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- Smedby, Örjan, et al.
(författare)
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Development of femoral atherosclerosis in relation to flow disturbances.
- 1996
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Ingår i: Journal of Biomechanics. - : Elsevier BV. - 0021-9290 .- 1873-2380. ; 29:4, s. 543-547
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Tidskriftsartikel (refereegranskat)abstract
- Angiography and post-mortem studies have indicated that disturbed blood flow may promote atherogenesis. Our aim was to demonstrate flow disturbances in vivo and correlate them to the subsequent development of atherosclerosis. The femoral arteries of 17 patients with early atherosclerosis were studied with cineangiography. The films are digitized and analyzed with an image analysis computer. From the time-intensity curves, the arrival time of the contrast medium at each pixel was calculated. In the resulting parametric images, the computer identified zones of delayed contrast filling, (ZDF) which have been shown to correspond to disturbed flow. The progression or regression of atherosclerosis was followed with another angiography 3 years later by computing changes in edge roughness. Arterial segments without flow disturbances (defined as ZDF) showed a more marked decrease in edge roughness than those with flow disturbances (p < 0.05). In addition, the edge roughness tended to increase more in segments with larger ZDF area. Angiographic studies of fluid mechanics and atherogenesis are feasible, but larger patient materials are needed.
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- Smedby, Örjan, et al.
(författare)
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Flow disturbances in early femoral atherosclerosis : An in vivo study with digitized cineangiography
- 1993
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Ingår i: Journal of Biomechanics. - 0021-9290 .- 1873-2380. ; 26:9, s. 1105-1115
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Tidskriftsartikel (refereegranskat)abstract
- Disturbances in arterial flow are believed to influence the localization and development of atherosclerotic plaques. The femoral arteries of 26 patients were studied with cineangiography, after which the films were digitized and analyzed with an image analysis computer. The image sequence was converted to a set of time-intensity curves, from which time parameters were calculated, representing the arrival time of the contrast medium at each pixel. In the resulting parametric images, zones of delayed contrast filling (ZDF) were identified by an adaptive thresholding, which identifies lighter regions within the vessel, excluding the smallest ones. The ZDF, which have been shown, in a model study, to correspond to disturbed flow, were more frequent in the inner curvature than in the outer curvature of the curved vessels. Accordingly, they were more frequent along the lateral wall than along the medial wall of the artery. Several ZDF were also found in the vicinity of bifurcations. Most of the findings tally closely with fluid mechanical theory. In future studies, flow disturbances are to be correlated with the progression of atherosclerotic lesions.
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- Smedby, Örjan, et al.
(författare)
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Two-dimensional tortuosity of the superficial femoral artery in early atherosclerosis.
- 1993
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1018-1172 .- 1423-0135. ; 30:4, s. 181-191
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Tidskriftsartikel (refereegranskat)abstract
- Tortuosity of an artery can disturb fluid mechanics and cause flow separation, which might in turn promote atherogenesis. This study discusses theoretically several quantitative measures of arterial tortuosity and curvature in two dimensions and tests them with computations from digitized femoral arteriograms. When reproducibility, sensitivity to scaling and computational procedure, and agreement between the measures were all taken into account, the total curvature and distance factor were considered the most suitable measures. Significant correlations were found between tortuosity and atherosclerosis measures, but the interpretation of this finding is not straightforward.
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