C-arm Cone-beam CT Systems Research Articles

WE-A-202-01: Dose and Image Quality in C-Arm CT Rotational Angiography

Conebeam CT using C-arm mounted large area flat panels (FPs) is becoming more commonly used in neuro- and body-interventional suites. The ability to visualize vascular geometry in 3D along with soft tissue during an intervention is providing information that may increase accuracy, shorten procedure time and may even change the course of treatment. However, acquisition of the projection data required for volume imaging requires dose to the patient, and understanding the trade-offs between acquisition parameters, dose and image quality is critical to the appropriate adoption of this imaging technique. Unlike conventional CT, the beam length in conebeam CT can cover the entire length of the object to be imaged or can be varied with the use of collimation, and the concept of CTDI is not, therefore, the metric of choice for measurement of dose. In addition, most C-arm conebeam CT systems use a short-scan (pi plus fan-angle) acquisition, and the dose distribution within the object is not cylindrically symmetric. Finally, since FP design has been optimized for fluoroscopy, image quality when used for CT must be carefully evaluated. This lecture will describe a dose metric that is appropriate for conebeam CT and allows direct comparison with the CTDIw of conventional CT, and will summarize dose-image quality trade-offs. A discussion of measured dose metrics and recently published Monte Carlo-based Effective Dose calculations for head and body applications will be presented. New results from our ongoing clinical study investigating the overall dose impact of 3D C-arm CT on body interventions will be summarized. Research sponsored by Siemens AG, Healthcare Sector, by NIH grant R01 HL087917 and by the Lucas Foundation. Learning Objectives: 1. Understand how differences in acquisition geometry between conebeam and conventional CT affect dose measurement and dose distribution. 2. Understand the necessary dose-image-quality trade-offs when using C-arm CT in the interventional suite

C-Arm Cone Beam CT for Hepatic Tumor Ablation Under Real-Time 3D Imaging

We describe our experience with the application of a novel technology in which fluoroscopy and 3D imaging from C-arm cone beam CT systems are combined with integrated navigation software. We applied this technology to five cases in which radiofrequency ablation was performed for hepatocellular carcinoma. Technical success was achieved without treatment-related complications in all cases. We conclude that this novel technology is potentially useful for targeting hepatic lesions.

Initial experience of percutaneous transthoracic needle biopsy of lung nodules using C-arm cone-beam CT systems

To describe our initial experience with percutaneous transthoracic biopsy (PCNB) of lung nodules using C-arm cone-beam CT (CBCT). Seventy-one consecutive patients with lung nodules of 30 mm or smaller underwent CBCT-guided PCNB using a coaxial cutting needle. We evaluated the procedure time, coaxial introducer dwell time, the numbers of pleural passages, coaxial introducer repositionings and CT acquisitions, as well as the technical success rate and radiation doses. Diagnostic accuracy, sensitivity, specificity and incidence of complications were also evaluated. PCNB was performed for 71 nodules: 63 solid, 6 part-solid and 2 ground-glass nodules. The procedure time, coaxial introducer dwell time, numbers of pleural passages, coaxial introducer repositionings and CT acquisitions were 17.9+/-5.9 min, 8.7+/-3.8 min, 1.1+/-0.4, 0.2+/-0.5 and 2.9+/-0.7, respectively. The technical success rate was 100% and the radiation dose was 272+/-116 mGy. Thirty-six nodules (50.7%) were diagnosed as malignant, 25 (35.2%) as benign and 10 (14.1%) as indeterminate. Diagnostic accuracy, sensitivity, specificity and incidence of complications were 98.4%, 97%, 100% and 38%, respectively. Complications included pneumothorax in 18 patients (25.4%), haemoptysis in 10 (14.1%) and chest pain in one (1.4%). Under CBCT guidance, PCNB of lung nodules can be performed accurately, providing both real-time fluoroscopic guidance and CT imaging capabilities.

C-arm Cone-beam CT: General Principles and Technical Considerations for Use in Interventional Radiology

Digital flat-panel detector cone-beam computed tomography (CBCT) has recently been adapted for use with C-arm systems. This configuration provides projection radiography, fluoroscopy, digital subtraction angiography, and volumetric computed tomography (CT) capabilities in a single patient setup, within the interventional suite. Such capabilities allow the interventionalist to perform intraprocedural volumetric imaging without the need for patient transportation. Proper use of this new technology requires an understanding of both its capabilities and limitations. This article provides an overview of C-arm CBCT with particular attention to trade-offs between C-arm CBCT systems and conventional multi-detector CT.

Three-dimensional C-arm Cone-beam CT: Applications in the Interventional Suite

C-arm cone-beam computed tomography (CT) with a flat-panel detector represents the next generation of imaging technology available in the interventional radiology suite and is predicted to be the platform for many of the three-dimensional (3D) roadmapping and navigational tools that will emerge in parallel with its integration. The combination of current and unappreciated capabilities may be the foundation on which improvements in both safety and effectiveness of complex vascular and nonvascular interventional procedures become possible. These improvements include multiplanar soft tissue imaging, enhanced pretreatment target lesion roadmapping and guidance, and the ability for immediate multiplanar posttreatment assessment. These key features alone may translate to a reduction in the use of iodinated contrast media, a decrease in the radiation dose to the patient and operator, and an increase in the therapeutic index (increase in safety-vs-benefit ratio). In routine practice, imaging information obtained with C-arm cone-beam CT provides a subjective level of confidence factor to the operator that has not yet been thoroughly quantified.