The role of brain MRI in mitochondrial neurogastrointestinal encephalomyopathy
Mauro Scarpelli1, Giuseppe Kenneth Ricciardi, Alberto Beltramello
1Department of Neurological and Movement Sciences, Section of Neurology, University of Verona; Verona, Italy - mauro.scarpelli@univr.it.
Abstract:
Leukoencephalopathy is a hallmark of mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) a devastating disorder characterized by ptosis, ophthalmoparesis, gastrointestinal dysfunction and polyneuropathy. To characterize MNGIE-associated leukoencephalopathy and to correlate it with clinical, biochemical and molecular data, four MNGIE patients with heterogeneous clinical phenotypes (enteropathic arthritis, exercise intolerance, CIDP-like phenotype and typical presentation) were studied by magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps were also obtained. In two patients we also investigated the role of brain MRI in monitoring the evolution of leukoencephalopathy by performing follow-up imaging studies at an interval of one and two years. The extension and distribution of leukoencephalopathy were not clearly linked with age, phenotype or disease severity, and did not seem to be related to TYMP mutations, enzyme activity or pyrimidine levels. In the studied patients MRS revealed reduced N-acetyl-aspartate and increased choline signals. Although DWI appeared normal in all patients but one, ADC maps always showed moderate increased diffusivity. Leukoencephalopathy worsened over a two-year period in two patients, regardless of the clinical course, indicating a lack of correlation between clinical phenotype, size and progression of white matter abnormalities during this period. Brain MRI should be considered a very useful tool to diagnose both classical and atypical MNGIE. Serial MRIs in untreated and treated MNGIE patients will help to establish whether the leukoencephalopathy is a reversible condition or not.
Insights
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) involves leukoencephalopathy, a white matter abnormality. Brain MRI is crucial for diagnosing MNGIE and monitoring its progression, though its reversibility remains uncertain.
Area of Science:
- Neuroimaging
- Neurology
- Biochemistry
Background:
- Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare, severe disorder.
- Leukoencephalopathy is a key feature of MNGIE, impacting the brain's white matter.
- Clinical presentations of MNGIE are diverse, including ptosis, ophthalmoparesis, gastrointestinal issues, and polyneuropathy.
Purpose of the Study:
- To characterize leukoencephalopathy in MNGIE patients using advanced MRI techniques.
- To correlate imaging findings with clinical, biochemical, and molecular data.
- To assess the utility of brain MRI in diagnosing and monitoring MNGIE progression.
Main Methods:
- Four MNGIE patients with varied phenotypes underwent MRI, including diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS).
- Apparent diffusion coefficient (ADC) maps were analyzed to assess water diffusion in white matter.
- Follow-up imaging was performed on two patients over two years to track leukoencephalopathy evolution.
Main Results:
- Leukoencephalopathy extension and distribution showed no clear link to age, phenotype, disease severity, TYMP mutations, enzyme activity, or pyrimidine levels.
- MRS revealed reduced N-acetyl-aspartate and elevated choline signals in affected patients.
- While DWI was mostly normal, ADC maps consistently indicated increased diffusivity; leukoencephalopathy worsened over two years in two patients, irrespective of clinical course.
Conclusions:
- Brain MRI is a valuable tool for diagnosing both typical and atypical MNGIE presentations.
- The study highlights a lack of correlation between clinical phenotype and the progression of white matter abnormalities.
- Serial MRIs are essential for determining if MNGIE-associated leukoencephalopathy is reversible.
