Optimised real time catheter tracking on a conventional MR Scanner

Abstract Commercial high-field magnetic resonance (MR) scanners are generally not equipped with measurement software and hardware to perform interventional studies with active devices that contain small radiofrequency (rf) coils for localisation. In this study, with only minimal modifications to the MR scanner, the active catheter tracking technique is implemented on a clinical MR system. Small rf-coils are attached to a commercial angiography catheter and the movement of the coils is observed with fast MR tracking and imaging techniques. Optimised imaging strategies are explored for both static and moving anatomical regions. Image calculation and display software is implemented using both the MR scanner's fast image reconstruction processor, together with the main console computer and a separate personal computer. With the current implementation, image update rates of up to several Hertz can be achieved, if a roadmap imaging technique is used, where rapid coordinate updates are projected onto previously acquired overview images. To account for cardiac and breathing motion, an interleaved imaging strategy is presented where coordinate and image updates are acquired in rapid succession. With this approach, image update rates of 1–2 Hz are obtained, depending on the details of the image reconstruction process.