The MRI pattern and specific imaging findings in neurometabolic diseases and other inherited metabolic disorders with profound CNS manifestations.
| Neurometabolic Disorders & other Inherited Metabolic disorders (with profound CNS manifestations) | Inheritance | Brain Magnetic Resonance Imaging Findings | Magnetic Resonance Spectroscopy | |
|---|---|---|---|---|
| Disorders of Protein metabolism | Organic aciduria (glutaric aciduria) | AR | Bilateral basal ganglia lesions with restricted diffusion during acute encephalopathy, cerebral dysgenesis (enlarged Sylvian fissures, wide CSF spaces anterior to the temporal poles), macrocephaly | Decreased N-acetyl-aspartate (NAA)/ creatine (Cr) ratio, lactate peak within basal ganglia acutely |
| Urea cycle defect(Citrullinemia) | AR | White matter edema as result of hyperammonemia, basal ganglia involvement | Prominent increase of glutamine/ glutamate and lipid/lactate complexes, decrease of NAA | |
| Aminoacidopathy (MSUD) | AR | Vacuolating myelinopathy (intramyelinic edema), edematous lesions with restricted diffusion in the peri-rolandic white matter, posterior limb of the internal capsules, cerebral peduncles, brainstem, deep cerebellar white matter, and globi pallidi | Decreased N-acetylaspartate, methyl resonances of branched amino acids at 0.9–1.0 ppm, and lactate in acute metabolic decompensation | |
| Carbohydrate metabolism | Galactosemia | AR | Diffuse edema, diffusion restriction | Galactitol (Gal-ol) doublet peak at 3.7 parts per million |
| G6PD deficiency | X-linked | Symmetrical lesions in bilateral globus pallidus, hyperintense on T2/FLAIR | Kernicterus; increased levels of glutamine and glutamate along with decreased levels of choline and N-acetyl-aspartate | |
| Fatty Acid Oxidation Disorder | Carnitine deficiency, Acyl-Coenzyme Dehydrogenase Deficiency, glutaric aciduria type 2 | AR | Underdeveloped frontal and temporal lobes with enlarged sylvian fissures, delayed myelination,Multifocal parenchymal and intraventricular hemorrhages as well as white matter signal intensity changes | Normal N-acetylaspartate and an increased choline-creatine ratio |
| Peroxisomal disorders | Adrenoleukodystrophy (ALD) | X-linked | Deep white matter in the parieto-occipital lobes and splenium of the corpus callosum, cortical and subcortical U-fiber sparing, enhancement in 50% | Neuronal loss manifested by a decrease in the NAA peak and an elevation in the lactate peak |
| Zellweger Syndrome | AR | Ventricular enlargement, abnormal gyration patterns (pachygyria; especially medial gyri around peri-rolandic regions, polymicrogyria; laterally), cerebral periventricular pseudocysts | Nonspecific reduction of N-acetylaspartate with lipid accumulation | |
| Lysosomal disorders | Mucopolysaccharidosis | AR (except Hunter, MP-II; X-linked) | Enlarged perivascular spaces (“cribriform” or “spindle-like”), white matter lesions, hydrocephalus, cortical atrophy, ‘honeycomb-like’ appearance in the basal ganglia and thalami | Decreased N-acetylaspartate, total choline and glutamate in the white matter, and an elevation of myo-inositol, glucose-aminoglycans (GAG) peak at 3.7 ppm (higher than myoinositol) |
| Metachromatic Leucodystrophy (MLD) | AR | Bilateral symmetrical abnormal high SI on T2 and FLAIR images in the deep periventricular white matter, with sparing of the subcortical U fibers and peripheral “tigroid” or “leopard pattern” of dysmyelination | Reduced N-acetyl aspartate (NAA), increased myoinositol, increased lactate | |
| Krabbe disease(Globoid cell Leucodystrophy) | AR | High signal involving periventricular white matter, centrum semiovale and deep grey matter, sparing of subcortical U-fibres | Markedly reduced NAA, Abnormally high Cho/Cr ratio | |
| Neuronal Ceroid Lipofuscinosis (NCL) | AR | Generalized brain atrophy and hyperintense white matter changes | Reduced NAA, elevated lipids | |
| Mitochondrial Disorders | Leigh Syndrome | AR, X-linked | Symmetrical hyperintense lesions in the basal ganglia and/or brain stem on T2-weighted MR images | Elevated choline, occasionally elevated lactate, reduced NAA |
| Disorders of purine and pyrimidine metabolism | Lesch-Nyhan disease | X-linked | Decreased cerebral volume with a predilection for white matter, cortical and/or brainstem atrophy | Decreased metabolites, especially N-acetylaspartate and glutamate/glutamine, only in the prefrontal cortex |