MR diffusion imaging and MR spectroscopy of maple syrup urine disease during acute metabolic decompensation.
Maple syrup urine disease (MSUD) is an inborn error of amino acid metabolism, which affects the brain tissue resulting in impairment or death if untreated. Imaging studies have shown reversible brain edema during acute metabolic decompensation. The purpose of this paper is to describe the diffusion-weighted imaging (DWI) and spectroscopy findings during metabolic decompensation and to assess the value of these findings in the prediction of patient outcome. Six patients with the diagnosis of MSUD underwent conventional MR imaging with DWI during acute presentation with metabolic decompensation. Spectroscopy with long TE was performed in four of the six patients. Follow-up examinations were performed after clinical and metabolic recovery. DWI demonstrated marked restriction of proton diffusion compatible with cytotoxic or intramyelinic sheath edema in the brainstem, basal ganglia, thalami, cerebellar and periventricular white matter and the cerebral cortex. This was accompanied by the presence of an abnormal branched-chain amino acids (BCAA) and branched-chain alpha-keto acids (BCKA) peak at 0.9 ppm as well as elevated lactate on proton spectroscopy in all four patients. The changes in all six patients were reversed with treatment without evidence of volume loss or persistent tissue damage. The presence of cytotoxic or intramyelinic edema as evidenced by restricted water diffusion on DWI, with the presence of lactate on spectroscopy, could imply imminent cell death. However, in the context of metabolic decompensation in MSUD, it appears that changes in cell osmolarity and metabolism can reverse completely after metabolic correction.
Department of Radiology, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Wajanat
W
Jan
Robert A
RA
Zimmerman
Zhiyue J
ZJ
Wang
Gerard T
GT
Berry
Paige B
PB
Kaplan
Edward M
EM
Kaye
D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D000597:Amino Acids, Branched-Chain / Q000378:metabolism; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001479:Basal Ganglia / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis; D001933:Brain Stem / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000378:metabolism; D002531:Cerebellum / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000378:metabolism; D002540:Cerebral Cortex / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D007658:Ketone Oxidoreductases / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008375:Maple Syrup Urine Disease / Q000175:diagnosis* / Q000378:metabolism*; D008661:Metabolism, Inborn Errors / Q000175:diagnosis*; D009097:Multienzyme Complexes / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D011859:Radiography; D013223:Statistics as Topic; D013997:Time Factors
D000597:Amino Acids, Branched-Chain; D015415:Biomarkers; D009097:Multienzyme Complexes; D010725:Phosphocreatine; D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate; D007658:Ketone Oxidoreductases; D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D003401:Creatine