INSERTING CATHETERS, WITHOUT THE NEED FOR X-RAYS, BENEFITS ALL

Have the patient's coronary vessels, heart valves or myocardial muscle changed abnormally? Doctors can verify this and administer the necessary therapy with the help of a catheter. A metal guide wire inside the catheter serves as a navigational aid.

The catheter's position is monitored with X-Rays. The problem with this computer tomography method is that it exposes the patient to quite a high dose of radiation. In addition, a contrast medium has to be injected into the patient's body in order to make the vascular system and the soft tissue visible on the X-Ray images.

R esearchers at the Fraunhofer Institute for Production Technology IP T in Aachen, Germany, have now found a way of avoiding both the radiation and the contrast medium. In collaboration with colleagues at Philips and University Hospital Aachen, they have developed a guide wire made of glass-fiber-reinforced plastic. "Because the guide wire is made of plastic the imaging can be performed by magnetic resonance tomography instead of computer tomography," says IP T scientist Adrian Schütte. "This is not possible with metal guide wires as the metal wire acts as an antenna and heats up too much - this would damage the vessels, and could cause proteins to clot." Magnetic resonance tomography has many advantages for doctors and patients. It does not produce ionizing radiation like computer tomography, and soft tissue is clearly visible, so there is no need for a contrast medium.

F or the manufacture of the 2m guide wires the researchers use the pultrusion method, which is the standard procedure for making continuous profiles from glass-fiber-reinforced plastic. "Diameters of half a millimeter or less are required for the guide wires - that is the absolute minimum," Schütte concludes.

ipt.fraunhofer.de