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Ahlström, Håkan
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Publications (10 of 215) Show all publications
Sjöholm, T., Ekström, S., Strand, R., Ahlström, H., Lind, L., Malmberg, F. & Kullberg, J. (2019). A whole-body FDG PET/MR atlas for multiparametric voxel-based analysis. Scientific Reports, 9, Article ID 6158.
Open this publication in new window or tab >>A whole-body FDG PET/MR atlas for multiparametric voxel-based analysis
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 6158Article in journal (Refereed) Published
National Category
Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-382934 (URN)10.1038/s41598-019-42613-z (DOI)000464652400029 ()30992502 (PubMedID)
Available from: 2019-04-16 Created: 2019-05-07 Last updated: 2019-06-14Bibliographically approved
Marchesi, S., Ortiz-Nieto, F., Ahlgren, K. M., Roneus, A., Feinstein, R., Lipcsey, M., . . . Hedenstierna, G. (2019). Abdominal organ perfusion and inflammation in experimental sepsis: a magnetic resonance imaging study. American Journal of Physiology - Gastrointestinal and Liver Physiology, 316(1), G187-G196
Open this publication in new window or tab >>Abdominal organ perfusion and inflammation in experimental sepsis: a magnetic resonance imaging study
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2019 (English)In: American Journal of Physiology - Gastrointestinal and Liver Physiology, ISSN 0193-1857, E-ISSN 1522-1547, Vol. 316, no 1, p. G187-G196Article in journal (Refereed) Published
Abstract [en]

Diffusion-weighted magnetic resonance imaging (DW-MRI) uses water as contrast and enables the study of perfusion in many organs simultaneously in situ. We used DW-MRI in a sepsis model, comparing abdominal organs perfusion with global hemodynamic measurements and inflammation. Sixteen anesthetized piglets were randomized into 3 groups: HighMAP (mean arterial pressure, MAP > 65 mmHg), LowMAP (MAP between 50 and 60 mmHg) and Healthy Controls (HC). Sepsis was obtained with endotoxin and the desired MAP maintained with noradrenaline. After 6 hours DW-MRI was performed. Acute inflammation was assessed with IL-6 and TNFα in abdominal organs, ascites, and blood and by histology of intestine (duodenum). Perfusion of abdominal organs was reduced in the LowMAP group compared to the HighMAP group and HC. Liver perfusion was still reduced by 25% in the HighMAP group compared with HC. Intestinal perfusion did not differ significantly between the study groups. Cytokines concentration were generally higher in the LowMAP group but did not correlate with global hemodynamics. However, cytokines correlated with regional perfusion and, for liver and intestine, also with intra-abdominal pressure. Histopathology of intestine worsened with decreasing perfusion. In conclusion, although a low MAP (≤60 mmHg) indicated impeded abdominal perfusion in experimental sepsis, it did not predict inflammation, nor did other global measures of circulation. Decreased abdominal perfusion predicted partially inflammation but intestine, occupying most of the abdomen, and liver, were also affected by intra-abdominal pressure.

Keywords
Abdominal organs, inflammation, magnetic resonance, perfusion, sepsis
National Category
Surgery Anesthesiology and Intensive Care
Identifiers
urn:nbn:se:uu:diva-364356 (URN)10.1152/ajpgi.00151.2018 (DOI)000455670700012 ()30335473 (PubMedID)
Funder
Swedish Heart Lung FoundationSwedish Research Council
Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2019-02-05Bibliographically approved
Langner, T., Hedström, A., Mörwald, K., Weghuber, D., Forslund, A., Bergsten, P., . . . Kullberg, J. (2019). Fully convolutional networks for automated segmentation of abdominal adipose tissue depots in multicenter water–fat MRI. Magnetic Resonance in Medicine, 81(4), 2736-2745
Open this publication in new window or tab >>Fully convolutional networks for automated segmentation of abdominal adipose tissue depots in multicenter water–fat MRI
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2019 (English)In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 81, no 4, p. 2736-2745Article in journal (Refereed) Published
Abstract [en]

Purpose: An approach for the automated segmentation of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in multicenter water–fat MRI scans of the abdomen was investigated, using 2 different neural network architectures.

Methods: The 2 fully convolutional network architectures U‐Net and V‐Net were trained, evaluated, and compared using the water–fat MRI data. Data of the study Tellus with 90 scans from a single center was used for a 10‐fold cross‐validation in which the most successful configuration for both networks was determined. These configurations were then tested on 20 scans of the multicenter study beta‐cell function in JUvenile Diabetes and Obesity (BetaJudo), which involved a different study population and scanning device.

Results: The U‐Net outperformed the used implementation of the V‐Net in both cross‐validation and testing. In cross‐validation, the U‐Net reached average dice scores of 0.988 (VAT) and 0.992 (SAT). The average of the absolute quantification errors amount to 0.67% (VAT) and 0.39% (SAT). On the multicenter test data, the U‐Net performs only slightly worse, with average dice scores of 0.970 (VAT) and 0.987 (SAT) and quantification errors of 2.80% (VAT) and 1.65% (SAT).

Conclusion: The segmentations generated by the U‐Net allow for reliable quantification and could therefore be viable for high‐quality automated measurements of VAT and SAT in large‐scale studies with minimal need for human intervention. The high performance on the multicenter test data furthermore shows the robustness of this approach for data of different patient demographics and imaging centers, as long as a consistent imaging protocol is used.

Keywords
abdominal, adipose tissue, deep learning, fully convolutional networks, segmentation, water-fat MRI
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-364355 (URN)10.1002/mrm.27550 (DOI)000462092100044 ()30311704 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 279153
Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2019-04-17Bibliographically approved
Andersson, J., Roswall, J., Kjellberg, E., Ahlström, H., Dahlgren, J. & Kullberg, J. (2019). MRI estimates of brown adipose tissue in children - Associations to adiposity, osteocalcin, and thigh muscle volume. Magnetic Resonance Imaging, 58, 135-142
Open this publication in new window or tab >>MRI estimates of brown adipose tissue in children - Associations to adiposity, osteocalcin, and thigh muscle volume
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2019 (English)In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 58, p. 135-142Article in journal (Refereed) Published
Abstract [en]

Context: Brown adipose tissue is of metabolic interest. The tissue is however poorly explored in children.

Methods: Sixty-three 7-year old subjects from the Swedish birth-cohort Halland Health and Growth Study were recruited. Care was taken to include both normal weight and overweight children, but the subjects were otherwise healthy. Only children born full term were included. Water-fat separated whole-body MRI scans, anthropometric measurements, and measurements of fasting glucose and levels of energy homeostasis related hormones, including the insulin-sensitizer osteocalcin, were performed. The fat fraction (FF) and effective transverse relaxation time (T-2(star)) of suspected brown adipose tissue in the cervical-supraclavicular-axillary fat depot (sBAT) and the FFs of abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) were measured. Volumes of sBAT, abdominal VAT and SAT, and thigh muscle volumes were measured.

Results: The FF in the sBAT depot was lower than in VAT and SAT for all children. In linear correlations including sex and age as explanatory variables, sBAT FF correlated positively with all measures of adiposity (p < 0.01), except for VAT FF and weight, positively with sBAT T-2* (p = 0.036), and negatively with osteocalcin (p = 0.017). When adding measures of adiposity as explanatory variables, sBAT FF also correlated negatively with thigh muscle volume (p < 0.01).

Conclusions: Whole-body water-fat MRI of children allows for measurements of sBAT. The FF of sBAT was lower than that of VAT and SAT, indicating presence of BAT. Future studies could confirm whether the observed correlations corresponds to a hormonally active BAT.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE INC, 2019
Keywords
Brown adipose tissue, Magnetic resonance imaging, Adiposity, Osteocalcin, Muscle volume, Quantitative MRI
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-380416 (URN)10.1016/j.mri.2019.02.001 (DOI)000461412300018 ()30742901 (PubMedID)
Funder
Swedish Research Council, 2013-3013Swedish Research Council, 2016-01040Region Västra Götaland
Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-08-14Bibliographically approved
Lind, L., Kullberg, J., Ahlström, H., Michaëlsson, K. & Strand, R. (2019). Proof of principle study of a detailed whole-body image analysis technique, "Imiomics", regarding adipose and lean tissue distribution. Scientific Reports, 9, Article ID 7388.
Open this publication in new window or tab >>Proof of principle study of a detailed whole-body image analysis technique, "Imiomics", regarding adipose and lean tissue distribution
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 7388Article in journal (Refereed) Published
Abstract [en]

This "proof-of-principle" study evaluates if the recently presented "Imiomics" technique could visualize how fat and lean tissue mass are associated with local tissue volume and fat content at high/unprecedented resolution. A whole-body quantitative water-fat MRI scan was performed in 159 men and 167 women aged 50 in the population-based POEM study. Total fat and lean mass were measured by DXA. Fat content was measured by the water-fat MRI. Fat mass and distribution measures were associated to the detailed differences in tissue volume and fat concentration throughout the body using Imiomics. Fat mass was positively correlated (r > 0.50, p < 0.05) with tissue volume in all subcutaneous areas of the body, as well as volumes of the liver, intraperitoneal fat, retroperitoneal fat and perirenal fat, but negatively to lung volume. Fat mass correlated positively with volumes of paravertebral muscles, and muscles in the ventral part of the thigh and lower limb. Fat mass was distinctly correlated with the fat content in subcutaneous adipose tissue at the trunk. Lean mass was positively related to the large skeletal muscles and the skeleton. The present study indicates the Imiomics technique to be suitable for studies of fat and lean tissue distribution, and feasible for large scale studies.

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-383519 (URN)10.1038/s41598-019-43690-w (DOI)000467839800059 ()31089168 (PubMedID)
Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2019-06-19Bibliographically approved
Andersson, C., Trampal Pulido, C., Ahlström, H. & Johansson, B. (2019). Randomized Controlled Trial Examining Effects of Web-Based Information on Patient Satisfaction and Image Quality in 18F-FDG PET/CT Examinations. Journal of Nuclear Medicine Technology (1), 36-46
Open this publication in new window or tab >>Randomized Controlled Trial Examining Effects of Web-Based Information on Patient Satisfaction and Image Quality in 18F-FDG PET/CT Examinations
2019 (English)In: Journal of Nuclear Medicine Technology, ISSN 0091-4916, E-ISSN 1535-5675, no 1, p. 36-46Article in journal (Refereed) Published
Abstract [en]

Our aim was to compare the effect that having access, versus not having access, to web-based patient information on 18F-FDG PET/CT has on image quality and on patient satisfaction with their care during and knowledge about the examination, as well as to explore whether patients utilized and were satisfied with the web-based information.

Methods: We recruited 148 patients between October 2015 and December 2016 and randomly assigned them to a standard-care group or an intervention group. Both groups received standard information about the 18F-FDG PET/CT examination, but the intervention group also received access to web-based information. A questionnaire was used to evaluate patient satisfaction with, knowledge about, and discomfort during the examination, and a masked assessment of image quality was conducted.

Results: Overall satisfaction was high in both groups. The lowest satisfaction was with information about how the patients would receive the results of the examination. More patients in the intervention group than in the standard-care group knew how the 18F-FDG PET/CT examination would be conducted. Descriptive data suggest that image quality was slightly better in the intervention group than in the standard-care group, but none of the outcomes significantly differed between the groups. However, several obstacles were encountered during recruitment that led to insufficient power to detect differences. Also, only 54 of 75 patients (72%) in the intervention group utilized the web-based information. However, those who did utilize the information were satisfied with it and found it helpful.

Conclusion: The effects of web-based information need to be investigated in a larger sample of patients. Having access to improved information before undergoing 18F-FDG PET/CT may help patients prepare for and undergo the examination. It may also improve image quality. However, this possibility needs to be investigated using image quality as the primary outcome. The results may be used to improve patient information and care and thereby optimize the 18F-FDG PET/CT procedure.

Keywords
F-18-FDG PET/CT, web-based information, image quality, satisfaction, randomized controlled trial
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-356789 (URN)10.2967/jnmt.118.213116 (DOI)000460344600010 ()30076254 (PubMedID)
Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2019-03-25Bibliographically approved
Boersma, G. J., Johansson, E., Pereira, M. J., Heurling, K., Skrtic, S., Lau, J., . . . Eriksson, J. (2018). Altered Glucose Uptake in Muscle, Visceral Adipose Tissue, and Brain Predict Whole-Body Insulin Resistance and may Contribute to the Development of Type 2 Diabetes: A Combined PET/MR Study. Hormone and Metabolic Research, 50(8), 627-639
Open this publication in new window or tab >>Altered Glucose Uptake in Muscle, Visceral Adipose Tissue, and Brain Predict Whole-Body Insulin Resistance and may Contribute to the Development of Type 2 Diabetes: A Combined PET/MR Study
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2018 (English)In: Hormone and Metabolic Research, ISSN 0018-5043, E-ISSN 1439-4286, Vol. 50, no 8, p. 627-639Article in journal (Refereed) Published
Abstract [en]

We assessed glucose uptake in different tissues in type 2 diabetes (T2D), prediabetes, and control subjects to elucidate its impact in the development of whole-body insulin resistance and T2D. Thirteen T2D, 12 prediabetes, and 10 control subjects, matched for age and BMI, underwent OGTT and abdominal subcutaneous adipose tissue (SAT) biopsies. Integrated whole-body 18F-FDG PET and MRI were performed during a hyperinsulinemic euglycemic clamp to asses glucose uptake rate (MRglu) in several tissues. MRglu in skeletal muscle, SAT, visceral adipose tissue (VAT), and liver was significantly reduced in T2D subjects and correlated positively with M-values (r=0.884, r=0.574, r=0.707 and r=0.403, respectively). Brain MRglu was significantly higher in T2D and prediabetes subjects and had a significant inverse correlation with M-values (r=-0.616). Myocardial MRglu did not differ between groups and did not correlate with the M-values. A multivariate model including skeletal muscle, brain and VAT MRglu best predicted the M-values (adjusted r2=0.85). In addition, SAT MRglu correlated with SAT glucose uptake ex vivo (r=0.491). In different stages of the development of T2D, glucose uptake during hyperinsulinemia is elevated in the brain in parallel with an impairment in peripheral organs. Impaired glucose uptake in skeletal muscle and VAT together with elevated glucose uptake in brain were independently associated with whole-body insulin resistance, and these tissue-specific alterations may contribute to T2D development.

Place, publisher, year, edition, pages
Georg Thieme Verlag KG, 2018
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-356788 (URN)10.1055/a-0643-4739 (DOI)000440872200007 ()30001566 (PubMedID)
Funder
AstraZenecaEXODIAB - Excellence of Diabetes Research in SwedenSwedish Diabetes AssociationSwedish Research CouncilErnfors Foundation
Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2018-11-08Bibliographically approved
Andersson, C., Trampal Pulido, C., Ahlström, H. & Johansson, B. (2018). Effects of web-based information on patient satisfaction and image quality in patients undergoing an 18F-FDG PET/CT examination: a randomized controlled trial. Paper presented at 31st Annual Congress of the European-Association-of-Nuclear-Medicine (EANM), Düsseldorf, Germany October 13 – 17, 2018.. European Journal of Nuclear Medicine and Molecular Imaging, 45(Suppl 1), S783-S784
Open this publication in new window or tab >>Effects of web-based information on patient satisfaction and image quality in patients undergoing an 18F-FDG PET/CT examination: a randomized controlled trial
2018 (English)In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 45, no Suppl 1, p. S783-S784Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Springer, 2018
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-335669 (URN)000449266207145 ()
Conference
31st Annual Congress of the European-Association-of-Nuclear-Medicine (EANM), Düsseldorf, Germany October 13 – 17, 2018.
Available from: 2017-12-17 Created: 2017-12-17 Last updated: 2019-01-24Bibliographically approved
Sousa, J. M., Appel, L., Engström, M., Papadimitriou, S., Nyholm, D., Larsson, E.-M., . . . Lubberink, M. (2018). Evaluation of zero-echo-time attenuation correction for integrated PET/MR brain imaging-comparison to head atlas and 68Ge-transmission-based attenuation correction. EJNMMI Physics, 5(20)
Open this publication in new window or tab >>Evaluation of zero-echo-time attenuation correction for integrated PET/MR brain imaging-comparison to head atlas and 68Ge-transmission-based attenuation correction
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2018 (English)In: EJNMMI Physics, ISSN 2197-7364, E-ISSN 2191-219X, Vol. 5, no 20Article in journal (Refereed) Published
Abstract [en]

Background: MRI does not offer a direct method to obtain attenuation correction maps as its predecessors (stand-alone PET and PET/CT), and bone visualisation is particularly challenging. Recently, zero-echo-time (ZTE) was suggested for MR-based attenuation correction (AC). The aim of this work was to evaluate ZTE- and atlas-AC by comparison to 68Ge-transmission scan-based AC.

Nine patients underwent brain PET/MR and stand-alone PET scanning using the dopamine transporter ligand 11C-PE2I. For each of them, two AC maps were obtained from the MR images: an atlas-based, obtained from T1-weighted LAVA-FLEX imaging with cortical bone inserted using a CT-based atlas, and an AC map generated from proton-density-weighted ZTE images. Stand-alone PET 68Ge-transmission AC map was used as gold standard. PET images were reconstructed using the three AC methods and standardised uptake value (SUV) values for the striatal, limbic and cortical regions, as well as the cerebellum (VOIs) were compared. SUV ratio (SUVR) values normalised for the cerebellum were also assessed. Bias, precision and agreement were calculated; statistical significance was evaluated using Wilcoxon matched-pairs signed-rank test.

Results: Both ZTE- and atlas-AC showed a similar bias of 6–8% in SUV values across the regions. Correlation coefficients with 68Ge-AC were consistently high for ZTE-AC (r 0.99 for all regions), whereas they were lower for atlas-AC, varying from 0.99 in the striatum to 0.88 in the posterior cortical regions. SUVR showed an overall bias of 2.9 and 0.5% for atlas-AC and ZTE-AC, respectively. Correlations with 68Ge-AC were higher for ZTE-AC, varying from 0.99 in the striatum to 0.96 in the limbic regions, compared to atlas-AC (0.99 striatum to 0.77 posterior cortex).

Conclusions: Absolute SUV values showed less variability for ZTE-AC than for atlas-AC when compared to 68Ge-AC, but bias was similar for both methods. This bias is largely caused by higher linear attenuation coefficients in atlas- and ZTE-AC image compared to 68Ge-images. For SUVR, bias was lower when using ZTE-AC than for atlas-AC. ZTE-AC shows to be a more robust technique than atlas-AC in terms of both intra- and inter-patient variability.

Keywords
Atlas-AC, Attenuation correction, PET/MR, Static imaging, ZTE-AC
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-364358 (URN)10.1186/s40658-018-0220-0 (DOI)000447946100001 ()30345471 (PubMedID)
Funder
Swedish Research Council
Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2019-01-14Bibliographically approved
Stenlid, R., Manell, H., Halldin, M., Kullberg, J., Ahlström, H., Manukyan, L., . . . Forslund, A. (2018). High DPP-4 concentrations in adolescents are associated with low intact GLP-1. Journal of Clinical Endocrinology and Metabolism, 103(8), 2958-2966
Open this publication in new window or tab >>High DPP-4 concentrations in adolescents are associated with low intact GLP-1
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2018 (English)In: Journal of Clinical Endocrinology and Metabolism, ISSN 0021-972X, E-ISSN 1945-7197, Vol. 103, no 8, p. 2958-2966Article in journal (Refereed) Published
Abstract [en]

Context: Dipeptidyl Peptidase-4 (DPP-4) metabolizes glucagon-like peptide-1 (GLP-1) and increased DPP4 levels are associated with obesity and visceral adiposity in adults.

Objective: Investigating DPP-4 levels in adolescents and association with, firstly, circulating intact GLP-1 levels and glucose tolerance, secondly, BMI, and, thirdly visceral, subcutaneous and liver fat compartments.

Design: Cross-sectional study, July 2012 to April 2015.

Setting: Pediatric obesity clinic, Uppsala University Hospital.

Patients and participants: Children and adolescents with obesity (n=59) and lean controls (n=21), age 8-18.

Main outcome measures: BMI SDS, fasting plasma concentrations of DPP-4, total and intact GLP-1, fasting and OGTT concentrations of glucose and visceral (VAT) and subcutaneous (SAT) adipose tissue volumes and liver fat fraction.

Results: Plasma DPP-4 decreased with age both in obese (41 ng/ml per year) and lean subjects (48 ng/ml per year). Plasma DPP-4 was higher in males both in the obesity and lean group. When adjusting for age and sex, plasma DPP-4 was negatively associated with intact GLP-1 at fasting, B=-12.3, 95% CI [-22.9, -1.8] and during OGTT, B=-12.1, 95% CI [-22.5, -1.7]. No associations were found between DPP-4 and plasma glucose measured at fasting or after a 2-hour OGTT. Plasma DPP-4 was 19% higher in the obese subjects. Among adipose tissue compartments the strongest association was with VAT, B=0.05, 95% CI [-0.02, 0.12].

Conclusions: In adolescents, high plasma DPP-4 concentrations are associated with low proportion of intact GLP-1, high BMI, young age and male sex. The observed associations are compatible with an increased metabolism of GLP-1 in childhood obesity.

Place, publisher, year, edition, pages
Endocrine Society, 2018
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-354234 (URN)10.1210/jc.2018-00194 (DOI)000442236900022 ()29850829 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 279153Swedish Diabetes Association, DIA 2016-146Ernfors Foundation, 160504Swedish Research Council, 2016-01040EXODIAB - Excellence of Diabetes Research in SwedenErik, Karin och Gösta Selanders Foundation
Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2019-03-28Bibliographically approved
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