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- Brydegaard, Mikkel, et al.
(författare)
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Short-Wave infrared atmospheric scheimpflug lidar
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. ; 176
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Konferensbidrag (refereegranskat)abstract
- Atmospheric dual-band Scheimpflug lidar is demonstrated at 980 and 1550 nm. Signals are compared during three weather conditions, and the spatio-temporal resolution of the atmospheric structure is considered. The potential for aerosol classification is evaluated, and future directions are discussed.
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- Larsson, Jim, et al.
(författare)
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Thermometry in porous media using GASMAS - a feasibility study
- 2016
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Ingår i: Laser Applications to Chemical, Security and Environmental Analysis, LACSEA 2016. - 9781943580156 ; Part F10-LACSEA 2016
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Konferensbidrag (refereegranskat)abstract
- The line shape of an absorption line from molecular oxygen enclosed in the pores of a ceramic material has been studied at different temperatures. By evaluating the line width it is feasible to extract temperature information of the gas inside porous scattering materials.
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| 8. |
- Larsson, Sune, et al.
(författare)
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Augmentation of Tibial Plateau Fractures with Calcium Phosphate Cement : A Randomized Study Using Radiostereometry
- 2004
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Konferensbidrag (refereegranskat)abstract
- Purpose: One problem with tibial plateau fractures that involve a depressed articular fragment is the difficulty of maintaining reduction until healing. The conventional method is to fill the subchondral void with autologous bone transplant followed by restricted weightbearing for 8 to 12 weeks. Recently, biomaterials have been introduced that might overcome several problems associated with bone transplant. The purpose of this study was to evaluate an injectible calcium-phosphate cement when used as a bone graft substitute in lateral tibial plateau fractures, with special emphasis on the stability of the elevated articular fragment.Methods: Twenty-four patients with a lateral tibial plateau fracture type 41-B2 or 41-B3 (OTA classification) were included. The authors operated on all patients. Conventional metal fixation was used to fix the fracture following elevation of the articular fragment. The subchondral void was filled with injectable calcium-phosphate cement (Norian SRS, Synthes) or conventional iliac bone graft according to randomization during surgery. There were 12 patients in each group with an average age of 50 and 52 years, respectively. During surgery, tantalum markers were inserted for subsequent radio stereometry (RSA) (RSA Biomedical Innovation, Umeå, Sweden), a radiologic technique that enables measurement of movement along and around three orthogonal axes with a precision of less than 0.5 mm and 0.7°. Continuous passive motion was begun immediately after surgery. Weightbearing was restricted to 20 kg for 6 weeks in the SRS group and for 12 weeks in the control group. Radio stereometry was performed before weightbearing and at 1, 6, and 12 weeks and at 6 and 12 months. Conventional radiographs were used for assessment of reduction and healing. Clinical evaluation (Lysholm score and a visual analog scale score of 0 to 10 for pain) was conducted by a physiotherapist. For assessment of compliance with regard to weightbearing, patients were examined with F Scan (Tecscan, Inc., Boston, Massachusetts, USA) at each time point.Results: No patients were lost but two were excluded from the RSA evaluation due to technical problems. All fractures healed. There was one deep infection (SRS). At 6 weeks, average weightbearing was 22 kg in the SRS group and 19 kg among the controls (NS); at 12 weeks, 66 kg vs. 28 kg (P <0.001); and at 6 and 12 months, on average, between 66 and 72 kg with no difference between groups. Pain during activity was lower in the SRS group at 1 week (P <0.01), 6 weeks (P <0.004), 3 months (P <0.005), and at 6 months (P <0.02), with no difference at 1 year. The Lysholm knee score was better at 6 weeks (P <0.01), 12 weeks (P <0.002), and 6 months (P <0.02) in the SRS group, and there was no significant difference at 1 year. Radio stereometry revealed movement of the articular fragment in all patients. The total translation was, on average, 1.41 mm in the SRS group and 3.88 mm in the controls (P <0.001). In both groups the most significant movement occurred during the first 6 weeks, and there was no significant movement of the articular fragment from 6 to 12 months, indicating stable healing. The most typical pattern of movement was subsidence along the vertical axis or rotation in the transversal axis (forward tilt) or both, and as toe-out rotation around the vertical axis. One patient from the SRS group had a migration exceeding 3 mm, and two controls had a migration exceeding 5 mm.Conclusion/Significance: Injectable calcium-phosphate cement provided a more stable fixation of the elevated articular fragment in lateral tibial plateau fractures when compared with conventional bone graft, despite the fact that cement-augmented patients were allowed earlier weightbearing. Patients treated with cement also had less pain during the entire course of healing when compared with controls. Bone graft substitutes can offer new perspectives for treatment of fractures involving metaphyseal defects, without the side effects associated with bone grafting.
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- Nysjö, Johan, et al.
(författare)
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Precise 3D Angle Measurements in CT Wrist Images
- 2013
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Ingår i: Image Analysis and Processing – ICIAP 2013. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642411830 ; 8157, s. 479-488
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Konferensbidrag (refereegranskat)abstract
- The clinically established method to assess the displacement of a distal radius fracture is to manually measure two reference angles,the dorsal angle and the radial angle, in consecutive 2D X-ray images of the wrist. This approach has the disadvantage of being sensitive to operator errors since the measurements are performed on 2D projections of a 3D structure. In this paper, we present a semi-automatic system for measuring relative changes in the dorsal angle in 3D computed tomography (CT) images of fractured wrists. We evaluate the proposed 3D measurement method on 28 post-operative CT images of fractured wrists and compare it with the radiographic 2D measurement method used in clinical practice. The results show that our proposed 3D measurement method has a high intra- and inter-operator precision and is more precise and robust than the conventional 2D measurement method.
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