Reduced R 2′ in multiple sclerosis normal appearing white matter and lesions may reflect decreased myelin and iron content

David Paling, Daniel Tozer, Claudia Wheeler-Kingshott, R. Kapoor, David H. Miller, Xavier Golay

Research output: Contribution to journalArticlepeer-review

Abstract

Background: R 2′ is an MRI measure of microscopic magnetic field inhomogeneity, and is increased by the paramagnetic effect of iron and the diamagnetic effect of myelin. R 2′ may detect features of multiple sclerosis (MS) not evident with conventional MRI. Methods: Multiecho T 2 and T 2* weighted sequences were obtained from 21 healthy controls (nine men, 12 women; mean age 36 years) and 28 MS patients (seven men, 21 women; 18 relapsing remitting, 10 secondary progressive; mean age 42 years). T 2 and T 2* relaxation time maps were created from the multiecho sequences, and R 2′ maps were created using the formula R 2′ = R 2*-R 2 = 1/T 2*-1/T 2. R 2′ was measured in MS white matter lesions and in regions of interest in normal appearing white matter (NAWM) and grey matter in all subjects. Results: R 2′ was reduced in NAWM in MS compared with controls (9.5/s vs 10.1/s, p=0.05). R 2′ was additionally reduced in lesions, both T 1 isointense (8.5/s vs 9.5/s, p=0.02) and T 1 hypointense (7.7/s vs 9.5/s, p=0.003) compared with NAWM. R 2′ tended to be higher in the basal ganglia of MS patients compared with controls, and was significantly higher in the caudate nucleus in secondary progressive MS (12.9/s vs 10.9/s, p=0.03). Increased T 2 lesion volume predicted an increase in R 2′ in the caudate (β=0.412, p=0.02). Conclusions: Reduction in R 2′ in NAWM and lesions is consistent with a decreases in myelin, tissue iron and/or deoxyhaemoglobin. Increased caudate R 2′ in patients with secondary progressive MS is consistent with increased iron deposition, as corroborated by other techniques.

Original languageEnglish (US)
Pages (from-to)785-792
Number of pages8
JournalJournal of Neurology, Neurosurgery and Psychiatry
Volume83
Issue number8
DOIs
StatePublished - Aug 2012

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology
  • Psychiatry and Mental health

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