In vivo dentate nucleus MRI relaxometry correlates with previous administration of Gadolinium-based contrast agents

To evaluate changes in T1 and T2* relaxometry of dentate nuclei (DN) with respect to the number of previous administrations of Gadolinium-based contrast agents (GBCA). In 74 relapsing-remitting multiple sclerosis (RR-MS) patients with variable disease duration (9.8 +/- 6.8 years) and severity (Expanded Disability Status Scale scores:3.1 +/- 0.9), the DN R1 (1/T1) and R2* (1/T2*) relaxation rates were measured using two unenhanced 3D Dual-Echo spoiled Gradient-Echo sequences with different flip angles. Correlations of the number of previous GBCA administrations with DN R1 and R2* relaxation rates were tested, including gender and age effect, in a multivariate regression analysis. The DN R1 (normalized by brainstem) significantly correlated with the number of GBCA administrations (p < 0.001), maintaining the same significance even when including MS-related factors. Instead, the DN R2* values correlated only with age (p=0.003), and not with GBCA administrations (p=0.67). In a subgroup of 35 patients for whom the administered GBCA subtype was known, the effect of GBCA on DN R1 appeared mainly related to linear GBCA. In RR-MS patients, the number of previous GBCA administrations correlates with R1 relaxation rates of DN, while R2* values remain unaffected, suggesting that T1-shortening in these patients is related to the amount of Gadolinium given. aEuro cent In multiple sclerosis, previous Gadolinium administrations correlate with dentate nuclei T1 relaxometry. aEuro cent Such correlation is linked to linear Gadolinium chelates and unrelated to disease duration or severity. aEuro cent Dentate nuclei T2* relaxometry is age-related and independent of previous Gadolinium administrations. aEuro cent Changes in dentate nuclei T1 relaxometry are not determined by iron accumulation. aEuro cent MR relaxometry can quantitatively assess Gadolinium accumulation in dentate nuclei.