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Woisetschläger, M., Blomma, J., Dahlström, N., Bivik Stadler, C. & Forsberg, D. (2019). Liver data from the Visual Sweden project DROID: Analytic Imaging Diagnostics Arena (AIDA). Linköping: Analytic Imaging Diagnostics Arena
Open this publication in new window or tab >>Liver data from the Visual Sweden project DROID: Analytic Imaging Diagnostics Arena (AIDA)
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2019 (English)Data set
Place, publisher, year
Linköping: Analytic Imaging Diagnostics Arena, 2019
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-154903 (URN)10.23698/aida/drli (DOI)
Note

Restricted access, Please contact Mischa.Woisetschlager@regionostergotland.se, claes.lundstrom@liu.se or joel.hedlund@liu.se to request access.

Available from: 2019-03-04 Created: 2019-03-04 Last updated: 2019-03-13Bibliographically approved
Daghighi, A., Tropp, H., Dahlström, N. & Klarbring, A. (2018). Correction: F.E.M. Stress-Investigation of Scolios Apex. Open Biomedical Engineering Journal, 12, 51-71
Open this publication in new window or tab >>Correction: F.E.M. Stress-Investigation of Scolios Apex
2018 (English)In: Open Biomedical Engineering Journal, ISSN 1874-1207, E-ISSN 1874-1207, Vol. 12, p. 51-71Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Sharjah, United Arab Emirates: Bentham Open, 2018
National Category
Computer Engineering
Identifiers
urn:nbn:se:liu:diva-156039 (URN)10.2174/1874120701812010090 (DOI)30450136 (PubMedID)2-s2.0-85056615684 (Scopus ID)
Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-06-28Bibliographically approved
Daghighi, A., Tropp, H., Dahlström, N. & Klarbring, A. (2018). F.E.M. Stress-Investigation of Scolios Apex. Open Biomedical Engineering Journal, 12, 51-71
Open this publication in new window or tab >>F.E.M. Stress-Investigation of Scolios Apex
2018 (English)In: Open Biomedical Engineering Journal, ISSN 1874-1207, E-ISSN 1874-1207, Vol. 12, p. 51-71Article in journal (Refereed) Published
Abstract [en]

In scoliosis, kypholordos and wedge properties of the vertebrae should be involved in determining how stress is distributed in the vertebral column. The impact is logically expected to be maximal at the apex.

Place, publisher, year, edition, pages
Bentham Open, 2018
Keywords
Comsol model; FEM Stress-Investigation; Mechanical loading; Pathological mechanisms; Scoliosis; Thoracal Idiopathic
National Category
Computer Engineering
Identifiers
urn:nbn:se:liu:diva-152506 (URN)10.2174/1874120701812010051 (DOI)30258499 (PubMedID)
Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-05-01
Vavruch, L., Forsberg, D., Dahlström, N. & Tropp, H. (2018). Vertebral Axial Asymmetry in Adolescent Idiopathic Scoliosis.. Spine Deformity, 6(2), 112-120.e1
Open this publication in new window or tab >>Vertebral Axial Asymmetry in Adolescent Idiopathic Scoliosis.
2018 (English)In: Spine Deformity, ISSN 2212-134X, Vol. 6, no 2, p. 112-120.e1Article in journal (Refereed) Published
Abstract [en]

Study Design

Retrospective study.

Objectives

To investigate parameters of axial vertebral deformation in patients with scoliosis compared to a control group, and to determine whether these parameters correlated with the severity of spine curvature, measured as the Cobb angle.

Summary of Background Data

Adolescent idiopathic scoliosis (AIS) is the most common type of spinal deformity. Many studies have investigated vertebral deformation, in terms of wedging and pedicle deformations, but few studies have investigated actual structural changes within vertebrae.

Methods

This study included 20 patients with AIS (Lenke 1–3, mean age: 15.6 years, range: 11–20). We compared preoperative low-dose computed tomography(CT) examinations of patients with AIS to those of a control group matched for age and sex. The control individuals had no spinal deformity, but they were admitted to the emergency department for trauma CTs. We measured the Cobb angles and the axial vertebral rotation (AVR), axial vertebral bodyasymmetry (AVBA), and frontal vertebral body rotation (FVBR) for the superior end, inferior end, and apical vertebrae, with in-house–developed software. Correlations between entities were investigated with the Pearson correlation test.

Results

The average Cobb angles were 49.3° and 1.3° for the scoliotic and control groups, respectively. The patient and control groups showed significant differences in the AVRs of all three vertebra levels (p < .01), the AVBAs of the superior end and apical vertebrae (p < .008), and the FVBR of the apical vertebra (p = .011). Correlations were only found between the AVBA and FVBR in the superior end vertebra (r = 0.728, p < .001) and in the apical vertebra (r = 0.713, p < .001).

Conclusions

Compared with controls, patients with scoliosis showed clear morphologic differences in the midaxial plane vertebrae. Differences in AVR, AVBA, and FVBR were most pronounced at the apical vertebra. The FVBR provided valuable additional information about the internal rotation and deformation of vertebrae.

Level of Evidence

Level III.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Scoliosis; Morphology; Three-dimensional; Vertebral rotation; Low-dose CT
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-145864 (URN)10.1016/j.jspd.2017.09.001 (DOI)29413732 (PubMedID)2-s2.0-85032338953 (Scopus ID)
Available from: 2018-03-20 Created: 2018-03-20 Last updated: 2019-05-01Bibliographically approved
Romu, T., Camilla, V., Dahlqvist Leinhard, O., Tallberg, J., Dahlström, N., Persson, A., . . . Nyström, F. (2016). A randomized trial of cold-exposure on energy expenditure and supraclavicular brown adipose tissue volume in humans. Metabolism: Clinical and Experimental, 65(6), 926-934
Open this publication in new window or tab >>A randomized trial of cold-exposure on energy expenditure and supraclavicular brown adipose tissue volume in humans
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2016 (English)In: Metabolism: Clinical and Experimental, ISSN 0026-0495, E-ISSN 1532-8600, Vol. 65, no 6, p. 926-934Article in journal (Refereed) Published
Abstract [en]

Objective

To study if repeated cold-exposure increases metabolic rate and/or brown adipose tissue (BAT) volume in humans when compared with avoiding to freeze.

Design

Randomized, open, parallel-group trial.

Methods

Healthy non-selected participants were randomized to achieve cold-exposure 1 hour/day, or to avoid any sense of feeling cold, for 6 weeks. Metabolic rate (MR) was measured by indirect calorimetry before and after acute cold-exposure with cold vests and ingestion of cold water. The BAT volumes in the supraclavicular region were measured with magnetic resonance imaging (MRI).

Results

Twenty-eight participants were recruited, 12 were allocated to controls and 16 to cold-exposure. Two participants in the cold group dropped out and one was excluded. Both the non-stimulated and the cold-stimulated MR were lowered within the group randomized to avoid cold (MR at room temperature from 1841 ± 199 kCal/24 h to 1795 ± 213 kCal/24 h, p = 0.047 cold-activated MR from 1900 ± 150 kCal/24 h to 1793 ± 215 kCal/24 h, p = 0.028). There was a trend towards increased MR at room temperature following the intervention in the cold-group (p = 0.052). The difference between MR changes by the interventions between groups was statistically significant (p = 0.008 at room temperature, p = 0.032 after cold-activation). In an on-treatment analysis after exclusion of two participants that reported ≥ 8 days without cold-exposure, supraclavicular BAT volume had increased in the cold-exposure group (from 0.0175 ± 0.015 l to 0.0216 ± 0.014 l, p = 0.049).

Conclusions

We found evidence for plasticity in metabolic rate by avoiding to freeze compared with cold-exposure in a randomized setting in non-selected humans.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Brown adipose tissue; Cold exposure; Magnetic resonance imaging; Metabolic rate
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:liu:diva-128200 (URN)10.1016/j.metabol.2016.03.012 (DOI)000376145100013 ()27173471 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation
Note

Funding agencies: Linkoping University; County Council of Ostergotland (LUA-ALF), Sweden; Swedish Research Council [2013-4466, 2012-1652, 2014-2516]; Knut and Alice Wallenberg Foundation; Sahlgrenskas University Hospital (LUA-ALF); European Union grant (DIABAT) [HEALTH-F2-

Available from: 2016-05-22 Created: 2016-05-22 Last updated: 2019-06-14
Tesselaar, E., Dahlström, N. & Sandborg, M. (2016). CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS. Radiation Protection Dosimetry, 169(1-4), 340-346
Open this publication in new window or tab >>CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS
2016 (English)In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, no 1-4, p. 340-346Article in journal (Refereed) Published
Abstract [en]

The aim of this work was to assess whether an audit of clinical image quality could be efficiently implemented within a limited time frame using visual grading characteristics (VGC) analysis. Lumbar spine radiography, bedside chest radiography and abdominal CT were selected. For each examination, images were acquired or reconstructed in two ways. Twenty images per examination were assessed by 40 radiology residents using visual grading of image criteria. The results were analysed using VGC. Inter-observer reliability was assessed. The results of the visual grading analysis were consistent with expected outcomes. The inter-observer reliability was moderate to good and correlated with perceived image quality (r2 5 0.47). The median observation time per image or image series was within 2 min. These results suggest that the use of visual grading of image criteria to assess the quality of radiographs provides a rapid method for performing an image quality audit in a clinical environment.

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-123019 (URN)10.1093/rpd/ncv411 (DOI)000383492100054 ()26410763 (PubMedID)
Available from: 2015-12-02 Created: 2015-12-02 Last updated: 2017-05-03
Wang, C., Dahlström, N., Fransson, S. G., Lundström, C. & Smedby, Ö. (2015). Real-Time Interactive 3D Tumor Segmentation Using a Fast Level-Set Algorithm. Journal of Medical Imaging and Health Informatics, 5(8), 1998-2002
Open this publication in new window or tab >>Real-Time Interactive 3D Tumor Segmentation Using a Fast Level-Set Algorithm
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2015 (English)In: Journal of Medical Imaging and Health Informatics, ISSN 2156-7018, E-ISSN 2156-7026, Vol. 5, no 8, p. 1998-2002Article in journal (Refereed) Published
Abstract [en]

A new level-set based interactive segmentation framework is introduced, where the algorithm learns the intensity distributions of the tumor and surrounding tissue from a line segment drawn by the user from the middle of the lesion towards the border. This information is used to design a likelihood function, which is then incorporated into the level-set framework as an external speed function guiding the segmentation. The endpoint of the input line segment sets a limit to the propagation of 3D region, i.e., when the zero-level-set crosses this point, the propagation is forced to stop. Finally, a fast level set algorithm with coherent propagation is used to solve the level set equation in real time. This allows the user to instantly see the 3D result while adjusting the position of the line segment to tune the parameters implicitly. The "fluctuating" character of the coherent propagation also enables the contour to coherently follow the mouse cursors motion when the user tries to fine-tune the position of the contour on the boundary, where the learned likelihood function may not necessarily change much. Preliminary results suggest that radiologists can easily learn how to use the proposed segmentation tool and perform relatively accurate segmentation with much less time than the conventional slice-by-slice based manual procedure.

Place, publisher, year, edition, pages
AMER SCIENTIFIC PUBLISHERS, 2015
Keywords
Interactive Image Segmentation; Level Set; Coherent Propagation; Tumor Segmentation
National Category
Computer Vision and Robotics (Autonomous Systems)
Identifiers
urn:nbn:se:liu:diva-125166 (URN)10.1166/jmihi.2015.1685 (DOI)000368564700072 ()
Available from: 2016-02-15 Created: 2016-02-15 Last updated: 2018-01-10
Norén, B., Dahlström, N., Forsgren, M., Dahlqvist Leinhard, O., Kechagias, S., Almer, S., . . . Lundberg, P. (2015). Visual assessment of biliary excretion of Gd-EOB-DTPA in patients with suspected diffuse liver disease – a biopsy-controlled prospective study. European Journal of Radiology Open, 2, 19-25
Open this publication in new window or tab >>Visual assessment of biliary excretion of Gd-EOB-DTPA in patients with suspected diffuse liver disease – a biopsy-controlled prospective study
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2015 (English)In: European Journal of Radiology Open, ISSN 2352-0477, Vol. 2, p. 19-25Article in journal (Refereed) Published
Abstract [en]

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 any 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 1.5-T MRI. The visually assessed presence (1) or absence (0) of contrast agent for each of five anatomical regions in randomly reviewed time-series was summarised on a four grade scale. The scores, including a total visual score, were related to the histo-pathological findings, the quantitative contrast agent uptake parameters and blood tests

Results: No relationship between the fibrosis grade or contrast uptake parameters expressed as KHep or LSC_N could be established. A negative correlation between the visual assessment and ALP was found. Comparing a sub-group of cholestatic patients with fibrosis score and Gd-EOB-DTPAdynamic parameters did not add any additional significant correlation.

Conclusions: In this prospective study with a limited number of patients we were not able to demonstrate a correlation between visually assessed biliary excretion of Gd-EOB-DTPA and  histo-pathological or contrast uptake parameters.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Gd-EOB-­DTPA, Dynamic contrast enhanced MRI, Liver, Bile, Excretion
National Category
Radiology, Nuclear Medicine and Medical Imaging Physical Chemistry
Identifiers
urn:nbn:se:liu:diva-90159 (URN)10.1016/j.ejro.2014.12.004 (DOI)
Projects
NILB
Available from: 2013-03-20 Created: 2013-03-20 Last updated: 2019-06-14Bibliographically approved
Forsgren, M., Dahlqvist Leinhard, O., Dahlström, N., Cedersund, G. & Lundberg, P. (2014). Physiologically Realistic and Validated Mathematical Liver Model Revels Hepatobiliary Transfer Rates for Gd-EOB-DTPA Using Human DCE-MRI Data. PLoS ONE, 9(4), 0095700
Open this publication in new window or tab >>Physiologically Realistic and Validated Mathematical Liver Model Revels Hepatobiliary Transfer Rates for Gd-EOB-DTPA Using Human DCE-MRI Data
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2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 4, p. 0095700-Article in journal (Refereed) Published
Abstract [en]

Objectives: Diffuse liver disease (DLD), such as non-alcoholic fatty liver disease (NASH) and cirrhosis, is a rapidly growing problem throughout the Westernized world. Magnetic resonance imaging (MRI), based on uptake of the hepatocyte-specific contrast agent (CA) Gd-EOB-DTPA, is a promising non-invasive approach for diagnosing DLD. However, to fully utilize the potential of such dynamic measurements for clinical or research purposes, more advanced methods for data analysis are required. Methods: A mathematical model that can be used for such data-analysis was developed. Data was obtained from healthy human subjects using a clinical protocol with high spatial resolution. The model is based on ordinary differential equations and goes beyond local diffusion modeling, taking into account the complete system accessible to the CA. Results: The presented model can describe the data accurately, which was confirmed using chi-square statistics. Furthermore, the model is minimal and identifiable, meaning that all parameters were determined with small degree of uncertainty. The model was also validated using independent data. Conclusions: We have developed a novel approach for determining previously undescribed physiological hepatic parameters in humans, associated with CA transport across the liver. The method has a potential for assessing regional liver function in clinical examinations of patients that are suffering of DLD and compromised hepatic function.

Place, publisher, year, edition, pages
Public Library of Science, 2014
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-106962 (URN)10.1371/journal.pone.0095700 (DOI)000335226500139 ()
Available from: 2014-06-04 Created: 2014-06-02 Last updated: 2019-06-14
Forsgren, M., Dahlström, N., Karlsson, M., Dahlqvist Leinhard, O., Smedby, Ö., Cedersund, G. & Lundberg, P. (2014). Whole Body Mechanistic Minimal Model for Gd-EOB-DTPA Contrast Agent Pharmacokinetics in Evaluation of Diffuse Liver Disease. In: : . Paper presented at Society of Abdominal Radiology (SAR) 2014 Boca Raton, Florida, USA.
Open this publication in new window or tab >>Whole Body Mechanistic Minimal Model for Gd-EOB-DTPA Contrast Agent Pharmacokinetics in Evaluation of Diffuse Liver Disease
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2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Purpose: Aiming for non-invasive diagnostic tools to decrease the need for biopsy in diffuse liver disease and to quantitatively describe liver function, we applied a mechanistic pharmacokinetic modelling analysis of liver MRI with Gd-EOB-DTPA. This modelling method yields physiologically relevant parameters and was compared to previously developed methods in a patient group with diffuse liver disease. Materials and Methods: Using data from healthy volunteers undergoing liver MRI, an identifiable mechanistic model was developed, based on compartments described by ordinary differential equations and kinetic expressions, and validated with independent data including Gd-EOB-DTPA concentration measurements in blood samples. Patients (n=37) with diffuse liver disease underwent liver biopsy and MRI with Gd-EOB-DTPA. The model was used to derive pharmacokinetic parameters which were then compared with other quantitative estimates in their ability to separate mild from severe liver fibrosis. Results: The estimations produced by the mechanistic model allowed better separation between mild and severe fibrosis than previously described methods for quantifying hepatic Gd-EOB-DTPA uptake. Conclusions: With a mechanistic pharmacokinetic modelling approach, the estimation of liver uptake function and its diagnostic information can be improved compared to current methods.

National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114363 (URN)
Conference
Society of Abdominal Radiology (SAR) 2014 Boca Raton, Florida, USA
Available from: 2015-02-19 Created: 2015-02-19 Last updated: 2019-06-14
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4111-1693

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