Increased signal intensities in the dentate nucleus and globus pallidus on unenhanced T1-weighted images: evidence in children undergoing multiple gadolinium MRI exams

Houchun H. Hu, Amber Pokorney, Richard B. Towbin, Jeffrey H. Miller

Recent reports have suggested residual gadolinium deposition in the brain in subjects undergoing multiple contrast-enhanced MRI exams. These findings have raised some concerns regarding gadolinium-based contrast agent (GBCA) usage and retention in brain tissues. To summarize findings of hyperintense brain structures on precontrast T1-weighted images in 21 children undergoing multiple GBCA MRI exams. This retrospective study involved 21 patients, each of whom received multiple MRI examinations (range: 5-37 exams) with GBCA over the course of their medical treatment (duration from first to most recent exam: 1.2-12.9 years). The patients were between 0.9 and 14.4 years of age at the time of their first GBCA exam. Regions of interest were drawn in the dentate nucleus and the globus pallidus on 2-D fast spin echo images acquired at 1.5 T. The signal intensities of these two structures were normalized by that of the corpus callosum genu. Signal intensity ratios from these patients were compared to control patients of similar ages who have never received GBCA. Signal intensity ratios increased between the first and the most recent MRI exam in all 21 patients receiving GBCA, with an increase of 18.6%±12.7% (range: 0.5% to 47.5%) for the dentate nucleus and 12.4%±7.4% (range: -1.2% to 33.7%) for the globus pallidus (P<0.0001). Signal intensity ratios were also higher in GBCA patients than in controls (P<0.01). The degree of signal intensity enhancement did not correlate with statistical significance to the cumulative number or volume of GBCA administrations each patient received, the patient's age or the elapsed time between the first and most recent GBCA MRI exams. These results in children are consistent with recent findings in adults, suggesting possible gadolinium deposition in the brain.