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White matter ischemic changes in hyperacute ischemic stroke: voxel-based analysis using diffusion tensor imaging and

Kambiz Nael1, Theodore P Trouard2, Scott R Lafleur2

  • 1From the Departments of Medical Imaging (K.N., T.P.T., E.A.K., C.S.K.), Biomedical Engineering (T.P.T., S.R.L., E.A.K.), Neurology (C.S.K.), University of Arizona, Tucson; and Department of Radiology, University of California, Los Angeles (N.S.). Kambiznael@gmail.com.

Stroke
|December 20, 2014
PubMed
Abstract

Insights

Diffusion tensor imaging reveals altered white matter (WM) fractional anisotropy (FA) in acute ischemic stroke. FA is decreased in infarcted areas and increased in hypoperfused WM, indicating early microstructural changes.

Area of Science:

  • Neuroimaging
  • Stroke Research
  • Diffusion Tensor Imaging

Background:

  • Acute ischemic stroke leads to white matter (WM) damage.
  • Diffusion tensor imaging (DTI) measures WM integrity.
  • Fractional anisotropy (FA) is a key DTI metric.

Purpose of the Study:

  • To quantitatively assess changes in WM fractional anisotropy (FA) using DTI in acute ischemic stroke.
  • To differentiate between infarcted and hypoperfused WM regions.
  • To correlate FA changes with perfusion parameters like Tmax.

Main Methods:

  • Prospective study of 21 acute ischemic stroke patients within 6 hours of onset.
  • Acquired DTI and dynamic susceptibility contrast perfusion imaging.
  • Voxel-based analysis of FA, ADC, and Tmax maps in affected and contralateral WM.

Main Results:

  • Significant differences in FA, ADC, and Tmax were found across normal, hypoperfused, and infarcted WM (P<0.001).
  • FA was significantly higher in hypoperfused WM (0.397±0.019) and lower in infarcted WM (0.313±0.037) compared to normal WM (0.360±0.020).
  • Regression analysis identified a significant FA difference in hypoperfused WM at Tmax ≥ 5.4 s (P=0.0096).

Conclusions:

  • DTI-FA is decreased in infarcted WM and increased in hypoperfused WM in hyperacute ischemic stroke.
  • Elevated FA in hypoperfused WM with Tmax ≥ 5.4 s suggests early microstructural alterations.
  • Quantitative DTI analysis can detect early ischemic changes in WM.
Keywords:
diffusion imagingischemiamagnetic resonance imagingperfusion imagingstroke

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