Redrawing contrast dose limits in MRI

Gadolinium-based MRI contrast agents can help doctors answer key clinical questions regarding the diagnosis, characterisation and monitoring of diseases, and assist them in the course of treatment. While the positive risk-benefit profile of gadolinium-containing MRI contrast agents has been confirmed in the vast majority of patients, health authorities and medical societies consistently recommend keeping the gadolinium dose as low as possible for the diagnosis at hand.  For Prof. Pietsch’s team at Bayer, this translated into a clear goal: not only focusing on the highest possible stability, but also directed towards a significantly reduced dose. 

This was achieved by increasing the relaxivity – that is, the ability to amplify the signal of a contrast agent in MRI. The higher the relaxivity, the less active ingredient is needed to produce diagnostically meaningful images. ‘We want to equip MRI with a contrast agent that can generate diagnostically meaningful images using the lowest possible dose of gadolinium. That was effectively the initial spark,’ explains Pietsch. The result is gadoquatrane, which requires a dose of 0.04 mmol Gd per kilogram of body weight – compared with the 0.1 mmol/kg typically used in standard macrocyclic preparations. 

Who benefits the most?

‘Lower doses of contrast agents generally benefit every patient – but for those who regularly undergo imaging examinations, the positive effects stack up, of course.’ Pietsch provides specific examples: young women with a genetically determined increased risk of breast cancer who undergo regular screening; multiple sclerosis patients requiring annual follow-up checks; children with vascular malformations or heart conditions, which require image-guided monitoring of surgical procedures and their aftercare. Additionally, many cancer patients now require close monitoring of their treatment – for example, in cases of gastric cancer involving multiple lines of therapy, including checkpoint inhibitors – which is increasingly becoming standard practice. 

QUANTI programme provides new subgroup data

At ECR 2026, Bayer presented subgroup analyses from the pivotal Phase III QUANTI study, which evaluated patients across 15 countries in the key MRI indications: CNS, abdomen, vascular imaging and cardiac imaging. All study endpoints were met, clinically confirming diagnostic equivalence with existing standard preparations – with up to 60% less gadolinium. 

Pietsch explains why each indication had to be examined individually: depending on the clinical question and the technique used, the requirements vary fundamentally – from soft-tissue visualisation in the CNS to imaging of the beating heart. The objective was to demonstrate, for every clinically relevant MRI indication, that the concept of increased relaxivity holds true – and this was accomplished in all areas examined. 

Increased imaging demand and its impact on the environment

Behind the growing importance of dose reduction lies a demographic trend: the world’s population is ageing, leading to an increase in demand for imaging diagnostics. At the same time, increasingly effective treatments are opening up new possibilities, which in turn require more frequent monitoring. This has consequences – not only from a medical perspective, but also in terms of the environment and healthcare infrastructure. Gadolinium is a rare earth element whose extraction is resource-intensive and whose release into the environment is increasingly regarded with concern. Using less gadolinium per examination therefore benefits individual patients, reduces the burden on the environment and helps to secure supply chains in a sustainable manner. 

Based on the QUANTI data, Bayer has submitted marketing authorisation applications in several markets worldwide, including the EU, the US, Japan and China. Upon approval, gadoquatrane would be the macrocyclic gadolinium-based contrast agent with the lowest approved dose on the market – and a further step towards a radiology that is not only more diagnostically precise, but also more tolerable and sustainable. 

Profile: 

Prof. Dr Hubertus Pietsch heads the Department of MRI & CT Contrast Media Research at Bayer AG. A graduate in veterinary medicine, he is responsible for the research and characterisation of contrast agents for various imaging modalities in radiological imaging, with a particular focus on safety, tolerability and dose reduction whilst maintaining consistent diagnostic image quality. Prof. Pietsch is also an adjunct professor of experimental radiology at Essen University Hospital. 

19.03.2026

• contrast agents (144)
• diagnostics (571)
• imaging (1648)
• MRI (837)
• radiology (738)

• Bayer HealthCare, MEDRAD Europe B.V.