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Wallerian degeneration after cerebral infarction: evaluation with sequential MR imaging
M J Kuhn1, D J Mikulis, D M Ayoub
1Department of Radiology, St John's Hospital, Southern Illinois University School of Medicine, Springfield 62708.
Radiology
|July 1, 1989
Summary
Magnetic resonance (MR) imaging reveals distinct signal changes in Wallerian degeneration of the corticospinal tract. These changes, including a dark signal then a bright signal, aid in tracking degeneration after stroke.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Wallerian degeneration is a process that affects the corticospinal tract following cerebral infarction.
- Understanding its dynamic changes on magnetic resonance (MR) imaging is crucial for diagnosis and prognosis.
Purpose of the Study:
- To evaluate the dynamic signal intensity changes in active and chronic Wallerian degeneration of the corticospinal tract using MR imaging.
- To correlate MR imaging findings with the timeline of Wallerian degeneration post-stroke.
Main Methods:
- MR imaging was performed on 43 patients with Wallerian degeneration after cerebral infarction.
- Prospective imaging at weekly intervals for several months was conducted for acute stroke patients.
- T2-weighted images were analyzed for signal intensity changes in the corticospinal tract.
Main Results:
- Focal infarction without distal axonal degeneration was observed for the first month post-symptom onset.
- A hypointense signal band appeared in the corticospinal tract at 4 weeks on T2-weighted images.
- The signal became permanently hyperintense after 10-14 weeks, with accompanying brainstem shrinkage over years.
Conclusions:
- Dynamic MR imaging signal changes characterize active and chronic Wallerian degeneration.
- The transitory hypointense signal between 4-14 weeks is likely due to increased lipid-protein ratio.
- MR imaging findings provide insights into the temporal evolution of Wallerian degeneration.