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- Koutouzi, Giasemi, 1984, et al.
(författare)
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Orthogonal Rings, Fiducial Markers, and Overlay Accuracy When Image Fusion is Used for EVAR Guidance.
- 2016
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Ingår i: European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery. - : Elsevier BV. - 1532-2165. ; 52:5, s. 604-611
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Tidskriftsartikel (refereegranskat)abstract
- Evaluation of orthogonal rings, fiducial markers, and overlay accuracy when image fusion is used for endovascular aortic repair (EVAR).This was a prospective single centre study. In 19 patients undergoing standard EVAR, 3D image fusion was used for intra-operative guidance. Renal arteries and targeted stent graft positions were marked with rings orthogonal to the respective centre lines from pre-operative computed tomography (CT). Radiopaque reference objects attached to the back of the patient were used as fiducial markers to detect patient movement intra-operatively. Automatic 3D-3D registration of the pre-operative CT with an intra-operative cone beam computed tomography (CBCT) as well as 3D-3D registration after manual alignment of nearby vertebrae were evaluated. Registration was defined as being sufficient for EVAR guidance if the deviation of the origin of the lower renal artery was less than 3mm. For final overlay registration, the renal arteries were manually aligned using aortic calcification and vessel outlines. The accuracy of the overlay before stent graft deployment was evaluated using digital subtraction angiography (DSA) as direct comparison.Fiducial markers helped in detecting misalignment caused by patient movement during the procedure. Use of automatic intensity based registration alone was insufficient for EVAR guidance. Manual registration based on vertebrae L1-L2 was sufficient in 7/19 patients (37%). Using the final adjusted registration as overlay, the median alignment error of the lower renal artery marking at pre-deployment DSA was 2mm (0-5) sideways and 2mm (0-9) longitudinally, mostly in a caudal direction.3D image fusion can facilitate intra-operative guidance during EVAR. Orthogonal rings and fiducial markers are useful for visualization and overlay correction. However, the accuracy of the overlaid 3D image is not always ideal and further technical development is needed.
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| 2. |
- Koutouzi, Giasemi, 1984, et al.
(författare)
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Performance of a feature-based algorithm for 3D-3D registration of CT angiography to cone-beam CT for endovascular repair of complex abdominal aortic aneurysms
- 2018
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Ingår i: BMC Medical Imaging. - : Springer Science and Business Media LLC. - 1471-2342. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: A crucial step in image fusion for intraoperative guidance during endovascular procedures is the registration of preoperative computed tomography angiography (CTA) with intraoperative Cone Beam CT (CBCT). Automatic tools for image registration facilitate the 3D image guidance workflow. However their performance is not always satisfactory. The aim of this study is to assess the accuracy of a new fully automatic, feature-based algorithm for 3D3D registration of CTA to CBCT. Methods: The feature-based algorithm was tested on clinical image datasets from 14 patients undergoing complex endovascular aortic repair. Deviations in Euclidian distances between vascular as well as bony landmarks were measured and compared to an intensity-based, normalized mutual information algorithm. Results: The results for the feature-based algorithm showed that the median 3D registration error between the anatomical landmarks of CBCT and CT images was less than 3mm. The feature-based algorithm showed significantly better accuracy compared to the intensity-based algorithm (p<0.001). Conclusion: A feature-based algorithm for 3D image registration is presented.
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| 4. |
- Waldenström, Ann-Charlotte, 1950, et al.
(författare)
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A comparison of two imaging modalities for detecting lymphatic nodal spread in radiochemotherapy of locally advanced cervical cancer
- 2018
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Ingår i: Physics and Imaging in Radiation Oncology. - : Elsevier BV. - 2405-6316. ; 8, s. 33-37
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: In uterine cervical cancer tumour spread reaching the para-aortic lymph nodes is the most significant independent pre-treatment predictor of progression-free survival. When introducing [18F] fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) in our clinic for patients with advanced cervical cancer planned for definitive radiochemotherapy, the purpose of this study was to quantify to what extent the added information lead to changes in radiotherapy planning. Material and methods: We included 25 consecutive patients with cervical cancer stages IB2 – IIIB planned for definitive radiochemotherapy between November 2010 and May 2012. The patients were examined both with magnetic resonance imaging (MRI) and FDG-PET/CT before treatment and after four weeks of treatment. Results: In 11/24 (46%) of the patients the FDG-PET/CT before treatment provided additional diagnostic information leading to changes in treatment planning compared to information from MRI. Seven of these eleven patients (64%) were alive and without evidence of disease at four-year follow-up. The MRI detected pelvic tumour spread not seen on the FDG-PET/CT in 2/24 patients. The disease-free four-year survival was 59%. Conclusions: Additional diagnostic information from FDG-PET/CT changed treatment strategy in almost half of the patients and may have increased chances of survival in this limited group of patients with locally advanced uterine cervical cancer. We recommend both modalities for nodal detection.
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