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Spinal Cord Normalization in Multiple Sclerosis
Author(s) -
Oh Jiwon,
Seigo Michaela,
Saidha Shiv,
Sotirchos Elias,
Zackowski Kathy,
Chen Min,
Prince Jerry,
DienerWest Marie,
Calabresi Peter A.,
Reich Daniel S.
Publication year - 2014
Publication title -
journal of neuroimaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.822
H-Index - 64
eISSN - 1552-6569
pISSN - 1051-2284
DOI - 10.1111/jon.12097
Subject(s) - medicine , normalization (sociology) , multiple sclerosis , expanded disability status scale , clinical significance , spinal cord , nuclear medicine , psychiatry , sociology , anthropology
BACKGROUND Spinal cord (SC) pathology is common in multiple sclerosis (MS), and measures of SC‐atrophy are increasingly utilized. Normalization reduces biological variation of structural measurements unrelated to disease, but optimal parameters for SC volume (SCV)‐normalization remain unclear. Using a variety of normalization factors and clinical measures, we assessed the effect of SCV normalization on detecting group differences and clarifying clinical–radiological correlations in MS. METHODS 3T cervical SC‐MRI was performed in 133 MS cases and 11 healthy controls (HC). Clinical assessment included expanded disability status scale (EDSS), MS functional composite (MSFC), quantitative hip‐flexion strength (“strength”), and vibration sensation threshold (“vibration”). SCV between C3 and C4 was measured and normalized individually by subject height, SC‐length, and intracranial volume (ICV). RESULTS There were group differences in raw‐SCV and after normalization by height and length (MS vs. HC; progressive vs. relapsing MS‐subtypes, P < .05). There were correlations between clinical measures and raw‐SCV (EDSS: r = –.20; MSFC: r = .16; strength: r = .35; vibration: r = –.19). Correlations consistently strengthened with normalization by length (EDSS: r = –.43; MSFC: r = .33; strength: r = .38; vibration: r = –.40), and height (EDSS: r = –.26; MSFC: r = .28; strength: r = .22; vibration: r = –.29), but diminished with normalization by ICV (EDSS: r = –.23; MSFC: r = –.10; strength: r = .23; vibration: r = –.35). In relapsing MS, normalization by length allowed statistical detection of correlations that were not apparent with raw‐SCV. CONCLUSIONS SCV‐normalization by length improves the ability to detect group differences, strengthens clinical–radiological correlations, and is particularly relevant in settings of subtle disease‐related SC‐atrophy in MS. SCV‐normalization by length may enhance the clinical utility of measures of SC‐atrophy.