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Ahlström, Håkan
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Publications (10 of 224) 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
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
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-393367 (URN)10.1038/s41598-019-42613-z (DOI)
Available from: 2019-04-16 Created: 2019-09-20 Last updated: 2019-09-20Bibliographically 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
Lundström, E., Ljungberg, J., Andersson, J., Manell, H., Strand, R., Forslund, A., . . . Kullberg, J. (2019). Brown adipose tissue estimated with the magnetic resonance imaging fat fraction is associated with glucose metabolism in adolescents. Pediatric Obesity, 14(9), Article ID e12531.
Open this publication in new window or tab >>Brown adipose tissue estimated with the magnetic resonance imaging fat fraction is associated with glucose metabolism in adolescents
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2019 (English)In: Pediatric Obesity, ISSN 2047-6302, E-ISSN 2047-6310, Vol. 14, no 9, article id e12531Article in journal (Refereed) Published
National Category
Medical Image Processing
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-392829 (URN)10.1111/ijpo.12531 (DOI)31290284 (PubMedID)
Available from: 2019-07-09 Created: 2019-09-10 Last updated: 2019-09-20Bibliographically approved
Andersson, J., Lundström, E., Engström, M., Lubberink, M., Ahlström, H. & Kullberg, J. (2019). Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI. Scientific Reports, 9, Article ID 12358.
Open this publication in new window or tab >>Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 12358Article in journal (Refereed) Published
Abstract [en]

Brown adipose tissue (BAT) expends chemical energy to produce heat, which makes it a potential therapeutic target for combating metabolic dysfunction and overweight/obesity by increasing its metabolic activity. The most well-established method for measuring BAT metabolic activity is glucose uptake rate (GUR) measured using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET). However, this is expensive and exposes the subjects to potentially harmful radiation. Cheaper and safer methods are warranted for large-scale or longitudinal studies. Potential alternatives include infrared thermography (IRT) and magnetic resonance imaging (MRI). The aim of this study was to evaluate and further develop these techniques. Twelve healthy adult subjects were studied. The BAT GUR was measured using 18F-FDG PET during individualized cooling. The temperatures of the supraclavicular fossae and a control region were measured using IRT during a simple cooling protocol. The fat fraction and effective transverse relaxation rate of BAT were measured using MRI without any cooling intervention. Simple and multiple linear regressions were employed to evaluate how well the MRI and IRT measurements could estimate the GUR. Results showed that both IRT and MRI measurements correlated with the GUR. This suggest that these measurements may be suitable for estimating the cold-induced BAT GUR in future studies.

Keywords
brown adipose tissue, 18F-FDG positron emission tomography, infrared thermography, magnetic resonance imagingm PET/MRI, water–fat signal separation
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Radiology
Identifiers
urn:nbn:se:uu:diva-390410 (URN)10.1038/s41598-019-48879-7 (DOI)000482564800014 ()31451711 (PubMedID)
Funder
Swedish Research Council, 2016-01040Swedish Heart Lung Foundation, 2170492EXODIAB - Excellence of Diabetes Research in Sweden
Available from: 2019-08-09 Created: 2019-08-09 Last updated: 2019-10-18Bibliographically approved
Linder, G., Korsavidou Hult, N., Bjerner, T., Ahlström, H. & Hedberg, J. (2019). F-18-FDG-PET/MRI in preoperative staging of oesophageal and gastroesophageal junctional cancer. Clinical Radiology, 74(9), 718-725
Open this publication in new window or tab >>F-18-FDG-PET/MRI in preoperative staging of oesophageal and gastroesophageal junctional cancer
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2019 (English)In: Clinical Radiology, ISSN 0009-9260, E-ISSN 1365-229X, Vol. 74, no 9, p. 718-725Article in journal (Refereed) Published
Abstract [en]

AIM: To evaluate integrated 2-[F-18]-fluoro-2-deoxy-D-glucose (F-18-FDG) positron-emission tomography (PET)/magnetic resonance imaging (MRI), in comparison with the standard technique, integrated F-18-FDG-PET/computed tomography (CT), in preoperative staging of oesophageal or gastroesophageal junctional cancer.

MATERIALS AND METHODS: In the preoperative staging of 16 patients with oesophageal or gastroesophageal junctional cancer, F-18-FDG-PET/MRI was performed immediately following the clinically indicated F-18-FDG-PET/CT. MRI-sequences included T1-weighted fat-water separation (Dixon's technique), T2-weighted, diffusion-weighted imaging (DWI), and gadolinium contrast-enhanced T1-weighted three-dimensional (3D) imaging. PET was performed with F-18-FDG. Two separate teams of radiologists conducted structured blinded readings of F-18-FDG-PET/MRI or F-18-FDG-PET/CT, which were then compared regarding tumour measurements and characteristics as well as assessment of inter-rater agreement (Cohen's kappa) for the clinical tumour, nodal and metastatic (TNM) stage.

RESULTS: There were no medical complications. Comparison of tumour measurements revealed high correlations without significant differences between modalities. The maximum standardised uptake value (SUVmax) values of the primary tumour with F-18-FDG-PET/MRI had excellent correlation to those of F-18-FDG-PET/CT (0.912, Spearman's rho). Inter-rater agreement between the techniques regarding T-stage was only fair (Cohen's kappa, 0.333), arguably owing to relative over-classification of the T-stage using F-18-FDG-PET/CT. Agreements in the assessment of N- and M-stage were substantial (Cohen's kappa, 0.849 and 0.871 respectively).

CONCLUSION: Preoperative staging with F-18-FDG-PET/MRI is safe and promising with the potential to enhance tissue resolution in the area of interest. F-18-FDG-PET/MRI and F-18-FDG-PET/CT correlated well for most of the measured values and discrepancies were seen mainly in the assessment of the T-stage. These results facilitate further studies investigating the role of F-18-FDG-PET/MRI in, e.g., predicting or determining the response to neoadjuvant therapy. 

Place, publisher, year, edition, pages
W B SAUNDERS CO LTD, 2019
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-392125 (URN)10.1016/j.crad.2019.05.016 (DOI)000477841300010 ()31221468 (PubMedID)
Funder
Swedish Cancer Society
Available from: 2019-09-03 Created: 2019-09-03 Last updated: 2019-09-03Bibliographically 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., Michaëlsson, K., Söderberg, S., Larsson, A., Johansson, L., Kullberg, J., . . . Sundström, J. (2019). On the association between body fat and left ventricular mass. Journal of Hypertension, 37(8), 1699-1704
Open this publication in new window or tab >>On the association between body fat and left ventricular mass
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2019 (English)In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 37, no 8, p. 1699-1704Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: As intervention studies have shown a reduction in body weight to be paralleled with a reduction in left ventricular mass (LVM), we quantified a hypothesized causal relationship between fat mass and LVM, and how much of these effects that was mediated by blood pressure (BP), diabetes and adipokines. Also visceral and subcutaneous adipose tissue (VAT and SAT) were explored in the same fashion.

METHODS: In the Prospective Study of the Vasculature in Uppsala Seniors study (n = 1016, 50% women, all aged 70 years), LVM was measured by echocardiography (indexed for lean mass, LVMI), fat and lean mass by dual-energy X-ray. VAT and SAT were measured by abdominal MRI (in n = 275).

RESULTS: In a structural equation model adjusting for sex, the total effect of fat mass on LVMI was large (standardized coefficient 0.280, P = 3.2 × 10, 95% confidence interval 0.210-0.349). Out of the total effect of fat mass on LVMI, 29.0% was mediated by BP and glucose (P = 2.4 × 10). The BP pathway was most important, mediating 24.4% of the total effect of fat mass on LVMI (P = 4.6 × 10), while the glucose pathway accounted for 4.6% (P = 0.033). The association of VAT with LVMI (0.202, P = 2.4 × 10) was slightly weaker than that of SAT with LVMI (0.283, P = 1.0 × 10). Of several measured adipokines, leptin was a significant mediator of the effect of fat mass on LVMI (P = 3.0 × 10).

CONCLUSION: One-third of the hypothesized association between body fat and LVMI was mediated by BP and glucose in this population-based cohort. Leptin was also an important mediator. Visceral adipose tissue was not more closely related to LVMI than subcutaneous abdominal fat.

National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:uu:diva-382932 (URN)10.1097/HJH.0000000000002095 (DOI)000480767600020 ()31058795 (PubMedID)
Available from: 2019-05-07 Created: 2019-05-07 Last updated: 2019-10-01Bibliographically 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
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