Proton MR spectroscopic imaging in Pelizaeus-Merzbacher disease.
OBJECTIVE
Pelizeaus-Merzbacher disease (PMD) is a clinically and molecularly heterogeneous disorder linked to deletion, mutations, or duplication of the proteolipid protein (PLP1) gene locus at Xq22. The current study was conducted to characterize the results of proton MR spectroscopic (MRS) imaging in PMD.


METHODS
Three boys with PMD (one with the severe connatal form and two with a more mild clinical phenotype [spastic paraplegia type 2]). and three age-matched healthy control subjects (age range, 2-7 years) underwent MR and MRS imaging. All imaging was performed at 1.5 T. For MRS imaging, oblique-axial sections (thickness, 15 mm; intersection gap, 2.5 mm) were recorded parallel to the anterior commissure-posterior commissure line (TR/TE/NEX, 2300/272/1) with lipid and water suppression. Ratios of metabolite peak areas were calculated, and spectra were bilaterally evaluated.


RESULTS
Diffuse or focal reductions in N-acetylaspartate were observed in the affected white matter in all three cases. These reductions seemed to be consistent with axonal damage. In addition, mild increases in choline and creatine levels were observed; these may have been due to astrocytic changes.


CONCLUSIONS
Proton MRS imaging may be helpful in evaluating regional pathophysiologic abnormalities in PMD and in distinguishing PMD from other leukodystrophies, which exhibit different metabolic profiles.
D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003937:Diagnosis, Differential; D004292:Dominance, Cerebral / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008565:Membrane Proteins; D018991:Myelin Proteolipid Protein / Q000235:genetics; D020371:Pelizaeus-Merzbacher Disease / Q000175:diagnosis* / Q000235:genetics; D010641:Phenotype; D018807:Polymorphism, Single-Stranded Conformational; D012016:Reference Values; D015419:Spastic Paraplegia, Hereditary / Q000175:diagnosis / Q000235:genetics
D008565:Membrane Proteins; D018991:Myelin Proteolipid Protein; C472930:PLP1 protein, human; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline