Less is better? Intraindividual and interindividual comparison between 0.075mmol/kg of gadobenate dimeglumine and 0.1mmol/kg of gadoterate meglumine for cranial MRI

Purpose To retrospectively compare a reduced dose (RD) (0.075 mmol/kg) of gadobenate dimeglumine (RD-gadobenate) with standard single dose (SSD) (0.1 mmol/kg) of gadoterate meglumine (SSD-gadoterate) for cranial MRI. Materials and methods Thirty-one patients (12 males; aged 52 \ub1 16 years) underwent cranial MRI with SSD-gadoterate and repeated the examination with RD-gadobenate after a median interval of 10 months. Signal-to-noise ratio (SNR) was obtained on contrast-enhanced images for enhancing lesions (n = 10) as well as for right and left transverse venous sinuses, internal carotid arteries, and parotid glands. Moreover, a consecutive series of 100 cranial MRI with SSD-gadoterate (49 males; aged 51 \ub1 19 years) was compared with a consecutive series of 100 cranial MRI with RD-gadobenate (45 males; aged 54 \ub1 18 years). Two blinded neuroradiologists (R1, R2) judged contrast enhancement as sufficient, good, or optimal. Wilcoxon, Mann-Whitney, \u3c72, and Cohen \u3ba statistics were used. Results At intraindividual analysis, median SNR ranged 57-88 for SSD-gadoterate and 79-99 for RD-gadobenate, the latter being systematically higher, the difference being significant for both transverse venous sinuses (p 64 0.011), not significant for both internal carotid arteries and both parotid glands, and enhancing lesions (p 0.101). The two series of interindividual analysis were not significantly different for gender/age (p > 0.415). Contrast enhancement was optimal in 59% (R1) and 76% (R2) of patients using RD-gadobenate, in 39% (R1) and 49% (R2) of patients using SSD-gadoterate (p 64 0.016), with substantial reproducibility (\u3ba 65 0.606). Conclusion Both analyses showed an equal or better contrast enhancement when using RD-gadobenate compared to SSD-gadoterate for routine cranial MRI. The high relaxivity of gadobenate allowed for a 25% dose reduction