title: Neurofibromatosis type 1: the evolution of deep gray and white matter MR abnormalities.
abstract: OBJECTIVE
  To investigate the evolution of deeply located high-signal-intensity abnormalities of the brain on T2-weighted MR images of patients with neurofibromatosis type 1 (NF-1).
  
  
  METHODS
  The study consists of two patient groups: 1) retrospective evaluation of MR scans of 24 symptomatic NF-1 patients, 10 of whom were sequentially studied, and 2) prospective MR evaluations of 20 asymptomatic NF-1 subjects from 14 families; 2 of these families were sequentially studied.
  
  
  RESULTS
  Deeply located, high-signal-intensity abnormalities on T2-weighted images were noted in 34 of 44 NF-1 subjects (77%). If NF-1 patients are grouped according to age, 28 of 30 subjects (93%) younger than 15 years had the lesions, whereas 4 of 7 subjects (57%) between 16 and 30 years, and 2 of 7 subjects (29%) older than 31 years had lesions. High-signal lesions in basal ganglia and brain stem were demonstrated in all decades with relatively high frequency. Lesions in the cerebellar white matter and dentate nuclei were mainly found in the patients younger than 10 years, and never found after the third decade. In 13 sequential studies (mean interval, 24 months), lesions appeared to increase in size in 3, remain unchanged in size in 2, and decrease in size in 7. One subject showed a mixed pattern of lesion size change.
  
  
  CONCLUSIONS
  Deeply located high-signal-intensity lesions on T2-weighted MR images are more evident in young NF-1 patients. The underlying brain abnormality, while pathologically unproved, is probably transient.
authors.affiliation: Johns Hopkins University School of Medicine, Division of Neuroradiology, Baltimore, MD 21205.
authors.forename: T
authors.initials: T
authors.lastname: Itoh
authors.forename: S
authors.initials: S
authors.lastname: Magnaldi
authors.forename: R M
authors.initials: RM
authors.lastname: White
authors.forename: M B
authors.initials: MB
authors.lastname: Denckla
authors.forename: K
authors.initials: K
authors.lastname: Hofman
authors.forename: S
authors.initials: S
authors.lastname: Naidu
authors.forename: R N
authors.initials: RN
authors.lastname: Bryan
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001480:Basal Ganglia Diseases / Q000473:pathology; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology*; D001933:Brain Stem / Q000473:pathology; D002528:Cerebellar Neoplasms / Q000473:pathology; D002529:Cerebellar Nuclei / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009456:Neurofibromatosis 1 / Q000235:genetics / Q000473:pathology*; D011446:Prospective Studies; D012189:Retrospective Studies