Gadolinium concentration dependent signal enhancement profiles using routine clinical sequences with gadopiclenol, gadoterate, gadobutrol, and gadoxetate at 1.5, 3 and 7 Tesla

Gadopiclenol, a new gadolinium-(Gd) based contrast agent (GBCA), exhibits a higher longitudinal relaxivity (r1) than current standard GBCAs, and, thus, has the potential to be used at lower dose or to generate a brighter T1-weighted (T1w) signal at equivalent dose. As the relationship between enhancement and contrast agent concentration is non-linear, the signal profiles should be experimentally explored and compared to those of current GBCAs. Standardized aqueous dilution series (0.0 to 25 mmol/L) of gadopiclenol, and current standard GBCAs gadoterate, gadobutrol, and gadoxetate were imaged with nine clinical sequences at 1.5, 3, and 7 Tesla(T). Signal intensities(SIs) were measured for each concentration and set in relation to the SI of water(rSI). Additionally, T1 relaxation times were measured at 3 T and r1 was calculated. The maximum rSI in T1w fast-spin-echo images was observed at a lower Gd concentration (1.0 mmol/L) at all three field strengths in the gadopiclenol series than in the current standard GBCAs series (gadoterate and gadobutrol, 2.5 mmol/L, all field strengths, gadoxetate, 2.5 mmol/L at 1.5 and 3 T, 1.0 and 2.5 mmol/L at 7 T). The maximum rSI measured at 1.0 mmol/l gadopiclenol was comparable (±12 %rSI) to the rSI at 2.5 mmol/l of standard GBCAs. Molar gadopiclenol relaxivity, r1, (13.5 ± 1.5 s-1∙mM-1) was three to four times higher than r1 of gadoterate and gadobutrol (3.4 ± 0.4 and 4.1 ± 0.5 s-1∙mM-1, respectively), and 2.2 times higher than of that of gadoxetate (6.0 ± 0.7 s-1∙mM-1). Our results confirm the maximum signal intensity in clinical T1w images to be shifted to lower gadolinium concentrations of gadopiclenol compared to standard GBCAs at all field strengths.