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

Abstract

BACKGROUND AND AIMS:

The apparent diffusion coefficient (ADC) and anisotropy (eg, fractional anisotropy (FA)) of ischaemic tissue evolve over time. A reduction in diffusivity (ie, lambda(2) and lambda(3)) 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: (lambda(ipsi)-lambda(contra))/lambda(contra). 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 (lambda(2) or lambda(3)) 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.

• Authors: K Sakai, K Yamada, Y Nagakane, S Mori, M Nakagawa, T Nishimura
• Journal: Journal of neurology, neurosurgery, and psychiatry (J Neurol Neurosurg Psychiatry) Vol. 80 Issue 9 Pg. 986-90 (Sep 2009) ISSN: 1468-330X [Electronic] England
• PMID: 19684233 (Publication Type: Comparative Study, Journal Article)

Topics

• Acute Disease
• Aged
• Aged, 80 and over
• Anisotropy
• Brain Ischemia (complications, diagnosis, pathology)
• Cerebral Infarction (diagnosis, pathology)
• Diffusion Magnetic Resonance Imaging
• Female
• Functional Laterality (physiology)
• Humans
• Male
• Middle Aged
• Nerve Fibers (pathology)
• Stroke (diagnosis, etiology, pathology)