiac SPECT perfusion imaging [1]. Motion signals obtained from the markers were separated into two components, body motion (BM) and respiratory motion (RM). In this paper we studied the frequency of occurrence, the time and the extent of estimated body motion of patients, and the extent of respiratory motion. Additionally, studies were grouped by Stress or Rest imaging to determine statistically significant differences in respiratory and body motion. Based on 80 studies, with 40 pairs of Stress and Rest motion data, we found 39% of studies containing 3-6 mm and 10% containing more than 6 mm of body motion during emission imaging. About 26% of the studies contained body motion more than 3 mm during transmission imaging. In 21% of the studies, large respiratory baseline drift of more than 6 mm was observed. Stress and Rest studies showed significant differences in body motion and respiratory motion, all of which were associated with change in respiration due to stress.