title: Urea cycle disorders: brain MRI and neurological outcome.
abstract: BACKGROUND
  Urea cycle disorders encompass several enzyme deficiencies that can result in cerebral damage, with a wide clinical spectrum from asymptomatic to severe.
  
  
  OBJECTIVE
  The goal of this study was to correlate brain MRI abnormalities in urea cycle disorders with clinical neurological sequelae to evaluate whether MRI abnormalities can assist in guiding difficult treatment decisions.
  
  
  METHODS
  We performed a retrospective chart review of patients with urea cycle disorders and symptomatic hyperammonemia. Brain MRI images were reviewed for abnormalities that correlated with severity of clinical neurological sequelae.
  
  
  RESULTS
  Our case series comprises six urea cycle disorder patients, five with ornithine transcarbamylase deficiency and one with citrullinemia type 1. The observed trend in distribution of brain MRI abnormalities as the severity of neurological sequelae increased was the peri-insular region first, extending into the frontal, parietal, temporal and, finally, the occipital lobes. There was thalamic restricted diffusion in three children with prolonged hyperammonemia. Prior to death, this site is typically reported to be spared in urea cycle disorders.
  
  
  CONCLUSIONS
  The pattern and extent of brain MRI abnormalities correlate with clinical neurological outcome in our case series. This suggests that brain MRI abnormalities may assist in determining prognosis and helping clinicians with subsequent treatment decisions.
authors: Department of Radiology, University of Colorado, 12631 E. 17th Ave., Aurora, CO 80045, USA. william.bireley@ucdenver.edu
authors: William R
authors: WR
authors: Bireley
authors: Johan L K
authors: JL
authors: Van Hove
authors: Renata C
authors: RC
authors: Gallagher
authors: Laura Z
authors: LZ
authors: Fenton
mesh_terms: D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000175:diagnosis* / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009422:Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D056806:Urea Cycle Disorders, Inborn / Q000150:complications / Q000175:diagnosis*