Pediatric Brain: Repeated Exposure to Linear Gadolinium-based Contrast Material Is Associated with Increased Signal Intensity at Unenhanced T1-weighted MR Imaging

Purpose: To determine whether repeated exposure of the pediatric brain to a linear gadolinium-based contrast agent (GBCA) is associated with an increase in signal intensity (SI) relative to that in GBCA-naive control subjects at unenhanced T1-weighted magnetic resonance (MR) imaging. Materials and Methods: This single-center, retrospective study was approved by the institutional review board and compliant with HIPAA. The authors evaluated 46 pediatric patients who had undergone at least three GBCA-enhanced MR examinations (30 patients for two-group analysis and 16 for pre- and post-GBCA exposure comparisons) and 57 age-matched GBCA-naive control subjects. The SI in the globus pallidus, thalamus, dentate nucleus, and pons was measured at unenhanced T1-weighted MR imaging. Globus pallidusthalamus and dentate nucleuspons SI ratios were calculated and compared between groups and relative to total cumulative gadolinium dose, age, sex, and number of and mean time between GBCA-enhanced examinations. Analysis included the Wilcoxon signed rank test, Wilcoxon rank sum test, and Spearman correlation coefficient. Results: Patients who underwent multiple GBCA-enhanced examinations had increased SI ratios within the dentate nucleus (mean SI ratio +/- standard error of the mean for two-group comparison: 1.007 +/- 0.0058 for GBCA-naive group and 1.046 +/- 0.0060 for GBCA-exposed group [P < .001]; mean SI ratio for pre- and post-GBCA comparison: 0.995 +/- 0.0062 for pre-GBCA group and 1.035 +/- 0.0063 for post-GBCA group [P < .001]) but not the globus pallidus (mean SI ratio for two-group comparison: 1.131 +/- 0.0070 for GBCA-naive group and 1.014 +/- 0.0091 for GBCA-exposed group [P = .21]; mean SI ratio for pre- and post-GBCA comparison: 1.068 +/- 0.0094 for pre-GBCA group and 1.093 +/- 0.0134 for post-GBCA group [P = .12]). There was a significant correlation between dentate nucleus SI and total cumulative gadolinium dose (r = 0.4; 95% confidence interval [CI]: 0.03, 0.67; P = .03), but not between dentate nucleus SI and patient age (r = 0.23; 95% CI: -0.15, 0.56; P = .22), sex (mean SI ratio: 1.046 +/- 0.0072 for boys and 1.045 +/- 0.0110 for girls; P = .88), number of contrast-enhanced examinations (r = 0.13; 95% CI: -0.25, 0.48; P = .49), or time between contrast-enhanced examinations (r = -0.06; 95% CI: -0.42, 0.32; P = .75). Conclusion: SI in the pediatric brain increases on unenhanced T1-weighted MR images with repeated exposure to a linear GBCA. (C) RSNA, 2016