| 1. |
- Persson, Magnus, et al.
(författare)
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A new non-invasive ultrasonic method for simultaneous measurements of longitudinal and radial arterial wall movements: first in vivo trial.
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 23:5, s. 247-251
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Tidskriftsartikel (refereegranskat)abstract
- During recent years, the radial movement of the arterial wall has been extensively studied, and measurements of the radial movement are now an important tool in cardiovascular research for characterizing the mechanical properties of the arterial wall. In contrast, the longitudinal movement of vessels has gained little or no attention as it has been presumed that this movement is negligible. With modern high-resolution ultrasound, it can, however, be seen that the intima-media complex of the arterial wall moves not only in the radial direction, but also in the longitudinal direction during pulse-wave propagation. This paper describes a new non-invasive ultrasonic method that is able to measure simultaneously two dimensionally arterial vessel wall movements. The method is demonstrated in a limited in vivo trial. Results from the in vivo trial show that, apart from the well-known radial movement, there is a distinct longitudinal movement in the human common carotid artery with, in this case, the intima-media complex moving substantially as compared with the region of the tunica adventitia. Two-dimensional evaluation of the vessel-wall movements, taking not only the radial movement, but also the longitudinal movement into account, may provide novel information of importance in the evaluation of vessel-wall function.
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| 2. |
- Persson, Magnus, et al.
(författare)
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Non-invasive measurement of arterial longitudinal movement
- 2002
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Ingår i: Proceedings of the IEEE Ultrasonics Symposium. - 1051-0117. ; 2, s. 1783-1786
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Konferensbidrag (refereegranskat)abstract
- In arterial vessel wall characterisation the longitudinal movements of vessels have gained little or no attention. It has been presumed that the arterial vessels move very little in the longitudinal direction. With modern high resolution ultrasound it can, however, be seen that arterial vessels move not only in the circumferential, but also in longitudinal direction. This paper describes a non-invasive, ultrasound based method which estimates the longitudinal and the circumferential movement, respectively. The method is demonstrated in a limited in vivo study of the common carotid artery. Results show that, apart from the well known circumferential movement, there is a distinct longitudinal movement.
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| 3. |
- 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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| 4. |
- Cinthio, Magnus, et al.
(författare)
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A NEW NON-INVASIVE ULTRASONIC METHOD FOR MEASUREMENTS OF LONGITUDINAL LENGTH ALTERATION OF THE ARTERIAL WALL - FIRST IN VIVO TRIAL
- 2008
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Ingår i: Acoustical Imaging. - 0270-5117. ; 29, s. 39-43
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Konferensbidrag (refereegranskat)abstract
- We have recently shown that there is a previous unknown longitudinal movement present in the arterial wall. We aim now to investigate whether the longitudinal movement causes length alteration of the arterial wall. The objective of this paper was to describe a new non-invasive ultrasonic technique that measures the length alteration of arteries in human in-vivo. Results indicate that a significant length alteration is present in the common carotid artery.
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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. |
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| 8. |
- Cinthio, Magnus, et al.
(författare)
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Longitudinal movements and resulting shear strain of the arterial wall
- 2006
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Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 291:1, s. 394-402
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Tidskriftsartikel (refereegranskat)abstract
- There has been little interest in the longitudinal movement of the arterial wall. It has been assumed that this movement is negligible compared with the diameter change. Using a new high-resolution noninvasive ultrasonic method, we measured longitudinal movements and diameter change of the common carotid artery of 10 healthy humans. During the cardiac cycle, a distinct bidirectional longitudinal movement of the intima-media complex could be observed in all the subjects. An antegrade longitudinal movement, i.e., in the direction of blood flow, in early systole [ 0.39 mm ( SD 0.26)] was followed by a retrograde longitudinal movement, i.e., in the direction opposite blood flow [ -0.52 mm ( SD 0.27)], later in systole and a second antegrade longitudinal movement [ 0.41 mm ( SD 0.33)] in diastole. The corresponding diameter change was 0.65 mm ( SD 0.19). The adventitial region showed the same basic pattern of longitudinal movement; however, the magnitude of the movements was smaller than that of the intimamedia complex, thereby introducing shear strain and, thus, shear stress within the wall [ maximum shear strain between the intima-media complex and the adventitial region was 0.36 rad ( SD 0.26). These phenomena have not previously been described. Measurements were also performed on the abdominal aorta ( n = 3) and brachial ( n = 3) and popliteal ( n = 3) arteries. Our new information seems to be of fundamental importance for further study and evaluation of vascular biology and hemodynamics and, thus, for study of atherosclerosis and vascular diseases.
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| 9. |
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| 10. |
- Cinthio, Magnus, et al.
(författare)
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New Approaches in Arterial Characterisation
- 2008
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Ingår i: Proceedings of 11th International Symposium on Advanced Biomedical Ultrasound (Invited). ; , s. 3-8
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- —The aim of this paper is to briefly present the historyand the status of the arterial characterization of today as wellas summarize our work on two new approaches in arterialcharacterization – measurements of the longitudinal movementand the minute roughness of the arterial wall.
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