CT fluoroscopy
Computed tomography (CT) fluoroscopy combines the conventional advantages of both CT and fluoroscopy and has an important role in image-guided interventions where real-time imaging is required.
Historically, fluoroscopy was the main image guidance tool for interventional radiology procedures. The developments in CT led to it becoming an increasingly used tool in image-guided procedures e.g. chest biopsies. CT fluoroscopy combines the cross-sectional image targeting provided by CT with the real-time imaging, tracking and movement perception of fluoroscopy for interventional procedures. It allows continuous update of images at a fixed position and is commonly used for CT-guided biopsies and fluid drainages.
Advantages
- overlapping structures can be removed, providing accurate spatial information
- real-time display of images
- consequent reduction in complications through finer needle control
- reduced procedure time
- increased operator confidence
Technical considerations
- video monitor will need to be displayed in the scanning room
- an operator panel is required in the scanning room – with controls available for table movement, gantry lift, laser light control and fluoroscopic factors. Exposures will usually be activated using a footswitch
- involves an x-ray tube current of 30-50 mA, compared with conventional fluoroscopy with approximately 4 mA, or conventional CT with approximately 150-400 mA
- need for additional beam filtration to decrease patient radiation exposure
- consideration for radiation exposure to the interventionalist
- multislice machines have finer z-axis resolution, which improves localization accuracy
- CT fluoroscopy requires special techniques for image reconstruction, due to the need for rapid imaging feedback
See also
