title: Quantitative determination of regional lesion volume and distribution in children and adults with relapsing-remitting multiple sclerosis.
abstract: BACKGROUND
  Onset of MS occurs during childhood in about 5% of cases. It is unclear whether very young age at MS onset, when the nervous system is still myelinating, affects MS lesion accrual or regional distribution.
  
  
  OBJECTIVE
  To compare the frequency, volume and distribution of T2 and T1 lesions in children and adults with relapsing-remitting multiple sclerosis (RRMS).
  
  
  METHODS
  Lesions were segmented on T2- and T1-weighted MRI images from 29 children and 29 adults with RRMS, matched for disease duration.
  
  
  RESULTS
  All subjects exhibited T2-weighted brain lesions. Children had higher whole-brain T2-weighted-lesion-volume (T2LV) compared to adults (mean (SD) in cm(3): 12.76(2.7) vs. 10.03(3.4), p<0.0013). The supratentorial-T2LV was similar in children and adults (8.45(1.7) vs. 7.94(1.7), mean (SD), p = 0.2582), but adults were more likely to have supratentorial lesions (96.5% vs. 68.9%, p<0.012). Children were more likely to have infratentorial-T2-weighted lesions (75.9% vs. 43.4%, p<0.03), specifically in the brainstem (62.1% vs. 26.7%, p<0.019) and the pons (48.3% vs. 17.24%, p<0.024), had higher infratentorial-T2-weighted-lesion counts (4.1(5.6) vs. 1.45(2.3), p<0.021), a greater infratentorial-T2LV (4.31(2.7) vs. 2.08(2.4), p<0.0013), and a greater infratentorial-T1-weighted-lesion-volume (T1LV) (3.7(2.5) vs. 1.08(1.9), p<0.0007). Whole-brain-T1LV was higher in children (9.3(2.5) vs. 6.43(2.1), p>0.001). Adult MS patients had higher supratentorial-T1LV (5.5(0.92) vs. 6.41(2.1), mean (SD), p<0.034), whereas children were more likely to have infratentorial-T1-weighted lesions (58.6% vs. 23.3%, p<0.015).
  
  
  CONCLUSIONS
  Onset of MS during childhood is associated with a higher volume of brain lesions in the first few years of disease relative to adults. Children with MS are more likely than adults to have T2 and T1 lesions in the infratentorial white matter, raising the possibility of preferential immune targeting of more mature myelin. Children with MS have a lower supratentorial T1 lesion burden, possibly reflecting more effective remyelination and repair in brain regions that are still engaged in active primary myelination.
authors.affiliation: Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
authors.forename: Rezwan
authors.initials: R
authors.lastname: Ghassemi
authors.affiliation: Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
authors.forename: Sridar
authors.initials: S
authors.lastname: Narayanan
authors.affiliation: The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada ; The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America.
authors.forename: Brenda
authors.initials: B
authors.lastname: Banwell
authors.affiliation: The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John G
authors.initials: JG
authors.lastname: Sled
authors.affiliation: The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Manohar
authors.initials: M
authors.lastname: Shroff
authors.affiliation: Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Arnold
mesh_terms: D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000473:pathology*