Objective: The objective of this study was to evaluate signal changes in the dentate nucleus on unenhanced T1-weighted MR images after multiple administrations of gadopentetate dimeglumine versus gadobutrol.
Materials and methods: Two study groups were identified, each of which included 25 consecutive patients. Each group received six or more administrations of either gadobutrol only or gadopentetate dimeglumine only, without having had exposure to any other gadolinium-based contrast agent (GBCA). The mean signal intensity (SI) in the dentate nucleus on unenhanced T1-weighted MR images was measured, with the use of the pons and the cerebellar peduncle as references to calculate the DNP SI ratio (i.e., the ratio of the SI in the dentate nucleus to the SI in the pons) and the DCP SI ratio (i.e., the ratio of the SI in the dentate nucleus to the SI in the cerebellar peduncle).
Results: After six administrations of gadopentetate dimeglumine, the SI in the dentate nucleus on unenhanced T1-weighted MR images increased from a DCP SI ratio of 0.997 before administration to 1.034 after the last of six administrations (p = 0.0007) and then to 1.063 after all administrations (p = 0.0004). No statistically significant increase was noted in association with administration of gadobutrol, for which the DCP SI ratio was 0.995 before administration, 1.009 after the last of six administrations (p = 0.1172), and 0.992 after all administrations (p = 0.7592). The change in the DCP SI ratio after administration of gadopentetate dimeglumine correlated with the number of administrations the patient received (p < 0.0001).
Conclusion: Unenhanced T1 signal hyperintensity was observed in the dentate nucleus after multiple administrations of gadopentetate dimeglumine, a linear ionic agent, but not after multiple administrations of gadobutrol, a macrocyclic GBCA.
Keywords: MRI; contrast agents; dentate nucleus; gadobutrol; gadolinium; gadopentetate dimeglumine; globus pallidus; safety.