title: A system for real-time XMR guided cardiovascular intervention.
abstract: The hybrid magnetic resonance (MR)/X-ray suite (XMR) is a recently introduced imaging solution that provides new possibilities for guidance of cardiovascular catheterization procedures. We have previously described and validated a technique based on optical tracking to register MR and X-ray images obtained from the sliding table XMR configuration. The aim of our recent work was to extend our technique by providing an improved calibration stage, real-time guidance during cardiovascular catheterization procedures, and further off-line analysis for mapping cardiac electrical data to patient anatomy. Specially designed optical trackers and a dedicated calibration object have resulted in a single calibration step that can be efficiently checked and updated before each procedure. An X-ray distortion model has been implemented that allows for distortion correction for arbitrary c-arm orientations. During procedures, the guidance system provides a real-time combined MR/X-ray image display consisting of live X-ray images with registered recently acquired MR derived anatomy. It is also possible to reconstruct the location of catheters seen during X-ray imaging in the MR derived patient anatomy. We have applied our registration technique to 13 cardiovascular catheterization procedures. Our system has been used for the real-time guidance of ten radiofrequency ablations and one aortic stent implantation. We demonstrate the real-time guidance using two exemplar cases. In a further two cases we show how off-line analysis of registered image data, acquired during electrophysiology study procedures, has been used to map cardiac electrical measurements to patient anatomy for two different types of mapping catheters. The cardiologists that have used the guidance system suggest that real-time XMR guidance could have substantial value in difficult interventional and electrophysiological procedures, potentially reducing procedure time and delivered radiation dose. Also, the ability to map measured electrical data to patient specific anatomy provides improved visualization and a path to investigation of cardiac electromechanical models.
authors.affiliation: Division of Imaging Sciences, Guy's, King's & St. Thomas' School of Medicine, King's College London, Guy's Hospital, London SEI 9RT, UK.
authors.forename: Kawal S
authors.initials: KS
authors.lastname: Rhode
authors.forename: Maxime
authors.initials: M
authors.lastname: Sermesant
authors.forename: David
authors.initials: D
authors.lastname: Brogan
authors.forename: Sanjeet
authors.initials: S
authors.lastname: Hegde
authors.forename: John
authors.initials: J
authors.lastname: Hipwell
authors.forename: Pier
authors.initials: P
authors.lastname: Lambiase
authors.forename: Eric
authors.initials: E
authors.lastname: Rosenthal
authors.forename: Clifford
authors.initials: C
authors.lastname: Bucknall
authors.forename: Shakeel A
authors.initials: SA
authors.lastname: Qureshi
authors.forename: Jaswinder S
authors.initials: JS
authors.lastname: Gill
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Derek L G
authors.initials: DL
authors.lastname: Hill
mesh_terms: D006328:Cardiac Catheterization / Q000295:instrumentation* / Q000379:methods; D003199:Computer Systems; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008954:Models, Biological; D015233:Models, Statistical; D011859:Radiography / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique / Q000295:instrumentation; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D018511:Systems Integration