| 1. |
- Andersson, Jonathan
(författare)
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Water–fat separation in magnetic resonance imaging and its application in studies of brown adipose tissue
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Virtually all the magnetic resonance imaging (MRI) signal of a human originates from water and fat molecules. By utilizing the property chemical shift the signal can be separated, creating water- and fat-only images. From these images it is possible to calculate quantitative fat fraction (FF) images, where the value of each voxel is equal to the percentage of its signal originating from fat. In papers I and II methods for water–fat signal separation are presented and evaluated.The method in paper I utilizes a graph-cut to separate the signal and was designed to perform well even for a low signal-to-noise ratio (SNR). The method was shown to perform as well as previous methods at high SNRs, and better at low SNRs.The method presented in paper II uses convolutional neural networks to perform the signal separation. The method was shown to perform similarly to a previous method using a graph-cut when provided non-undersampled input data. Furthermore, the method was shown to be able to separate the signal using undersampled data. This may allow for accelerated MRI scans in the future.Brown adipose tissue (BAT) is a thermogenic organ with the main purpose of expending chemical energy to prevent the body temperature from falling too low. Its energy expending capability makes it a potential target for treating overweight/obesity and metabolic dysfunctions, such as type 2 diabetes. The most well-established way of estimating the metabolic potential of BAT is through measuring glucose uptake using 18F-fludeoxyglucose (18F-FDG) positron emission tomography (PET) during cooling. This technique exposes subjects to potentially harmful ionizing radiation, and alternative methods are desired. One alternative method is measuring the BAT FF using MRI.In paper III the BAT FF in 7-year olds was shown to be negatively associated with blood serum levels of the bone-specific protein osteocalcin and, after correction for adiposity, thigh muscle volume. This may have implications for how BAT interacts with both bone and muscle tissue.In paper IV the glucose uptake of BAT during cooling of adult humans was measured using 18F-FDG PET. Additionally, their BAT FF was measured using MRI, and their skin temperature during cooling near a major BAT depot was measured using infrared thermography (IRT). It was found that both the BAT FF and the temperature measured using IRT correlated with the BAT glucose uptake, meaning these measurements could be potential alternatives to 18F-FDG PET in future studies of BAT.
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| 2. |
- Boersma, Greta J., et al.
(författare)
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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
- 2018
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 50:8
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
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| 4. |
- Callegari, Julia, 1988-
(författare)
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Att göras fri från skuld : Konstruktioner av klientskap och kön i det svenska skuldsaneringssystemet
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis studies how over-indebted women and men are constructed as clients within the Swedish debt reconstruction system. The aim is to contribute with knowledge about how over-indebted women and men are understood, problematised, and handled in research literature and the debt reconstruction system. The focus is on analysing the client identities that are constructed when over-indebted women and men are described and describe themselves, highlight how these descriptions relate to dominant understandings about over-indebtedness and gender, and consider their implications for the support provided.The thesis is based on four substudies and the empirical material consists of research literature, focus group interviews and individual interviews with budget- and debt counsellors, documentation, and letters attached to applications for debt reconstruction written by over-indebted women and men. Deriving from a constructionist approach, the study draws on theories about how clienthoods are constructed through language use in human service organisations and how prevailing societal norms and notions condition this process.The results show that descriptions made by and about over-indebted women and men portray their underlying reasons for the debt problems, ability to manage money, and help-need in a variety of ways. As a consequence, the descriptions are found to contain elements that both challenge and reproduce dominant understandings about over-indebted individuals being financially irresponsible or ignorant. Prevailing conceptions about gender and women and men’s financial skills are found to influence how the individuals responsibility for the debt problems, and capability to solve their financial predicaments, are portrayed. The result show that descriptions made by and about over-indebted women and men thereby construct client identities that are attributed with varying responsibilities and capabilities, shaping how the budget- and debt counsellors approaches the individual and the content of the support provided. The conclusion is that the process of constructing clienthoods in part is conditioned by prevailing societal notions, but also has potential to challenge dominant notions emphasising citizens’ responsibility for creating welfare.
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| 5. |
- Johansson, Emil, et al.
(författare)
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Whole-Body Imaging of Tissue-specific Insulin Sensitivity and Body Composition by Using an Integrated PET/MR System: A Feasibility Study
- 2018
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Ingår i: Radiology. - : Radiological Society of North America (RSNA). - 0033-8419 .- 1527-1315. ; 286:1, s. 271-278
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To develop, evaluate, and demonstrate the feasibility of a whole-body protocol for simultaneous assessment of tissue-specific insulin-mediated fluorine 18 (F-18) fluorodeoxyglucose (FDG) influx rates, tissue depots, and whole-body insulin sensitivity (referred to as the M value). Materials and Methods: An integrated positron emission tomography (PET)/magnetic resonance (MR) imaging system combined with hyperinsulinemic euglycemic clamp (HEC) was used. Dynamic whole-body PET imaging was used to determine the insulin-mediated F-18-FDG tissue influx rate (K-i) in the whole-body region by using the Patlak method. M value was determined with the HEC method at PET imaging. Tissue depots were quantified by using water-fat separated MR imaging and manual segmentations. Feasibility of the imaging protocol was demonstrated by using five healthy control participants and five patients with type 2 diabetes. Associations between M value and K-i were studied in multiple tissues by using the Pearson correlation. Results: Positive correlations were found between M value and K-i in multiple tissues: the gluteus muscle (r = 0.875; P = .001), thigh muscle (r = 0.903; P < .001), calf muscle (r = 0.825; P = .003), and abdominal visceral adipose tissue (r = 0.820; P = .004). A negative correlation was found in the brain (r = 0.798; P = .006). The MR imaging-based method for quantification of tissue depots was feasible for determining adipose tissue volumes and fat fractions. Conclusion: This PET/MR imaging protocol may be feasible for simultaneous assessment of tissue-specific insulin-mediated F-18-FDG influx rates, tissue depots, and M value. (C) RSNA, 2017
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| 6. |
- Karlsson, Ann-Katrine, 1950, et al.
(författare)
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Abdominal fat distribution correlates to aromatase activity in pre-school girls
- 2013
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Ingår i: 9th Joint Meeting of Paediatric Endocrinology. Milan, Italy , September 19–22, 2013. Hormone research in paediatrics. - Milan, Italy : Horm Res in Ped. - 1663-2818 .- 1663-2826. ; 80:suppl 1, s. 109-110
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Karlsson, Ann-Katrine, 1950, et al.
(författare)
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Measurements of total and regional body composition in preschool children: A comparison of MRI, DXA, and anthropometric data.
- 2013
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Ingår i: Obesity (Silver Spring, Md.). - : Wiley. - 1930-739X .- 1930-7381. ; 21:5, s. 1018-24
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Tidskriftsartikel (refereegranskat)abstract
- There are clear sex differences in the distribution of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in adults, with males having more VAT and less SAT than females. This study assessed whether these differences between the sexes were already present in preschool children. It also evaluated which measures of body composition were most appropriate for assessing abdominal obesity in this age group.
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| 8. |
- Kullberg, C, et al.
(författare)
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Prevalence of retinopathy differs with age at onset of diabetes in a population of patients with Type 1 diabetes
- 2002
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Ingår i: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 19:11, s. 924-931
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Tidskriftsartikel (refereegranskat)abstract
- Aim. The VISS study (Vascular complications in South-east Sweden) investigates prevalence and incidence of vascular complications in a population with Type 1 diabetes, from a well-defined geographical area and followed from diag-nosis with HbA1c measurement. Method. The study population comprised all 440 patients with Type 1 diabetes onset before the age of 36 years, onset during 1983-1987, and at the time of onset living within the counties of J÷nk÷ping, Kalmar or ╓sterg÷tland. Retinopathy was examined with fundus photography 1994-1995, and classified according to a modified Airlie House protocol. Results. Fundus photographs from 390 patients were evaluated. In 277 (71%) patients no retinopathy was seen. The prevalence of retinopathy increased from 11% among patients < 5 years old at diabetes onset, to 48% among those 15-19 years old at diabetes onset, and then decreased to 30% for patients 30-35 years old at diabetes onset (P for ?2 for linear trend for all ages 0.017, for age at onset 0-19 yearsP = 0.0003), without corresponding differences in duration or HbA1c between patients with different onset age. Patients with HbA1c in the highest quartile (> 8.3% HbA1c) had a relative risk of 2.4 (95% confidence) interval (CI) 1.7-3.2) of having any retinopathy compared with patients with lower HbA1c, and a relative risk of 7.1 (95% CI 3.0-16.7) of having other forms of retinopathy than microaneurysms. Conclusion. In patients with diabetes duration of 6-13 years, the prevalence of retinopathy is clearly related to glycaemic control. Furthermore, the risk of retinopathy varies with different age at onset, independently of differences in duration or glycaemic control.
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| 9. |
- Kullberg, Kerstin, et al.
(författare)
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Daily eating events among co-living and single-living diseased older men
- 2008
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Ingår i: The Journal of Nutrition, Health & Aging. - 1279-7707 .- 1760-4788. ; 12:3, s. 176-182
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To analyse, describe and compare the frequency and energy intake of eating events, including specific food items, among diseased older men living in ordinary housing. Design: Descriptive and explorative. Setting: Interviews were performed in the participants’ home. Participants: Thirty-five co-living and 26 single-living men, 64-88 years of age. Participants had one of three chronic diseases associated with difficulties in buying and preparing food and with difficulties related to the meal situation: Parkinson’s disease, rheumatoid arthritis or stroke. Measurements: A repeated 24-h recall was used to assess food intake and meal patterns. Results: Eating events were distributed over a 24-h period. Co-living men had a higher (p=0.001) number of eating events/day; both hot and cold eating events were consumed more frequently. There was no difference between groups concerning energy intake. Co-living men had more often hot eating events cooked from raw ingredients (p=0.001) and more various vegetables/roots (p=0.003) included in such eating events. Conclusion: Single-living men may constitute a vulnerable group from a nutritional perspective, while co-living men, besides the pleasure of eating together, seem to get support with food and eating events from their partners. Hence, the group of single-living men, particularly those with a disability, should receive particular attention with regard to possible food-related difficulties.
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