title: Age-related findings on MRI in neurofibromatosis type 1.
abstract: BACKGROUND
  T2 hyperintensities (T2H) on MRI are the most common CNS lesions in individuals with neurofibromatosis type 1 (NF1).
  
  
  OBJECTIVE
  The aim was to determine the frequency, signal characteristics and localization of T2H at different ages. In addition, we examined the sensitivity of different MR imaging sequences in detecting these lesions.
  
  
  METHODS
  We studied prospectively a cohort of children, adolescents and young adults with NF1 using T2-volume (T2-V) and conventional MRI sequences. Lesions were designated as either discrete or diffuse, and the region of signal abnormality was recorded. A total of 103 patients were studied (age range 8.0-25.4 years, mean 13.9 years).
  
  
  RESULTS
  The frequency, size, and intensity of T2H decreased with age in the basal ganglia (BG) and the cerebellum/brainstem (CB/BS). The majority of thalamic and CB/BS lesions were diffuse. Of the total cohort, 80% had diffuse bilateral hippocampal hyperintensities and 18.4% had hemispheric lesions best demonstrated on FLAIR; there was no significant difference in the frequency or signal intensity of hemispheric lesions with age.
  
  
  CONCLUSIONS
  Lesions in the cerebral hemispheres and hippocampus imaged by MR do not change in prevalence over time, suggesting a different pathological basis from the lesions in the in BG and CB/BS that resolve with age. FLAIR and T2-V sequences are more sensitive in detecting lesions than standard T2-weighted sequences.
authors.affiliation: The T. Y. Nelson Department of Neurology, The Children's Hospital at Westmead, Sydney, NSW, Australia.
authors.forename: Deepak S
authors.initials: DS
authors.lastname: Gill
authors.forename: Shelley L
authors.initials: SL
authors.lastname: Hyman
authors.forename: Adam
authors.initials: A
authors.lastname: Steinberg
authors.forename: Kathryn N
authors.initials: KN
authors.lastname: North
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009456:Neurofibromatosis 1 / Q000473:pathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA