title: Magnetic resonance imaging and diffusion-weighted imaging of normal-appearing white matter in children and young adults with tuberous sclerosis complex.
abstract: BACKGROUND
  Patients with tuberous sclerosis complex (TSC) frequently present with neurocognitive deficits which may be related to impaired white matter maturation. The purposes of our study were (a) to evaluate the white matter maturation in children and young adults with TSC by comparing the apparent diffusion coefficient (ADC) values of normal-appearing white matter (NAWM) with age-matched healthy controls and (b) to determine the association of NAWM-ADC values with the severity of neurological symptoms in TSC patients.
  
  
  METHODS
  Twenty-three TSC patients who underwent magnetic resonance imaging/diffusion-weighted imaging between January 2000 and January 2009 were studied. ADC values of NAWM were measured in the frontal, parietal, occipital lobes, and in the pons. ADC data were compared with age-matched normative data derived from healthy controls. Patients were neurologically scored by a pediatric neurologist. Two-sample t tests and linear regression were conducted using STATA software.
  
  
  RESULTS
  ADC values of NAWM were higher in TSC patients compared with healthy controls; the increase, however, only reached statistical significance in the frontal white matter and pons in the age group between 96 and 144 months and in the right parietal and occipital white matter in the age group above 144 months. There was no significant change in neurological severity score per unit increase in ADC measurement.
  
  
  CONCLUSIONS
  ADC values of NAWM appear increased in TSC patients. The abnormal ADC values suggest that myelination may be delayed/impaired in TSC patients, which could explain global neurocognitive deficits. Larger prospective studies, including diffusion tensor imaging, are necessary to validate our results.
authors: Division of Pediatric Radiology, Department of Radiology and Radiological Science, Johns Hopkins Hospital, 600 North Wolfe Street, Nelson Basement, B-173, Baltimore, MD 21287-0842, USA.
authors: Sahayini
authors: S
authors: Arulrajah
authors: Gulhan
authors: G
authors: Ertan
authors: Lori
authors: L
authors: Jordan
authors: Aylin
authors: A
authors: Tekes
authors: Elizabeth
authors: E
authors: Khaykin
authors: Izlem
authors: I
authors: Izbudak
authors: Thierry A G M
authors: TA
authors: Huisman
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000254:growth & development* / Q000473:pathology*; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging; D005625:Frontal Lobe / Q000254:growth & development / Q000473:pathology; D006801:Humans; D007223:Infant; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009778:Occipital Lobe / Q000254:growth & development / Q000473:pathology; D010296:Parietal Lobe / Q000254:growth & development / Q000473:pathology; D011149:Pons / Q000254:growth & development / Q000473:pathology; D012720:Severity of Illness Index; D014402:Tuberous Sclerosis / Q000473:pathology*; D055815:Young Adult