Brain and Nerve No to Shinkei Volume 43, Issue 7 (July 1991)

The Application of In Vivo Diffusion Weighted Magnetic Resonance Imaging to Intracranial Disorders Toshihiko Ebisu 1 , Shoji Naruse 1 , Yoshiharu Horikawa 1 , Satoshi Ueda 1 , Chuzo Tanaka 2 , Masahiro Umeda 2 , Toshihiro Higuchi 2 , Koji Shimizu 3 , Naojiro Nishimura 3 , Shoichi Okamura 3 , Yasushi Hashimoto 3 , Masaya Takahashi 4 , Bernhard Fritz-Zieroth 4 1Department of Neurosurgery, Kyoto Prefectural University of Medicine 2Meiji College of Oriental Medicine 3Medical Systems Division, Shimadzu Corporation 4Research Division, Nihon Schering K.K. Keyword: anisotropy , diffusion , edema , ischemia , infarction pp.677-684
Published Date 1991/7/1
  • Abstract
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We have developed a magnetic resonance (MR) spin echo method to obtain diffusion weighted imag-ing using motion-probing gradient (MPG) pulses in one or three orthogonal directions before and after a 180 degree pulse. Phantom models containing water and acetone, normal volunteers and patients with brain tumors, brain edema and infarction were examined. Experimental models of brain edema including triethyltin intoxication and cold injuries were also examined in Wistar rats. MRI was perfor-med at a 1.0-T clinical machine or a 4.7-T experi-mental machine using spin echo pulse sequences with or without additional MPGs on one or three orthogonal axes.

The one direction method was useful to define diffusion anisotropy of myelinated axonal fibers in white matter. Faster diffusion was detected in the white matter parallel to the direction of MPGs. On the other hand, slower diffusion was detected per-pendicular to the direction of MPGs because the myelin sheath restricted water diffusion.

The three orthogonal gradients method was use-ful to demonstrate the difference in the diffusion coefficients in various diseases due to its larger total gradient strength. The clear distinction between the cytotoxic edema, which revealed slower diffusion, and the vasogenic edema, which revealed faster diffusion, was demonstrated in the experimental models using diffusion weighted image. In the clini-cal cases, faster diffusion was demonstrated in the brain tumor and perifocal vasogenic edema, whichwas in agreement with the results in the experimen-tal models of rats. Brain tumors such as low grade astroytoma with microcysts and perifocal vasogenic edema have very wide extracellular space. It is considered that water diffusion in the extracellular space is not restricted so tightly as in the intracel-lular space with many intracellular organs. On the other hand, slower diffusion was demonstrated in the cerebral ischemia and infarction. Intracellular edema may have a influence on slower diffusion, andmoreover, in consideration of Einstein's equation, lower tissue temperature may also influence on slower diffusion. The changes in edema can also detected by examining diffusion of water molecules. Resolving edema revealed medium speed diffusion which was neither especially fast nor very slow.

New clinical information obtainable with this method on molecular diffusion will prove to be useful in various clinical studies.

Copyright © 1991, Igaku-Shoin Ltd. All rights reserved.


Brain and Nerve 脳と神経
43巻7号 (1991年7月)
電子版ISSN 2185-405X 印刷版ISSN 0006-8969 医学書院