TY - JOUR
T1 - Reduced R 2′ in multiple sclerosis normal appearing white matter and lesions may reflect decreased myelin and iron content
AU - Paling, David
AU - Tozer, Daniel
AU - Wheeler-Kingshott, Claudia
AU - Kapoor, R.
AU - Miller, David H.
AU - Golay, Xavier
PY - 2012/8
Y1 - 2012/8
N2 - 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.
AB - 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.
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U2 - 10.1136/jnnp-2012-302541
DO - 10.1136/jnnp-2012-302541
M3 - Article
C2 - 22626944
AN - SCOPUS:84863988982
VL - 83
SP - 785
EP - 792
JO - Journal of Neurology, Neurosurgery and Psychiatry
JF - Journal of Neurology, Neurosurgery and Psychiatry
SN - 0022-3050
IS - 8
ER -