Within just a few years, the technique of diffusion imaging using magnetic resonance technology has become an established procedure in everyday clinical practice, especially for rapid diagnosis of strokes. Thanks to the inventions of Dr. Thorsten Feiweier (41), the image quality has improved to the point where this imaging procedure is now increasingly the preferred method for performing tumor diagnostics and surgical planning. 

Like classic magnetic resonance tomography (MRT), diffusion imaging puts minimal strain on the patient, because it requires no contrast agents, X-rays, or radioactive markers. It depicts the movement of water molecules in tissue. This movement depends on both the microscopic composition of cells and their orientation in tissues like nerve pathways or muscle fibers, for example. When there are changes in the tissue, the mobility of the water molecules changes too. These changes are converted into measurable signals. Compared with other diagnostic images, however, diffusion imaging has so far suffered from the drawback that its image quality is limited. The reason is that the mobility of the water molecules is measured by determining the attenuation of the echo signal emitted by hydrogen nuclei revolving around the magnetic field. That means the noise of the measuring instrument has a relatively strong impact on the signal. Calculating interpretable images from the huge amount of data despite this difficulty requires the application of a variety of techniques, but these lead to spatial distortions of the picture. By means of new arrangements of the high-frequency and gradient field pulses, Feiweier has succeeded in improving the measuring procedure so that the diffusion images are displayed on the monitor with less distortion, and at the same time with a reduced level of noise, and are therefore easier to interpret.

Many of Feiweier's 57 inventions are aimed at improving the quality of MRI images. During his physics studies at Dortmund University, he specialized in magnetic resonance processes. While he was still a student, the physics department established a chair for magnetic resonance spectroscopy, and Feiweier took the opportunity to acquire new knowledge: "For the chair, quite a few measuring instruments were developed by the faculty and students, and I helped with that in the framework of my masters thesis." After completing his doctorate on the application of magnetic resonance techniques to the study of membrane models, Feiweier began looking for a job in industry where he could make good use of his qualifications — "and of course Siemens was just the right place for me." As the world's leading company for MRT, Siemens Healthcare in Erlangen, Germany, offered the young researcher the ideal conditions for his work.

Invented in the mid-1980s, the process of diffusion imaging with MRT was initially hardly used at all as a diagnostic instrument — the image quality was too low. Then physicians recognized its usefulness for the identification of regions of the brain that were still vital but in danger of incurring severe damage following a stroke. Whereas it takes hours for undersupplied tissue to become visible in a CT scan following a stroke, tissue changes are apparent immediately in a diffusion image. This means that the therapy, a medication that thins the blood to a great degree, need not be administered based on suspicion alone. "With the diffusion image, physicians can identify the extent of the damage and see whether tissue can still be saved," says Feiweier. In this context, the familiar expression "time is brain" illustrates the great importance of rapid and reliable diagnosis.

Thanks to his inventions, new applications of diffusion imaging are beginning to emerge. For example, full-body images of cancer patients can be made in order to identify and locate metastases. "That wasn't possible three or four years ago, because the depiction of the anatomy was too poor," says Feiweier. With his colleagues, he has worked steadily on new techniques for improving signal recording and data processing. Feiweier's process is currently being tested in cooperation with hospitals — with promising results. His inventions could also have benefits for complicated brain surgeries: for example, brain neurologists can check the position of nerve pathways with improved precision before and during the operation. However, intraoperative measurements do require special equipment in the operating room that makes it possible to generate images of the brain after the calvaria is opened. The surgeons must also have experience in evaluating the images: "There are currently only a handful of specialists in the world who use diffusion images during surgery," says Feiweier. He is convinced that in a few years diffusion imaging will play a much larger role in diagnostics.

The 57 inventions developed by Feiweier are protected by 50 individual patents in 45 patent families. In his leisure time, Feiweier likes to relax by going on hikes with his wife in the “Fränkischen Schweiz” region. About ten years ago, he discovered the hobby of dressage. Concentration is a must there, just as it is on the job: "The horse notices right away if you're not really keeping your mind on it."

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