The relation between motor function of stroke patients and diffusion tensor imaging findings for the corticospinal tract.

Although the corticospinal tract (CST) is a major neural tract for motor function, the detailed role of the CST has not been clearly elucidated. We investigated relations between motor function of patients with chronic hemiparetic stroke and diffusion tensor imaging (DTI) findings for the CST. We recruited 82 consecutive chronic stroke patients. Medical Research Council, Modified Brunnstrom Classification, and Functional Ambulatory Category were used in measurement of the affected side. All motor functions showed positive correlations with fractional anisotropy (FA) and fiber number (FN) ratios (p<0.05). With regard to Medical Research Council, shoulder abductor (r=0.70, 0.68), elbow flexor (r=0.75, 0.72), finger flexor (r=0.73, 0.74), and finger extensor (r=0.69, 0.77) showed strong correlations with FA and FN ratios. Modified Brunnstrom Classification (r=0.70, 0.73) also showed strong correlation. According to our findings, it appears that the CST is related to motor function of upper and lower extremities, with particular relation to motor function of upper extremities, including the hand, compared with other motor functions.