Objectives: The aim of this study was to compare changes in signal intensity (SI) ratios of the dentate nucleus (DN) to pons and cerebrospinal fluid (CSF) on unenhanced T1-weighted magnetic resonance imaging (MRI) scans between the first and last MRI using the linear gadolinium-based contrast agent gadobenate dimeglumine.
Materials and methods: The study was approved by the ethical committee of the University of Heidelberg (S-324/2014), and written informed consent was waived due to the retrospective character of the study. Fifty patients who underwent at least 5 consecutive MRI examinations (plus an additional last MRI for reference) with the exclusive use of gadobenate dimeglumine were analyzed retrospectively. The difference of DN-to-pons and DN-to-CSF mean SI ratios was calculated on unenhanced T1-weighted images between the first and last examination. Results were compared with previously published data on gadopentetate dimeglumine and gadoterate meglumine.
Results: Signal intensity ratio differences for DN-to-pons and DN-to-CSF were significantly greater than 0 (pons: 0.0399 ± 0.0307, P < 0.001; CSF: 0.1439 ± 0.1524, P < 0.001). No control variable consistently predicted the SI ratio difference for the DN-to-pons and the DN-to-CSF ratio. Compared with previously published data, the difference in SI increase between gadopentetate dimeglumine and gadobenate dimeglumine was not significant for the DN-to-pons ratio (P = 0.906). In contrast, the DN-to-CSF ratio difference was significantly lower (P < 0.001) for gadobenate dimeglumine. Dentate nucleus-to-pons (P < 0.001) and DN-to-CSF (P = 0.017) ratio differences were both significantly higher for gadobenate dimeglumine than for gadoterate meglumine.
Conclusions: The present study found an increase in SI in the DN after serial injections of gadobenate dimeglumine. Further studies are needed to clarify the potential of different linear gadolinium-based contrast agents to cause SI increase in the DN.