Prediction of motor outcome in ischemic stroke involving the pyramidal tract using diffusion tensor imaging

Early evaluation of the pyramidal tract is a prerequisite in patients with ischemic stroke in order to decide the optimal treatment or to assess appropriate rehabilitation. The aim of this study was to predict motor outcome using quantitative and qualitative diffusion tensor parameters and their correlations with severity of stroke as defined by the National Institutes of Health Stroke Scale (NIHSS). Twenty-one patients presenting with ischemic stroke were studied with DTI. All patients had diffusion measurements such as FA values of the affected and unaffected regions and the FA ratio between them. Color FA maps of the pyramidal tract were constructed and the degree of infarctions was classified into groups according to the involvements of the pyramidal tracts. The motor performance of the upper and lower extremities was assessed using the NIHSS on the day of patients’ admission and discharge. The motor outcomes were correlated with the FA values of the pyramidal tract. The FA values of the affected pyramidal tracts were significantly lower as compared with the unaffected side (p-value <0.01). The reduction in the FA values of the affected side was significantly correlated (r = 0.41 and p-value <0.001) with the degree of pyramidal tract involvements that were significantly correlated with the motor outcome on patients’ discharge day. Quantitative (FA values) and qualitative (the diffusion tensor tractography) diffusion parameters have potential to predict motor outcome in patients with ischemic stroke.