uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Lundström, Elin
Publications (4 of 4) Show all publications
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
Show others...
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
Lundström, E. (2019). Magnetic Resonance Imaging of Human Brown Adipose Tissue: Methodological Development and Application. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Magnetic Resonance Imaging of Human Brown Adipose Tissue: Methodological Development and Application
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Brown adipose tissue (BAT) is a thermogenic organ with the main human depot located in the cervical-supraclavicular (sBAT) region. BAT is proposed as a potential therapeutic target for obesity and diabetes. This thesis aims to contribute to the development of magnetic resonance imaging (MRI)-based methods and to the application of these in studies of human BAT. Water-fat MRI enables separation of water and fat, the dominant contributors to the MR signal, and the quantification of fat fraction (FF) and effective transverse relaxation rate (R2*). FF and R2* are often used in studies of human BAT, e.g. for characterizing the tissue and distinguishing it from white adipose tissue. A Cooling-reheating protocol was introduced for studying changes in sBAT, related to lipid content and perfusion. sBAT FF decreased after cold exposure. The sustained low FF after reheating suggested lipid consumption as the primary cause. This conclusion was based on the assumption of a normalized perfusion after reheating. An automated method for segmentation of sBAT was developed. The method compared well with a semi-automated reference method with respect to segmentation overlap and estimated mean sBAT FF and R2*. A modified version of the automated method was applied to a large-scale study where an association between sBAT FF and glucose tolerance indicated a role for BAT in glucose metabolism, potentially linked to the risk of developing diabetes.  A Cooling-reheating protocol was evaluated with positron emission tomography measurements of perfusion and cold-stimulated BAT activity. Inverse correlations between sBAT FF and BAT activity suggested sBAT FF to predict cold-induced BAT activity. After reheating, the cold-induced increase in perfusion normalized and the cold-induced decrease in FF partially normalized. This suggested potential decreases in FF after reheating to mainly be due to lipid consumption and decreases in FF after cold exposure to possibly be influenced by perfusion.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 83
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1572
Keywords
Brown adipose tissue, Magnetic resonance imaging, Positron emission tomography, Image segmentation, Glucose metabolism
National Category
Medical and Health Sciences Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-381766 (URN)978-91-513-0651-3 (ISBN)
Public defence
2019-06-07, Rosénsalen, Entrance 95/96, Akademiska sjukhuset, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2019-05-17 Created: 2019-04-15 Last updated: 2019-06-18
Lundström, E., Strand, R., Johansson, L., Bergsten, P., Ahlström, H. & Kullberg, J. (2015). Magnetic resonance imaging cooling–reheating protocol indicates decreased fat fraction via lipid consumption in suspected brown adipose tissue. PLoS ONE, 10(4), Article ID e0126705.
Open this publication in new window or tab >>Magnetic resonance imaging cooling–reheating protocol indicates decreased fat fraction via lipid consumption in suspected brown adipose tissue
Show others...
2015 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 4, article id e0126705Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: To evaluate whether a water-fat magnetic resonance imaging (MRI) cooling-reheating protocol could be used to detect changes in lipid content and perfusion in the main human brown adipose tissue (BAT) depot after a three-hour long mild cold exposure.

MATERIALS AND METHODS: Nine volunteers were investigated with chemical-shift-encoded water-fat MRI at baseline, after a three-hour long cold exposure and after subsequent short reheating. Changes in fat fraction (FF) and R2*, related to ambient temperature, were quantified within cervical-supraclavicular adipose tissue (considered as suspected BAT, denoted sBAT) after semi-automatic segmentation. In addition, FF and R2* were quantified fully automatically in subcutaneous adipose tissue (not considered as suspected BAT, denoted SAT) for comparison. By assuming different time scales for the regulation of lipid turnover and perfusion in BAT, the changes were determined as resulting from either altered absolute fat content (lipid-related) or altered absolute water content (perfusion-related).

RESULTS: sBAT-FF decreased after cold exposure (mean change in percentage points = -1.94 pp, P = 0.021) whereas no change was observed in SAT-FF (mean = 0.23 pp, P = 0.314). sBAT-R2* tended to increase (mean = 0.65 s-1, P = 0.051) and SAT-R2* increased (mean = 0.40 s-1, P = 0.038) after cold exposure. sBAT-FF remained decreased after reheating (mean = -1.92 pp, P = 0.008, compared to baseline) whereas SAT-FF decreased (mean = -0.79 pp, P = 0.008, compared to after cold exposure).

CONCLUSIONS: The sustained low sBAT-FF after reheating suggests lipid consumption, rather than altered perfusion, as the main cause to the decreased sBAT-FF. The results obtained demonstrate the use of the cooling-reheating protocol for detecting changes in the cervical-supraclavicular fat depot, being the main human brown adipose tissue depot, in terms of lipid content and perfusion.

National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-254074 (URN)10.1371/journal.pone.0126705 (DOI)000353713100132 ()25928226 (PubMedID)
Available from: 2015-04-30 Created: 2015-06-04 Last updated: 2019-04-15Bibliographically approved
Jonsson, O., Morell, A., Zemgulis, V., Lundström, E., Tovedal, T., Myrdal Einarsson, G., . . . Lennmyr, F. (2011). Minimal Safe Arterial Blood Flow During Selective Antegrade Cerebral Perfusion at 20° Centigrade. Annals of Thoracic Surgery, 91(4), 1198-1205
Open this publication in new window or tab >>Minimal Safe Arterial Blood Flow During Selective Antegrade Cerebral Perfusion at 20° Centigrade
Show others...
2011 (English)In: Annals of Thoracic Surgery, ISSN 0003-4975, E-ISSN 1552-6259, Vol. 91, no 4, p. 1198-1205Article in journal (Refereed) Published
Abstract [en]

Background

Selective antegrade cerebral perfusion (SACP) enables surgery on the aortic arch, where cerebral ischemia may cause neurologic sequels. This study aims to identify the minimum arterial flow level to maintain adequate cerebral perfusion during SACP in deep hypothermia in the pig.

Methods

Two groups of pigs were subjected to SACP at 20°C α-stat. In group 1 (n = 6), flow was stepwise adjusted from 8-6-4-2-8 mL · kg−1 · min−1 and in group 2 (n = 5), flow was kept constant at 6 mL · kg−1 · min−1. Magnetic resonance imaging and spectroscopy were performed at each flow level together with hemodynamic monitoring and blood gas analysis. The biochemical marker of cerebral damage protein S100β was measured in peripheral blood.

Results

Decreased mixed venous oxygen saturation and increased lactate in magnetic resonance spectroscopy was seen as a sign of anaerobic metabolism below 6 mL · kg−1 · min−1. No ischemic damage was seen on diffusion-weighted imaging, but the concentrations of S100β were significantly elevated in group 1 compared with group 2 at the end of the experiment (p < 0.05). Perfusion-weighted imaging showed coherence between flow setting and cerebral perfusion, increase of blood volume across time, and regional differences in perfusion during SACP.

Conclusions

The findings suggest an ischemic threshold close to 6 mL · kg−1 · min−1 in the present model. Regional differences in perfusion during SACP may be of pathogenic importance to focal cerebral ischemia.

Keywords
cerebral perfusion
National Category
Physiology
Research subject
Thorax Surgery
Identifiers
urn:nbn:se:uu:diva-147480 (URN)10.1016/j.athoracsur.2010.12.066 (DOI)000288785800057 ()21353198 (PubMedID)
Funder
Swedish Research Council, k2010-64x-08268-23-3
Available from: 2011-02-25 Created: 2011-02-25 Last updated: 2018-01-12Bibliographically approved
Organisations

Search in DiVA

Show all publications