Early abnormalities related to postinfarction Wallerian degeneration: Evaluation with MR diffusion-weighted imaging

Purpose: Wallerian degeneration (WD) is most commonly seen after cerebral infarctions and results in persistent neurological deficits. MRI may detect changes related to WD as early as 4 weeks after the insult. We sought to determine if MR diffusion-weighted imaging (DWI) detects changes of WD during the acute period that follows a cerebral infarction, Method: Eleven patients with cerebral infarctions underwent DWI within 72 h of the onset of symptoms. DWI was performed using a high diffusion gradient strength (B = 1,000) in a single axis and, trace imaging. We reviewed all images with special attention to the signal intensity in the location of the corticospinal tracts. Results: Ten patients harbored II middle cerebral artery (MCA) infarcts, and one patient had an anterior cerebral artery (ACA) infarction. Only one patient with an MCA infarct showed a subtle abnormality in the ipsilateral corticospinal tract. The patient with the ACA infarct showed an abnormality in the region of the corticopontine tract. Conclusion: As used in this study, DWI depicted presumed early WD in only 20% of instances.