Intra-individual comparison between gadopiclenol (0.05 mmol/kg)-and gadobutrol (0.1 mmol/kg)-enhanced MRI in terms of brain metastases visualization

Purpose: Gadopiclenol is a new high-relaxivity macrocyclic gadolinium-based contrast agent. This post-hoc analysis aimed to compare contrast-enhanced MRI with gadopiclenol at 0.05 mmol/kg and gadobutrol at 0.1 mmol/kg in terms of visualization of brain metastases (BM).

Methods/Materials: The analysis was performed on the data from the prospective phase III PICTURE study (conducted between 06/2019 and 09/2020) for the subgroup of patients with BM (N=46) who underwent two separate MRIs with gadopiclenol and gadobutrol in a cross-over design. Lesion visualization parameters (border delineation, internal morphology, and contrast enhancement) were qualitatively assessed by three off-site blinded readers on a 4-point scale. Quantitative measurements included percentage of enhancement (E%), lesion-to-background ratio (LBR), and contrast-to-noise ratio (CNR). Overall diagnostic preference was assessed in a global matched-pairs fashion by three additional blinded readers.

Results: For all readers, and all visualization parameters, the difference in mean of scores showed the non-inferiority of gadopiclenol to gadobutrol (lower limit of 95% CI between -0.04 and -0.30 depending on the reader, above the non-inferiority margin [ 0.35], p  < 0.0001).
There was no significant difference between gadopiclenol and gadobutrol in terms of CNR (least square [LS] mean of the difference: 3.0 to 6.4, p>0.07), while a higher E% was observed with gadopiclenol for two of three readers (LS mean of the difference: 17.4% and 17.6%, p≤0.0097), and a higher LBR for the three readers (LS mean of the difference: 0.1, p≤0.0036).
Readers preferred images with gadopiclenol in 54% to 59% of evaluations, reported no preference for 13% to 24% of evaluations, and preferred images with gadobutrol in 22% to 30% of evaluations (p=0.0091, 0.0249, and 0.0567 for readers 4, 5, and 6, respectively).

Conclusions: MRI with gadopiclenol at 0.05 mmol/kg is non-inferior to gadobutrol at 0.1 mmol/kg for BM visualization. The high relaxivity of gadopiclenol holds the potential to improve its risk-benefit profile by enabling a reduction in the administered gadolinium dose, while maintaining optimal imaging performance in BM.