title: Visualization of active devices and automatic slice repositioning ("SnapTo") for MRI-guided interventions.
abstract: The accurate visualization of interventional devices is crucial for the safety and effectiveness of MRI-guided interventional procedures. In this paper, we introduce an improvement to the visualization of active devices. The key component is a fast, robust method ("CurveFind") that reconstructs the three-dimensional trajectory of the device from projection images in a fraction of a second. CurveFind is an iterative prediction-correction algorithm that acts on a product of orthogonal projection images. By varying step size and search direction, it is robust to signal inhomogeneities. At the touch of a key, the imaged slice is repositioned to contain the relevant section of the device ("SnapTo"), the curve of the device is plotted in a three-dimensional display, and the point on a target slice, which the device will intersect, is displayed. These features have been incorporated into a real-time MRI system. Experiments in vitro and in vivo (in a pig) have produced successful results using a variety of single- and multichannel devices designed to produce both spatially continuous and discrete signals. CurveFind is typically able to reconstruct the device curve, with an average error of approximately 2 mm, even in the case of complex geometries.
authors.affiliation: Translational Medicine Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA. georgeak@nhlbi.nih.gov
authors.forename: Ashvin K
authors.initials: AK
authors.lastname: George
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Derbyshire
authors.forename: Haris
authors.initials: H
authors.lastname: Saybasili
authors.forename: Christina E
authors.initials: CE
authors.lastname: Saikus
authors.forename: Ozgur
authors.initials: O
authors.lastname: Kocaturk
authors.forename: Michael A
authors.initials: MA
authors.lastname: Guttman
authors.forename: Elliot R
authors.initials: ER
authors.lastname: McVeigh
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lederman
authors.forename: Anthony Z
authors.initials: AZ
authors.lastname: Faranesh
mesh_terms: D000465:Algorithms; D000818:Animals; D001707:Biopsy, Needle / Q000295:instrumentation; D007089:Image Enhancement / Q000295:instrumentation*; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation*; D019047:Phantoms, Imaging; D013552:Swine; D014652:Vascular Diseases / Q000601:surgery