Diffusion tensor imaging may help the determination of time at onset in cerebral ischaemia

K. Sakai, K. Yamada, Y. Nagakane, S. Mori, M. Nakagawa, T. Nishimura

Research output: Contribution to journalArticlepeer-review

Abstract

Background and aim: The apparent diffusion coefficient (ADC) and anisotropy (eg, fractional anisotropy (FA)) of ischaemic tissue evolve over time. A reduction in diffusivity (ie, λ2 and λ3) is an important marker for characterising hyperacute-stage infarction, as these parameters may reflect axonal membrane status. The study examines whether transverse diffusivity could be useful in assessing white matter infarcts of various ages. Methods: Diffusion tensor imaging data from 44 adult patients (34 men, 10 women, aged 46 to 89 years, mean=70.3) with acute white matter infarction (1-168 h) of the internal capsule were analysed. Relative eigenvalues were calculated as: (λipsicontra)/λcontra. Lesions were classified based on theoretically expected evolution of diffusivity over time as follows: stage I, FA higher than the contralesional region of interest (ROI); stage II, diffusivity lower than the contralesional side for all eigenvalues; stage III, one of two transverse eigenvalues (λ2 or λ3) higher than the contralesional ROI. Results: Stage I infarcts (n=5) were found primarily within 24 h of the onset of symptoms, with one case found on the third day. Stage II infarcts were found most commonly within 24 h (n=18), and fewer after 24 h. After the first day, the ratio of stage III infarcts increased significantly. Thus, diffusivity-based classification of white matter infarcts seems to show a chronological trend. Conclusions: Diffusion anisotropy may be useful for defining the biological tissue clock of white matter infarctions.

Original languageEnglish (US)
Pages (from-to)986-990
Number of pages5
JournalJournal of Neurology, Neurosurgery and Psychiatry
Volume80
Issue number9
DOIs
StatePublished - Sep 2009

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology
  • Psychiatry and Mental health

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