PurposeTo evaluate the accuracy and technical success of positioning a radiofrequency ablation (RFA) electrode in osteoid osteomas by use of a new real-time needle guidance technology combining cone-beam computed tomography (CT) and fluoroscopy.Materials and MethodsPercutaneous RFA of osteoid osteomas was performed in five patients (median age 18 years), under general anesthesia, with the use of cone-beam CT and fluoroscopic guidance for electrode positioning. The outcome parameters were technical success, meaning correct needle placement in the nidus; accuracy defined as the deviation (in mm) from the center of the nidus; and clinical outcome at follow-up.ResultsIn all five cases, positioning was possible within 3 mm of the determined target location (median nidus size 6.8 mm; range 5–10.2 mm). All procedures were technically successful. All patients were free of pain at clinical follow-up. No complications were observed.ConclusionReal-time fluoroscopy needle guidance based on cone-beam CT is a useful tool to accurately position radiofrequency needles for minimally invasive treatment of osteoid osteomas.

Objective: To determine the accuracy of cone beam CT (CBCT) guidance and CT guidance in reaching small targets in relation to needle path complexity in a phantom. Methods: CBCT guidance combines three-dimensional CBCT imaging with fluoroscopy overlay and needle planning software to provide real-time needle guidance. The accuracy of needle positioning, quantified as deviation from a target, was assessed for inplane, angulated and double angulated needle paths. Four interventional radiologists reached four targets along the three paths using CBCT and CT guidance. Accuracies were compared between CBCT and CT for each needle path and between the three approaches within both modalities. The effect of user experience in CBCT guidance was also assessed. Results: Accuracies for CBCT were significantly better than CT for the double angulated needle path (2.2 vs 6.7 mm, p,0.001) for all radiologists. CBCT guidance showed no significant differences between the three approaches. For CT, deviations increased with increasing needle path complexity from 3.3 mm for the inplane placements to 4.4 mm (p50.007) and 6.7 mm (p,0.001) for the angulated and double angulated CT-guided needle placements, respectively. For double angulated needle paths, experienced CBCT users showed consistently higher accuracies than trained users [1.8 mm (range 1.2-2.2) vs 3.3 mm (range 2.1-7.2) deviation from target, respectively; p50.003]. Conclusion: In terms of accuracy, CBCT is the preferred modality, irrespective of the level of user experience, for more difficult guidance procedures requiring double angulated needle paths as in oncological interventions. Advances in knowledge: Accuracy of CBCT guidance has not been discussed before. CBCT guidance allows accurate needle placement irrespective of needle path complexity. For angulated and double-angulated needle paths, CBCT is more accurate than CT guidance.Needle guidance for puncture or other minimally invasive procedures is increasing in standard interventional radiology practice. In local therapy procedures, such as percutaneous ablations, accurate placement of one or more needles is important in order to provide effective treatment [1]. This is especially the case in treatment or biopsy procedures of small lesions, in which the tip of the needle needs to be placed within a range of millimetres of the target point. Therefore, image guidance plays a significant role in accurate percutaneous needle placement [2].Currently, most needle placement procedures are performed using CT guidance, fluoroscopy or ultrasound [3]. CT images provide good visualisation of the target and surrounding tissues. For needle guidance, however, CT has limitations mainly because it does not allow real-time feedback on needle progression. For semi-real-time imaging within the CT scanner, CT-fluoroscopy can be used at the expense of a higher radiation dose to the patient and operator [4]. Acquiring CT fluoroscopy images to check needle position takes approximately 1 s, time in which the needle cannot be progressed.Fluorosc...

Guidance based on registration of CBCT and previously acquired diagnostic CE-CT can aid in enhancing localization of the adrenal veins thereby increasing the success rate of first-attempt AVS with a significant decrease in the number of used DSA runs and, consequently, radiation dose required.

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