Background Detection of cerebral lesions at MRI may benefit from a chemically stable and more sensitively detected
gadolinium-based
contrast agent (GBCA).
Gadopiclenol, a macrocyclic GBCA with at least twofold higher relaxivity, is currently undergoing clinical trials in humans. Purpose To determine the relationship between MRI contrast enhancement and the injected dose of
gadopiclenol in a
glioma rat model compared with those of conventional GBCA at label dose. Materials and Methods Between April and July 2012, 32 rats implanted with C6
glioma received two
intravenous injections at a 24-hour interval. The
injections were randomly selected among five doses of
gadopiclenol (0.025, 0.05, 0.075, 0.1, and 0.2 mmol/kg) and three reference GBCAs (
gadoterate meglumine,
gadobutrol, and
gadobenate dimeglumine) at 0.1 mmol/kg. MRI
tumor enhancement was assessed on T1-weighted images before and up to 30 minutes after injection. Two blinded radiologists visually and qualitatively scored contrast enhancement, border delineation, and visualization of
tumor morphology. Quantitatively, variations in contrast-to-noise ratio (ΔCNR) between
tumor and contralateral parenchyma were calculated at each time point and were compared for each treatment at 5 minutes by using a mixed model after normality test. Results A total of 24 rats underwent the complete protocol (n = 5-7 per group). A linear dose-dependent ΔCNR relationship was observed between 0.025 and 0.1 mmol/kg for
gadopiclenol (R 2 = 0.99). No difference in ΔCNR was observed between the three reference GBCAs (P ≥ .55).
Gadopiclenol resulted in twofold higher ΔCNR at 0.1 mmol/kg (P < .001 vs
gadobutrol and
gadoterate, P = .002 vs gadobenate) and similar ΔCNR at 0.05 mmol/kg (P = .56, P > .99, and P = .44 compared with
gadobutrol, gadobenate, and
gadoterate, respectively). For both readers, 0.05 mmol/kg of
gadopiclenol improved contrast enhancement, border delineation, and visualization of
tumor morphology (scores > 3 compared with scores between 2 and 3 for the marketed GBCA). Conclusion
Gadopiclenol at 0.05 mmol/kg yielded comparable change in contrast-to-noise ratio and morphologic characterization of
brain tumors compared with gadobenate,
gadoterate, or
gadobutrol at 0.1 mmol/kg. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Tweedle in this issue.