The Usefulness of Diffusion Tensor MRI for the Prediction of Clinical Outcome in Patients with Acute Subcortical Infarction

Background: Diffusion tensor MRI (DTI) is a new imaging technique and enables us to analyze the structural damage of fiber pathways and to monitor the time course of Wallerian degeneration of the pyramidal tract in stroke patients. We used DTI to investigate structural changes of the infarct area and the associated descending corticospinal tract in patients with subcortical infarct. Methods: We examined 24 consecutive patients who presented with acute single cerebral infarct in the subcortical area and who also had undergone an MRI study within 7 days after symptom onset. Clinical outcome was assessed using the National Institutes of Health Stroke Scale ( NIHSS) at admission, 7 days, 14 days and 30 days and modified Rankin Scale (mRS) at admission and 30 days. Each of the indices was achieved by post processing the acquired DTI data and correlated with the NIHSS. Results: In infarct region, fractional anisotropy (FA) was significantly decreased compared with matched-contra- lateral regions (0.39 vs. 0.53, p<0.001). In the distal to the infarct, FA was significantly decreased at internal capsule (0.62 vs. 0.64, p=0.019), not at pons (0.51 vs. 0.53, p=0.103). The decrease of anisotropy at infarct region correlated positively with the NIHSS at 7, 14 and 30 days and mRS at 30 days after stroke, but the decrease of anisotropy at internal capsule did not correlate with the NIHSS. Conclusions: This study shows the potential of DTI to detect and monitor the structural degeneration of fiber pathways and to establish the prognosis in patients with acute subcortical cerebral infarct. J Korean Neurol Assoc 24(5):447-451, 2006