Lower Gadobutrol Dose Effective for Contrast-Enhanced Brain MRI

A lower dose of gadobutrol performs equally as well with contrast-enhanced brain MRI when compared to a full standard dose of gadoterate, according to new research.

In a study published June 16 in the American Journal of Roentgenology, investigators from Germany’s University Medical School of Saarland shared results that showed reduced gadobutrol dose by one-fourth could change treatment decisions for some patients.

“A 25-percent reduced gadobutrol dose demonstrated non-inferior efficacy versus standard dose gadoterate for contrast-enhanced brain MRI,” said corresponding author Jan Endrikat, professor of medicine, “warranting particular consideration in patients undergoing multiple contrast-enhanced examinations.”

61-year-old man with left hemispheric brain metastasis from lung cancer. Axial T1-weighted MR images obtained using (A) standard-dose gadoterate and (B) reduced-dose gadobutrol 4 days later.

Credit: American Journal of Roentgenology

To determine the impact of a lower dose, Endrikat’s team conducted an international, prospective, multi-center, open-label, crossover trial called LEADER-75. They enrolled 141 patients – 78 men and 63 women who averaged age 58.5. All patients either had or were suspected of central nervous system pathology, and they underwent contrast-enhanced brain MRI with the standard gadoterate dose – 0.1 mmol/kg.

Patients who had an enhancing lesion emerge on the first MRI had a second scan with reduced-dose gadobutrol – 0.075 mmol/kg – after 15 days.

The team looked at three efficacy measures – subjective lesion enhancement, lesion border delineation, and lesion internal morphology – when comparing the lower-dose gadobutrol and standard-dose gadoterate to unenhanced imaging. Based on their analysis, they determined non-inferiority using a 20-percent margin for those measures.

In addition, in a post-hoc analysis, the team calculated that the mean readings for subjective lesion enhancement, lesion border delineation, and lesion internal morphology differed by less than 1 percent, supporting equivalence using a narrow +/- 5-percent margin.

Specifically, 301 total lesions were detected by mean reading for reduced-dose gadobutrol, and 291 were detected for standard-dose gadoterate. In addition, mean confidence was 3.3 +/- 0.6 for both reduced dose and standard dose. Sensitivity, specificity, and accuracy were also identical for both from majority reading – 58.7 percent, 91.8 percent, and 70.2 percent, respectively.

Alongside these measures, the team said, other secondary variables also supported the non-inferiority of reduced-dose gadobutrol.

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