Evaluating ischemic stroke with diffusion tensor imaging

In recent years, diffusion tensor imaging (DTI) has emerged as a promising tool to study ischemic stroke. The aim of this study is to evaluate the anisotropic changes of cerebral white matter tracks in patients with ischemic stroke using DTI, and investigate the correlation between corticospinal tract damage and muscle strength in such patients during acute ischemia.

Nine patients with acute ischemic stroke and nine healthy subjects were examined with T1 weighted magnetic resonance imaging (MRI), T2 weighted MRI and DTI. Fractional anisotropy (FA) was measured and the three-dimensional fibrous band images of bilateral corticospinal tracts were reconstructed. The muscle strength of the affected hand was assessed by Brunnstorm standard.

In the control group, there was no significant difference in FA between the bilateral corticospinal tracts, but FA in different white matter structures of the same side was significantly different (t=3.12, p<0.05); while in the patient group, FA of the infarcted sites was significantly lower than the contralateral ones (t=5.570, p<0.01). The ipsilateral corticospinal tract demonstrated continuous interruption and the loss of consistent anatomic structure. The involved severity of corticospinal tract had significant correlation with that of muscle strength of the ipsilateral hand (r=1.30, p<0.01).

This study shows that DTI can be used to investigate ischemic stroke and assess ischemic stroke-induced damage. The damaged severity of corticospinal tracts is correlated with that of muscle strength.