Background The relationship between administration of macrocyclic
gadolinium-based
contrast agents and T1-weighted signal intensity (SI) change of the globus pallidus (GP) and dentate nucleus (DN) is, to the knowledge of the authors, not known. Purpose To determine if quantitative susceptibility mapping (QSM) can detect changes in magnetic susceptibility of the GP and DN after serial administration of macrocyclic
gadobutrol in patients with
primary brain tumors. Materials and Methods Patients diagnosed with
primary brain tumors from August 2014 to February 2019 were eligible for this single-center retrospective study. Among 501 consecutive adult patients who were given at least one administration of
gadobutrol, those who were previously administered an unknown or linear
gadolinium-based
contrast agent were excluded. Brain MRI scans with three-dimensional gradient-recalled-echo image phase data for QSM processing were reviewed. Regions of interest were drawn on the GP and DN on the basis of semiautomatic thresholding. Univariable generalized estimation equations were used to determine the associations between MRI measures (SI on T1-weighted images and magnetic susceptibility on QSM) and number of
gadobutrol doses. Potential confounding factors were adjusted for in multivariable generalized estimating equation. Results Ninety patients (mean age, 51 years ± 17 [standard deviation]; 51 men) with 199 MRI scans were analyzed. In models adjusted for repeated observations between
injections, the number of
injections of
gadobutrol was associated with the magnetic susceptibility of the GP (1.4 × 10-3 ppm/number of
gadobutrol injections; P = .01) and DN (8.1 × 10-4 ppm/number of
gadobutrol injections; P = .03). After adjustment for confounders, the number of
gadobutrol injections remained an independent predictor of increased magnetic susceptibility in the GP (1.3 × 10-3 ppm/number of
gadobutrol injections; 95% confidence interval: 0.39 × 10-3, -2.4 × 10-3; P = .006). There were no associations between number of
gadobutrol injections and SI or magnetic susceptibility in the DN. Conclusion The magnetic susceptibility of the globus pallidus increased after serial administration of
gadobutrol. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Wang and Prince in this issue.