Pushing MRI Beyond Its Limits

Benedikt Poser advances High-Field MRI Research at the Institute.
 

Magnetic resonance imaging (MRI) provides insights into neural processes that were long hidden from view. To fully harness this potential, the Institute is developing a versatile MRI infrastructure that comprises a mobile 1.5-Tesla scanner, a new 3-Tesla scanner, and a planned ultra-high field 7-Tesla scanner. Higher magnetic field strengths open up new possibilities for visualizing brain structures that were previously difficult or impossible to see. At the same time, they bring new technical and methodological challenges.

This is precisely the starting point of Benedikt Poser's work. The physicist, who spent the last 12 years researching and teaching at Maastricht University, joined the Institute as Head of the Max Planck Research Group MR Physics in February 2026. He is responsible for advancing MRI methods, and is overseeing the expansion of the Institute's MRI infrastructure.

Poser specializes in high-field MRI with magnetic fields so strong that they achieve a resolution far beyond what conventional scanners can provide. He sums up the difference as follows: "Everything that works well at low field strengths works better at high ones—and everything that's difficult becomes much more difficult." Higher field strengths offer new image contrasts and finer detail, but they also introduce challenges such as uneven fields, image distortions, and motion artefacts. For over two decades, Poser has been developing methods to minimize these effects and make measurements faster and more precise.

The benefits of these advances are particularly apparent when imaging the brainstem. Its tiny control centers are among the most difficult regions of the brain to access. Poser is particularly fascinated by the locus coeruleus—an area only a few millimeters in size that helps regulate sleep-wake rhythms, emotions, and attention, and is associated with various psychiatric disorders. "At 3 Tesla, it is very difficult to visualize such structures clearly," he explains. Only higher field strengths combined with optimized contrasts provide the necessary level of detail. This offers new perspectives for research groups investigating cognitive control, emotional regulation, or the neural foundations of learning and development.

Poser takes on a dual role at the Institute: His group both conducts its own research and serves as a support unit for all MRI-based projects: "I see it as one of my main tasks to ensure that my colleagues can collect truly high-quality data," he says. This includes choosing the most suitable scanner for each study and developing robust measurement protocols. Poser also sees himself as a networker. Within the Max Planck Society, he works closely with the MRI groups at the MPI for Human Cognitive and Brain Sciences in Leipzig and the MPI for Empirical Aesthetics in Frankfurt. He also sees great potential for collaboration in Berlin itself, building on long-standing and intensive ties with institutions such as the Physikalisch-Technische Bundesanstalt (PTB), Charité – Universitätsmedizin Berlin, and the Max Delbrück Center in Buch, which currently operates the only 7 T MRI scanner in Berlin, albeit an older model. With its state-of-the-art 1.5 T, 3 T, and 7 T MRI scanners, the Institute is set to become a key hub in Berlin's MRI landscape—a position that will be especially beneficial as it expands its expertise in ultrahigh field MRI methods.

In addition to developing new methods, Poser is particularly excited about working closely with neuroscientists. Every new research question places fresh demands on imaging techniques. Or, as Poser puts it: "The bar is constantly being raised." For him, this is the essence of his work—pushing the boundaries of what can be visualized in the brain.