PT  - JOURNAL ARTICLE
AU  - Baker, E.H.
AU  - Sloan, J.L.
AU  - Hauser, N.S.
AU  - Gropman, A.L.
AU  - Adams, D.R.
AU  - Toro, C.
AU  - Manoli, I.
AU  - Venditti, C.P.
TI  - MRI Characteristics of Globus Pallidus Infarcts in Isolated Methylmalonic Acidemia
AID  - 10.3174/ajnr.A4087
DP  - 2015 Jan 01
TA  - American Journal of Neuroradiology
PG  - 194--201
VI  - 36
IP  - 1
4099  - http://www.ajnr.org/content/36/1/194.short
4100  - http://www.ajnr.org/content/36/1/194.full
SO  - Am. J. Neuroradiol.2015 Jan 01; 36
AB  - BACKGROUND: Bilateral infarcts confined to the globus pallidus are unusual and occur in conjunction with only a few disorders, including isolated methylmalonic acidemia, a heterogeneous inborn error of metabolism. On the basis of neuroradiographic features of metabolic strokes observed in a large cohort of patients with methylmalonic acidemia, we have devised a staging system for methylmalonic acidemia–related globus pallidus infarcts. MATERIALS AND METHODS: Forty patients with isolated methylmalonic acidemia and neurologic symptoms underwent clinical brain MR imaging studies, which included 3D-T1WI. Infarcted globus pallidus segments were neuroanatomically characterized, and infarct volumes were measured. RESULTS: Globus pallidus infarcts were present in 19 patients; all were bilateral, and most were left-dominant. A neuroanatomic scoring system based on the infarct patterns was devised; this revealed a 5-stage hierarchical susceptibility to metabolic infarct, with the posterior portion of the globus pallidus externa being the most vulnerable. Globus pallidus infarct prevalence by methylmalonic acidemia class was the following: cblA (5/7, 71%), cblB (3/7, 43%), muto (10/22, 45%), and mut- (1/4, 25%). Tiny lacunar infarcts in the pars reticulata of the substantia nigra, previously unrecognized in methylmalonic acidemia, were found in 17 patients, 13 of whom also had a globus pallidus infarct. CONCLUSIONS: The staged pattern of globus pallidus infarcts in isolated methylmalonic acidemia suggests a nonuniform, regionally specific cellular susceptibility to metabolic injury, even for patients having milder biochemical phenotypes. In support of this hypothesis, the delineation of lacunar infarcts in the pars reticulata of the substantia nigra, a tissue functionally and histologically identical to the globus pallidus interna, supports the concept of cell-specific pathology. bFFEbalanced fast-field echoGPglobus pallidusGPeglobus pallidus externaGPiglobus pallidus internaMMAmethylmalonic acidemiaMUTmethylmalonyl-coenzyme A mutaseSNrpars reticulata of the substantia nigra