| 1. |
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| 2. |
- Ahlbeck Bergendahl, Ida, et al.
(författare)
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Fisk- och skaldjursbestånd i hav och sötvatten 2016 : Resursöversikt
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES).De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.Rapporten omfattar 41 fiskarter uppdelade i olika bestånd, samt sju skal- och blötdjursarter.Nytt för årets upplaga är kapitlet om ekosystemtjänster. Avsnittet beskriver de fördelar människan får genom ekosystemen, till exempel hur fisk och skaldjur kommer till nytta för människan genom föda, rekreation och biologisk mångfald. Nytt för i år är också att rapportens diagram och figurer anpassats för läsare med defekt färgseende.Översikten är utarbetad av SLU Aqua på uppdrag av Havs- och vattenmyndigheten.
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| 3. |
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| 4. |
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| 5. |
- Andersson, Thord, et al.
(författare)
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Consistent intensity inhomogeneity correction in water-fat MRI
- 2015
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley-Blackwell. - 1053-1807 .- 1522-2586. ; 42:2
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To quantitatively and qualitatively evaluate the water-signal performance of the consistent intensity inhomogeneity correction (CIIC) method to correct for intensity inhomogeneitiesMETHODS: Water-fat volumes were acquired using 1.5 Tesla (T) and 3.0T symmetrically sampled 2-point Dixon three-dimensional MRI. Two datasets: (i) 10 muscle tissue regions of interest (ROIs) from 10 subjects acquired with both 1.5T and 3.0T whole-body MRI. (ii) Seven liver tissue ROIs from 36 patients imaged using 1.5T MRI at six time points after Gd-EOB-DTPA injection. The performance of CIIC was evaluated quantitatively by analyzing its impact on the dispersion and bias of the water image ROI intensities, and qualitatively using side-by-side image comparisons.RESULTS: CIIC significantly ( P1.5T≤2.3×10-4,P3.0T≤1.0×10-6) decreased the nonphysiological intensity variance while preserving the average intensity levels. The side-by-side comparisons showed improved intensity consistency ( Pint≤10-6) while not introducing artifacts ( Part=0.024) nor changed appearances ( Papp≤10-6).CONCLUSION: CIIC improves the spatiotemporal intensity consistency in regions of a homogenous tissue type.
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| 6. |
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| 7. |
- Angerbjörn, Anders, et al.
(författare)
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The Effect of Winter Food on Reproduction in the Arctic Fox, Alopex-Lagopus - a Field Experiment
- 1991
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Ingår i: Journal of Animal Ecology. ; 60:2, s. 705-714
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Tidskriftsartikel (refereegranskat)abstract
- (1) The population of arctic foxes in Fennoscandia is very small and has been so for around 60 years in spite of total protection for over half a century. The reasons why the arctic fox population has not increased to its former size are unknown. The population numbers fluctuate highly in relation to vole numbers. There is also very high interannual variation in reproduction among arctic foxes. (2) To determine the effect of winter food availability on reproductive success, we carried out a feeding experiment. The study area is situated above the treeline from an altitude of 700 m to mountains of 1600 m in Swedish Lapland. We added food (reindeer and moose carcasses) to dens during the winter months, January-April 1985-89. To determine the effect of this extra food on reproduction, we made inventories at both food-manipulated dens and control dens. These inventories of dens took place during July so we could check not only if dens were occupied, but also whether a litter was born and assess the number of cubs appearing outside the den. (3) The proportion of occupied dens in the experimental group was significantly higher than in the control group. The number of cubs at weaning in the food-manipulated dens was also higher than in control dens in each year. However, no effect on litter size was found. (4) From these results we conclude that the larger number of cubs produced in dens with extra winter food shows that reproduction under present dietary poor conditions was limited by available food. Many canid species show this close relation between reproduction and food availability, with pregnancy rates and litter sizes declining with the abundance of the main food.
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| 8. |
- Forsgren, Mikael, et al.
(författare)
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Comparing 2D and 3D Magnetic Resonance Elastography Techniques in a Clinical Setting: Initial Experiences
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: It has been shown that liver fibrosis, and even cirrhosis, may be reversible in humans. For this reason there is a great need for the imminent introduction of non-invasive and clinically useful methods in order to monitor fibrosis in patients [1, 2]. A body of evidence points to the fact that MRE is a highly useful candidate towards this end [3]. However, before using such techniques more widely, it is important to verify that comparable physical measures are provided by alternative and clinically relevant MRE approaches. The aim of this pilot study was to compare 2D and 3D MRE, also known as MR Rheology, using a commercially available 2D system, with an acoustic transducer, and 3D MRE research system, with an electromagnetic transducer, with respect to liver stiffness and elasticity in patients with diffuse or suspected diffuse liver disease. Materials and Methods: Seven patients, referred to our hospital for evaluation of elevated serum alanine aminotransferase (ALT) and/or alkaline phosphatase (ALP) levels but without signs of cirrhosis on physical examination, were recruited from a previous study [4], and examined in the course of one day. Fibrosis staging from prior biopsy were gained from [4], see Table 1. The 3D MRE method included an active electromagnetic transducer generating waves at 56 Hz, and a 1.5 T Philips Achieva MR-scanner, with a phased array body coil (Sense TorsoXL, all 16 coil elements), GRE sequence parameters include; FOV = 320x256 mm2, matrix = 80x38, slice thickness = 4 mm, # slices = 9, FA = 15°, TR = 112 ms, TE = 9.21 ms, SENSE = 2. The 2D MRE method included a passive acoustic transducer generating waves at 60 Hz, and a 1.5 T GE 450W MR-scanner, with a phased array body coil (HD8 Torso, all 8 coil elements), GRE sequence parameters include; FOV = 440x440 mm2, matrix = 256x64, slice thickness = 10 mm, # slices = 4, FA = 30°, TR = 50 ms, TE = 21.7 ms, ASSET = 2. The transducers were on both systems placed on the anterior chest wall to the right of xiphoid process (patient in a supine position), the time between each MRE acquisition was dependent on how long it took to transfer the patient between the two MR systems in the hospital (<10 min) A region of interest (ROI) was placed in an appropriate single 10 mm slice acquired using the GE MR-scanner. A corresponding ROI for the Philips system, covering the same anatomical region, was placed over three slices (4 mm thickness each). This yielded a total cranio-caudal coverage of the ROIs equal to 10 mm (on the GE data) and 12 mm (on the Philips data). The mean and standard deviations of the stiffness (GE), elasticity (Philips) and Gabs,Elastic (Philips) were calculated. Gabs,Elastic is the absolute value of the shear modulus, which in principle is equivalent to the viscoelastic property, shear stiffness. In the 3D method the shear waves were obtained by applying the curl operator and using the Voigt rheological model to obtain shear elasticity maps [5, 6]. In the 2D method the GE system provided the stiffness maps. Statistics was performed using Mathematica 9. ROI drawing and quantification of the data from the GE system was performed using Sectra PACS IDS7, and ROI drawing and quantification of the data from the Philips system was performed using a custom software package implemented in ROOT, generously provided by R. Sinkus (Kings College, London, UK). Results: The measured values are presented in Table 1. Both elasticity and Gabs,Elastic correlates well with the stiffness measurement carried out in the GE system (Fig. 1), as was shown by the elasticity and stiffness correlation R2 = 0.96 (P < 0.001) slope = 1.08 (P < 0.001), intercept = 0.61 kPa (P = 0.08), Gabs,Elastic and stiffness correlation R2 = 0.96 (P < 0.001), slope = 0.95 (P< 0.001) intercept = 0.28 kPa (P = 0.43)
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| 9. |
- Forsgren, Mikael, et al.
(författare)
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Comparing hepatic 2D and 3D magnetic resonance elastography methods in a clinical setting – Initial experiences
- 2015
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Ingår i: European Journal of Radiology Open. - : Elsevier. - 2352-0477. ; 2, s. 66-70
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Tidskriftsartikel (refereegranskat)abstract
- PurposeContinuous monitoring of liver fibrosis progression in patients is not feasible with the current diagnostic golden standard (needle biopsy). Recently, magnetic resonance elastography (MRE) has emerged as a promising method for such continuous monitoring. Since there are different MRE methods that could be used in a clinical setting there is a need to investigate whether measurements produced by these MRE methods are comparable. Hence, the purpose of this pilot study was to evaluate whether the measurements of the viscoelastic properties produced by 2D (stiffness) and 3D (elasticity and ‘Gabs,Elastic’) MRE are comparable.Materials and methodsSeven patients with diffuse or suspect diffuse liver disease were examined in the same day with the two MRE methods. 2D MRE was performed using an acoustic passive transducer, with a 1.5 T GE 450 W MR system. 3D MRE was performed using an electromagnetic active transducer, with a 1.5 T Philips Achieva MR system. Finally, mean viscoelastic values were extracted from the same anatomical region for both methods by an experienced radiologist.ResultsStiffness correlated well with the elasticity, R2 = 0.96 (P < 0.001; slope = 1.08, intercept = 0.61 kPa), as well as with ‘Gabs,Elastic’ R2 = 0.96 (P < 0.001; slope = 0.95, intercept = 0.28 kPa).ConclusionThis pilot study shows that different MRE methods can produce comparable measurements of the viscoelastic properties of the liver. The existence of such comparable measurements is important, both from a clinical as well as a research perspective, since it allows for equipment-independent monitoring of disease progression.
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| 10. |
- Forsgren, Mikael F, 1983-, et al.
(författare)
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Biomarkers of liver fibrosis : prospective comparison of multimodal magnetic resonance, serum algorithms and transient elastography.
- 2020
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Ingår i: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 55:7, s. 848-859
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Accurate biomarkers for quantifying liver fibrosis are important for clinical practice and trial end-points. We compared the diagnostic performance of magnetic resonance imaging (MRI), including gadoxetate-enhanced MRI and 31P-MR spectroscopy, with fibrosis stage and serum fibrosis algorithms in a clinical setting. Also, in a subset of patients, MR- and transient elastography (MRE and TE) was evaluated when available.METHODS: Patients were recruited prospectively if they were scheduled to undergo liver biopsy on a clinical indication due to elevated liver enzyme levels without decompensated cirrhosis. Within a month of the clinical work-up, an MR-examination and liver needle biopsy were performed on the same day. Based on late-phase gadoxetate-enhanced MRI, a mathematical model calculated hepatobiliary function (relating to OATP1 and MRP2). The hepatocyte gadoxetate uptake rate (KHep) and the normalised liver-to-spleen contrast ratio (LSC_N10) were also calculated. Nine serum fibrosis algorithms were investigated (GUCI, King's Score, APRI, FIB-4, Lok-Index, NIKEI, NASH-CRN regression score, Forns' score, and NAFLD-fibrosis score).RESULTS: The diagnostic performance (AUROC) for identification of significant fibrosis (F2-4) was 0.78, 0.80, 0.69, and 0.78 for MRE, TE, LSC_N10, and GUCI, respectively. For the identification of advanced fibrosis (F3-4), the AUROCs were 0.93, 0.84, 0.81, and 0.82 respectively.CONCLUSION: MRE and TE were superior for non-invasive identification of significant fibrosis. Serum fibrosis algorithms developed for specific liver diseases are applicable in this cohort of diverse liver diseases aetiologies. Gadoxetate-MRI was sufficiently sensitive to detect the low function losses associated with fibrosis. None was able to efficiently distinguish between stages within the low fibrosis stages.Lay summaryExcessive accumulation of scar tissue, fibrosis, in the liver is an important aspect in chronic liver disease. To replace the invasive needle biopsy, we have explored non-invasive methods to assess liver fibrosis. In our study we found that elastographic methods, which assess the mechanical properties of the liver, are superior in assessing fibrosis in a clinical setting. Of interest from a clinical trial point-of-view, none of the tested methods was sufficiently accurate to distinguish between adjacent moderate fibrosis stages.
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| 11. |
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| 12. |
- Forsgren, Mikael, et al.
(författare)
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Model-inferred mechanisms of liver function from magnetic resonance imaging data : Validation and variation across a clinically relevant cohort
- 2019
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Ingår i: PloS Computational Biology. - San Francisco, CA, United States : Public Library of Science. - 1553-734X .- 1553-7358. ; 15:6
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Tidskriftsartikel (refereegranskat)abstract
- Estimation of liver function is important to monitor progression of chronic liver disease (CLD). A promising method is magnetic resonance imaging (MRI) combined with gadoxetate, a liver-specific contrast agent. For this method, we have previously developed a model for an average healthy human. Herein, we extended this model, by combining it with a patient-specific non-linear mixed-effects modeling framework. We validated the model by recruiting 100 patients with CLD of varying severity and etiologies. The model explained all MRI data and adequately predicted both timepoints saved for validation and gadoxetate concentrations in both plasma and biopsies. The validated model provides a new and deeper look into how the mechanisms of liver function vary across a wide variety of liver diseases. The basic mechanisms remain the same, but increasing fibrosis reduces uptake and increases excretion of gadoxetate. These mechanisms are shared across many liver functions and can now be estimated from standard clinical images.Author summaryBeing able to accurately and reliably estimate liver function is important when monitoring the progression of patients with liver disease, as well as when identifying drug-induced liver injury during drug development. A promising method for quantifying liver function is to use magnetic resonance imaging combined with gadoxetate. Gadoxetate is a liver-specific contrast agent, which is taken up by the hepatocytes and excreted into the bile. We have previously developed a mechanistic model for gadoxetate dynamics using averaged data from healthy volunteers. In this work, we extended our model with a non-linear mixed-effects modeling framework to give patient-specific estimates of the gadoxetate transport-rates. We validated the model by recruiting 100 patients with liver disease, covering a range of severity and etiologies. All patients underwent an MRI-examination and provided both blood and liver biopsies. Our validated model provides a new and deeper look into how the mechanisms of liver function varies across a wide variety of liver diseases. The basic mechanisms remain the same, but increasing fibrosis reduces uptake and increases excretion of gadoxetate.
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| 13. |
- Forsgren, Mikael
(författare)
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The Non-Invasive Liver Biopsy : Determining Hepatic Function in Diffuse and Focal LiverDisease
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The liver is one of the largest organs within the human body and it handles many vital tasks such as nutrient processing, toxin removal, and synthesis of important proteins. The number of people suffering from chronic liver disease is on the rise, likely due to the present ‘western’ lifestyle. As disease develops in the liver there are pathophysiological manifestations within the liver parenchyma that are both common and important to monitor. These manifestations include inflammation, fatty infiltration (steatosis), excessive scar tissue formation (fibrosis and cirrhosis), and iron loading. Importantly, as the disease progresses there is concurrent loss of liver function. Furthermore, postoperative liver function insufficiency is an important concern when planning surgical treatment of the liver, because it is associated with both morbidity and mortality. Liver function can also be hampered due to drug-induced injuries, an important aspect to consider in drug-development.Currently, an invasive liver needle biopsy is required to determine the aetiology and to stage or grade the pathophysiological manifestations. There are important limitations with the biopsy, which include, risk of serious complications, mortality, morbidity, inter- and intra-observer variability, sampling error, and sampling variability. Cleary, it would be beneficial to be able investigate the pathophysiological manifestations accurately, non-invasively, and on regional level.Current available laboratory liver function blood panels are typically insufficient and often only indicate damage at a late stage. Thus, it would be beneficial to have access to biomarkers that are both sensitive and responds to early changes in liver function in both clinical settings and for the pharmaceutical industry and regulatory agencies.The main aim of this thesis was to develop and evaluate methods that can be used for a ‘non-invasive liver biopsy’ using magnetic resonance (MR). We also aimed to develop sensitive methods for measure liver function based on gadoxetate-enhanced MR imaging (MRI).The presented work is primarily based on a prospective study on c. 100 patients suffering from chronic liver disease of varying aetiologies recruited due to elevated liver enzyme levels, without clear signs of decompensated cirrhosis. Our results show that the commonly used liver fat cut-off for diagnosing steatosis should be lowered from 5% to 3% when using MR proton-density fat fraction (PDFF). We also show that MR elastography (MRE) is superior in staging fibrosis.Finally we presented a framework for quantifying liver function based on gadoxetate-enhanced MRI. The method is based on clinical images and a clinical approved contrast agent (gadoxetate). The framework consists of; state-of the-art image reconstruction and correction methods, a mathematical model, and a precise model parametrization method. The model was developed and validated on healthy subjects. Thereafter the model was found applicable on the chronic liver disease cohort as well as validated using gadoxetate levels in biopsy samples and blood samples. The liver function parameters correlated with clinical markers for liver function and liver fibrosis (used as a surrogate marker for liver function).In summary, it should be possible to perform a non-invasive liver biopsy using: MRI-PDFF for liver fat and iron loading, MRE for liver fibrosis and possibly also inflammation, and measure liver function using the presented framework for analysing gadoxetate-enhanced MRI. With the exception of an MREtransducer no additional hardware is required on the MR scanner. The liver function method is likely to be useful both in a clinical setting and in pharmaceutical trials.
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| 14. |
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| 15. |
- Hedström, Brita, et al.
(författare)
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Visby Innerstad : En användningsplan
- 1973
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Rapport (populärvet., debatt m.m.)abstract
- Sedan lång tid föreligger i stort sett enighet om att bevara innerstadens bebyggelse och att anpassa eventuella nytillskott till det redan bestående. Med den inställningen har förändringsprocessen både dämpats och mildrats men ändå inte bragts att avstanna. Förändringar sker ständigt om det också huvudsakligen i smått: de många synbart så anspråkslösa byggnadsåtgärderna adderar efterhand ihop sig till något större och mer genomgripande. Långsamt, nästan omärkligt, ändrar innerstaden sitt ansikte.Ändå är det inte själva husen som förändrats mest utan användningen av dem. Ur funktionell synpunkt har 1950 - och 60-talen har varit något av en omstörtning i innerstadens historia: den har förlorat nästan hälften av de boende, en stor del av detaljhandeln och praktiskt taget helt sin gamla roll som skolcentrum. I gengäld har ytterstaden vuxit ut till ett sammanhängande kilometerbrett bälte. Till stor del av denna funktionella förändring en följd av beslutet att bevara innerstadens bebyggelse. Vad som inte fått plats inom den gamla ramen har etablerats utandör den.Föreliggande arbete vill ge en översiktlig bild av förändringsförloppen, sedda i ett långt tidsperspektiv men med tonvikt på dagsläget. Bebyggelsen tas upp till utförlig granskning men också användningen av den. Det är just samspelet mellan husen och de funtkioner, de fyller, som kan sägas utgöra bokens huvudtema. I de flesta fall är detta sammanhang hus-användning alldeles konfliktfritt och föranleder därför inte heller någon diskussion. Vad som behandlas är de relativt få problematiska fallen, hus som borde rustas upp för att fylla sin uppgift, hus som är olämpligt nyttjade eller inte använda alls. En serie sådana fall tas upp till systematisk genomgång; samtidigt berörs också de trafik - och miljömässiga konsekvenserna. Bokens syfte är alltså klart: den ger ett underlag av fakta för arbetet med att jämka samman byggnader och användningsformer. I den meningen kan skriften kallas en anvädningsplan för Visby innanför murarna.Arkitekturskolanas arbete har bedrivitis parallellt med den kommunala Innerstadskommitténs verksamhet. Något organiserat samarbete har inte förekommit med de informella kontakterna har varit både täta och goda. Att likheterna mellan Innerstadskommittén och Arkitekturskolans slutsatser blivit så pass stora, kan tillskrivas en gemensam helhetssyn.En av Arkitekturskolans elever, arkitekt Lars-Ingvar Larsson, har tidigare självständigt genomfört en undersökning av förändringar i innerstaden 1945-70- Denna studie publicerats separat och bör uppfattas som ett komplement till den hör föreliggande.Förutom de i innehållsförteckningen nämnda har ytterligare några aktivt medverkat i arbetet. Studiet av trafikfrågorna i innerstaden, i hamnen och öster om ringmuren leddes av Åke Claesson, I fältstudier och diskussioner medverkande Göran Månsson.Arkitekturskolan har fått god hjälp av ett antal initierade personer i Visby. Särskild tacksamhet är vi skyldiga byggnadsnämnden ordförande Henning Jacobson, kommunalrådet C B Stenström, stadsarkitekten Måns Hagbergm f. länsbostadsdorektören Åke Malmberg och landsantikvarien Gunnar Svahnström. I boken publiceringskostnaderna har ekonomiskt bidrag lämnats av Gotlands kommun och Riksantikvarieämbetet.Boken har redigerats av Sture Balgård och Ann Mari Westerlind med hjälp av Henrik O Andersson, Bo Ek, Göran Lindahl, Fredrik von Platen, John Sjöström Gunnar Westerlind och Hans Wetterfors.Skeppsholmen, Stockholm, sommaren 1973.Arkitekturskolans lärare och elever.
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| 16. |
- Johansson, Folke, 1943, et al.
(författare)
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Kommunstorlek och demokrati
- 2007
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Föreliggande rapport har utarbetats vid CEFOS, Centrum för forskning om offentlig sektor, Göteborgs universitet. Huvudsyftet har varit att ta fram aktuell och systematisk kunskap om den betydelse kommunstorleken har för hur den kommunala demokratin i Sverige fungerar. Rapporten bygger till största delen på reanalyser av ett befintligt omfattande empiriskt material som innefattar kommunstudier av såväl medborgare som politiker, studier av massmediers innehåll och de mer generella enkätundersökningar som sedan lång tid utförs vid SOM-institutet, Göteborgs universitet. Beträffande politiker har också nytt material samlats in. Huvudansvariga för rapporten är professor Folke Johansson och fil dr David Karlsson. Docent Bengt Johansson har medverkat med analys av massmedias roll och fil dr Ylva Norén Bretzer har medverkat med analys av förtroende för politiker.
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| 17. |
- Karlsson, Markus, et al.
(författare)
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Diffuse Liver Disease: Measurements of Liver Trace Metal Concentrations and R2* Relaxation Rates
- 2016
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Ingår i: Magnetic Resonance Materials in Physics, Biology and Medicine. - : Springer. - 0968-5243 .- 1352-8661. ; 29:1, s. S395-S395
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionOver the past decade, several methods for measuring of liver iron content (LIC) non-invasively with MRI have been developed and verified. The most promising methods uses relaxometry, measuring either R2- or R2* relaxation rate in the liver1,2. For instance, several studies have shown that there seems to be a linear relationship between R2* and LIC1. However, few of these studies have measured the liver content of other metals, which could also affect the relaxation rates. The goal of this study was to investigate if any trace metals, other than iron could affect the R2* relaxation rate in liver tissue in a patients with diffuse liver disease.Subjects and methods75 patients with suspected diffuse liver disease underwent an MRI examination followed by a liver biopsy the same day. The R2* relaxation rate of the water protons in the liver was measured using an axial 3D multi-slice fat-saturated multi-echo turbo field echo sequence (TE=4.60/9.20/13.80/18.40/23.00ms). Regions of interest (ROI) were drawn and R2* was estimated by fitting the mean signal intensity from the ROIs to a mono-exponential decay model. The biopsies were freeze dried and the concentrations of iron, manganese, copper, cobalt and gadolinium were measured using Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP-SFMS). A multiple linear regression analysis was applied to determine which of the measured metals significantly affected the relaxation rate.ResultsA linear regression with the LIC and R2* showed a reasonable fit (Figure 1). The multiple linear regression analysis (Table 1) showed that iron as well as manganese had a significant affect on R2*. Unlike iron however, the regression coefficient of manganese was negative, meaning that an increasing manganese concentration gave a shorter R2* relaxation rate. The same trend can be seen when plotting the manganese concentration against R2* (Figure 2).
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| 18. |
- Karlsson, Markus, et al.
(författare)
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Increased bile excretion of Gd-EOB-DTPA in diffuse liver disease : mechanistic modeling of qDCE-MRI in patients with severe fibro-sis
- 2016
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Ingår i: Magnetic Resonance Materials in Physics, Biology and Medicine. - : Springer. - 0968-5243 .- 1352-8661. ; 29:1, s. S272-S273
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionOver the past decades, several different non-invasive methods for staging hepatic fibrosis have been proposed. One such method is dynamic contrast enhanced MRI (DCE-MRI) using the contrast agent (CA) Gd-EOB-DTPA. Gd-EOB-DTPA is liver specific, which means that it is taken up specifically by the hepatocytes via the OATP3B1/B3 transporters and excreted into the bile via the MRP2 transporter. Several studies have shown that DCE-MRI and Gd-EOBDTPA can separate patients with advanced (F3-F4) from mild (F0-F2) hepatic fibrosis by measuring the signal intensity, where patients with advanced fibrosis have a lower signal intensity than the mild fibrosis cases.1 However, none of the studies up to date have been able to differentiate if the reduced signal intensity in the liver is because of an decreased uptake of CA or an increased excretion. Analyzing the DCE-MRI data with mechanistic mathematical modelling has the possibility of investigating such a differentiation.Subjects and methods88 patients with diffuse liver disease were examined using DCE-MRI (1.5 T Philips Achieva, two-point Dixon, TR=6.5 ms, TE=2.3/4.6 ms, FA=13) after a bolus injection of Gd-EOB-DTPA, followed by a liver biopsy. Regions of interest were placed within the liver, spleen and veins and a whole-body mechanistic pharmacokinetic model2 was fitted to the data. The fitted parameters in the model correspond to the rate of CA transport between different compartments, e.g. hepatocytes, blood plasma, and bile (Fig. 1).ResultsAs can be seen in Fig. 2, the parameter corresponding to the transport of CA from the blood plasma to the hepatocytes, kph, is lower for patients with advanced fibrosis (p=0.01). Fig. 3 shows that the parameter corresponding to the CA excretion into the bile, khb, is higher for patients with advanced fibrosis (p<0.01).Discussion/ConclusionThis work shows that the decreased signal intensity in DCE-MRI images in patients with advanced fibrosis depends on both a decreased uptake of CA in the hepatocytes and an increased excretion into the bile. Similar results have also been observed in a rat study3. In that study, rats with induced cirrhosis had a higher MRP2-activity than the healthy control rats.References1Norén et al: Eur. Radiol, 23(1), 174-181, 2013.2Forsgren et al: PloS One, 9(4): e95700, 2014.3Tsuda & Matsui: Radiol, 256(3): 767-773, 2010.
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| 19. |
- Karlsson, Markus, et al.
(författare)
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Liver R2*is affected by both iron and fat: A dual biopsy-validated study of chronic liver disease
- 2019
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Ingår i: Journal of Magnetic Resonance Imaging. - : WILEY. - 1053-1807 .- 1522-2586. ; 50:1, s. 325-333
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Tidskriftsartikel (refereegranskat)abstract
- Background Liver iron content (LIC) in chronic liver disease (CLD) is currently determined by performing an invasive liver biopsy. MRI using R2* relaxometry is a noninvasive alternative for estimating LIC. Fat accumulation in the liver, or proton density fat fraction (PDFF), may be a possible confounder of R2* measurements. Previous studies of the effect of PDFF on R2* have not used quantitative LIC measurement. Purpose To assess the associations between R2*, LIC, PDFF, and liver histology in patients with suspected CLD. Study Type Prospective. Population Eighty-one patients with suspected CLD. Field Strength/Sequence 1.5 T. Multiecho turbo field echo to quantify R2*. PRESS MRS to quantify PDFF. Assessment Each patient underwent an MR examination, followed by two needle biopsies immediately following the MR examination. The first biopsy was used for conventional histological assessment of LIC, whereas the second biopsy was used to quantitatively measure LIC using mass spectrometry. R2* was correlated with both LIC and PDFF. A correction for the influence of fat on R2* was calculated. Statistical Tests Pearson correlation, linear regression, and area under the receiver operating curve. Results There was a positive linear correlation between R2* and PDFF (R = 0.69), after removing data from patients with elevated iron levels, as defined by LIC. R2*, corrected for PDFF, was the best method for identifying patients with elevated iron levels, with a correlation of R = 0.87 and a sensitivity and specificity of 87.5% and 98.6%, respectively. Data Conclusion PDFF increases R2*. Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:325-333.
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| 20. |
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| 21. |
- Matthiessen, P., et al.
(författare)
-
Increase of serum C-reactive protein is an early indicator of subsequent symptomatic anastomotic leakage after anterior resection
- 2008
-
Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 10:1, s. 75-80
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: This prospective study investigated the factors which might indicate anastomotic leakage after low anterior resection. Method: Thirty-three patients who underwent anterior resection for rectal carcinoma (n = 32) and severe dysplasia (n = 1), were monitored daily by serum C-reactive protein (CRP) and white blood cell count (WBC) estimations until discharge from hospital. Computed tomography (CT) scans were performed on postoperative days 2 and 7 and the amount of presacral fluid collection was assessed. All patients had a pelvic drain and the volume of drainage was measured daily. Results: The level of the anastomosis was at a median 5 cm (3-12 cm) above the anal verge. There was no 30-day mortality. Nine (27.2%) of the 33 patients developed a symptomatic anastomotic leakage which was diagnosed at a median of 8 days (range 4-14) postoperatively. The serum CRP was increased in patients who leaked from postoperative day 2 onwards (P = 0.004 on day 2, P < 0.001 on day 3-8). The WBC was decreased in preoperatively irradiated patients on days 1-5 (P = 0.021), with no difference seen between patients with or without leakage. Patients with leakage had a larger presacral fluid collection on CT on day 7 (median 76 ml vs 52 ml, P = 0.016) and a larger increase in the fluid collection between the first and the second CT examinations (28 ml vs 3 ml, P = 0.046). Conclusion: An early rise in serum CRP was a strong indicator of leakage. Monitoring of CRP for possible early detection of symptomatic anastomotic leakage is recommended.
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| 22. |
- Murgovski, Nikolce, 1980, et al.
(författare)
-
Hybrid powertrain concept evaluation using optimization
- 2010
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Ingår i: EVS-25.
-
Konferensbidrag (refereegranskat)abstract
- This paper describes automatic evaluation of series-parallel (combined) powertrain models using optimization. The novelty with the approach is the possibility to work with non-transparent industrial vehicle models, hidden for intellectual property reasons. The contribution extends the functionality of a recently developed tool for parallel hybrids, with the ability to operate on combined powertrains. Given the user inputs, which include dynamic vehicle model and driving cycle, the tool first produces a simplified powertrain model in the form of static maps, before dynamic programming is used to find an optimal torque split that minimizes fuel consumption. The main use of the tool is to evaluate the potential of a powertrain configuration. The paper contains an illustration of the tool operation on a non-transparent industrial vehicle model. The only requirement on the model is to provide access to some general variables and that it has a torque split that can be fully controlled.
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| 23. |
- Nasr, Patrik, 1987-, et al.
(författare)
-
Using a 3% Proton Density Fat Fraction as a Cut-off Value Increases Sensitivity of Detection of Hepatic Steatosis, Based on Results from Histopathology Analysis
- 2017
-
Ingår i: Gastroenterology. - : Elsevier. - 0016-5085 .- 1528-0012. ; 153:1, s. 53-
-
Tidskriftsartikel (refereegranskat)abstract
- It is possible to estimate hepatic triglyceride content by calculating the proton density fat fraction (PDFF), using proton magnetic resonance spectroscopy (less thansuperscriptgreater than1less than/superscriptgreater thanH-MRS), instead of collecting and analyzing liver biopsies to detect steatosis. However, the current PDFF cut-off value (5%) used to define steatosis by magnetic resonance was derived from studies that did not use histopathology as the reference standard. We performed a prospective study to determine the accuracy of less thansuperscriptgreater than1less than/superscriptgreater thanH-MRS PDFF in measurement of steatosis using histopathology analysis as the standard. We collected clinical, serologic, less thansuperscriptgreater than1less than/superscriptgreater thanH-MRS PDFF, and liver biopsy data from 94 adult patients with increased levels of liver enzymes (6 months or more) referred to the Department of Gastroenterology and Hepatology at Linköping University Hospital in Sweden from 2007 through 2014. Steatosis was graded using the conventional histopathology method and fat content was quantified in biopsy samples using stereological point counts (SPCs). We correlated less thansuperscriptgreater than1less than/superscriptgreater thanH-MRS PDFF findings with SPCs (r = 0.92; P less than.001). less thansuperscriptgreater than1less than/superscriptgreater thanH-MRS PDFF results correlated with histopathology results (ρ = 0.87; P less than.001), and SPCs correlated with histopathology results (ρ = 0.88; P less than.001). All 25 subjects with PDFF values of 5.0% or more had steatosis based on histopathology findings (100% specificity for PDFF). However, of 69 subjects with PDFF values below 5.0% (negative result), 22 were determined to have steatosis based on histopathology findings (53% sensitivity for PDFF). Reducing the PDFF cut-off value to 3.0% identified patients with steatosis with 100% specificity and 79% sensitivity; a PDFF cut-off value of 2.0% identified patients with steatosis with 94% specificity and 87% sensitivity. These findings might be used to improve non-invasive detection of steatosis.
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| 24. |
- Norén, Agneta, et al.
(författare)
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Identification of Inequalities in the Selection of Liver Surgery for Colorectal Liver Metastases in Sweden
- 2018
-
Ingår i: Scandinavian Journal of Surgery. - : SAGE Publications. - 1457-4969 .- 1799-7267. ; 107:4, s. 294-301
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Liver resection for colorectal liver metastases offers a 5-year survival rate of 25%-58%. This study aimed to analyze whether patients with colorectal liver metastases undergo resection to an equal extent and whether selection factors play a role in the selection process. Material and Methods: Data were retrieved from the Swedish Colorectal Cancer Registry (2007-2011) for colorectal cancer and colorectal liver metastases. The patients identified were linked to the Swedish Registry of Liver and Bile surgery and the National Patient Registry to identify whether liver surgery or ablative treatment was performed. Analyses for age, sex, type of primary tumor and treating hospital (university, county, or district), American Society of Anesthesiologists class, and radiology for detection of metastatic disease were performed. Results: Of 28,355 patients with colorectal cancer, 21.6% (6127/28,355) presented with liver metastases. Of the patients with liver metastases, 18.5% (1134/6127) underwent liver resection or ablation. The cumulative proportion of liver resection/ablation was 4% (1134/28,355) of all colorectal cancer. If "not bowel resected" were excluded, the proportion slightly increased to 4.7% (1134/24,262). Around 15% of the patients with metastases were registered as referrals for liver surgery. In a multivariable analysis patients treated at a university hospital for primary tumor were more frequently surgically treated for liver metastases (p < 0.0001). Patients with liver metastases from rectal cancer (p < 0.0001) and men more often underwent liver resection (p = 0.006). A difference was found between health-care regions for the frequency of liver surgery (p < 0.0001). Patients >70 years and those with American Society of Anesthesiologists class >2 underwent liver resection less frequently. Magnetic resonance imaging of the liver was more often used in diagnostic work-up in men. Conclusion: Patients with colorectal liver metastases are unequally treated in Sweden, as indicated by the low referral rate. The proximity to a hepatobiliary unit seems important to enhance the patient's chances of being offered liver surgery.
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| 25. |
- Norén, Bengt, 1955-, et al.
(författare)
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Absolute quantification of human liver metabolite concentrations by localized in vivo 31P NMR spectroscopy in diffuse liver disease
- 2005
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Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 15:1, s. 148-157
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorus-31 NMR spectroscopy using slice selection (DRESS) was used to investigate the absolute concentrations of metabolites in the human liver. Absolute concentrations provide more specific biochemical information compared to spectrum integral ratios. Nine patients with histopathologically proven diffuse liver disease and 12 healthy individuals were examined in a 1.5-T MR scanner (GE Signa LX Echospeed plus). The metabolite concentration quantification procedures included: (1) determination of optimal depth for the in vivo measurements, (2) mapping the detection coil characteristics, (3) calculation of selected slice and liver volume ratios using simple segmentation procedures and (4) spectral analysis in the time domain. The patients had significantly lower concentrations of phosphodiesters (PDE), 6.3±3.9 mM, and ATP-β, 3.6±1.1 mM, (P<0.05) compared with the control group (10.0±4.2 mM and 4.2±0.3 mM, respectively). The concentrations of phosphomonoesters (PME) were higher in the patient group, although this was not significant. Constructing an anabolic charge (AC) based on absolute concentrations, [PME]/([PME] + [PDE]), the patients had a significantly larger AC than the control subjects, 0.29 vs. 0.16 (P<0.005). Absolute concentration measurements of phosphorus metabolites in the liver are feasible using a slice selective sequence, and the technique demonstrates significant differences between patients and healthy subjects.
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| 26. |
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| 27. |
- Norén, Bengt
(författare)
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Matching of wood for testing purpose
- 1994
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Ingår i: European Journal of Wood and Wood Products. - 0018-3768 .- 1436-736X. ; 52:3, s. 191-197
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Tidskriftsartikel (refereegranskat)abstract
- Different methods of pair matching both small "clean" wood specimens and structural timber are described. Matching of structural timber according to modulus of elasticy and knots results in pairs that differ in strength by an average of about 15 percent with extremes up to 40 percent. These differences are due to other parameters such as fibre deviation, number of cut fibres, tension strength perpendicular to grain, whose influence is not sufficiently reflected in the deviation of local stiffness. Här beskrivs olika sätt att tillverka par av likvärdiga provkroppar av trä för hållfasthetsbestämning. "Matchning" av helrent trä och förband ingår, men tyngdpunkten är lagd på matchning av konstruktionsvirke såsom den tillämpats vid Träteks långtidsundersökning av tid till brott som funktion av belastningsgraden.
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| 28. |
- Norén, Bengt, 1955-
(författare)
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MECP möjligheter, begränsningar, utveckling
- 2002
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Ingår i: Läkarmöte "ERCP-Nyheter inom gallvägsdiagnostik och handläggning", Norrköping 24 sept 2002,2002.
-
Konferensbidrag (refereegranskat)
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| 29. |
- Norén, Bengt, 1955-
(författare)
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Non-Invasive Assessment of Liver Fibrosis with 31P-Magnetic Resonance Spectroscopy and Dynamic Contrast Enhanced Magnetic Resonance Imaging
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present study aims at demonstrating phosphorus metabolite concentration changes and alterations in uptake/excretion of a hepatocyte specific contrast agent in patients with diffuse - or suspected diffuse - liver disease by applying two non-invasive quantitative MR techniques and to compare the results with histo-pathological findings, with focus on liver fibrosis.In the first study phosphorus-31 MR spectroscopy using slice selection (DRESS) was implemented. Patients with histopathologically proven diffuse liver disease (n = 9) and healthy individuals (n = 12) were examined. The patients had significantly lower concentrations of phosphodiesters (PDE) and ATP compared with controls. Constructing an ‘anabolic charge’ (AC) based on absolute concentrations, [PME] / ([PME] + [PDE]), the patients had a significant larger AC than the control subjects.The MRS technique was then, in a second study, applied on two distinct groups of patients, one group with steatosis and none-to-moderate inflammation (n = 13) and one group with severe fibrosis or cirrhosis (n = 16). A control group (n = 13) was also included. Lower concentrations of PDE and a higher AC were found in the cirrhosis group compared to the control group. Also compared to the steatosis group, the cirrhosis group had lower concentrations of PDE and a higher AC. A significant correlation between fibrosis stage and PDE and fibrosis stage and AC was found. Using an AC cut-off value of 0.27 to discriminate between mild (stage 0-2) and advanced (stage 3-4) fibrosis yielded an AUROC value of 0.78, similar as for discriminating between F0-1 vs. F2-4.Dynamic contrast enhanced MRI (DCE-MRI) was performed prospectively in a third study on 38 patients referred for evaluation of elevated serum alanine aminotransferase (ALT) and/or alkaline phosphatase (ALP) levels. Data were acquired from regions of interest in the liver and spleen by using single-breath-hold symmetrically sampled two-point Dixon 3D images time-series (non-enhanced, arterial and venous portal phase; 3, 10, 20 and 30 min) following a bolus injection of Gd-EOB-DTPA (0.025 mmol/kg). A new quantification procedure for calculation of the ‘hepatocyte specific uptake rate’, KHep, was applied on a two-compartment pharmacokinetic model. Liver-to-spleen contrast ratios (LSC_N) were also calculated. AUROC values of 0.71, 0.80 and 0.78, respectively, were found for KHep, LSC_N10 and LSC_N20 with regard to severe versus mild fibrosis. Significant group differences were found for KHep (borderline), LSC_N10 and LSC_N20.In study four no significant correlation between visual assessments of bile ducts excretion of Gd-EOB-DTPA and histo-pathological grading of fibrosis or the quantified uptake of Gd-EOB-DTPA defined as KHep and LSC_N.In conclusion 31P-MRS and DCE-MRI show promising results for achieving a non-invasive approach in discriminating different levels of fibrosis from each other.
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| 30. |
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| 31. |
- Norén, Bengt
(författare)
-
Princip för beräkning av spikförbands bärförmåga
- 1995
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten beskriver en princip för beräkning av spikförbands bärförmåga vid varierande materialhållfasthet. Den första delen ger exempel på hållfasthetsvariationer och jämviktskrav. Den andra delen ger uttryck för beräkning av spikars kapacitet att överföra krafter och moment i infästningar och fogar vid olika deformationsmoder.
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Norén, Bengt, 1955-
(författare)
-
Quantitative 31P magnetic resonance spectroscopy in diffuse liver disease
- 2006
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The studies in this thesis were delineated to evaluate the diagnostic possibilities in patients with diffuse liver disease by using phosphorus-31 MR spectroscopy and comparing the results with clinical, laboratory and histopathological findings. For this purpose in all 38 patients and 25 controls without evidence of liver disease were examined.In the first study 31P-MRS using slice selection (DRESS) was implemented to investigate the absolute concentrations of metabolites in human liver. The metabolite concentration quantification procedures included: 1. Determination of optimal depth for the in vivo measurements, 2. Mapping the detection coil characteristics, 3. Calculation of selected slice and liver volume ratios using simple segmentation procedures, and 4. Spectral analysis in the time domain. Patients with histopathologically proven diffuse liver disease (n = 9) and healthy individuals (n = 12) were examined. The patients had significantly lower concentrations of phosphodiesters (PDE) and ATP-ß compared with the control group. Constructing an anabolic charge (AC) based on absolute concentrations, [PME] / ([PME] + [PDE]), the patients had a significant larger AC than the control subjects, 0.29 vs. 0.16 (p < 0.005).In the second study the MRS technique was applied on two distinct groups of patients with diffuse chronic liver disorders, one group with steatosis and none-to-moderate inflammation (n = 13) and one group with severe fibrosis or cirrhosis (n = 16). All patients underwent liver biopsy and extensive biochemical evaluation. A control group (n = 13) was also included. Lower concentrations of PDE (p = 0.025) and a higher AC (p = 0.001) were found in the cirrhosis group compared to the control group.Using a PDE concentration of 10.5 mM as a cut-off value to discriminate between mild (stage 0-2) and advanced (stage 3-4) fibrosis the sensitivity and specificity were 81% and 69% respectively. An AC cut-off value of 0.27 showed a sensitivity of 93% and a specificity of 54%.In conclusion the results indicates that a decrease in PDE concentration is a marker of liver fibrosis and that AC is a potentially clinically useful parameter indiscriminating mild fibrosis from advanced. No significant relationship between the MRS data and the degree of steatosis or inflammation was found.
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| 36. |
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| 37. |
- Norén, Bengt, 1955-, et al.
(författare)
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Separation of advanced from mild fibrosis in diffuse liver disease using 31P magnetic resonance spectroscopy
- 2008
-
Ingår i: European Journal of Radiology. - : Elsevier. - 0720-048X .- 1872-7727. ; 66:2, s. 313-320
-
Tidskriftsartikel (refereegranskat)abstract
- 31P-MRS using DRESS was used to compare absolute liver metabolite concentrations (PME, Pi, PDE, γATP, αATP, βATP) in two distinct groups of patients with chronic diffuse liver disorders, one group with steatosis (NAFLD) and none to moderate inflammation (n = 13), and one group with severe fibrosis or cirrhosis (n = 16). All patients underwent liver biopsy and extensive biochemical evaluation. A control group (n = 13) was also included. Absolute concentrations and the anabolic charge, AC = {PME}/({PME} + {PDE}), were calculated.Comparing the control and cirrhosis groups, lower concentrations of PDE (p = 0.025) and a higher AC (p < 0.001) were found in the cirrhosis group. Also compared to the NAFLD group, the cirrhosis group had lower concentrations of PDE (p = 0.01) and a higher AC (p = 0.009). No significant differences were found between the control and NAFLD group. When the MRS findings were related to the fibrosis stage obtained at biopsy, there were significant differences in PDE between stage F0–1 and stage F4 and in AC between stage F0–1 and stage F2–3.Using a PDE concentration of 10.5 mM as a cut-off value to discriminate between mild, F0–2, and advanced, F3–4, fibrosis the sensitivity and specificity were 81% and 69%, respectively. An AC cut-off value of 0.27 showed a sensitivity of 93% and a specificity of 54%.In conclusion, the results suggest that PDE is a marker of liver fibrosis, and that AC is a potentially clinically useful parameter in discriminating mild fibrosis from advanced.
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| 38. |
- Norén, Bengt, et al.
(författare)
-
Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA
- 2013
-
Ingår i: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 23:1, s. 174-181
-
Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo apply dynamic contrast-enhanced (DCE) MRI on patients presenting with elevated liver enzymes without clinical signs of hepatic decompensation in order to quantitatively compare the hepatocyte-specific uptake of Gd-EOB-DTPA with histopathological fibrosis stage.MethodsA total of 38 patients were prospectively examined using 1.5-T MRI. Data were acquired from regions of interest in the liver and spleen by using time series of single-breath-hold symmetrically sampled two-point Dixon 3D images (non-enhanced, arterial and venous portal phase; 3, 10, 20 and 30 min) following a bolus injection of Gd-EOB-DTPA (0.025 mmol/kg). The signal intensity (SI) values were reconstructed using a phase-sensitive technique and normalised using multiscale adaptive normalising averaging (MANA). Liver-to-spleen contrast ratios (LSC_N) and the contrast uptake rate (KHep) were calculated. Liver biopsy was performed and classified according to the Batts and Ludwig system.ResultsArea under the receiver-operating characteristic curve (AUROC) values of 0.71, 0.80 and 0.78, respectively, were found for KHep, LSC_N10 and LSC_N20 with regard to severe versus mild fibrosis. Significant group differences were found for KHep (borderline), LSC_N10 and LSC_N20.ConclusionsLiver fibrosis stage strongly influences the hepatocyte-specific uptake of Gd-EOB-DTPA. Potentially the normalisation technique and KHep will reduce patient and system bias, yielding a robust approach to non-invasive liver function determination.
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| 39. |
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| 40. |
- Norén, Bengt, et al.
(författare)
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Visual assessment of biliary excretion of Gd-EOB-DTPA in patients with suspected diffuse liver disease–A biopsy-verified prospective study
- 2015
-
Ingår i: European Journal of Radiology Open. - : Elsevier BV. - 2352-0477. ; 2, s. 19-25
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To qualitatively evaluate late dynamic contrast phases, 10, 20 and 30. min, after administration of Gd-EOB-DTPA with regard to biliary excretion in patients presenting with elevated liver enzymes without clinical signs of cirrhosis or hepatic decompensation and to compare the visual assessment of contrast agent excretion with histo-pathological fibrosis stage, contrast uptake parameters and blood tests. Methods: 29 patients were prospectively examined using 1.5T MRI. The visually assessed presence or absence of contrast agent for each of five anatomical regions in randomly reviewed time-series was summarized on a four grade scale for each patient. The scores, including a total visual score, were related to the histo-pathological findings, the quantitative contrast agent uptake parameters, expressed as KHep or LSC_N, and blood tests. Results: No relationship between the fibrosis grade or contrast uptake parameters could be established. A negative correlation between the visual assessment and alkaline phosphatase (ALP) was found. Comparing a sub-group of cholestatic patients with fibrosis score and Gd-EOB-DTPA dynamic parameters did not add any additional significant correlation. Conclusions: No correlation between visually assessed biliary excretion of Gd-EOB-DTPA and histo-pathological or contrast uptake parameters was found. A negative correlation between the visual assessment and alkaline phosphatase (ALP) was found.
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| 41. |
- Norén Bretzer, Ylva, 1969, et al.
(författare)
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Is public procurement efficiency conditioned by market types? A critical test in park and road sectors in Sweden
- 2016
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Ingår i: International Journal of Public Sector Management. - 0951-3558. ; 29:5, s. 488-501
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The purpose of this paper is to investigate to what extent contracting out practices has led to perceived resource cuts in the Swedish park and road sectors. Design/methodology/approach – E-survey sent to managers in park and technical departments in the municipalities. Response rate: 39.7 percent. Findings – Decreased costs were found in 25 percent of the responding road departments, in 20 percent of park departments. 49 percent of the road departments responded “ no change ” or “ increase ” (48 percent parks). Findings indicate that tendering practices tend to be most commonly centered in Swedish municipalities situated in the three metropolitan regions (Stockholm, Gothenburg and Malmö with suburbs), while such practices are not as common in mid-sized and rural municipalities. In addition, contracting out practices correspond with higher per capita budgets, not with smaller. Research limitations/implications – The research implications are that contracting out tend to occur “ where the resources are, ” while poorer municipalities either have to contract even if it is more expensive, or, contracting out is combined with other provision models. The limitation of the data are that it based on managers’ perceptions, while hard data have been impossible to map. Practical implications – The uniform assumption that contracting out saves public resources need to be conditioned with context, and initial resources at hand. Contracting out is one option among several possible strategies, especially for mid-sized and smaller municipalities with small budgets. Social implications – The rationalities of local government procurements are bounded by the local market situations and local the budget capacities. Originality/value – This is the first study of manager ’ s perceptions in the Swedish park and road contexts. Keywords Market structure, Contracting out, Cost-efficiency, Local park management, Local road management, Metropolitan municipalities Paper type Research paper
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| 42. |
- Norén Bretzer, Ylva, 1969, et al.
(författare)
-
Local Marketization 1980-2018: Incremental Tendencies and Deviances
- 2020
-
Ingår i: Marketization in Local Government: Diffusion and Evolution in Scandinavia and England. Andrej Christian Lindholst, Morten Balle Hansen (red.). - Cham, Switzerland : Palgrave Macmillan, Springer Nature. - 9783030324773 ; , s. 117-139
-
Bokkapitel (refereegranskat)abstract
- Relations between the public sector and the market have a long history in Sweden. The opening section discusses relations between public and private governance at the national level across the past four decades in Sweden. Next, the discussion is narrowed to the municipal park and road sectors of the local municipalities, as the early marketization reforms were initiated there. In the closing section several lessons are discussed. First, the actual selling-off of public companies on the open market primarily relates to the national level, while corporatization and market imitation have been increasingly common features of the local administrative level. Second, in local government discussions of management form characterized the early period, while outcome and quality control dominated in later years. Third, contracting out has taken place due to procurement regulations. For the local road sector, the level external contracting has been roughly the same throughout the period, while for the park sector we found an increase from 3 percent in 1987 to 28 percent in 2015. This can be interpreted as the park sector imitating the road sector, which had been practicing external contracting for decades.
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| 43. |
- Norén Bretzer, Ylva, 1969, et al.
(författare)
-
Local marketization under the ‘new’ political governance in Sweden, 1980-2018
- 2018
-
Ingår i: NORKOM 2018, Aarhus.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper compares how the local public sector and the local markets have evolved from the 1980s up to 2018 at the municipal level in Sweden (2015; cf Montin 2000). The two examples of contracting out exercised are the organisational reforms in the municipal park and road sectors. Materials are primary data (INOPS 2015) combined with secondary data from previous scientific reports and governmental studies. The results are multifaceted. First, the market imitation has increasingly become the features of the local administrative level – but not to the expense of local government legitimacy. Second, the alternatives of management forms characterized the early period, while outcome and quality control dominated the more recent years. Third, for the local road sector, the level of external contracting has been stable throughout the period; while for the park sector we found an increase from 3 percent in 1987 to 28 percent in 2015. The general mimicking of the private sector seems to have kept local governance and legitimacy in line with the expectations of the Swedes.
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| 44. |
- Norén Bretzer, Ylva, 1969, et al.
(författare)
-
Local marketization under the ‘new’ political governance in Sweden, 1980-2018
- 2018
-
Ingår i: EGPA Conference. 5-7 September, Lausanne.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The opening section of the paper will discusses how the local public sector and the local market have evolved from the 1980s up to 2018 at the municipal level, in relation to the governance developments discussed at the national level by Pierre and Sundström (2015; cf Montin 2000). Next, the discussion is narrowed to the examples of contracting out and organisational reforms in the municipal park and road sectors of the Swedish municipalities. Materials used are primary data (INOPS 2015) (Norén Bretzer et al 2016) and secondary data based on previous scientific reports and governmental studies. Results are manifold. First, the corporatization and market imitation have been increasingly common features of the local administrative level – but not to the expense of local government legitimacy. Second, in local government discussions the alternatives of management forms characterized the early period, while outcome and quality control dominated the later years. Third, for the local road sector, the level external contracting has been roughly the same throughout the period; while for the park sector we found an increase from 3 percent in 1987 to 28 percent in 2015. This can be interpreted as the park sector imitating the road sector, which had been practicing external contracting for decades. The general mimicking of the private sector that has taken place throughout the past four decades seems to have kept local governance and legitimacy in line with the expectations of the Swedes.
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| 45. |
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| 46. |
- Rundblad, Bengt, et al.
(författare)
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Politiskt ledarskap i en kommun
- 1992
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Ingår i: Schaller, J., & Johansson, J., (red), Ledarskap och arbetsmiljö.. - Göteborg : Akademiförlaget. - 9124165557
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 47. |
- Stigebrandt, Anders, 1942, et al.
(författare)
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An Experiment with Forced Oxygenation of the Deepwater of the Anoxic By Fjord, Western Sweden
- 2015
-
Ingår i: Ambio. - : Springer Netherlands. - 0044-7447 .- 1654-7209. ; 44:1, s. 42-54
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Tidskriftsartikel (refereegranskat)abstract
- In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.
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| 48. |
- Sörstedt, Erik, 1980-, et al.
(författare)
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Computed tomographic colonography : Comparison of two workstations
- 2005
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 46:7, s. 671-678
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare two commercially available computed tomography (CT) colonography systems with respect to interobserver variability, the influence of level of expertise, and the gradual reduction of reviewing time for each system. Material and Methods: Two residents and two radiologists using Siemens CTAPP Colography software and Viatronix V3DColon software reviewed supine and prone CT acquisitions from 24 patients in a primary 3D endoluminal view. The observers graded each case with respect to technical quality and diagnostic value, assessed the presence of pathology, and indicated the time spent on the viewing. Results: Significant differences were found in technical quality ( P <0.001) and diagnostic value ( P <0.001) depending on which system was used, with higher scores for the Viatronix software. The agreement between specialists tended to be higher than that between residents (κ = 0.63 (0.30-0.95) vs. κ = 0.51 (0.21-0.81)), and the residents gave significantly ( P <0.001) higher scores of technical quality. However, the level of expertise had no significant impact on the assessments. We noted extensive variability in pathological lesions found by the different observers. The number of findings did not differ between workstations, but the viewers tended to report larger polyp sizes with the Viatronix software. The time needed for viewing decreased significantly from the first to the last examination viewed by each observer. Conclusion: Both the evaluated systems present trustworthy images of the human colon, but in a primary 3D setting the Viatronix software is favored owing to the userfriendly interface, higher experienced technical quality, and better diagnostic value. © 2005 Taylor & Francis.
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| 49. |
- Tourancheau, Sylvain, 1982-, et al.
(författare)
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Subjective evaluation of user experience in interactive 3D-visualization in a medical context
- 2012
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Ingår i: Proceedings of the SPIE, vol 8318: Conference on Image Perception, Observer Performance, and Technology Assessment, San Diego, CA, USA, 4 - 9 February 2012. - : SPIE - International Society for Optical Engineering. ; , s. Art. no. 831814-
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Konferensbidrag (refereegranskat)abstract
- New display technologies enable the usage of 3D-visualization in a medical context. Even though user performance seems to be enhanced with respect to 2D thanks to the addition of recreated depth cues, human factors, and more particularly visual comfort and visual fatigue can still be a bridle to the widespread use of these systems. This study aimed at evaluating and comparing two different 3D visualization systems (a market stereoscopic display, and a state-of-the-art multi-view display) in terms of quality of experience (QoE), in the context of interactive medical visualization. An adapted methodology was designed in order to subjectively evaluate the experience of users. 14 medical doctors and 15 medical students took part in the experiment. After solving different tasks using the 3D reconstruction of a phantom object, they were asked to judge their quality of the experience, according to specific features. They were also asked to give their opinion about the influence of 3D-systems on their work conditions. Results suggest that medical doctors are opened to 3D-visualization techniques and are confident concerning their beneficial influence on their work. However, visual comfort and visual fatigue are still an issue of 3D-displays. Results obtained with the multi-view display suggest that the use of continuous horizontal parallax might be the future response to these current limitations.
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| 50. |
- Valdimarsson, Valentinus T., et al.
(författare)
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Outcomes of liver-first strategy and classical strategy for synchronous colorectal liver metastases in Sweden
- 2018
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Ingår i: HPB. - : Elsevier BV. - 1365-182X .- 1477-2574. ; 20:5, s. 441-447
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with synchronous colorectal liver metastases (sCRLM) are increasingly operated with liver resection before resection of the primary cancer. The aim of this study was to compare outcomes in patients following the liver-first strategy and the classical strategy (resection of the bowel first) using prospectively registered data from two nationwide registries. Methods: Clinical, pathological and survival outcomes were compared between the liver-first strategy and the classical strategy (2008-2015). Overall survival was calculated. Results: A total of 623 patients were identified, of which 246 were treated with the liver-first strategy and 377 with the classical strategy. The median follow-up was 40 months. Patients chosen for the classical strategy more often had T4 primary tumours (23% vs 14%, P = 0.012) and node-positive primaries (70 vs 61%, P = 0.015). The liver-first patients had a higher liver tumour burden score (4.1 (2.5-6.3) vs 3.6 (2.2-5.1), P = 0.003). No difference was seen in five-year overall survival between the groups (54% vs 49%, P = 0.344). A majority (59%) of patients with rectal cancer were treated with the liver-first strategy. Conclusion: The liver-first strategy is currently the dominant strategy for sCRLM in patients with rectal cancer in Sweden. No difference in overall survival was noted between strategies.
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