Signal Changes in the Dentate Nucleus and Globus Pallidus on Unenhanced T1-Weighted Magnetic Resonance Images After Intrathecal Administration of Macrocyclic Gadolinium Contrast Agent.

OBJECTIVES: The aim of this study was to evaluate signal changes in the dentate nucleus and globus pallidus (GP) on unenhanced T1-weighted magnetic resonance (MR) images (T1 WI) in a cohort of patients who have received intrathecal macrocyclic ionic gadolinium-based contrast agent (GBCA) gadoterate meglumine.

MATERIALS AND METHODS: A group of 20 patients (male/female ratio, 8:12; mean age, 39.5 ± 15.5 years) who had not received intravenous GBCA but had received an intrathecal macrocyclic ionic GBCA (plus baseline and an additional final magnetic resonance imaging [MRI] for reference) from 2012 to 2017 were retrospectively included in this institutional review board-approved study. Two radiologists inspected T1-weighted 2-dimensional spin echo (n = 7) and 3-dimensional isotropic turbo field echo (n = 13) images on a 3 T MRI system to conduct visual evaluation and quantitative analysis. Baseline and final examination signal intensity (SI) ratios were assessed across time by using the same pulse sequences. For visual analysis, SI changes on the GP, thalamus (Th), cerebellar peduncle (CP), and dentate nucleus (DN) were graded as a 3-point scale. For quantitative analysis, SI ratio differences between the baseline and final MR examinations were estimated for the DN-to-CP and GP-to-Th ratios. One-sample t tests were used to investigate whether they differed from 0. In addition, to investigate significant differences between the SI ratios for various pulse sequences, t tests were performed. The regression analysis was additionally used to find any correlation between SI ratio differences and various confounding variables including age, sex, or the mean interval between the baseline and final MR examinations.

RESULTS: The SI ratio differences did not deviate significantly from 0, neither for the DN/CP ratio (0.013 ± 0.0584, P = 0.287) nor the GP/Th ratio (-0.0113 ± 0.0546, P = 0.366). The DN-to-CP and GP-to-Th SI ratio differences did not significantly deviate from 0 in the patient groups in either of the imaging sequences (P > 0.05) as well. Age, sex, and the mean interval between examinations did not influence SI ratio differences between examinations (P > 0.05).

CONCLUSIONS: Intrathecal macrocyclic GBCA administration was not associated with measurable T1 SI changes in the GP and DN as an indicator of brain gadolinium deposition detectable by MRI.