Évolution du signal des noyaux gris centraux au cours de 10 injections d'un chélate de gadolinium

Médecine. Radiodiagnostic. Imagerie médicaleBACKGROUND AND PURPOSE: over the past five years, concern has grown worldwide about the finding of gadolinium deposits in brain after repeated administrations of gadolinium-based contrast agents (GBCAs).The mechanism of gadolinium deposition remains unclear and several additional related questions remain uncertain, including the stability over time of this accumulation. Therefore, we have conducted a three time points study to explore T1 signal changes in the dentate nucleus (DN) and globus pallidus (GP) using automatic segmentation, after the first, fifth and tenth injection of either a macrocyclic agent, gadoterate meglumine, or a linear agent, gadobenate dimeglumine. MATERIALS AND METHODS: For this retrospective multicenter longitudinal study, two groups were identified. One included 18 patients and one 19 patients, who were respectively exclusively exposed at gadoterate meglumine or gadobenate dimeglumine. The evolution of the signal during time was analysed with the help of an automatic segmentation as an alternative to manual ROI delineation and the use of DN/Pons (DN/P) and GP/Thalamus (GP/T) signal intensity (SI) ratios. RESULTS: The DN/P and GP/T SI ratios increased at the fifth and tenth administration of the linear GBCA. The SI increase at the tenth injection was at a lower rate than at the fifth. No increased signal was found after the use of macrocyclic GBCA. CONCLUSION: Our study using an automated analysis, found no measurable SI increased in the DN and GP after exclusively exposure to a macrocyclic GBCA, thus confirming its stability, less prone to be retain in rain. After exposure to a linear GBCA, the SI tended to increase due to gadolinium accumulation, and then slightly decrease supporting the hypothesis of a slow elimination from the brain of the previous retained gadolinium or of a change of form, causing the signal to fade. This evolution of accumulated gadolinium is an important but not well-known aspect that requires further investigation. To do so, automatic segmentation appears to be a valuable help, reproductible and accurate