Abstract: A magnetic resonance imaging (MRI) system is provided with an interventional instrument with an indicator element which influences, for example locally disturbs, the magnetic resonance image. The position of the interventional instrument within the patient to be examined is derived from the local disturbances in the image as caused by the interventional instrument. The degree of influencing of the magnetic resonance image is adjustable notably by rotation of the interventional instrument with the indicator element relative to the direction of the steady magnetic field of the magnetic resonance imaging system. For example, the indicator element is a paramagnetic strip which may include several segments of different magnetic susceptibility.