@article{LinsenmannCattaneoMaerzetal.2021,
  author    = {Linsenmann, Thomas and Cattaneo, Andrea and M{\"a}rz, Alexander and Weiland, Judith and Stetter, Christian and Nickl, Robert and Westermaier, Thomas},
  title     = {Combined frameless stereotactical biopsy and intraoperative cerebral angiography by 3D-rotational fluoroscopy with intravenous contrast administration: a feasibility study},
  series = {BMC Medical Imaging},
  volume    = {21},
  journal   = {BMC Medical Imaging},
  doi       = {10.1186/s12880-021-00622-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270370},
  year      = {2021},
  abstract  = {Background Mobile 3-dimensional fluoroscopes are an integral part of modern neurosurgical operating theatres and can also be used in combination with free available image post processing to depict cerebral vessels. In preparation of stereotactic surgery, preoperative Computed Tomography (CT) may be required for image fusion. Contrast CT may be of further advantage for image fusion as it regards the vessel anatomy in trajectory planning. Time-consuming in-hospital transports are necessary for this purpose. Mobile 3D-fluoroscopes may be used to generate a CT equal preoperative data set without an in-hospital transport. This study was performed to determine the feasibility and image quality of intraoperative 3-dimensional fluoroscopy with intravenous contrast administration in combination with stereotactical procedures. Methods 6 patients were included in this feasibility study. After fixation in a radiolucent Mayfield clamp a rotational fluoroscopy scan was performed with 50 mL iodine contrast agent. The image data sets were merged with the existing MRI images at a planning station and visually evaluated by two observer. The operation times were compared between the frame-based and frameless systems ("skin-to-skin" and "OR entry to exit"). Results The procedure proves to be safe. The entire procedure from fluoroscope positioning to the transfer to the planning station took 5-6 min with an image acquisition time of 24 s. In 5 of 6 cases, the fused imaging was able to reproduce the vascular anatomy accurately and in good quality. Both time end-points were significantly shorter compared to frame-based interventions. Conclusion The images could easily be transferred to the planning and navigation system and were successfully merged with the MRI data set. The procedure can be completely integrated into the surgical workflow. Preoperative CT imaging or transport under anaesthesia may even be replaced by this technique in the future. Furthermore, hemorrhages can be successfully visualized intraoperatively and might prevent time delays in emergencies.},
  language  = {en}
}
@article{LinsenmannMaerzDufneretal.2021,
  author    = {Linsenmann, Thomas and M{\"a}rz, Alexander and Dufner, Vera and Stetter, Christian and Weiland, Judith and Westermaier, Thomas},
  title     = {Optimization of radiation settings for angiography using 3D fluoroscopy for imaging of intracranial aneurysms},
  series = {Computer Assisted Surgery},
  volume    = {26},
  journal   = {Computer Assisted Surgery},
  number    = {1},
  doi       = {10.1080/24699322.2021.1894240},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259251},
  pages     = {22-30},
  year      = {2021},
  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(R) workstation, subtracted and reconstructed using OsiriX(R) 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.},
  language  = {en}
}