Daniel Robert Elgort MS, Presenter: Nothing to Disclose

Claudia Maria Hillenbrand PhD, Abstract Co-Author: Nothing to Disclose

Eddy Wong MS, Abstract Co-Author: Nothing to Disclose

Shaoxiong Zhang MD, Abstract Co-Author: Nothing to Disclose

Frank K. Wacker MD, Abstract Co-Author: Nothing to Disclose

Jonathan Stuart Lewin MD, Abstract Co-Author: Nothing to Disclose

Jeffrey Lewis Duerk PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To develop a robust catheter tracking and adaptive image parameter system that facilitates image-guided cardiovascular interventions in near real-time.

An interventional software package was developed for a standard 1.5T MR scanner. No external workstation was required. The system included: (1) a tracking module that continually monitors the catheter’s position, orientation, and insertion speed as it is moved through the vascular tree; (2) adaptive parameter software that allows specific image parameters to react to changes in catheter speed, e.g. to decrease the FOV for greater detail/inspection of suspicious pathology; (3) near real-time radial TrueFISP imaging (TR/TE 4.3/2.15ms, SL=5mm, FOV=400mm², 128 lines). Tip tracking employs active RF antennas/markers and a novel localization algorithm that requires 3-8 non-selective projections. The software can accommodate multiple-channel phased array coils for combined tracking and catheter-based micro-imaging. After localization, the system updates the scan plane position/orientation and specified adaptive parameters (FOV, spatial/temporal resolution, number of radial projections, etc). Gradients and RF pulses are recalculated automatically. Adaptive imaging has been tested in vessel phantoms and in vivo porcine imaging experiments (n=8). Applications included renal stent deployments, to evaluate the performance in future clinical trials.

The tracking software placed the scan plane with less than 2mm error 98% of the time. Responding to changes in the catheter’s insertion speed, the system facilitated vessel wall inspection by adapting the FOV to 80mm², 256 lines, and in some cases, switching off external coils and reconstructing images using catheter coils only. Radial imaging’s aliasing properties and temporal efficiency enabled seamless transition to small FOV mode.

The adaptive tracking system developed here was able to effectively guide the catheter through the vascular tree to the target anatomy using near real-time images that followed its position and orientation. Detailed inspection of localized pathology was facilitated by image parameters that automatically responded to changes in catheter insertion speed.

J.S.L.,J.L.D.,F.K.W.,D.R.E.,C.M.H.,S.Z.,E.W.: Siemens Medical Solutions grant support

Elgort, D, Hillenbrand, C, Wong, E, Zhang, S, Wacker, F, Lewin, J, Duerk, J, et al, , Interventional Cardiovascular MRI Using Radial TRUE-FISP Acquisitions, Real-time Catheter Tracking, and Adaptive Imaging Parameters.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4412036.html