| 1. |
- Bengtsson Bernander, Karl, et al.
(författare)
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Classification of rotation-invariant biomedical images using equivariant neural networks
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Transmission electron microscopy (TEM) is an imaging technique used to visualize and analyze nano-sized structures and objects such as virus particles. Light microscopy can be used to diagnose diseases or characterize e.g. blood cells. Since samples under microscopes exhibit certain symmetries, such as global rotation invariance, equivariant neural networks are presumed to be useful. In this study, a baseline convolutional neural network is constructed in the form of the commonly used VGG16 classifier. Thereafter, it is modified to be equivariant to the p4 symmetry group of rotations of multiples of 90 degrees using group convolutions. This yields a number of benefits on a TEM virus dataset, including higher top validation set accuracy by on average 7.6% and faster convergence during training by on average 23.1% of that of the baseline. Similarly, when training and testing on images of blood cells, the convergence time for the equivariant neural network is 7.9% of that of the baseline. From this it is concluded that augmentation strategies for rotation can be skipped. Furthermore, when modelling the accuracy versus amount of TEM virus training data with a power law, the equivariant network has a slope of - 0.43 compared to - 0.26 of the baseline. Thus the equivariant network learns faster than the baseline when more training data is added. This study extends previous research on equivariant neural networks applied to images which exhibit symmetries to isometric transformations.
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| 2. |
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| 3. |
- Bodén, Ida, et al.
(författare)
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Development and optimization of a novel skin impedance instrument
- 2005
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Ingår i: Proceedings of the 13th Nordic-Baltic Conference of BioMedical Engineering and Medical Physics. - : Swedish Society for Medical Engineering and Medical Physics. ; , s. 162-163
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Konferensbidrag (refereegranskat)abstract
- A novel skin impedance instrument is presented. The reproducibility and stability of the measurements where evaluated with multivariate techniques and a tendency to separate different skin types with skin impedance measurements is seen.
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| 4. |
- Bodén, Ida, 1977-, et al.
(författare)
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NIR and skin impedance spectroscopic measurements for studying the effect of coffee and alcohol on skin, and dysplastic naevi
- 2012
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Ingår i: Skin research and technology. - : Wiley-Blackwell. - 0909-752X .- 1600-0846. ; 18:4, s. 486-494
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Tidskriftsartikel (refereegranskat)abstract
- Background/purpose: Near infrared (NIR) and impedance spectroscopy can be used for clinical skin measurements and need to be evaluated for possible confounding factors; (a) are skin conditions of the patient and the subsequent skin measurements influenced by alcohol and/or coffee consumption and (b) are measurements of dysplastic naevi (DN) reproducible over time and significantly different compared to reference skin.Methods: NIR and skin impedance spectroscopic data were analysed multivariately. In the first study, the skin characteristics of 15 healthy individuals were examined related to body location, gender, individual differences, and consumption of coffee or alcohol. The second study included five patients diagnosed with dysplastic naevi syndrome (DNS). Measurements were taken on DN and reference skin over time.Results: In the first study, body location and gender had a major influence on measurement scores. Inter-individual skin characteristics and coffee or alcohol effects on skin characteristics were of minor importance. In the second study, it was shown that DN can be differentiated from reference skin and the measurements are stable over time.Conclusions: Moderate consumption of alcohol and coffee did not influence the results of the measurements. It is possible to follow, stable or changed, characteristics of DN over time.
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| 5. |
- Bodén, Ida, 1977-, et al.
(författare)
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Non-invasive identification of melanoma with near-infrared and skin impedance spectroscopy
- 2013
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Ingår i: Skin research and technology. - : John Wiley & Sons. - 0909-752X .- 1600-0846. ; 19:1, s. e473-e478
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Tidskriftsartikel (refereegranskat)abstract
- Background/purpose: An early diagnosis of cutaneous malignant melanoma is of high importance for good prognosis. An objective, non-invasive instrument could improve the diagnostic accuracy of melanoma and decrease unnecessary biopsies. The aim of this study was to investigate the use of Near infrared and skin impedance spectroscopy in combination as a tool to distinguish between malignant and benign skin tumours.Methods: Near infrared and skin impedance spectra were collected in vivo on 50 naevi or suspect melanomas prior to excision. Received data was analysed with multivariate techniques and the results were compared to histopathology analyses of the tumours. A total of 12 cutaneous malignant melanomas, 19 dysplastic naevi and 19 benign naevi were included in the study.Results: The observed sensitivity and specificity of the proposed method were 83% and 95%, respectively, for malignant melanoma.Conclusions: The results indicate that the combination of near infrared and skin impedance spectroscopy is a promising tool for non-invasive diagnosis of suspect cutaneous malignant melanomas.
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| 6. |
- Borgefors, Gunilla, et al.
(författare)
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CBA Annual Report 2002
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Christersson, Albert, et al.
(författare)
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Comparison of 2D radiography and a semi-automatic CT-based 3D method for measuring change in dorsal angulation over time in distal radius fractures
- 2016
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Ingår i: Skeletal Radiology. - : Springer Science and Business Media LLC. - 0364-2348 .- 1432-2161. ; 45:6, s. 763-769
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Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of the present study was to compare the reliability and agreement between a computer tomography-based method (CT) and digitalised 2D radiographs (XR) when measuring change in dorsal angulation over time in distal radius fractures. Materials and methods Radiographs from 33 distal radius fractures treated with external fixation were retrospectively analysed. All fractures had been examined using both XR and CT at six times over 6 months postoperatively. The changes in dorsal angulation between the first reference images and the following examinations in every patient were calculated from 133 follow-up measurements by two assessors and repeated at two different time points. The measurements were analysed using Bland-Altman plots, comparing intra- and inter-observer agreement within and between XR and CT. Results The mean differences in intra- and inter-observer measurements for XR, CT, and between XR and CT were close to zero, implying equal validity. The average intra- and inter-observer limits of agreement for XR, CT, and between XR and CT were +/- 4.4 degrees, +/- 1.9 degrees and +/- 6.8 degrees respectively. Conclusions For scientific purpose, the reliability of XR seems unacceptably low when measuring changes in dorsal angulation in distal radius fractures, whereas the reliability for the semi-automatic CT-based method was higher and is therefore preferable when a more precise method is requested.
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| 9. |
- Eekers, Danielle B. P., et al.
(författare)
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The EPTN consensus-based atlas for CT- and MR-based contouring in neuro-oncology
- 2018
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Ingår i: Radiotherapy and Oncology. - : ELSEVIER IRELAND LTD. - 0167-8140 .- 1879-0887. ; 128:1, s. 37-43
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To create a digital, online atlas for organs at risk (OAR) delineation in neuro-oncology based on high-quality computed tomography (Cr) and magnetic resonance (MR) imaging. Methods: CT and 3 Tesla (3T) MR images (slice thickness 1 mm with intravenous contrast agent) were obtained from the same patient and subsequently fused. In addition, a 7T MR without intravenous contrast agent was obtained from a healthy volunteer. Based on discussion between experienced radiation oncologists, the clinically relevant organs at risk (OARs) to be included in the atlas for neuro-oncology were determined, excluding typical head and neck OARs previously published. The draft atlas was delineated by a senior radiation oncologist, 2 residents in radiation oncology, and a senior neuro-radiologist incorporating relevant available literature. The proposed atlas was then critically reviewed and discussed by European radiation oncologists until consensus was reached. Results: The online atlas includes one CT-scan at two different window settings and one MR scan (3T) showing the OARs in axial, coronal and sagittal view. This manuscript presents the three-dimensional descriptions of the fifteen consensus OARs for neuro-oncology. Among these is a new OAR relevant for neuro-cognition, the posterior cerebellum (illustrated on 7T MR images). Conclusion: In order to decrease inter- and intra-observer variability in delineating OARs relevant for neuro-oncology and thus derive consistent dosimetric data, we propose this atlas to be used in photon and particle therapy. The atlas is available online at w.cancerdata.c and will be updated whenever required.
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| 10. |
- Grdic Eliasson, Dubravka, et al.
(författare)
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A novel non-toxic combined CTA1-DD and ISCOMS adjuvant vector for effective mucosal immunization against influenza virus.
- 2011
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Ingår i: Vaccine. - : Elsevier BV. - 1873-2518 .- 0264-410X. ; 29:23, s. 3951-61
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Tidskriftsartikel (refereegranskat)abstract
- Here we demonstrate that by using non-toxic fractions of saponin combined with CTA1-DD we can achieve a safe and above all highly efficacious mucosal adjuvant vector. We optimized the construction, tested the requirements for function and evaluated proof-of-concept in an influenza A virus challenge model. We demonstrated that the CTA1-3M2e-DD/ISCOMS vector provided 100% protection against mortality and greatly reduced morbidity in the mouse model. The immunogenicity of the vector was superior to other vaccine formulations using the ISCOM or CTA1-DD adjuvants alone. The versatility of the vector was best exemplified by the many options to insert, incorporate or admix vaccine antigens with the vector. Furthermore, the CTA1-3M2e-DD/ISCOMS could be kept 1 year at 4°C or as a freeze-dried powder without affecting immunogenicity or adjuvanticity of the vector. Strong serum IgG and mucosal IgA responses were elicited and CD4 T cell responses were greatly enhanced after intranasal administration of the combined vector. Together these findings hold promise for the combined vector as a mucosal vaccine against influenza virus infections including pandemic influenza. The CTA1-DD/ISCOMS technology represents a breakthrough in mucosal vaccine vector design which successfully combines immunomodulation and targeting in a safe and stable particulate formation.
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