| 1. |
- Cros, Olivier, et al.
(författare)
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Mastoid structural properties determined by imaging analysis of high resolution CT-scanning
- 2010
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Ingår i: Hearing Research. - : Elsevier. - 0378-5955 .- 1878-5891. ; 263:1-2, s. 242-243
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Tidskriftsartikel (refereegranskat)abstract
- Hypothesis: The structure of the mastoid air cells can be described by quantitative imaging analysis of high-resolution CT-scans, which may contribute to understand its function in normal and pathological ears. Background: Negative middle ear pressure is a common factor in middle ear diseases resulting from an imbalance between mastoid gas exchange and Eustachian tube function. While the Eustachian tube function has been the main focus of research, more recent studies indicate that the mastoid may play an active role in pressure regulation. The mastoid structure with numerous air cells reflects a large area to volume ratio (AV-ratio) adapted to efficient gas exchange. Imaging analysis applied to high resolution CT-scanning can describe quantitative measures, which may reveal important information about mastoid function and its role in healthy and diseased ears. Materials and methods: Quantitative analysis was performed on a series of unselected high resolution CT-scans (voxel size: 0.29 _ 0.29 _ 0.625 mm) from 36 ears in 24 patients. Area and volume were determined using Cavalieri’s method, i.e. by summing cross-sectional areas. The AV-ratio was computed for each scan. Results: Mean area was 69 cm2 (range: 23–134cm2), mean volume was 4 cm3 (range: 1.3–10.8 cm3), and mean AV-ratio was 16 cm-1 (range: 11.2–21.0 cm-1). The area correlated linearly to the volume by A = 17.2*V-0.2. Conclusion: The area and volume values corresponded with previous studies, and the additional AV-ratio reflected the functional properties of the mastoid in terms of capability for gas exchange. Due to a series of similarities between structure and function of the lungs and mastoid, it seems likely to propose a tree-structure of dividing mastoid cells. In respiratory research, analysis describing the dimensions of series of bronchi generations has been applied, and based on current results; our aim of future research is to establish similar details of mastoid tree-structure. Funding source: Various private Danish funds.
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| 2. |
- Läthén, Gunnar, et al.
(författare)
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Blood vessel segmentation using multi-scale quadrature filtering
- 2010
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Ingår i: Pattern Recognition Letters. - : Elsevier. - 0167-8655 .- 1872-7344. ; 31:8, s. 762-767
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Tidskriftsartikel (refereegranskat)abstract
- The segmentation of blood vessels is a common problem in medical imagingand various applications are found in diagnostics, surgical planning, trainingand more. Among many dierent techniques, the use of multiple scales andline detectors is a popular approach. However, the typical line lters usedare sensitive to intensity variations and do not target the detection of vesselwalls explicitly. In this article, we combine both line and edge detection usingquadrature lters across multiple scales. The lter result gives well denedvessels as linear structures, while distinct edges facilitate a robust segmentation.We apply the lter output to energy optimization techniques for segmentationand show promising results in 2D and 3D to illustrate the behavior of ourmethod. The conference version of this article received the best paper award inthe bioinformatics and biomedical applications track at ICPR 2008.
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| 3. |
- Läthén, Gunnar, et al.
(författare)
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Non-ring Filters for Robust Detection of Linear Structures
- 2010
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Ingår i: Proceedings of the 20th International Conference on Pattern Recognition. - Los Alamitos, CA, USA : IEEE Computer Society. - 9781424475421 ; , s. 233-236
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Konferensbidrag (refereegranskat)abstract
- Many applications in image analysis include the problem of linear structure detection, e.g. segmentation of blood vessels in medical images, roads in satellite images, etc. A simple and efficient solution is to apply linear filters tuned to the structures of interest and extract line and edge positions from the filter output. However, if the filter is not carefully designed, artifacts such as ringing can distort the results and hinder a robust detection. In this paper, we study the ringing effects using a common Gabor filter for linear structure detection, and suggest a method for generating non-ring filters in 2D and 3D. The benefits of the non-ring design are motivated by results on both synthetic and natural images.
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| 4. |
- Åstrand, Olov, et al.
(författare)
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Weight gain by hyperalimentation elevates C-reactive protein levels but does not affect circulating levels of adiponectin or resistin in healthy subjects
- 2010
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Ingår i: European Journal of Endocrinology. - Bristol : BioScientifica. - 0804-4643 .- 1479-683X. ; 163:6, s. 879-885
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Increase of resistin and/or reduction of adiponectin have beenimplicated in the development of insulin resistance followingweight gain. We aimed to study this prospectively in humans.Design: Prospective and interventional with parallel control group.Methods: Twelve healthy men and six healthy women (age 26±6.6years) and an age-matched control group were recruited. Subjectsin the intervention group aimed for a bodyweight increase of5–15% by doubling the baseline caloric intake by eatingat least two fast food-based meals a day in combination withadoption of a sedentary lifestyle for 4 weeks.Results: Bodyweight increased from 67.6±9.1 to 74.0±11kg, P<0.001, by the intervention. Insulin levels increased(before: 27.4±12 pmol/l, after: 53.0±22 pmol/l,P=0.004), while plasma levels of adiponectin (before: 5038±3736ng/ml, after: 6739±7949 ng/ml, P=0.18) and resistin (before:21.8±19 ng/ml, after: 14.4±6.8 ng/ml, P=0.074)remained unchanged by the weight gain and were similar as incontrols. On the other hand, leptin levels increased about threefoldfollowing the intervention (before: 5.7±7.4, after: 16±20ng/ml, P=0.008), and also the inflammatory marker C-reactiveprotein (CRP) increased from 0.34±0.44 to 0.71±0.87mg/l, P=0.03, when two outliers >10 mg/l were disregarded.Conclusions: Hyperalimentation reduces insulin sensitivity when weight gainof 9% was combined with reduction of exercise. However, thelevels of resistin and adiponectin were unaffected by the intervention,while CRP levels increased within this short time period suggestingthat low-grade inflammation can occur early in the process ofdeveloping a metabolic syndrome.
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