The Propagation of Physiological Rhythms in Human Brain Pulsation Observed on Magnetic Resonance Images

• Main Authors: Chau-Chiun Hwang, 黃朝群
• Other Authors: Yi-Hsuan Kao
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/60239980381217595978

碩士 === 國立陽明大學 === 放射醫學科學研究所 === 95 === Purpose： Physiological rhythms can influence the pulsation of brain tissues. For example, respiration can affect the pulsation of cerebrospinal fluid and heart beat can modulate the cerebral blood flow. We investigated the spatial locations and temporal delays of physiological signals observed in human brains. Material and Methods： Twelve healthy volunteers were scanned by using an echo planar imaging technique on a 1.5 Tesla magnetic resonance scanner. They were instructed to performed normal breathing and breath-holding experiments during the scans. Respiratory signals, electrocardiography, and arterial blood pressure were simultaneously recorded. By using cross-correlation analysis in the frequency domain and measurements in selected regions of interest, the delays in physiological signals, the spatial locations and temporal delays of physiological signals in human brains were studied. Results： We found that signals from respiratory belts and tachogram, which was calculated form electrocardiography, oscillated in opposite amplitudes. Because respiration is a periodical motion, it is possible that these two signals are negatively correlated with zero delay, or they are positively correlated with a delay of half a cycle. Signals from tachogram and arterial blood pressure appeared in similar patterns. On MR images, we observed the propagation of respiratory and cardiac rhythms in ventricles. Conclusions： We proposed a MR imaging technique for studying the propagation of physiological rhythms in human brain. Spatial locations and temporal delays of the physiological in human brains can be calculated on a pixel by pixel basis.