Bringing diagnostic or therapeutic devices to a target tissue via vascular inserted catheters has been the mainstay of interventional radiology, vascular surgery, and interventional cardiology since the 1930s . Catheter technology has dramatically improved over time, a result of using novel mechanical engineering and materials science, leading to a variety of application-specific kits. There are, however, three issues that limit catheter applications and affect procedure duration, outcomes, and the number and severity of complications . The first issue is visualization of catheter position and orientation. The second is visualization of tissues that surround the catheter during various stages of the procedure. The third issue is improved catheter steering, because catheters are manipulated by hand motion occurring at large (1.2–1.6 m) distances from the catheter distal tip.
For catheter position and orientation visualization, the classic imaging modality of X-ray fluoroscopy, has many advantages, such as a high-temporal update and a strong contrast-to-noise ratio (CNR) between catheters and the vascular background . There are also a number of disadvantages: shadowing effects when multiple catheters are in proximity; interference from obstructing highly absorptive tissues, such as bones; the availability of projection views only, lacking depth localization; and a radiation dose to both patient and clinician. In addition, during navigation in small vessels, if the surrounding vascular bed is not well seen, repeated ionic-contrast injection is required. Finally, the interventional staff wears heavy lead aprons, which contributes to a high incidence of back pain.
The early 1990s saw the introduction of non–X-ray based techniques to track catheter position. The most widely used navigational tools are based on electromagnetic (EM) methods. These can either be magnetic or electrical . Using these systems significantly reduced the radiation dose during navigation and treatment and dramatically improved the three-dimensional (3D) visualization of catheter shape and its spatial localization.
Visualizing the tissues around the catheter remains a large problem. This dilemma was somewhat improved by using 3D rotational X-ray fluoroscopy , which created a 3D anatomic image. Yet, this did little to resolve X-ray’s weak CNR for soft tissues, and it increased the X-ray dose and required contrast injection.
Since the early 2000s, this issue is being addressed by registering images with improved soft-tissue and vascular CNR to the X-ray system , or later on to the EM tracking systems. Computed tomography or magnetic resonance imaging (MRI) scans, acquired before the intervention, are co-registered with the intraprocedural fluoroscopy frame of reference, or, using commercially available software packages , they are co-registered with the EM tracking systems. These strategies improve the visualization of the vascular anatomy and its surrounding tissues, and further reduce x-ray dose. Using EM tracked systems with co-registered imaging, the catheters’ 3D position relative to its surrounding structures can be nicely observed. However, distortions and inaccuracies remain , mainly because of changes in the anatomy shape, occurring between the preprocedural imaging session and the intervention, which may be large (>5 mm) in spinal, abdominal, and cardiac anatomy, and also from changes in anatomy that occur in the midst of the procedure.
Improvements in catheter steering started in the mid-2000s with the introduction of robotic technology that could deflect and advance intra vascular catheters. The most common commercial systems use strong magnetic field gradients to move a ferromagnetic catheter tip , or a pull-wire manipulated sheath, which is placed around the catheter . These systems have simplified navigation and may improve the consistency of therapy delivery. In addition, with the robot-controlling consoles placed outside the X-ray suite, radiation exposure to the physician is reduced.
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Get Radiology Tree app to read full this article<
Acknowledgments
Get Radiology Tree app to read full this article<
References
1. Mueller R., Sanborn T.: The history of interventional cardiology. Am Heart J 1995; 129: pp. 146-172.
2. Rudin S., Bednarek D.R., Hoffmann K.R.: Endovascular image-guided interventions (EIGIs). Med Phys 2008; 35: pp. 301-309.
3. CarTo-XP and Noga. Biosense-Webster Inc., Diamond Bar, CA. Available at: http://www.biosensewebster.com/ .
4. Aurora. Northern Digital Inc., Waterloo, Ontario. Available at: http://www.ndigital.com/medical/aurora.php .
5. Ensite-NavX. St. Jude Medical Inc., Minnetonka, MN. Available at: http://www.sjm.com/ .
6. Neubauer A.M., Garcia J.A., Messenger J.C., et. al.: Clinical feasibility of a fully automated 3d reconstruction of rotational coronary x-ray angiograms. Circulation Cardiovasc Interv 2010; 3: pp. 71-79.
7. Sra J., Krum D., Malloy A., et. al.: Registration of three-dimensional left atrial computed tomographic images with projection images obtained using fluoroscopy. Circulation 2005; 112: pp. 3763-3768.
8. Dong J., Dickfeld T., Dalal D., et. al.: Initial experience in the use of integrated electroanatomic mapping with three-dimensional MR/CT images to guide catheter ablation of atrial fibrillation. J Cardiovasc Electrophysiol 2006; 17: pp. 459-466.
9. Brooks A.G., Wilson L., Kuklik P., et. al.: Image integration using NavX Fusion: initial experience and validation. Heart Rhythm 2008; 5: pp. 526-535.
10. Malchano Z.J., Neuzil P., Cury R.C., et. al.: Integration of cardiac CT/MR imaging with three-dimensional electroanatomical mapping to guide catheter manipulation in the left atrium: implications for catheter ablation of atrial fibrillation. J Cardiovasc Electrophysiol 2006; 17: pp. 1221-1229.
11. Kistler P.M., Schilling R.J., Rajappan K., et. al.: Image integration for atrial fibrillation ablation—pearls and pitfalls. Heart Rhythm 2007; 4: pp. 1216-1221.
12. Heist E.K., Chevalier J., Holmvang G., et. al.: Factors affecting error in integration of electroanatomic mapping with CT and MR imaging during catheter ablation of atrial fibrillation. J Interv Card Electrophysiol 2006; 17: pp. 21-27.
13. Steriotaxis Inc. St. Louis, MO. Available at: http://www.stereotaxis.com/ .
14. Sensei, Hansen Medical Inc. Mountain View, CA. Available at: http://www.hansenmedical.com/ .
15. Dumoulin C.L., Souza S.P., Darrow R.D.: Real-time position monitoring of invasive devices using magnetic resonance. Magn Reson Med 1993; 29: pp. 411-415.
16. Surgivision, Inc. Baltimore, MD. Available at: http://www.surgivision.com/ .
17. IMRICOR Medical Inc. Burnsville, MN. Available at: http://www.imricor.com/ .
18. Robin Medical Inc. Baltimore, MD. Available at: http://www.robinmedical.com/ .
19. Roberts T.P., Hassenzahl W.V., Hetts S.W., et. al.: Remote control of catheter tip deflection: an opportunity for interventional MRI. Magn Reson Med 2002; 48: pp. 1091-1095.
20. Settecase F., Sussman M.S., Wilson M.W., et. al.: Magnetically-assisted remote control (MARC) steering of endovascular catheters for interventional MRI: a model for deflection and design implications. Med Phys 2007; 34: pp. 3135-3142.
21. Bernhardt A., Wilson M.W., Settecase F., et. al.: Steerable catheter microcoils for interventional MRI: reducing resistive heating. Acad Radiol 2011; 18: pp. 270-276.
22. Settecase F., Hetts S.W., Martin A.J., et. al.: RF heating of MRI-assisted catheter steering coils for interventional MRI. Acad Radiol 2011; 18: pp. 277-285.
23. Pictet J., Meuli R., Wicky S., et. al.: Radiofrequency heating effects around resonant lengths of wire in MRI. Phys Med Biol 2002; 47: pp. 2973-2985.
24. Atalar E.: Radiofrequency safety for interventional MRI procedures. Acad Radiol 2005; 12: pp. 1149-1157.
25. Tong N., Shmatukha A., Asmah P., et. al.: Practical aspects of MR imaging in the presence of conductive guide wires. Phys Med Biol 2010; 55: N13
26. Settecase F, Sussman MS, Wilson MW, et al. Evaluation of RF and resistive heating due to magnetically-assisted remote control (MARC) steering coils for endovascular interventional MRI. Proceedings of the 16th Annual Meeting of the ISMRM 2008, Toronto, ON, Canada.
27. Glover P.M.: Interaction of MRI field gradients with the human body. Phys Med Biol 2009; 54: R99
28. Weiss S., Vernickel P., Schaeffter T., et. al.: Transmission line for improved RF safety of interventional devices. Magn Reson Med 2005; 54: pp. 182-189.
29. Nordbeck P., Bauer W.R., Fidler F., et. al.: Feasibility of real-time MRI with a novel carbon catheter for interventional electrophysiology. Circ Arrhythm Electrophysiol 2009; 2: pp. 258-267.
30. Dukkipati S.R., Mallozzi R., Schmidt E.J., et. al.: Electroanatomic mapping of the left ventricle in a porcine model of chronic myocardial infarction with magnetic resonance-based catheter tracking. Circulation 2008; 118: pp. 853-862.
31. Schmidt E.J., Mallozzi R.P., Thiagalingam A., et. al.: Electro-anatomic mapping and radio-frequency ablation of porcine left atria and atrio-ventricular nodes using magnetic resonance catheter tracking. Circ Arrhythm Electrophysiol 2009; 2: pp. 695-704.
32. Krueger S., Lips O., David B., et. al.: Towards MR-guided EP interventions using an RF-safe approach. J Cardiovasc Magnetic Res 2009; 11: pp. O84.