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Passive tracking of catheters and guidewires by contrast-enhanced MR fluoroscopy
C J Bakker1, C Bos, H J Weinmann
1Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands. c.j.g.bakker@azu.nl
Abstract:
Passive MR tracking of catheters and guidewires is usually done by dynamically imaging a single thick slab, subtracting a baseline image, and combining the result with a previously acquired MR angiogram. In the in vitro and in vivo experiments reported here, it is demonstrated that this approach may be greatly simplified by using a suitable intravascular contrast agent. The proposed method, contrast-enhanced MR fluoroscopy, combines tracking and angiography into a single sequence and allows direct visualization of the magnetically prepared parts of catheters and guidewires with respect to the vasculature at a frame rate of about one image per 1.5 seconds. Contrast-enhanced MR fluoroscopy, although still limited in temporal resolution, thus obviates the need for subtraction and overlay techniques and eliminates the sensitivity of tracking to subject motion between acquisitions. Magn Reson Med 45:17-23, 2001.
Insights
This study introduces contrast-enhanced MR fluoroscopy for simplified tracking of medical devices. This new method improves visualization of catheters and guidewires within blood vessels, reducing motion-related errors.
Area of Science:
- Medical Imaging
- Interventional Radiology
Background:
- Magnetic Resonance (MR) tracking of catheters and guidewires typically involves complex imaging techniques.
- Current methods often require dynamic imaging, baseline subtraction, and combining with MR angiography, making them sensitive to patient motion.
Purpose of the Study:
- To simplify passive MR tracking of intravascular devices.
- To develop a single-sequence method for simultaneous tracking and angiography.
Main Methods:
- Proposed a novel method: contrast-enhanced MR fluoroscopy.
- Utilized an intravascular contrast agent to directly visualize MR-tracked catheters and guidewires.
- Performed in vitro and in vivo experiments to validate the technique.
Main Results:
- Achieved direct visualization of catheter and guidewire positions relative to vasculature.
- Obtained images at a frame rate of approximately 1.5 seconds.
- Eliminated the need for subtraction and overlay techniques, reducing sensitivity to subject motion.
Conclusions:
- Contrast-enhanced MR fluoroscopy offers a simplified approach to passive MR tracking of intravascular devices.
- The method integrates tracking and angiography, improving visualization and reducing motion artifacts.
- Despite limitations in temporal resolution, this technique enhances the MR tracking process.