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Diffusion-weighted MR in reversible wernicke encephalopathy
M Bergui1, G B Bradac, J J Zhong
1Neuroradiology Department, SG Battista Hospital, University of Turin, Italy.
Abstract:
Diffusion-weighted images (DWI) of a patient with Wernicke encephalopathy were obtained during routine MR examination. Mammillary bodies were hyperintense on T2-weighted and enhanced on T1-weighted images; on DWI, a mild hyperintensity was noticed. Calculation of the apparent diffusion coefficient (ADC) demonstrated an increased diffusion on the affected regions; the hyperintensity on DWI was probably due to a "T2-shine-through" effect. These findings are consistent with the presence of extracellular oedema, without significant neuronal damage. The patient recovered promptly after thiamine administration, and MR alterations disappeared. The favourable evolution indicates that no relevant neuronal death occurred. This is consistent with DWI findings. DWI are more sensitive than ordinary T1- and T2-weighted images to neuronal irreversible damage, and may differentiate between neuronal necrosis and extracellular oedema in various brain pathologies. The demonstration of a limited neuronal damage may represent a favourable prognostic factor in patients with WE.
Insights
Diffusion-weighted imaging (DWI) in Wernicke encephalopathy shows extracellular edema, not significant neuronal damage. This finding predicts a favorable prognosis and recovery after thiamine treatment.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Wernicke encephalopathy (WE) is a neurological disorder caused by thiamine deficiency.
- Magnetic resonance imaging (MRI) is crucial for diagnosing WE and assessing its severity.
- Diffusion-weighted imaging (DWI) offers insights into tissue microstructure and potential neuronal damage.
Observation:
- Routine MRI revealed hyperintensity in mammillary bodies on T2-weighted and T1-weighted images.
- Mild hyperintensity was observed on DWI, with increased apparent diffusion coefficient (ADC) values.
- The DWI findings were attributed to a T2-shine-through effect, indicating extracellular edema.
Findings:
- DWI and ADC mapping suggest extracellular edema rather than significant neuronal necrosis in this WE case.
- The observed MRI alterations resolved following thiamine administration.
- These imaging findings correlate with the patient's prompt clinical recovery.
Implications:
- DWI may be more sensitive than conventional MRI sequences in detecting early, reversible neuronal injury.
- Identifying limited neuronal damage via DWI could serve as a favorable prognostic indicator in Wernicke encephalopathy.
- This approach may help differentiate between reversible edema and irreversible neuronal damage in various brain pathologies.