Optimization of radiation settings for angiography using 3D fluoroscopy for imaging of intracranial aneurysms

Abstract

Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. We recently reported its use for imaging cerebral vascular malformations and aneurysms. This study was conducted to evaluate various radiation settings for the imaging of cerebral aneurysms before and after surgical occlusion. Eighteen patients with cerebral aneurysms with the indication for surgical clipping were included in this prospective analysis. Before surgery the patients were randomized into one of three different scan protocols according (default settings of the 3D fluoroscope): Group 1: 110 kV, 80 mA (enhanced cranial mode), group 2: 120 kV, 64 mA (lumbar spine mode), group 3: 120 kV, 25 mA (head/neck settings). Prior to surgery, a rotational fluoroscopy scan (duration 24 s) was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac^® workstation, subtracted and reconstructed using OsiriX^® MD 10.0 software. The procedure was repeated after clip placement. The image quality regarding preoperative aneurysm configuration and postoperative assessment of aneurysm occlusion and vessel patency was analyzed by 2 independent reviewers using a 6-grade scale. This technique quickly supplies images of adequate quality to depict intracranial aneurysms and distal vessel patency after aneurysm clipping. Regarding these features, a further optimization to our previous protocol seems possible lowering the voltage and increasing tube current. For quick intraoperative assessment, image subtraction seems not necessary. Thus, a native scan without a contrast agent is not necessary. Further optimization may be possible using a different contrast injection protocol.

Keywords:

• 3D fluoroscopy
• aneurysm
• fluoroscopy
• intraoperative imaging

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

The authors cordially thank Mrs. Jennifer Rohmann and Mr. Ingolf Simon for technical assistance in the acquisition of the images.

Ethical approval and consent to participate

All patients in this analysis were informed of the potential risk of the administration of an iodine contrast agent and radiation exposure and all patients gave their written informed consent.

The study was approved by the ethics committee of the medical faculty of the University of Wuerzburg (Reference 263/16-ge.).

Disclosure statement

The project was supported by the External Research Fund of Medtronic Inc. The funder was not involved in the study design, collection, analysis, interpretation of the data or the decision to publish.

Dr. Westermaier received payments from Johnson&Johnson, Medtronic and Medicon for lectures in spinal neurosurgery. None of the other authors has a conflict of interest to declare.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This publication was supported by the Open Access Publication Fund of the University of Wuerzburg and the External Research Program of Medtronic.