[Wallerian degeneration demonstrated by MRI and functional outcome in patients suffering from supratentorial cerebrovascular disease].

An early diagnosis of the outcome of patients with cerebrovascular disease is important for selecting the optimal treatment strategy. The purpose of this study was to estimate the prognosis of Wallerian degeneration on MRI in stroke patients with hemiparesis. The subjects consisted of 87 stroke patients, 50 hemorrhagic patients and 37 ischemic patients, who were evaluated by MRI at 1 to 6,275 days after stroke onset. Among the 36 patients who were evaluated by consecutive MRI, 161 films were obtained and analyzed. Wallerian degeneration was diagnosed when a small prolonged T 2 lesion was seen in the corticospinal tract of the brainstem on at least two contiguous slices. The atrophic rate of the midbrain was calculated as: (the area of the unaffected side of the midbrain--the area of the affected side of the midbrain)/2 x (the area of the unaffected side of the midbrain). The patients' ability to perform the activities of daily living was scored by the Barthel index (BI). Wallerian degeneration in the ipsilateral brainstem was seen for two to three months in 32 cases (37%) and in 58 films (36%) and disappeared about 3 years after the onset of stroke. Wallerian degeneration correlated with the BI scores from 2 to 6 months after stroke (p < 0.05), although no relationship was observed at 7 months or later. From 2 to 6 months after stroke, the shrinkage of the midbrain on MRI correlated with the BI scores (p < 0.001), although no relationship was observed at 7 months or later. It was therefore both Wallerian degeneration and a shrunken midbrain observed on MRIs, evaluated from 2 to 6 months after stroke were thus suggested to indicate a poor outcome in such patients.