Local tissue anisotropy decreases in cerebellopetal fibers and pyramidal tract in multiple system atrophy.
BACKGROUND
One of the cardinal features in multiple system atrophy (MSA) is the white matter pathology: loss of myelin, astrocytosis, and glial cytoplasmic inclusions. The pathological changes of tissue microstructure can modify the diffusion behavior of water molecules, which can be assessed by diffusion tensor imaging (DTI).


OBJECTIVE
To explore the hypothesis of white matter degeneration in MSA.


METHODS
We studied 11 patients with clinically probable MSA and 10 age-matched controls. DTI was performed in both groups to measure fractional anisotropy (FA) in various regions of interest: the inferior cerebellar peduncle (ICP), middle cerebellar peduncle (MCP), superior cerebellar peduncle (SCP), basis pontis, internal capsule, and corpus callosum.


RESULTS
FA values in SCP and corpus callosum showed no significant difference between the MSA group and controls. By contrast, FA values decreased in the MSA group in the MCP, basis pontis and internal capsule. In addition, FA values in the MCP were negatively correlated with ataxia severity in the MSA group.


CONCLUSIONS
The areas showing decreased tissue anisotropy in DTI corresponded well with pathologically vulnerable areas in MSA. In addition, the local tissue anisotropy of MCP decreased in accordance with functional disability. These observations implied that DTI is a feasible method for in vivo evaluation of the white matter pathology in MSA.
Shiga
Kensuke
K
Department of Neurology and Geriatrics, Department of Radiology, Kyoto Prefectural University of Medicine, Kaijicho 465 Kamigyo-ku, Kyoto, 601-0841, Japan. kenshiga@koto.kpu-m.ac.jp
Yamada
Kei
K
Yoshikawa
Kenji
K
Mizuno
Toshiki
T
Nishimura
Tsuneo
T
Nakagawa
Masanori
M
D000368:Aged; D016880:Anisotropy; D002531:Cerebellum / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000473:pathology*; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011712:Pyramidal Tracts / Q000473:pathology*