Gadolinium presence, MRI hyperintensities, and glucose uptake in the hypoperfused rat brain after repeated administrations of gadodiamide

The discussed topic about gadolinium-based contrast agents (GBCA) safety has recently been revived due to the evidence of hyperintensities observed in the dentate nucleus (DN) and globus pallidus (GP) in the brain of patients with normal kidney function. Several preclinical studies have been conducted to understanding how the use of GBCAs can promote the gadolinium deposition in the brain. Here, we evaluate the impact of chronic cerebral hypoperfusion on gadolinium presence. T1 hyperintensities and BBB integrity were evaluated by MRI in chronically hypoperfused and healthy rats injected with either gadodiamide or hypertonic saline. Additionally, the assessment of glucose metabolism by PET imaging and the gadolinium content by ICP-MS was performed after the last MR scan. Chronically hypoperfused rats displayed a greater MRI T_1w signal in the DCN and hippocampus compared to Sham-operated animals, suggesting gadolinium accumulation. Dynamic contrast-enhanced (DCE) MRI assessment of BBB permeability revealed loss of integrity (high K ^trans) after rat injury in the dentate nuclei and hippocampus. Ex vivo tissue analysis showed greater gadolinium retention in the cerebellum and subcortical regions, supporting the imaging finding. FDG-PET imaging of the cerebellum did not reveal abnormal uptake in the DCN after chronic cerebral hypoperfusion. Higher signal intensity followed by higher Gd concentration observed in DCN and hippocampus of animals subjected to cerebral injury can be associated with an increase in BBB permeability due to the applied vascular dementia animal model. Nonetheless, no glucose metabolism abnormalities were detected in chronically hypoperfused cerebellum. (orig.)