Toru Yamamoto1, Osamu Tsuchida2, T. Omatsu3
1Graduate School of Health Sciences, Hokkaido University, Sapporo, Hokkaido, Japan; 2Teishinkai Hospital, Japan; 3Hokkaido Univeisity Hospital, Japan
Each red blood cell (RBC) that discretely flows through a capillary distorts the magnetic field of magnetic resonance imaging. This distortion spreads over a micrometer range around the RBC and moves along the capillary, causing fast transverse relaxation. To investigate the changes in this fast transverse relaxation that occur due to blood oxygenation changes, we performed consecutive spin-echo imaging of human brain for 50 minutes with short (5.5 ms) and long (88 ms) echo times. The signal in the sagittal sinus showed a gradual decrease in blood oxygenation. Changes in the transverse relaxation rate in brain parenchyma observed in images with short echo time were more than ten times of those with long echo time.
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