Motor outcome prediction using diffusion tensor tractography of the corticospinal tract in large middle cerebral artery territory infarct

Abstract

Middle cerebral artery (MCA) territory infarct is the most common type of cerebral vascular territory infarct. Accurate prediction of motor outcome is important for stroke rehabilitation. We conducted an investigation of prognostic factors of motor outcome in patients with a large MCAterritory infarction, using diffusion tensor tractography (DTT) of the corticospinal tract (CST). A total of 37 consecutive hemiparetic patients with a large MCA territory infarct were recruited for this study; DTT was performed within 5-30 days after onset. Patients were classified into three groups according to DTT findings: in group A - CST integrity was preserved around infarct regions, in group B - CSTs were discontinuous, and, in group C - the upper ends of CSTs did not reach infarcted regions. Fractional anisotropy (FA) ratio of the affected CST (versus the unaffected ipsilateral CST) was calculated, and evaluation of motor function was performed using the Motricity Index (MI), modified Brunnstrom classification (MBC) score, and the functional ambulation category (FAC) score at onset and at six months after onset. Significantly greater changes in motor function (MI, MBC, and FAC) were observed between onset and six months post-onset in group A, compared with groups B and C (p < 0.05). However, no significant difference was observed between groups B and C (p > 0.05). FA ratios showed positive correlation with six-month MIs, and scores for MBC and FAC (p < 0.05). Results of this study demonstrate the usefulness of early DTT findings of CSTs for prediction of motor outcome in patients with a large MCA territory infarct.