MRI-compatible ultrasonic probe for minimally invasive therapy

The effects of magnetic resonance imaging (MRI)-compatible ultrasound (US) probes on MRI monitoring were evaluated. It was found that MRI-compatible US probes with backing material containing 100 ppm ferrite, did not disturb MR monitoring except within a few mm radius from the US probe's position. MRI temperature monitoring of an excised swine liver irradiated with a high-intensity focused US beam from an MRI-compatible therapeutic transducer with US image guidance was then performed, and the potential usefulness of such a therapeutic system in minimally invasive therapy was demonstrated.