Publikationer från Linköpings universitet
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PlaqueViT: a vision transformer model for fully automatic vessel and plaque segmentation in coronary computed tomography angiography
No full textObjectivesTo develop and evaluate a deep learning model for segmentation of the coronary artery vessels and coronary plaques in coronary computed tomography angiography (CCTA).Materials and methodsCCTA image data from the Swedish CardioPulmonary BioImage Study (SCAPIS) was used for model development (n = 463 subjects) and testing (n = 123) and for an interobserver study (n = 65). A dataset from Link & ouml;ping University Hospital (n = 28) was used for external validation. The model's ability to detect coronary artery disease (CAD) was tested in a separate SCAPIS dataset (n = 684). A deep ensemble (k = 6) of a customized 3D vision transformer model was used for voxelwise classification. The Dice coefficient, the average surface distance, Pearson's correlation coefficient, analysis of segmented volumes by intraclass correlation coefficient (ICC), and agreement (sensitivity and specificity) were used to analyze model performance.ResultsPlaqueViT segmented coronary plaques with a Dice coefficient = 0.55, an average surface distance = 0.98 mm and ICC = 0.93 versus an expert reader. In the interobserver study, PlaqueViT performed as well as the expert reader (Dice coefficient = 0.51 and 0.50, average surface distance = 1.31 and 1.15 mm, ICC = 0.97 and 0.98, respectively). PlaqueViT achieved 88% agreement (sensitivity 97%, specificity 76%) in detecting any coronary plaque in the test dataset (n = 123) and 89% agreement (sensitivity 95%, specificity 83%) in the CAD detection dataset (n = 684).ConclusionWe developed a deep learning model for fully automatic plaque detection and segmentation that identifies and delineates coronary plaques and the arterial lumen with similar performance as an experienced reader.Key PointsQuestionA tool for fully automatic and voxelwise segmentation of coronary plaques in coronary CTA (CCTA) is important for both clinical and research usage of the CCTA examination.FindingsSegmentation of coronary artery plaques by PlaqueViT was comparable to an expert reader's performance.Clinical relevanceThis novel, fully automatic deep learning model for voxelwise segmentation of coronary plaques in CCTA is highly relevant for large population studies such as the Swedish CardioPulmonary BioImage Study.Key PointsQuestionA tool for fully automatic and voxelwise segmentation of coronary plaques in coronary CTA (CCTA) is important for both clinical and research usage of the CCTA examination.FindingsSegmentation of coronary artery plaques by PlaqueViT was comparable to an expert reader's performance.Clinical relevanceThis novel, fully automatic deep learning model for voxelwise segmentation of coronary plaques in CCTA is highly relevant for large population studies such as the Swedish CardioPulmonary BioImage Study.Key PointsQuestionA tool for fully automatic and voxelwise segmentation of coronary plaques in coronary CTA (CCTA) is important for both clinical and research usage of the CCTA examination.FindingsSegmentation of coronary artery plaques by PlaqueViT was comparable to an expert reader's performance.Clinical relevanceThis novel, fully automatic deep learning model for voxelwise segmentation of coronary plaques in CCTA is highly relevant for large population studies such as the Swedish CardioPulmonary BioImage Study.Funding Agencies|VINNOVA; Medis Medical Imaging for software development</p
Conformal chemical vapor deposition of B4C thin films onto carbon nanotubes
No full textThe unique attributes of carbon nanotubes (CNTs) establish them as the preferred material for fabricating sophisticated membrane architectures. However, CNT membranes are also susceptible to degradation under harsh environmental conditions, necessitating protective measures to maintain their functionalities. This study presents deposition of boron carbide (B4C) thin films as protective coatings on CNT membranes using chemical vapor deposition. Electron microscopy shows that B4C films were uniformly deposited on the CNTs. Raman spectroscopy shows the preservation of the G and D bands, with a notable stability in the RBM bands, while XPS measurements show sp2 hybridized C-C bonds and an additional shoulder characteristic of the deposited B4C film. This suggests that the CVD process does not degrade the CNTs, but merely adds a layer of B4C to their outer surface. This deposition process also allows for precise control over the membrane's pore size, offering the potential to fine-tune the properties of CNT membranes.Funding Agencies|Swedish Research Council (VR) [2018-05499]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoeping University [2009-00971]; Swedish Research Council VR-RFI [2019-00191]; Swedish Foundation for Strategic Research [2021-00171, RIF21-0026]</p
Using CT imaging to identify sarcopenia as a risk factor for severe falls in older adults
No full textBackground: Sarcopenia is a skeletal muscle disease primarily associated with ageing and progressive muscle decline and increases the risk of falls. The purpose of the present study was to investigate risk factors, including sarcopenia, for severe falls compared to non-severe falls. In addition, we wanted to explore possible associations between sarcopenia, bone mineral density (BMD), adipose tissue as well as clinical scores assessing frailty, nutritional status, and fall risk. Methods: This retrospective cohort study included 101 older patients that had experienced a fall incident during in-patient care at a geriatric ward between 2018 and 2020. The fall incidents were categorized into severe or non-severe falls. Clinical data, including risk assessment scores were retrospectively obtained from the participants' medical records. Body composition, including skeletal muscle quantity (SKM), adipose tissues, and BMD were assessed from abdominal CT-scans performed for any reason maximal 6 months before or after the fall. Skeletal muscle index ratio (SMI-ratio) was calculated using SKM cm(2)/height m(2) and divided with previous described cut off values for sarcopenia. An SMI ratio &lt; 100% indicated sarcopenia. Results: The severe fall group showed higher grade of sarcopenia compared to the non-severe fall group (SMI ratio of 71% vs. 83%, p = 0.041) as well as lower, though statistically non-significant, BMI and subcutaneous adipose tissue (SAT) (BMI 22 [20-24] vs. 24 [22-27] kg/m(2), p = 0.108, and SAT 95 +/- 70 cm(2) vs. 141 +/- 94 cm(2), p = 0.124). Overweight was more common in non-severe than severe fall group (43% vs. 14%, p = 0.048). SMI ratio correlated negatively with frailty and positive with BMI and the following body composition measurements: intramuscular-, subcutaneous, and visceral adipose tissue (IMAT, SAT and VAT). No correlation with other clinical risk assessment scores nor spine T-score was found. In the multivariate analysis, higher level of frailty, male sex as well as lower BMI, VAT and SAT remained as risk factors for low SMI ratio. Conclusions: These results underscore the importance of addressing sarcopenia and related risk factors, including malnutrition, in the management and prevention of severe falls in the elderly population. Body composition analyzed in CT-scans could add value in this risk assessment. This analysis could be conducted opportunistically during CT scans performed for other purposes.Funding Agencies|Linkping University</p
Super-resolution mapping of anisotropic tissue structure with diffusion MRI and deep learning
No full textDiffusion magnetic resonance imaging (diffusion MRI) is widely employed to probe the diffusive motion of water molecules within the tissue. Numerous diseases and processes affecting the central nervous system can be detected and monitored via diffusion MRI thanks to its sensitivity to microstructural alterations in tissue. The latter has prompted interest in quantitative mapping of the microstructural parameters, such as the fiber orientation distribution function (fODF), which is instrumental for noninvasively mapping the underlying axonal fiber tracts in white matter through a procedure known as tractography. However, such applications demand repeated acquisitions of MRI volumes with varied experimental parameters demanding long acquisition times and/or limited spatial resolution. In this work, we present a deep-learning-based approach for increasing the spatial resolution of diffusion MRI data in the form of fODFs obtained through constrained spherical deconvolution. The proposed approach is evaluated on high quality data from the Human Connectome Project, and is shown to generate upsampled results with a greater correspondence to ground truth high-resolution data than can be achieved with ordinary spline interpolation methods. Furthermore, we employ a measure based on the earth mover’s distance to assess the accuracy of the upsampled fODFs. At low signal-to-noise ratios, our super-resolution method provides more accurate estimates of the fODF compared to data collected with 8 times smaller voxel volume.Funding Agencies|Linkping University [2021-01954]; ITEA/VINNOVA project ASSIST (Automation)</p
Exploring the need for a clinical decision support system for deprescribing - A qualitative interview study
No full textBackground: Deprescribing (i.e., the process of discontinuing an inappropriate medication) requires time, knowledge, and care, but there is a lack of education, support, and guidelines for this important clinical task. A clinical decision support system (CDSS) aims to influence the quality of care by combining structured medical knowledge with patient-specific information to generate recommendations. Objective: The objective was to examine the need to develop a CDSS for drug deprescribing. Furthermore, this study aimed to examine the obstacles to deprescribing and potential users' requirements for a CDSS for deprescribing. Methods: The qualitative design consisted of semistructured interviews with physicians (n = 10) in Sweden from different disciplines, including geriatrics, primary care and internal medicine. The interviews were conducted using a predefined guide containing multiple questions about any challenges related to deprescribing and the perceived need for a CDSS. A qualitative content analysis was performed to analyse the empirical data. Results: The interviews provided several aspects of the difficulty of deprescribing medicines. The structure and usability of the CDSS knowledge database in clinical practice needs to be ensured from the outset. Physicians needs fast, simple and up-to-date information filtered, summarized and synthesized from reliable sources. The information should preferably be integrated into pre-existing electronic health record. Conclusion: There is a need to develop a CDSS for deprescribing. There is little, if any, guidelines or support for deprescribing, which is regarded as a large obstacle. The current findings contribute to further knowledge regarding the perspective of physicians when deprescribing medication
The Impact of Pain on Everyday Activities of People With Hypermobility Spectrum Disorders or Hypermobility Ehlers Danlos Syndrome
No full textBackground This study describes aspects of pain and how pain affects everyday life and examines the relation between chronic pain and activity limitations in people with hypermobility spectrum disorders (HSD) or hypermobility Ehlers Danlos syndrome (hEDS). Methods This cross-sectional study used data from 2016 to 2021 obtained from the Swedish quality registry for pain rehabilitation (SQRP), comparing those with HSD/hEDS with the larger group of people with mixed chronic pain conditions as a reference group (RG). Results Of the 43,801 people registered in the SQRP, 1211 (2.8%) were diagnosed with HSD/hEDS (88.9% women). The mean age of the HSD/hEDS group was younger (36.3 +/- 11.8) than the RG (45.7 +/- 12.8). The HSD/hEDS group had a statistically significant (p &lt; 0.001) earlier onset of pain (calculated in years) in contrast to the RG. In the HSD/hEDS group, 80.1% had persistent pain; in the RG, 74.2% had persistent pain. The HSD/hEDS group reported more pain locations (20.0 +/- 7.9) than the RG (14.8 +/- 8.8). The HSD/hEDS group reported more problems performing leisure, social, and household activities than the RG; however, pain intensity was statistically significantly lower (p &lt; 0.001) in the HSD/hEDS related to the RG. Conclusions There were indications that pain affected daily activities for people with HSD/hEDS, who had earlier onset of pain, marked more pain locations, and had more persistent pain, but pain intensity was not as decisive in contrast to the RG. Significance Statement In a comparison yielding statistically significant results (p &lt; 0.001), persons with hypermobility spectrum disorder (HSD) or hypermobility Ehlers-Danlos syndrome (hEDS) reported earlier pain onset, longer pain durations, and a greater number of pain locations but surprisingly, lower pain intensity than the reference group which consisted of a mixed group of pain conditions. These pain characteristics affected daily activities, indicating a substantial impact on daily life for those with HSD/hEDS.Funding Agencies|Southeast Region Healthcare FORSS [FORSS-968964]; Region Kalmar Country</p
Deciphering immune tolerance in allogeneic pig pregnancy
No full textEmbryo transfer (ET) has transformed swine biotechnology, enabling genetic advancements and disease control. However, its success remains inconsistent, partly due to immune-mediated challenges at the maternal-fetal interface. This study explores the immunological environment of hemi-allogeneic pregnancies (via artificial insemination, AI) versus allogeneic pregnancies (via ET) in pigs during the critical implantation phase. Sows were categorized into groups based on pregnancy type and fetal counts, reflecting varying outcomes. Endometrial immune cell populations, including T lymphocytes, regulatory T cells (Tregs), natural killer (NK) cells, and macrophages, were analyzed using immunohistochemistry. Notably, allogeneic pregnancies with poor outcomes displayed elevated NK cell and macrophage infiltration alongside reduced Treg presence, contributing to a proinflammatory environment. In contrast, allogeneic pregnancies with favorable outcomes exhibited immune profiles resembling hemi-allogeneic pregnancies, suggesting enhanced maternal-fetal tolerance. These findings underscore the immunological variability driving embryo survival rates in ET pregnancies and highlight key cellular targets for improving reproductive efficiency. Further research on immunomodulatory strategies is vital to optimize ET success in swine and other species.Funding Agencies|MCIU/AEI/FEDER/UE, Madrid, Spain [PID2022-137645OB-I00]; Swedish Research Council FORMAS [2019-00288]</p
Surfactant-induced hole concentration enhancement for highly efficient perovskite light-emitting diodes
No full textIt is widely acknowledged that constructing small injection barriers for balanced electron and hole injections is essential for light-emitting diodes (LEDs). However, in highly efficient LEDs based on metal halide perovskites, a seemingly large hole injection barrier is usually observed. Here we rationalize this high efficiency through a surfactant-induced effect where the hole concentration at the perovskite surface is enhanced to enable sufficient bimolecular recombination pathways with injected electrons. This effect originates from the additive engineering and is verified by a series of optical and electrical measurements. In addition, surfactant additives that induce an increased hole concentration also significantly improve the luminescence yield, an important parameter for the efficient operation of perovskite LEDs. Our results not only provide rational design rules to fabricate high-efficiency perovskite LEDs but also present new insights to benefit the design of other perovskite optoelectronic devices.Funding Agencies|ERC Consolidator Grant (LEAP) [101045098]; Swedish Energy Agency [P2022-00394]; Olle Engkvists Stiftelse; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Swedish Research Council (VR) [2023- 05247]; ERC synergy grant (FASTCORR project) [854843]; Wallenberg Scholar [KAW-2018.0194]; Knut and Alice Wallenberg Foundation (KAW) [2019.0082]; Marie Curie Fellowship (Horizon-MSCA-2021-PF) within the Horizon Europe [101066960]; Shanghai Pilot Program for Basic Research [22JC1403200]; Deutsche Forschungsgemeinschaft; The 2024 Shanghai Action Plan for Science, Technology and Innovation [KBH2323010]; The 2024 Shanghai Action Plan for Science, Technology and Innovation; Wallenberg Scholar; Wallenberg Scholar; Starting grant at Fudan University [JIH2323047Y]; Linkoping University; Swedish Research Council [2022-06725]</p
Functional brain connectivity in early adolescence after hypothermia-treated neonatal hypoxic-ischemic encephalopathy
No full textBackgroundNeonatal hypoxic-ischemic encephalopathy (HIE) injures the infant brain during the basic formation of the developing functional connectome. This study aimed to investigate long-term changes in the functional connectivity (FC) networks of the adolescent brain following neonatal HIE treated with therapeutic hypothermia (TH). MethodsThis prospective, population-based cohort study included all infants (n = 66) with TH-treated neonatal HIE in Stockholm during 2007-2009 and a control group (n = 43) of children with normal neonatal course. Assessment with resting-state functional magnetic resonance imaging (fMRI) was performed at Karolinska Institutet, Stockholm at age 9-12 years. ResultsfMRI data met quality criteria for 35 children in the HIE-cohort (mean [SD] age at MRI: 11.2 [0.74] years, 46% male) and 30 children in the control group (mean [SD] age at MRI: 10.1 [0.78] years, 53% male). Adverse outcome was present in 40% of children in the HIE-cohort. Non-parametric statistical analysis failed to detect any significant (p &lt; 0.001) alterations of FC networks in the HIE-cohort, nor between children in the HIE-cohort with or without neurological symptoms. ConclusionFindings of persistent alterations in specific functional networks did not remain significant after correction for multiple comparisons in this cohort of adolescent children exposed to TH-treated neonatal HIE. ImpactNeonatal hypoxic-ischemic encephalopathy (HIE) could not be associated with alterations in functional connectivity in this cohort of adolescent children.Findings of aberrant connectivity identified in two functional networks were no longer significant after correction for multiple comparisons.Larger, multi-center studies are needed to understand whether network abnormalities persist long term and are related to outcomes in neonatal HIEFunding Agencies|Stiftelsen Promobilia [F20501]; Stiftlesen Sunnerdahls Handikappfond [F18/20]; Drottning Silvias Jubileumsfond, Lilla Barnets Fond, Jerringfonden, Stiftelsen Kempe-Carlgrenska Fonden, HKH Kronprinsessan Lovisas Foerening foer Barnasjukvard, Norrbacka-Eugeniastiftelsen [866/20]; Neurofonden [F2020-0009]; Region Stockholm; Karolinska Institute</p
Quantification of 3D microstructures in Achilles tendons during in situ loading reveals anisotropic fiber response
No full textWhile the number of studies investigating Achilles tendon pathologies has grown exponentially, more research is needed to gain a better understanding of the complex relation between its hierarchical structure, mechanical response, and failure. At the microscale, collagen fibers are, with some degree of dispersion, primarily aligned along the principal loading direction. However, during tension, rearrangements and reorientations of these fibers are believed to occur. As 3D micro-movements are hard to capture, the precise nature of this fiber reorganization remains unknown. This study aimed to visualize and quantify the intricate fiber changes occurring within rat Achilles tendons under tension. Rat tendons were in situ loaded with concurrent synchrotron phase contrast microCT imaging. The results are heterogenous and show that collagen fibers' response to loading is nonuniform and depends on anatomical orientation. Furthermore, damage propagation could be visualized, revealing that in the presence of heterotopic ossification, damage proceeds within the ossified deposits rather than at the interface between hard and soft tissues. Our approach could effectively capture the microstructural changes occurring during loading and shows promise in understanding the relation between microstructure and mechanical response for ex-vivo Achilles tendons and other biological tissues. Statement of Significance: Achilles tendons endure high mechanical loads during daily motion and physical activities. Understanding the structural and mechanical responses of Achilles tendons to such loads is vital for elucidating their function in health and pathology. We have combined the use of synchrotron phase contrast microCT with in situ mechanical loading to contribute to a better understanding of the relation between microstructural response and organ scale mechanical properties. The proposed methodology will be valuable for future research into the interplay between structure, mechanics, and pathology of tendons, and for the development of more effective strategies to preserve tendon function and possibly mitigating musculoskeletal disorders.Funding Agencies|Knut and Alice Wallenberg Foundation [2017.0221]; Royal Physiographic Society of Lund; European Research Council (ERC) under the European Union [101002516]; Kocks foundation</p