Pictures of the Future    Spring 2007

Focusing on Single Cells

Thanks to constant improvements in imaging methods such as ultra-high field magnetic resonance tomography (UHF-MRT), physicians are getting closer to deciphering defective biological processes at the molecular level and tailoring treatments to disease even before the onset of symptoms. Siemens is working in this field with the Atomic Energy Commission (CEA), Guerbet, Alstom and Bruker BioSpin MRI, and with the University of Freiburg. It is also part of a German-French research project known as INUMAC (Imaging of neuro disease using high-field MR and contrastophores) that began in mid-2006. The project focuses on developing the world’s first 11.7 T UHF-MRT for studies on humans. At 11.7 T, the magnetic field is 235,000 times stronger than that of the Earth. By comparison, the most powerful clinical UHF-MRTs available today have only 7 T (see  MR Imaging in Pictures of the Future, Fall 2005).

Image quality can improve significantly with higher field strength. Whereas today’s magnetic resonance images have a resolution of 0.1 × 0.1 × 0.5 mm³, the 11.7 T system will yield images that have ten times higher resolution.

"In addition to improved image quality, this method will also have a much higher sensitivity. The new UHF-MRT will actually visualize molecular processes that take place only sporadically in the body," explains Dr. Robert Krieg, director of Molecular MRI at Siemens Medical Solutions in Erlangen, Germany. "INUMAC’s partners hope to use this new technology to research basic functions in the brain, and also study neurological diseases such as Alzheimer’s, Parkinson’s and multiple sclerosis," says Krieg. With the help of targeted contrast agents, scientists hope to label individual cells, and thereby be able to visualize their behavior in a living organism.

European Joint Venture. The UHF-MRT will be built at NeuroSpin—the new CEA center for imaging methods—in Saclay near Paris, France, and is expected to be ready in 2011. Siemens will provide expertise for its partners and will supply components such as gradient coils, high-frequency electronic systems, computers and software for visualization and analysis of image data. On the French side, Guerbet is bringing new molecular contrast agents into the joint effort, while Alstom is building the magnet according to CEA specifications and input from Siemens. Bruker BioSpin MRI is developing new MR components and applications similar to Siemens’ but for use with small animals—at CEA there will also be a 17 T MRT for preclinical research.

Siemens is building another UHF-MRT unit for research on humans in collaboration with the Jülich Research Center. And the new machine, which is scheduled to be ready for operation in approximately three years, won’t just be supplying detailed images of the brain. That’s because plans call for a combination MR-PET (positron emission tomography) 9.4 T scanner with which researchers will be able to visualize metabolic processes in detail. These processes are often altered in diseased cells.

For example, fast-growing tumors have increased energy consumption. "PET images alone are anatomically vague and therefore cannot be used to precisely localize the sites of elevated metabolic activity," says Professor Jon Shah, project head of the MRT group at the Jülich Institute for Medicine. "But with a combined, high-resolution MR-PET scanner we will be able to investigate metabolic processes even in the brain with a high degree of precision."

Fluorescent Plaques. In addition to these partnerships, Siemens will be supporting the European Institute of Molecular Imaging (EIMI) at the Westphalian Wilhelm University of Münster for a period of five years. The EIMI, which was established in 2006, is focusing its scientific work on researching molecular processes in the heart and blood vessels.

Building on this foundation, the institute intends to develop novel biomarkers with which arteriosclerotic plaques can be visualized with an MR-PET or by using fluorescence methods. Siemens will supply medical equipment and instrument-specific expertise. In return, it will gain access to state-of-the-art knowledge in the area of cardiovascular diseases as well as new EIMI developments such as biomarkers and algorithms.

"Thanks to this cooperation, we will be able to access innovative imaging techniques and thus strengthen our technological expertise in molecular imaging," says Professor Otmar Schober, who is both the principal investigator of the EIMI and the director of the Clinic and Polyclinic for Nuclear Medicine at the University of Münster.

Schober’s aim can be subdivided into three objectives. "First, we want to better understand biology on the basis of animal models," he says. "Second, we must recognize biomarkers and synthesize the corresponding ligands—in other words, substances that dock onto specific cells or molecules—and label them. Third is imaging in animals and ultimately in patients. We also want to compare the data sets of PET and MR to be able to recognize the probability of a disease at an early point in time."

Schober is certain about one thing: "In the future, we will concentrate more on preventive screening tests and early detection. Reacting to symptoms often late in the disease process with treatments that are invasive and subject to side effects will be slowly abandoned. The advantages for patients will include very early diagnosis of disease, and treatments that are tailored to the individual."
                                                                      Evdoxia Tsakiridou, Ulrike Zechbauer