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Sökning: WFRF:(Åström Karl) > Medicin och hälsovetenskap

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1.
  • Ede, Jacob, et al. (författare)
  • Retrograde cerebral perfusion reduces embolic and watershed lesions after acute type a aortic dissection repair with deep hypothermic circulatory arrest
  • 2024
  • Ingår i: Journal of Cardiothoracic Surgery. - : BioMed Central (BMC). - 1749-8090. ; 19:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: To assess whether retrograde cerebral perfusion reduces neurological injury and mortality in patients undergoing surgery for acute type A aortic dissection.Methods: Single-center, retrospective, observational study including all patients undergoing acute type A aortic dissection repair with deep hypothermic circulatory arrest between January 1998 and December 2022 with or without the adjunct of retrograde cerebral perfusion. 515 patients were included: 257 patients with hypothermic circulatory arrest only and 258 patients with hypothermic circulatory arrest and retrograde cerebral perfusion. The primary endpoints were clinical neurological injury, embolic lesions, and watershed lesions. Multivariable logistic regression was performed to identify independent predictors of the primary outcomes. Survival analysis was performed using Kaplan-Meier estimates.Results: Clinical neurological injury and embolic lesions were less frequent in patients with retrograde cerebral perfusion (20.2% vs. 28.4%, p = 0.041 and 13.7% vs. 23.4%, p = 0.010, respectively), but there was no significant difference in the occurrence of watershed lesions (3.0% vs. 6.1%, p = 0.156). However, after multivariable logistic regression, retrograde cerebral perfusion was associated with a significant reduction of clinical neurological injury (OR: 0.60; 95% CI 0.36–0.995, p = 0.049), embolic lesions (OR: 0.55; 95% CI 0.31–0.97, p = 0.041), and watershed lesions (OR: 0.25; 95%CI 0.07–0.80, p = 0.027). There was no significant difference in 30-day mortality (12.8% vs. 11.7%, p = ns) or long-term survival between groups.Conclusion: In this study, we showed that the addition of retrograde cerebral perfusion during hypothermic circulatory arrest in the setting of acute type A aortic dissection repair reduced the risk of clinical neurological injury, embolic lesions, and watershed lesions.
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2.
  • Ericsson, Anders, et al. (författare)
  • Automated interpretation of ventilation-perfusion lung scintigrams for the diagnosis of pulmonary embolism using support vector machines
  • 2003
  • Ingår i: 13th Scandinavian Conference, SCIA 2003 Halmstad, Sweden, June 29 – July 2, 2003 Proceedings/Lecture Notes in Computer Science. - 0302-9743 .- 1611-3349. - 9783540406013 ; 2749, s. 415-421
  • Konferensbidrag (refereegranskat)abstract
    • The purpose of this study was to develop a new completely automated method for the interpretation of ventilation-perfusion (V-P) lung scintigrams for the diagnosis of pulmonary embolism. A new way of extracting features, characteristic for pulmonary embolism is presented. These features are then used as input to a Support Vector Machine, which discriminates between pulmonary embolism or no embolism. Using a material of 509 training cases and 104 test cases, the performance of the system, measured as the area under the ROC curve, was 0.86 in the test group. It is concluded that a completely automatic method can be used for interpretation of V-P scintigrams. It is faster and more robust than a previously presented method [4,5] and the accuracy is at the same level as the the previous method. It also handles abnormalities in the lungs.
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3.
  • Li, Zhen, et al. (författare)
  • Cellular traction forces : a useful parameter in cancer research
  • 2017
  • Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 9:48, s. 19039-19044
  • Tidskriftsartikel (refereegranskat)abstract
    • The search for new cancer biomarkers is essential for fundamental research, diagnostics, as well as for patient treatment and monitoring. Whereas most cancer biomarkers are biomolecules, an increasing number of studies show that mechanical cues are promising biomarker candidates. Although cell deformability has been shown to be a possible cancer biomarker, cellular forces as cancer biomarkers have been left largely unexplored. Here, we measure traction forces of cancer and normal-like cells at high spatial resolution using a robust method based on dense vertical arrays of nanowires. A force map is created using automated image analysis based on the localization of the fluorescent tips of the nanowires. We show that the force distribution and magnitude differ between MCF7 breast cancer cells and MCF10A normal-like breast epithelial cells, and that monitoring traction forces can be used to investigate the effects of anticancer drugs.
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4.
  • Peréz Barrionuevo, Antonio Manuel, et al. (författare)
  • Periodontal health status and lung function in two Norwegian cohorts
  • 2018
  • Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Rationale and objectives: The oral cavity is united with the airways, and thus poor oral health may affect respiratory health. However, data on the interaction of periodontal and respiratory health is limited. We aimed to evaluate whether periodontal health status, assessed by the Community Periodontal Index (CPI), was related to lung function among young and middle-aged adults in two Norwegian cohorts.Methods: Periodontal health status and lung function were measured among 656 participants in the Norwegian part of the European Community Respiratory Health Survey (ECHRS III) and the RHINESSA offspring study. Each participant was given a CPI-index from 0 to 4 where higher values reflect poorer periodontal status. The association between CPI and lung function was estimated with linear regression adjusting for age, gender, smoking, body mass index, exercise, education, use of antibiotics, inhaled medication and corrected for clustering within families.Main results: Participants with CPI 3 +/- 4 had significantly lower FEV1/FVC ratio compared to participants with CPI 0, b (95% CI) = -0.032 (-0.055, -0.009). Poorer periodontal health was associated with a significant decrease in the FEV1/FVC ratio with an adjusted regression coefficient for linear trend b (95% CI) = -0.009 (-0.015, -0.004) per unit increase in CPI. This negative association remained when excluding asthmatics and smokers (-0.014 (-0.022, -0.006)).Conclusions: Poorer periodontal health was associated with increasing airways obstruction in a relatively young, healthy population. The oral cavity is united with the airways and our findings indicate an opportunity to influence respiratory health by improving oral health.
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5.
  • Richter, J, et al. (författare)
  • Automated interpretation of cardiac scintigrams
  • 2003
  • Ingår i: Lecture Notes in Computer Science (Image Analysis, Proceedings). - 0302-9743 .- 1611-3349. - 9783540406013 ; 2749, s. 565-570
  • Konferensbidrag (refereegranskat)abstract
    • The purpose of this study was to develop an automated method for the segmentation of the heart in a 3-D cardiac scintigram. This is immediately useful for eliminating a manual step in a previous version of a decision support system. The automatic segmentation method uses a statistical 3D-model, inspired by Active Shape, which locates the base and apex automatically from a cardiac scintigram. Key features of this algorithm are that it can handle cases where there is no or very little activity in the apex and also if there axe additional parts of the heart where there is little activity. The algorithm has been tested on approximately 2000 cardiac scintigrams.
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6.
  • Åström, Lennart, et al. (författare)
  • Long-term outcome of high dose rate brachytherapy in radiotherapy of localised prostate cancer
  • 2005
  • Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 74:2, s. 157-161
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and purpose: High dose rate brachytherapy (HDR-BT) in prostate cancer (PC) is receiving increasing interest. The steep dose gradient gives a possibility to escalate the dose to the prostate. If the a/b ratio is low for PC, hypofractionation will be of advantage. A retrospective analysis of outcome in patients (pts) consecutively treated with combined HDR-BT and conformal external beam radiotherapy (ERT) was performed. Material and methods: Data from 214 pts treated consecutively from 1988 to 2000 were analysed. The median age was 64 years (50–77). Median follow up was 4 years (12–165 months). Pre-irradiatory endocrine therapy was given to 150 pts (70%). The pts were divided into low-, intermediate- and high (80/87/47 pts) risk groups according to the occurrence of none, one, or more risk factors defined by T-classification, PSA and histopathology. ERT was given with 2 Gy fractions to 50 Gy. HDR-BT consisted of two 10 Gy fractions. Results: Overall 5-year biochemical no evidence of disease (bNED) was 82%, and for the low-, intermediate-, and high-risk group bNED was 92, 88 and 61%, respectively. PSA-relapse was found in 17, local recurrence in 3 and distant metastases in 13 pts. Five pts died of PC. No recurrences were observed after 5 years. Severe late complications were few. Urethral stricture (13 pts) was the most frequent. No severe rectal complications were seen. Conclusion: Dose escalation with HDR-BT is safe and effective in radiotherapy of localised PC.
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7.
  • Holst, Holger, et al. (författare)
  • An independent evaluation of a new method for automated interpretation of lung scintigrams using artificial neural networks
  • 2001
  • Ingår i: European Journal Of Nuclear Medicine. - : Springer Science and Business Media LLC. - 0340-6997 .- 1619-7089. ; 28:1, s. 33-38
  • Tidskriftsartikel (refereegranskat)abstract
    • The purpose of this study was to evaluate a new automated method for the interpretation of lung perfusion scintigrams using patients from a hospital other than that where the method was developed, and then to compare the performance of the technique against that of experienced physicians. A total of 1,087 scintigrams from patients with suspected pulmonary embolism comprised the training group. The test group consisted of scintigrams from 140 patients collected in a hospital different to that from which the training group had been drawn. An artificial neural network was trained using 18 automatically obtained features from each set of perfusion scintigrams. The image processing techniques included alignment to templates, construction of quotient images based on the perfusion/template images, and finally calculation of features describing segmental perfusion defects in the quotient images. The templates represented lungs of normal size and shape without any pathological changes. The performance of the neural network was compared with that of three experienced physicians who read the same test scintigrams according to the modified PIOPED criteria using, in addition to perfusion images, ventilation images when available and chest radiographs for all patients. Performances were measured as area under the receiver operating characteristic curve. The performance of the neural network evaluated in the test group was 0.88 (95% confidence limits 0.81–0.94). The performance of the three experienced experts was in the range 0.87–0.93 when using the perfusion images, chest radiographs and ventilation images when available. Perfusion scintigrams can be interpreted regarding the diagnosis of pulmonary embolism by the use of an automated method also in a hospital other than that where it was developed. The performance of this method is similar to that of experienced physicians even though the physicians, in addition to perfusion images, also had access to ventilation images for most patients and chest radiographs for all patients. These results show the high potential for the method as a clinical decision support system.
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8.
  • Arvidsson, Ida, et al. (författare)
  • Comparing a pre-defined versus deep learning approach for extracting brain atrophy patterns to predict cognitive decline due to Alzheimer’s disease in patients with mild cognitive symptoms
  • 2024
  • Ingår i: Alzheimer's Research and Therapy. - 1758-9193. ; 16:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Predicting future Alzheimer’s disease (AD)-related cognitive decline among individuals with subjective cognitive decline (SCD) or mild cognitive impairment (MCI) is an important task for healthcare. Structural brain imaging as measured by magnetic resonance imaging (MRI) could potentially contribute when making such predictions. It is unclear if the predictive performance of MRI can be improved using entire brain images in deep learning (DL) models compared to using pre-defined brain regions. Methods: A cohort of 332 individuals with SCD/MCI were included from the Swedish BioFINDER-1 study. The goal was to predict longitudinal SCD/MCI-to-AD dementia progression and change in Mini-Mental State Examination (MMSE) over four years. Four models were evaluated using different predictors: (1) clinical data only, including demographics, cognitive tests and APOE ε4 status, (2) clinical data plus hippocampal volume, (3) clinical data plus all regional MRI gray matter volumes (N = 68) extracted using FreeSurfer software, (4) a DL model trained using multi-task learning with MRI images, Jacobian determinant images and baseline cognition as input. A double cross-validation scheme, with five test folds and for each of those ten validation folds, was used. External evaluation was performed on part of the ADNI dataset, including 108 patients. Mann-Whitney U-test was used to determine statistically significant differences in performance, with p-values less than 0.05 considered significant. Results: In the BioFINDER cohort, 109 patients (33%) progressed to AD dementia. The performance of the clinical data model for prediction of progression to AD dementia was area under the curve (AUC) = 0.85 and four-year cognitive decline was R2 = 0.14. The performance was improved for both outcomes when adding hippocampal volume (AUC = 0.86, R2 = 0.16). Adding FreeSurfer brain regions improved prediction of four-year cognitive decline but not progression to AD (AUC = 0.83, R2 = 0.17), while the DL model worsened the performance for both outcomes (AUC = 0.84, R2 = 0.08). A sensitivity analysis showed that the Jacobian determinant image was more informative than the MRI image, but that performance was maximized when both were included. In the external evaluation cohort from ADNI, 23 patients (21%) progressed to AD dementia. The results for predicted progression to AD dementia were similar to the results for the BioFINDER test data, while the performance for the cognitive decline was deteriorated. Conclusions: The DL model did not significantly improve the prediction of clinical disease progression in AD, compared to regression models with a single pre-defined brain region.
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9.
  • Evander, Eva, et al. (författare)
  • Role of ventilation scintigraphy in diagnosis of acute pulmonary embolism: an evaluation using artificial neural networks.
  • 2003
  • Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 30:7, s. 961-965
  • Tidskriftsartikel (refereegranskat)abstract
    • The purpose of this study was to assess the value of the ventilation study in the diagnosis of acute pulmonary embolism using a new automated method. Either perfusion scintigrams alone or two different combinations of ventilation/perfusion scintigrams were used as the only source of information regarding pulmonary embolism. A completely automated method based on computerised image processing and artificial neural networks was used for the interpretation. Three artificial neural networks were trained for the diagnosis of pulmonary embolism. Each network was trained with 18 automatically obtained features. Three different sets of features originating from three sets of scintigrams were used. One network was trained using features obtained from each set of perfusion scintigrams, including six projections. The second network was trained using features from each set of (joint) ventilation and perfusion studies in six projections. A third network was trained using features from the perfusion study in six projections combined with a single ventilation image from the posterior view. A total of 1,087 scintigrams from patients with suspected pulmonary embolism were used for network training. The test group consisted of 102 patients who had undergone both scintigraphy and pulmonary angiography. Performances in the test group were measured as area under the receiver operation characteristic curve. The performance of the neural network in interpreting perfusion scintigrams alone was 0.79 (95% confidence limits 0.71–0.86). When one ventilation image (posterior view) was added to the perfusion study, the performance was 0.84 (0.77–0.90). This increase was statistically significant (P=0.022). The performance increased to 0.87 (0.81–0.93) when all perfusion and ventilation images were used, and the increase in performance from 0.79 to 0.87 was also statistically significant (P=0.016). The automated method presented here for the interpretation of lung scintigrams shows a significant increase in performance when one or all ventilation images are added to the six perfusion images. Thus, the ventilation study has a significant role in the diagnosis of acute lung embolism.
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10.
  • Henriksson, Karin, et al. (författare)
  • A pilot study of facial, cranial and brain MRI morphometry in men with schizophrenia: Part 2.
  • 2006
  • Ingår i: Psychiatry Research. - : Elsevier BV. - 1872-7123 .- 0925-4927 .- 0165-1781. ; 147:2-3, s. 187-195
  • Tidskriftsartikel (refereegranskat)abstract
    • This pilot study applies a new 3D morphometric MR method to test the hypothesis that men with schizophrenia (vs. controls) have deviant facial shapes and landmark relations in cranio/facialibrain (CFB) regions. This constitutes Part 2 of paired articles in this issue of Psychiatry Research: Neuroimaging, in which Part 1 presents the new method in detail. MRI coordinates from CFB landmarks of 23 patients and 15 controls were identified and then aligned with the Procrustes model, leaving shape as the only unitless geometrical information. Men with schizophrenia had significantly longer mid- and lower-facial heights, and greater lower (left) facial depth, with a tendency toward rotation along the facial midline. This supports findings from earlier anthropometric and 3D studies of the "exterior" (face). In contrast, none of the patient-control differences for the new "interior" (cranial-brain) distances reached statistical significance. These results need to be retested on a larger sample of both sexes. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
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