Visualization of active devices and automatic slice repositioning ("SnapTo") for MRI-guided interventions.
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.
George
Ashvin K
AK
Translational Medicine Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA. georgeak@nhlbi.nih.gov
Derbyshire
J Andrew
JA
Saybasili
Haris
H
Saikus
Christina E
CE
Kocaturk
Ozgur
O
Guttman
Michael A
MA
McVeigh
Elliot R
ER
Lederman
Robert J
RJ
Faranesh
Anthony Z
AZ
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