| 摘要 |
The invention relates to a catheter which is suitable in particular for use in MR imaging. In order to avoid undesirable heating of the tissue surrounding the catheter by the MR excitation field, the catheter in accordance with the invention comprises: a catheter sleeve ( 2 ), a hollow guide channel or lumen ( 3 ) within the catheter sleeve ( 2 ) for the introduction of a medical instrument, and two electrical conductors ( 4 ) which are enclosed by a cable sheath ( 5 ) of a dielectric material and serve to transmit RF signals within the catheter envelope ( 2 ), the dielectric material having a relative permittivity (epsilon<img id="custom-character-00001" he="2.46mm" wi="1.78mm" file="US20050261569A1-20051124-P00900.TIF" alt="custom character" img-content="character" img-format="tif"/>r?) smaller than 4, the diameter of the electrical conductors ( 4 ) being between 5 and 50 mum, notably between 10 and 30 mum, and the distance between the electrical conductors ( 4 ) being smaller than 300 mum, in particular smaller than 200 mum.
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