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dc.contributor.advisorHernes, Toril A. Nagelhus
dc.contributor.advisorReinertsen, Ingerid
dc.contributor.advisorLindseth, Frank
dc.contributor.advisorSolheim, Ole
dc.contributor.authorBø, Lars Eirik
dc.date.accessioned2018-09-28T08:55:12Z
dc.date.available2018-09-28T08:55:12Z
dc.date.issued2018
dc.identifier.isbn978-82-326-3305-0
dc.identifier.issn1503-8181
dc.identifier.urihttp://hdl.handle.net/11250/2565170
dc.description.abstractMost people experience back pain at some point in their life. While most of these conditions are treated nonoperatively, surgical treatment has been shown to be both effective and cost effective compared to nonoperative care for both intervertebral disc herniation and spinal stenosis in selected patients. Surgical navigation systems enabling image guidance based on preoperative or intraoperative computed tomography (CT) images have found some use in spine surgery. Here, they are most frequently used for spinal fusion, and the benefits of image guidance in such procedures, under given conditions, have been documented in several studies. In spite of this, few spine surgeons use navigation routinely. High cost is one of the most important barriers to a more widespread adoption of navigation systems in spine surgery. Extending the use of navigation to more than just fusion procedures, and to soft tissue procedures such as disk herniations in particular, could help the surgeon substantiate the cost of the equipment. A big step in this direction would be to enable navigation based on other imaging modalities than CT, such as magnetic resonance (MR) or ultrasound imaging. In this work, the goal has therefore been to enable the use of ultrasound imaging both for intraoperative imaging and for registration of preoperative MR images to the patient. Many spine procedures are today performed with a microsurgical approach, and the small incisions used in these procedures prohibit the use of standard probes. Our group has therefore, in a previous project, developed a new probe specifically designed to enable ultrasound imaging through such small incisions. The main part of the work has been directed towards enabling tracking and navigation with this probe. In addition, we have studied methods for registering MR images to ultrasound images of the spine. In Paper A, we looked at methods for reconstructing three-dimensional image volumes from tracked two-dimensional ultrasound images. Both different means of capturing the original ultrasound images and different reconstruction algorithms were thoroughly compared. We found that the differences were small, and while the various methods showed different strengths and weaknesses, the overall result was that they could not be separated. In Paper B, we explored the feasibility of using electromagnetic (EM) tracking in an operating room setting, both alone and in combination with a robotic C-arm. We also compared the performance of the standard EM field generator with a new prototype designed specifically for use with fluoroscopic imaging equipment. We found that while the accuracy decreased considerably with the C-arm inside the operating field, the measurements were still stable. We thus concluded that by implementing a suitable static correction scheme, the tracking system and the C-arm could potentially be used together. In Paper C, we presented a new method for ultrasound probe calibration, which is the process of finding the spatial relationship between the coordinate system of the tracking sensor that is integrated in the ultrasound probe and the coordinate system of the ultrasound images generated by the probe. In a research setting, such as ours, new probes are tested regularly, and the method was therefore designed to be used with a large variety of probes without any adaption. The method was tested on three very different probes demonstrating both great versatility and high accuracy. In Paper D, we developed a method for registration of preoperative MR images to the patient by means of intraoperative ultrasound imaging using a tracked ultrasound probe. The method segmented the posterior bone surface from both the ultrasound images and the MR images and registered the two surfaces to each other using a modified version of the Iterative Closest Point algorithm. For this paper, the method was only tested on one subject, but the accuracy of the registration on this subject was clinically relevant, and we concluded that the method was promising. In conclusion, we have developed and tested technology that enables tracking of small, intraoperative ultrasound probes and allows the generation of three-dimensional volumes suitable for navigation from such images. We have also investigated the use of intraoperative ultrasound imaging for registration of preoperative CT and MR images to the spine. The latter is, however, a work in progress, as the methods that we have tested have so far have not been sufficiently robust for clinical usenb_NO
dc.language.isoengnb_NO
dc.publisherNTNUnb_NO
dc.relation.ispartofseriesDoctoral theses at NTNU;2018:257
dc.relation.haspartPaper A: Solberg, Ole Vegard; Lindseth, Frank; Bø, Lars Eirik; Muller, Sebastien; Meland, Janne Beate Lervik; Tangen, Geir Arne; Hernes, Toril A. Nagelhus. 3D ultrasound reconstruction algorithms from analog and digital data. Ultrasonics 2011 ;Volum 51.(4) s. 405-419 https://doi.org/10.1016/j.ultras.2010.11.007nb_NO
dc.relation.haspartPaper B: Bø, Lars Eirik; Leira, Håkon Olav; Tangen, Geir Arne; Hofstad, Erlend Fagertun; Amundsen, Tore; Langø, Thomas. Accuracy of electromagnetic tracking with a prototype field generator in an interventional OR setting. Medical physics 2012 ;Volum 39.(1) s. 399-406 https://doi.org/10.1118/1.3666768 |nb_NO
dc.relation.haspartPaper C: Bø, Lars Eirik; Hofstad, Erlend Fagertun; Lindseth, Frank; Hernes, Toril A. Nagelhus. Versatile robotic probe calibration for position tracking in ultrasound imaging. Physics in Medicine and Biology 2015 ;Volum 60.(9) s. 3499-3513 https://doi.org/10.1088/0031-9155/60/9/3499 Attribution 3.0 Unported (CC BY 3.0) Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOInb_NO
dc.relation.haspartPaper D: Bø, Lars Eirik; Palomar, Rafael; Selbekk, Tormod; Reinertsen, Ingerid. Registration of MR to Percutaneous Ultrasound of the Spine for Image-Guided Surgery. I: Computational Methods and Clinical Applications for Spine Imaging. Lecture Notes in Computational Vision and Biomechanics, vol 17.p.209-218 Springer 2014 https://doi.org/10.1007/978-3-319-07269-2_18nb_NO
dc.titleUltrasound in image-guided spine surgery: Enabling technologies and first stepsnb_NO
dc.typeDoctoral thesisnb_NO
dc.subject.nsiVDP::Medical disciplines: 700::Clinical medical disciplines: 750nb_NO


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