New imaging method produces images with molecular information

An international research team involving the Technical University of Munich (TUM) has developed a new method of computed tomography, molecular insights into the brain allows. The new approach exploits the fact that molecular structures in the brain to different signatures in the scattered X-rays cause different. The method requires, however, the myelin sheath of nerve fibers in the brain and provides valuable information for research into diseases such as multiple sclerosis and Alzheimer's. In its online edition reported the prestigious journal NeuroImage on the results of research.

The myelin sheath in brain nerve cells consists of layered slats. They surround the nerve cells called axons. This myelin layers are therefore particularly important for the central nervous system because they provide a rapid release of the nerve signals. Changes or failures of this function are suspected of degenerative brain diseases, to be involved, such as Alzheimer's or multiple sclerosis.

"The detailed development of these diseases is not yet understood," said Professor Franz Pfeiffer TUM, "but is associated increasingly with changes in myelin-related layers, which are responsible for interruptions in signal transmission between nerve cells. Put simply, this is so, as if it is damaged electricity transmission lines and the isolation that is happening to short circuits and leakage currents. "

The new development is based on conventional computed tomography (CT) technology, which is well established and is used worldwide in clinical applications. In a CT scan of the body is illuminated by X-ray detector and an image will not, under different angles, the shadows on the human body. From these images is then calculated by image processing a three-dimensional image of the body.

"The new aspect of our methodology," said TUM researcher Dr. Martin Bech, "is that not only the body absorbed X-ray radiation is measured in such images, but also the exact scattering pattern formed by the interaction of X-rays with the structures in body inside produce. "Such scattering images are recorded for each point and at any angle, and this additional information allows to draw conclusions about the molecular structure in every part of the sample. "

The scattering images are processed with an algorithm developed by the research team. Torben Jensen, a researcher at the Niels Bohr Institute in Copenhagen and author of the paper, said: "We have developed an algorithm that computes high-resolution, three-dimensional images of the sample, and analyzed typically a few hundred thousand scattering images. This algorithm takes into account the particular scattering signature of the molecular structure in the sample.

As an application, the team with the way the brain examined a laboratory rat - and won amazingly accurate insights. "We can detail the myelin sheath of nerve cells visible and even distinguish different layers of only 17.6 nanometers," said Professor Robert Feidenhans'l from the Niels Bohr Institute in Copenhagen. "Until now we always had small pieces cut out from the sample analysis and to obtain similar information. With the new method, we can analyze 250,000 points in the sample at once. This will allow screening and the thickness and concentration of myelin sheaths associated with different diseases. "

The results were achieved in an international collaboration of researchers from Germany, Denmark, Switzerland, and France. The experiments were performed at the synchrotron light source at the Paul Scherrer Institute in Villigen (Switzerland). In the future they will be on the campus Garching am currently under development, "Centre for Advanced Laser Applications (CALA) is possible with new laser-based bright X-ray sources, as developed in the Excellence Cluster" Munich-Centre for Advanced Photonics ".

Source: Technical University Munich