Abstract
BACKGROUND AND PURPOSE: GM pathology is considered a major determinant of disability in MS, but the comprehension of its origin and progression rate is limited by the uncertainty of dating the biologic disease onset. Thus, we planned a longitudinal study aimed at analyzing and comparing cortical pathology in pediatric and adult MS patients at clinical onset.
MATERIALS AND METHODS: Within 12 months from clinical onset, 35 patients with cMS and 57 with aMS were included in a longitudinal study. At T0, GMf and CL number and volume were analyzed. Percentages of ΔGMf and number of new CLs were assessed every year for 3 years (T1-T3). Twenty-eight age- and sex-matched NCs constituted the reference population.
RESULTS: At T0, GMf did not differ between cMS and NC (P = .18), while it was lower in patients with aMS compared with both NCs (P < .001) and patients with cMS (P < .001). The number of patients with CLs, as well as CL number and volume, were higher in patients with aMS than in those with cMS (P < .001). At T3, ΔGMf was higher in both patients with cMS (1.6% ± 0.5%; range 0.7%–3.4%; P < .001) and aMS (1.6% ± 0.6%; range 0.6%–3.4%; P < .001) compared with NCs (0.7% ± 0.2%; range 0.4%–1.1%), whereas no difference was observed between patients with cMS and aMS (P = .93). ΔGMf significantly correlated with increased CL volume (cMS: r = 0.46; aMS: r = 0.48) and with the appearance of new CLs (cMS: r = 0.51; aMS: r = 0.49).
CONCLUSIONS: Our findings suggest that focal (CLs) and diffuse (atrophy) GM damage are strictly associated with the biologic onset of MS, and proceed linearly and partly independently of WM pathology.
Abbreviations
- aMS
- adult-onset multiple sclerosis
- CL
- cortical lesion
- cMS
- childhood-onset multiple sclerosis
- EDSS
- Expanded Disability Status Scale
- GM
- gray matter
- GMf
- gray matter fraction
- Δ-GMf
- delta gray matter fraction
- Δ-GMf_1
- delta gray matter fraction at T1
- Δ-GMf_2
- delta gray matter fraction at T2
- Δ-GMf_3
- delta gray matter fraction at T3
- NC
- healthy control
- T0
- baseline
- T2WMLV
- T2 white matter lesion volume
- © 2012 American Society of Neuroradiology