Sodium MRI of T1 High Signal Intensity in the Dentate Nucleus due to Gadolinium Deposition in Multiple Sclerosis

BACKGROUND AND PURPOSE Recently, several studies reported increased signal intensity (SI) of the dentate nucleus (DN) on unenhanced T1-weighted magnetic resonance imaging (MRI) as a possible consequence of multiple applications of gadolinium-based contrast agents. The aim of this study was to investigate with sodium (23Na) MRI possible tissue abnormalities of the DN in multiple sclerosis (MS) patients. METHODS Sodium and conventional MRI were performed on a clinical 3T scanner. Total sodium concentrations (TSCs) of the DN, as well as DN-to-pons and DN-to-cerebellum SI ratios on unenhanced T1-weighted MRI were calculated. RESULTS A total of 18 subjects (6/18 normal controls, 12/18 MS patients [6/12 with T1 hyperintense DN]) were investigated. There was no significant difference of TSC values of the DN in MS patients with a T1-hyperintense DN (33.70 ± 2.14 mM) compared to MS patients without those signal abnormalities (33.29 ± 1.67 mM; P = .67) or to healthy controls (33.14 ± 1.12; P = .32). CONCLUSIONS Normal sodium signal in the T1-hyperintense DN in MS patients may point to relative tissue integrity despite gadolinium deposition in this area.