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| 2. |
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| 3. |
- Ahlgren, Jennie, et al.
(författare)
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Consumers on the Internet : ethical and legal aspects of commercialization of personalized nutrition
- 2013
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Ingår i: Genes & Nutrition. - : Springer. - 1555-8932 .- 1865-3499. ; 8:4, s. 349-355
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Forskningsöversikt (refereegranskat)abstract
- Consumers often have a positive attitude to the option of receiving personalized nutrition advice based upon genetic testing, since the prospect of enhancing or maintaining one’s health can be perceived as empowering. Current direct-to-consumer services over the Internet, however, suffer from a questionable level of truthfulness and consumer protection, in addition to an imbalance between far-reaching promises and contrasting disclaimers. Psychological and behavioral studies indicate that consumer acceptance of a new technology is primarily explained by the end user’s rational and emotional interpretation as well as moral beliefs. Results from such studies indicate that personalized nutrition must create true value for the consumer. Also, the freedom to choose is crucial for consumer acceptance. From an ethical point of view, consumer protection is crucial, and caution must be exercised when putting nutrigenomic-based tests and advice services on the market. Current Internet offerings appear to reveal a need to further guaranty legal certainty by ensuring privacy, consumer protection and safety. Personalized nutrition services are on the borderline between nutrition and medicine. Current regulation of this area is incomplete and undergoing development. This situation entails the necessity for carefully assessing and developing existing rules that safeguard fundamental rights and data protection while taking into account the sensitivity of data, the risks posed by each step in their processing, and sufficient guarantees for consumers against potential misuse.
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| 4. |
- Cinthio, Magnus, et al.
(författare)
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A Method for Arterial Diameter Change Measurements Using Ultrasonic B-Mode Data.
- 2010
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Ingår i: Ultrasound in Medicine and Biology. - : Elsevier BV. - 0301-5629. ; 36:9, s. 1504-1512
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Tidskriftsartikel (refereegranskat)abstract
- Arterial diameter change is related to distending blood pressure and is used in estimation of arterial stiffness parameters. A common technique to track the arterial walls is by integration of wall velocities estimated by different methods using cross correlation or tissue Doppler. However, because of the high pulse repetition frequency and the need for separate pulsing sequences, the B-mode image quality is affected. We have previously developed a fast algorithm for direct measurement of lumen diameter using B-mode images. In this study we have improved the technique to be more robust and also implemented measurements of diameter change, maximum differential wall velocity and relative diameter change of the common carotid artery noninvasively in vivo. The influence of the lateral width of the region of interest (ROI; 1 pixel, 0.1 mm, 0.5 mm, 1 mm, 2.5 mm and 5 mm) was evaluated. Using the optimal lateral width (2.5 mm), the systematic and random differences between two consecutive measurements were 21 mum and 105 mum, respectively, for lumen diameter measurement; -7 mum and 39 mum, respectively, for lumen diameter change measurements; -0.2 mm/s and 0.9 mm/s, respectively, for maximum relative wall velocity; and -0.2 % and 0.8 %, respectively, for measurements of the relative diameter change. The coefficient of variation (CV) was 1.9%, 5.2%, 7.9% and 6.0%, respectively. The study indicates that the reproducibility is sufficient for in vivo studies when the width of the ROI is 1.0 mm or wider. (E-mail: magnus.cinthio@elmat.lth.se).
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| 5. |
- Cinthio, Magnus, et al.
(författare)
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An automatic method for measurements of arterial intima-media thickness using ultrasonic B-mode data
- 2012
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Ingår i: Acoustical Imaging. - Dordrecht : Springer Netherlands. - 9789400726185 - 9789400726192 ; 31, s. 115-122
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We have previously developed algorithms that use B-mode cineloops for simultaneous measurements of arterial diameter change and longitudinal movement of the arterial wall. In this study the lumen diameter algorithm was extended to also measure arterial intima-media thickness of the far wall. To optimize the algorithm the influence of the lateral width of the region-of-interest (1 pixel, 0.1 mm, 0.5 mm, 1 mm, 2.5 mm and 5 mm) was evaluated. The algorithm estimated intima-media thickness at diastole automatically by measuring the distance between the two positions where the laterally averaged B-mode intensity envelope crosses a threshold value relative to the maximum amplitudes of the intimal and adventitial echoes, respectively. The sub-pixel resolution is achieved by solving the equation of a straight line between the two samples on either side of the threshold value. The measurements were performed on 20 healthy normotensive volunteers (age 25–57 years) on the common carotid artery 2–3 cm proximal to the bifurcation. For the 2.5-mm width, which was considered the best, the intima-media thickness was mean 646 μm (SD 66) for men and 613 μm (SD 68) for women. The systematic difference was −5 μm and the random difference was 31 μm. The CV was 4.9%. The study indicates that the reproducibility is sufficient for in vivo studies when the width of the region-of-interest is 1.0 mm or wider.
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| 6. |
- Cinthio, Magnus, et al.
(författare)
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Evaluation of an algorithm for arterial lumen diameter measurements by means of ultrasound.
- 2010
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Ingår i: Medical & Biological Engineering & Computing. - : Springer Science and Business Media LLC. - 0140-0118 .- 1741-0444. ; 48, s. 1133-1140
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Tidskriftsartikel (refereegranskat)abstract
- We have developed an algorithm for arterial luminal diameter measurement by means of ultrasound and evaluated the algorithm on agar vessel phantoms and in vivo. The algorithm utilises relative threshold detection on the inner slopes of the arterial walls before the resolution is improved by solving the equation of a straight line between the samples around the threshold value. Further, correction distances added to compensate for the underestimation when using the inner slopes were found to be 304 mum for the near wall and 415 mum for the far wall. The measured mean diameters of ten consecutive images of 3-, 6- and 9-mm phantoms were 3,006 mum (SD 4), 5,918 mum (SD 1) and 8,936 mum (SD 2), respectively. The mean differences between the images were 0.19, 0.04 and 0.37 mum, respectively. In vivo, the intra- and inter-observer variabilities were -64 mum (2SD 358) and -57 mum (2SD 366), respectively.
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| 7. |
- Erlöv, Tobias, et al.
(författare)
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A fast 2D tissue motion estimator based on the phase of the intensity enables visualization of the propagation of the longitudinal movement in the carotid artery wall
- 2013
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Ingår i: 2013 IEEE International Ultrasonics Symposium (IUS). - 9781467356855 ; , s. 1761-1764
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Konferensbidrag (refereegranskat)abstract
- A fast 2D motion estimator has been developed and evaluated. The method does not utilize block-matching or iterative solutions and is thus more computationally efficient and suitable for real-time motion estimation over the entire image. The method has been evaluated on 1) phantom measurements and 2) in vivo on the carotid artery wall of 17 subjects, where measurements of the longitudinal displacement of the intima-media complex were compared to our previously validated method. The mean error of the phantom measurements was 2.0 +/- 3.3% (velocities between 2-15 mm/s; approx. 60 million estimations). In the in vivo measurements the mean difference (validated-proposed) was 18 +/- 44 mu m. Further the method has enabled visualization of the propagation of the longitudinal movement in the carotid artery wall. Several different phases of the longitudinal propagation, which seem to be connected to the multi-phasic pattern of the longitudinal movement, can be seen. All phases of the longitudinal propagation seem to originate from the direction of the heart.
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| 8. |
- Erlöv, Tobias, et al.
(författare)
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A method for measuring the variation of intima-media thickness during the entire cardiac cycle using B-Mode images
- 2011
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Ingår i: 2011 IEEE International Ultrasonics Symposium (IUS). - 9781457712531 ; , s. 2126-2129
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Konferensbidrag (refereegranskat)abstract
- Increased intima-media thickness (IMT) has been shown to predict cardiovascular risk, and measurement of intima-media thickness has been extensively used in medical research since the mid-1990s. IMT is conventionally measured by manual tracing, however this method is very time-consuming and suffers from large inter-observer variability. Numerous methods, both semi-automatic and fully-automatic, have been suggested to limit the influence of the observer. However, most methods only report one value per cardiac cycle instead of the variation of IMT over time. We propose a new method that measures the variation of IMT during the entire cardiac cycle. The method tracks spatial variations with compensation for both longitudinal movement and angle variations. This enables detection of positions where an inaccurate measurement of IMT has occurred. These can then be removed from the calculations in order to maximize the accuracy. The method was evaluated in vivo on 20 healthy individuals (mean age 38 years, range 25-57). The overall IMT in diastole (IMTdia) was 717+/-69 mu m and the intima-media compression (IMC) was 66+/-21 mu m which corresponds to a 9.2+/-2.6% maximal compression of the arterial wall during a cardiac cycle. The CV was 3.5% for IMTdia and 9.9% for IMC. Extending traditional IMT measurement to include also the variation of IMT during a cardiac cycle may improve the individual risk classification for cardiovascular diseases.
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| 9. |
- Erlöv, Tobias, et al.
(författare)
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A Method to Measure Shear Strain with High Spatial Resolution in the Arterial Wall Non-Invasively in vivo by Tracking Zero-Crossings of B-Mode Intensity Gradients
- 2010
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Ingår i: Proceedings - IEEE Ultrasonics Symposium. - 9781457703812 ; , s. 491-494
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Konferensbidrag (refereegranskat)abstract
- We have previously shown that there is a distinct longitudinal movement of the arterial wall during a cardiac cycle. This movement is larger in the intima-media region than in the adventitial region which introduces a substantial shear strain within the arterial wall. Our previously developed echo-tracking algorithm measured this shear strain by tracking two separate echoes, one in the intima-media region and one in the adventitia region and thus only a linear distribution was evaluated. The objective of this study was to suggest and evaluate a new improved method which can measure the intramural shear strain with higher spatial resolution and thereby provide more information on this new and rather unknown phenomenon. The mean maximum shear strain was 0.82 radians with a standard deviation of 0.17 radians and a CV-value of 14.2%. The total mean difference in measured longitudinal movement between the new and previous method was 10μm with a standard deviation of 90μm and a CV-value of 12.8%. The spatial distribution of the intramural shear strain seems to be very non-linear with a large amount of shear strain occurring in a small section around the transition between the media and adventitia layers.
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| 10. |
- Erlöv, Tobias, et al.
(författare)
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A robust and fast method for arterial lumen diameter and intima-media thickness measurements
- 2012
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Ingår i: 2012 IEEE International Ultrasonics Symposium (IUS). - 9781467345613 - 9781467345620 ; , s. 1678-1681
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Konferensbidrag (refereegranskat)abstract
- Lumen diameter, distension and intima-media thickness (IMT) in human arteries are important parameters in cardiovascular research. The signal reflected from the arterial wall strongly depends on the ultrasound scanner and settings. The signal also varies with age and health of the subject. A general method insensitive with respect to the subject and the scanner would be of great help. We have developed a novel and robust method for ARTerIal Characterization (ARTIC), suitable for real-time in vivo measurements of diameter, distension and IMT using B-Mode images. The aim of this study was to evaluate ARTIC on different subjects and scanners. ARTIC was evaluated in vivo in different groups of subjects using two scanners, HDI5000 (Philips Medical Systems, Bothell, WA, USA) and ULA-OP (University of Florence, Italy). First, a comparison was made against a previous method validated on phantoms. Then measurements of young (healthy) and old (healthy and unhealthy) subjects were evaluated for both scanners. Finally, a comparison between scanners was made. The evaluation of different subjects shows a coefficient of variation (CV) ranging from 1.4-2.0% for diameter, 4.3-8.8% for distension and 3.6-6.6% for IMT.
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| 11. |
- Lundblad, Mattias, et al.
(författare)
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Grenar och toppar istället för kol
- 2010
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Ingår i: Miljötrender från SLU. - 1403-4743. ; , s. 4-5
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 12. |
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| 13. |
- Rydén Ahlgren, Åsa, et al.
(författare)
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Different Patterns of Longitudinal Displacement of the Common Carotid Artery Wall in Healthy Humans are Stable over a Four-Month Period.
- 2012
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Ingår i: Ultrasound in Medicine and Biology. - : Elsevier BV. - 0301-5629. ; 38:6, s. 916-925
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Tidskriftsartikel (refereegranskat)abstract
- Using an in-house developed ultrasonic method, we have shown that there is distinct longitudinal multiphasic displacement of the human common carotid artery (CCA) wall during the cardiac cycle. Different subjects showed markedly different patterns of displacement. At present, it is not known if the pattern of displacement in an individual is stable over time. Therefore, in this study, we measured the longitudinal displacement of the right CCA in 10 healthy humans at two different occasions 4 months apart. The basic pattern of longitudinal displacement for an individual was highly stable, including intraclass correlation coefficient (ICC) of 0.88 for the ratio between the first antegrade and the retrograde displacement, and ICC of 0.76 for the magnitude of the first antegrade displacement. The stable basic pattern of displacement showed marked differences among subjects, also of the same age and gender. Further studies are needed to elucidate the underlying mechanisms, the physiologic, pathophysiologic and clinical implications of this phenomenon.
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| 14. |
- Rydén Ahlgren, Åsa, et al.
(författare)
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Longitudinal displacement and intramural shear strain of the porcine carotid artery undergo profound changes in response to catecholamines
- 2012
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Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 302:5, s. 1102-1115
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Tidskriftsartikel (refereegranskat)abstract
- Ahlgren AR, Cinthio M, Steen S, Nilsson T, Sjoberg T, Persson HW, Lindstrom K. Longitudinal displacement and intramural shear strain of the porcine carotid artery undergo profound changes in response to catecholamines. Am J Physiol Heart Circ Physiol 302: H1102-H1115, 2012. First published December 23, 2011; doi:10.1152/ajpheart.00470.2011.-The effects of catecholamines on longitudinal displacements and intramural shear strain of the arterial wall are unexplored. Therefore, the common carotid artery of five anaesthetized pigs was investigated using an in-house developed noninvasive ultrasonic technique. The study protocol included intravenous infusion of low-dose epinephrine (beta-adrenoceptor activation), as well as intravenous boluses of norepinephrine (alpha-adrenoceptor activation). Further, the effects of beta-blockade (metoprolol) were studied. There were significant positive correlations between pulse pressure and longitudinal displacement of the intima-media complex (r = 0.72; P < 0.001), as well as between pulse pressure and intramural shear strain (r = 0.48; P < 0.001). Following administration of norepinephrine, the longitudinal displacement of the intima-media complex and intramural shear strain profoundly increased (median 190%, range 102-296%, and median 141%, range 101-182%, respectively, compared with baseline), also when given during beta-blockade (median 228%, range 133-266%, and median 158%, range 152-235%, respectively). During infusion of low-dose epinephrine, the longitudinal displacement of the intima-media complex and intramural shear strain decreased (median 88%, range 69-122%, and median 69%, range 47-117%, respectively, compared with baseline). In conclusion, the present study shows, for the first time, that the longitudinal displacement and intramural shear strain of the porcine carotid artery undergo profound changes in response to catecholamines. Increase in longitudinal displacements seems to be strongly related to alpha-adrenoceptor activation. Thus metoprolol is insufficient to counteract a profound increase in longitudinal displacement and intramural shear strain following a surge of norepinephrine.
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