Neuroimaging of Pediatric Metabolic Disorders with Emphasis on Diffusion-Weighted Imaging and MR Spectroscopy: A Pictorial Essay

AbstractPurpose of ReviewAlthough individually rare, metabolic brain disorders together account for significant disease burden in infants and children. MRI evaluation of these disorders is daunting, but using a pattern-based approach is helpful. Here we present 10 of the most commonly encountered metabolic brain disorders, highlighting specific features on DWI and MR spectroscopy that help narrow the differential diagnosis.Recent findingsA number of metabolic diseases result in elevated lactate at 1.3  ppm in affected areas. Other metabolite derangements, though, are more helpful in determining the underlying disease. MR spectroscopy showing elevated glycine at 3.55 ppm indicates nonketotic hyperglycinemia, while markedly elevated NAA at 2.0 ppm is characteristic of Canavan disease. NAA will b e low in diseases causing neuronal loss, and can be even absent in Alexander disease. Absent or severely low creatine at 3.0 ppm is specific for the family of creatine deficiency syndromes. The pattern of restricted diffusion seen with DWI can also point to a specific diagnosis, especially with bra instem and cerebellar white matter involvement seen with maple syrup urine disease. Additionally, both MR spectroscopy and DWI can be used to follow disease progression or response to therapy.SummaryDWI and MR spectroscopy are useful adjuncts to anatomic brain imaging in the evaluation of pediatric metabolic brain disorders.
Source: Current Radiology Reports - Category: Radiology Source Type: research