The invention relates to a catheter system. The system comprises a catheter body having a chamber containing a low acoustic impedance medium. The catheter body includes an elongated body with an external surface and an ultrasound transducer having an external side between a first end and a second end....http://www.google.com.au/patents/US7186246?utm_source=gb-gplus-sharePatent US7186246 - Ultrasound catheter with utility lumen
