[Wallerian degeneration of the cortico-descending tract in the cerebral peduncle following a supratentorial cerebrovascular lesion detected by MRI--the relationship between Wallerian degeneration at the center of the cerebral peduncle and functional recovery of paresis].

We studied Wallerian degeneration of the cortico-descending tract in the cerebral peduncle following a supratentorial cerebrovascular lesion by MRI. A total of 57 patients with palsy following a supratentorial cerebrovascular lesion were prospectively studied. Wallerian degeneration was detected as a high signal intensity (HSI) in 37 patients between 70 days and 100 days after the onset, but not detected in the remaining 27 patients. Patient with an HSI in all area of the cerebral peduncle had a large lesion involving the hemisphere. Patient with an HSI at the center of the cerebral peduncle had a lesion confined to the paracentral gyrus, precentral gyrus, corona radiata or posterior limb of the internal capsule. Patient with an HSI at the lateral side of the cerebral peduncle had a lesion of parietal lobe or temporal lobe which spares the corticospinal tract originating from the paracentral gyrus, precentral gyrus, corona radiata or posterior limb of the internal capsule. These findings suggest that an HSI at the center of the cerebral peduncle may reveal Wallerian degeneration of the corticospinal tract, and an HSI at the lateral side of the cerebral peduncle may show Wallerian degeneration of the corticopontine tract. The functional recovery of paresis was poor in all patients with an HSI at the center of the cerebral peduncle, while it was good in all patients without an HSI in that region.(ABSTRACT TRUNCATED AT 250 WORDS)