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Egil Arnesen - One of the best experts on this subject based on the ideXlab platform.
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the difference between ultrasound and computed tomography ct measurements of aortic Diameter increases with aortic Diameter analysis of axial images of abdominal aortic and common iliac Artery Diameter in normal and aneurysmal aortas the tromso study 1994 1995
European Journal of Vascular and Endovascular Surgery, 2004Co-Authors: Kulbir Singh, Bjarne K Jacobsen, Steinar Solberg, S Kumar, Egil ArnesenAbstract:Abstract Objective. To assess agreement between ultrasound and computed tomography (CT) measurements from axial images of normal and aneurysmatic aortic and common iliac Artery Diameter. Design. Part of a population health screening for abdominal aortic aneurysm conducted in 1994–1995. Materials and methods. Three hundred and thirty-four subjects with and 221 subjects without ultrasound-detected aneurysm were scanned with CT. Three technicians and one radiologist measured ultrasonographic Diameters and five radiologists measured CT Diameters. The paired ultrasound-CT measurement differences were analyzed to assess agreement. Results. Compared to CT measurements, ultrasound slightly underestimated the Diameter in normal aortas and tended to overestimate the Diameter in aneurysmal aortas. In 555 ultrasound-CT pairs of measurements, the absolute differences for measurements of maximal aortic Diameter were 2 mm or less in 62, 60 and 77% in anterior–posterior, transverse and maximum Diameter in any plane, respectively. The corresponding figures for an absolute difference of 5 mm or more were 14, 18 and 8%, respectively. Variability increased with increasing Diameter. Conclusions. Both ultrasound and CT measurements of abdominal aortic Diameter are liable to variability and neither of these methods can be considered to be ‘gold standard'. Both methods can be used, while taking variability into consideration when making clinical decisions.
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intra and interobserver variability in the measurements of abdominal aortic and common iliac Artery Diameter with computed tomography the tromso study
European Journal of Vascular and Endovascular Surgery, 2003Co-Authors: Kulbir Singh, Bjarne K Jacobsen, Steinar Solberg, Kaare H Bonaa, S Kumar, R Bajic, Egil ArnesenAbstract:Abstract Objectives: to assess intra- and interobserver variability in the measurement of aortic and common iliac Artery Diameter by means of computed tomography (CT). Design: reproducibility study. Material and Methods: three radiologists performed measurements of aortic Diameter at five different levels and of both common iliac arteries with CT. Fifty-nine subjects were examined, 29 with and 30 without abdominal aortic aneurysms (AAA) as assessed by ultrasound. Results: intraobserver variability varied between radiologists, measurement plane (anterior-posterior vs transverse) and measurement level. The interobserver variability was markedly higher at the bifurcation than at the suprarenal level and higher than intraobserver variability for measurements at all levels. Both intraobserver and interobserver variability increased with increasing vessel Diameter and were largest in patients with AAA. The absolute intraobserver difference of the maximal infrarenal aortic Diameter was 2 mm or less in 94% of intraobserver pairs. The corresponding interobserver difference was 82%. Conclusions: interobserver variability of CT measurements of aortic and common iliac Artery Diameter is not negligible and should be taken into account when making clinical decisions. When assessing change in aortic Diameter, previous CT-scans should be reviewed simultaneously as a routine to exclude interobserver variability. Eur J Vasc Endovasc Surg 25 , 399-407 (2003)
C D A Stehouwer - One of the best experts on this subject based on the ideXlab platform.
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brachial Artery pulse pressure and common carotid Artery Diameter mutually independent associations with mortality in subjects with a recent history of impaired glucose tolerance
European Journal of Clinical Investigation, 2001Co-Authors: R A J M Van Dijk, Jacqueline M Dekker, Giel Nijpels, Robert J Heine, L M Bouter, C D A StehouwerAbstract:Background Decreased large Artery function, as reflected by increased brachial Artery pulse pressure and increased carotid Artery Diameter and stiffness, may contribute to the increased mortality risk that is observed in subjects with impaired glucose tolerance. We therefore investigated the association between brachial Artery pulse pressure and carotid Artery Diameter and stiffness, which are estimates of central Artery stiffness and arterial remodelling, respectively, and mortality in subjects with a recent history of impaired glucose tolerance. Design A prospective, population-based cohort study. We measured brachial Artery pulse pressure by oscillometric blood pressure measurements, and common carotid Artery Diameter and distensibility and compliance coefficients by ultrasound in 140 subjects with a recent history of impaired glucose tolerance. During a median 6·6-year follow-up, 16 subjects died. Results Brachial Artery pulse pressure and common carotid Artery Diameter were positively related to all-cause mortality [hazard ratios per standard deviation, 1·7 (1·2‐2·5) and 2·1 (1·3‐3·3), respectively]. Results were similar after adjustment for gender, age, waist-to-hip ratio, body mass index, total cholesterol concentration, pre-existent cardiovascular disease, and hypertension, and after additional mutual adjustment. Common carotid Artery distensibility and compliance coefficients were not statistically significantly associated with mortality. Conclusions Among subjects with a recent history of impaired glucose tolerance, brachial Artery pulse pressure and common carotid Artery Diameter are independently associated with mortality risk. Stiffness of the central arteries may explain the association between pulse pressure and mortality risk. The association between carotid Diameter and mortality risk is more likely to reflect arterial remodelling in response to atherosclerosis than that in response to increased local stiffness.
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change in common carotid Artery Diameter distensibility and compliance in subjects with a recent history of impaired glucose tolerance a 3 year follow up study
Journal of Hypertension, 2000Co-Authors: Giel Nijpels, Jacqueline M Dekker, Robert J Heine, Jos W R Twisk, M Steyn, A J M Donker, C D A StehouwerAbstract:Objective To assess the development of common carotid Artery properties (Diameter, distensibility and compliance) in a cohort of 140 subjects (mean age 65.8 years, SD 7.5 years) originally diagnosed as impaired glucose tolerant in a population-based study, and to explore determinants of changes observed. Design An observational, longitudinal study over a 3-year-period. Methods Vessel wall movement detector system based on ultrasonography, linear generalized estimating equations. Results Carotid Artery Diameter rose from 6.87-7.02 mm (+ 2.2%, P < 0.001). Distensibility decreased from 11.8 to 10.9 x 10 -3 kPa -1 (-8.3%, p = 0.009). Compliance decreased from 0.44-0.43 mm 2 kPa -1 (P= 0.17). Changes in blood pressure level were negatively associated with changes in distensibility and compliance. Baseline fasting glucose levels were positively associated with changes in Diameter, while fasting insulin levels were negatively associated with changes in distensibility and compliance in men, but not in women. Conclusions In subjects with a recent history of impaired glucose tolerance, we observed an increase in carotid Artery Diameter and a decrease in distensibility. Change in blood pressure level and baseline fasting glucose and HbA 1c levels were positively related to the increase in Diameter. In men, but not in women, baseline fasting insulin levels were associated with an acceleration of these changes.
Kulbir Singh - One of the best experts on this subject based on the ideXlab platform.
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the difference between ultrasound and computed tomography ct measurements of aortic Diameter increases with aortic Diameter analysis of axial images of abdominal aortic and common iliac Artery Diameter in normal and aneurysmal aortas the tromso study 1994 1995
European Journal of Vascular and Endovascular Surgery, 2004Co-Authors: Kulbir Singh, Bjarne K Jacobsen, Steinar Solberg, S Kumar, Egil ArnesenAbstract:Abstract Objective. To assess agreement between ultrasound and computed tomography (CT) measurements from axial images of normal and aneurysmatic aortic and common iliac Artery Diameter. Design. Part of a population health screening for abdominal aortic aneurysm conducted in 1994–1995. Materials and methods. Three hundred and thirty-four subjects with and 221 subjects without ultrasound-detected aneurysm were scanned with CT. Three technicians and one radiologist measured ultrasonographic Diameters and five radiologists measured CT Diameters. The paired ultrasound-CT measurement differences were analyzed to assess agreement. Results. Compared to CT measurements, ultrasound slightly underestimated the Diameter in normal aortas and tended to overestimate the Diameter in aneurysmal aortas. In 555 ultrasound-CT pairs of measurements, the absolute differences for measurements of maximal aortic Diameter were 2 mm or less in 62, 60 and 77% in anterior–posterior, transverse and maximum Diameter in any plane, respectively. The corresponding figures for an absolute difference of 5 mm or more were 14, 18 and 8%, respectively. Variability increased with increasing Diameter. Conclusions. Both ultrasound and CT measurements of abdominal aortic Diameter are liable to variability and neither of these methods can be considered to be ‘gold standard'. Both methods can be used, while taking variability into consideration when making clinical decisions.
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intra and interobserver variability in the measurements of abdominal aortic and common iliac Artery Diameter with computed tomography the tromso study
European Journal of Vascular and Endovascular Surgery, 2003Co-Authors: Kulbir Singh, Bjarne K Jacobsen, Steinar Solberg, Kaare H Bonaa, S Kumar, R Bajic, Egil ArnesenAbstract:Abstract Objectives: to assess intra- and interobserver variability in the measurement of aortic and common iliac Artery Diameter by means of computed tomography (CT). Design: reproducibility study. Material and Methods: three radiologists performed measurements of aortic Diameter at five different levels and of both common iliac arteries with CT. Fifty-nine subjects were examined, 29 with and 30 without abdominal aortic aneurysms (AAA) as assessed by ultrasound. Results: intraobserver variability varied between radiologists, measurement plane (anterior-posterior vs transverse) and measurement level. The interobserver variability was markedly higher at the bifurcation than at the suprarenal level and higher than intraobserver variability for measurements at all levels. Both intraobserver and interobserver variability increased with increasing vessel Diameter and were largest in patients with AAA. The absolute intraobserver difference of the maximal infrarenal aortic Diameter was 2 mm or less in 94% of intraobserver pairs. The corresponding interobserver difference was 82%. Conclusions: interobserver variability of CT measurements of aortic and common iliac Artery Diameter is not negligible and should be taken into account when making clinical decisions. When assessing change in aortic Diameter, previous CT-scans should be reviewed simultaneously as a routine to exclude interobserver variability. Eur J Vasc Endovasc Surg 25 , 399-407 (2003)
Daniel J Green - One of the best experts on this subject based on the ideXlab platform.
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opposing effects of shear mediated dilation and myogenic constriction on Artery Diameter in response to handgrip exercise in humans
Journal of Applied Physiology, 2015Co-Authors: Ceri L Atkinson, Howard H Carter, Louise H Naylor, Ellen A Dawson, Petra Marusic, Dagmara Hering, Markus P Schlaich, Dick H J Thijssen, Daniel J GreenAbstract:While the impact of changes in blood flow and shear stress on Artery function are well documented, the acute effects of increases in arterial pressure are less well described in humans. The aim of this study was to assess the effect of 30 min of elevated blood pressure, in the absence of changes in shear stress or sympathetic nervous system (SNS) activation, on conduit Artery Diameter. Ten healthy male subjects undertook three sessions of 30 min unilateral handgrip exercise at 5, 10, and 15% of maximal voluntary contractile (MVC) strength. Brachial Artery shear rate and blood flow profiles were measured simultaneously during exercise in the active and contralateral resting arms. Bilateral brachial Artery Diameter was simultaneously assessed before and immediately postexercise. In a second experiment, six subjects repeated the 15% MVC condition while continuous vascular measurements were collected during muscle sympathetic nerve activity (MSNA) assessment using peroneal microneurography. We found that unilateral handgrip exercise at 5, 10, and 15% MVC strength induced stepwise elevations in blood pressure (P < 0.01, Δmean arterial pressure: 7.06 ± 2.44, 8.50 ± 2.80, and 18.35 ± 3.52 mmHg, P < 0.01). Whereas stepwise increases were evident in shear rate in the exercising arm (P < 0.001), no changes were apparent in the nonexercising limb (P = 0.42). Brachial Artery Diameter increased in the exercising arm (P = 0.02), but significantly decreased in the nonexercising arm (P = 0.03). At 15% MVC, changes in Diameter were significantly different between arms (interaction effect: P = 0.01), whereas this level of exertion produced no significant changes in MSNA. We conclude that acute increases in transmural pressure, independent of shear rate and changes in SNS activation, reduce arterial caliber in normotensive humans in vivo. These changes in Diameter were mitigated by exercise-induced elevations in shear rate in the active limb.
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time course of arterial remodelling in Diameter and wall thickness above and below the lesion after a spinal cord injury
European Journal of Applied Physiology, 2012Co-Authors: Dick H J Thijssen, Daniel J Green, Patricia C E De Groot, Arne Van Den Bogerd, Matthijs T W Veltmeijer, Timothy N Cable, Maria T E HopmanAbstract:Physical inactivity in response to a spinal cord injury (SCI) represents a potent stimulus for conduit Artery remodelling. Changes in conduit Artery characteristics may be induced by the local effects of denervation (and consequent extreme inactivity below the level of the lesion), and also by systemic adaptations due to whole body inactivity. Therefore, we assessed the time course of carotid (i.e. above lesion) and common femoral Artery (i.e. below lesion) lumen Diameter and wall thickness across the first 24 weeks after an SCI. Eight male subjects (mean age 35 ± 14 years) with a traumatic motor complete spinal cord lesion between T5 and L1 (i.e. paraplegia) were included. Four subjects were measured across the first 6 weeks after SCI, whilst another four subjects were measured from 8 until 24 weeks after SCI. Ultrasound was used to examine the Diameter and wall thickness from the carotid and common femoral arteries. Carotid Artery Diameter did not change across 24 weeks, whilst femoral Artery Diameter stabilised after the rapid initial decrease during the first 3 weeks after the SCI. Carotid and femoral Artery wall thickness showed no change during the first few weeks, but increased both between 6 and 24 weeks (P < 0.05). In conclusion, SCI leads to a rapid and localised decrease in conduit Artery Diameter which is isolated to the denervated and paralyzed region, whilst wall thickness gradually increases both above and below the lesion. This distinct time course of change in conduit arterial Diameter and wall thickness suggests that distinct mechanisms may contribute to these adaptations.
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measuring peripheral resistance and conduit arterial structure in humans using doppler ultrasound
Journal of Applied Physiology, 2005Co-Authors: Louise H Naylor, Cara J Weisbrod, Gerry Odriscoll, Daniel J GreenAbstract:The purpose of this study was to establish valid indexes of conduit and resistance vessel structure in humans by using edge detection and wall tracking of high-resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, to calculate conduit Artery blood flow and Diameter continuously across the cardiac cycle. Nine subjects aged 36.7 (9.2) yr underwent, on separate days, assessment of brachial Artery blood flow and Diameter response to 5-, 10-, and 15-min periods of forearm ischemia in the presence and absence of combined sublingual glyceryl trinitrate (GTN) administration. Two further sessions examined responses to ischemic exercise, one in combination with GTN. The peak brachial Artery Diameter was observed in response to the combination of ischemic exercise and GTN; a significant difference existed between resting brachial Artery Diameter and peak brachial Artery Diameter, indicating that resting Diameter may be a poor measure of conduit vessel structure in vivo. Peak brachial Artery flow was also observed in response to a combination of forearm ischemia exercise and GTN administration, the response being greater than that induced by periods of ischemia, GTN, or ischemic exercise alone. These data indicate that noninvasive indexes of conduit and resistance vessel structure can be simultaneously determined in vivo in response to a single, brief, stimulus and that caution should be applied in using resting arterial Diameter as a surrogate measure of conduit Artery structure in vivo.
Richard Coulden - One of the best experts on this subject based on the ideXlab platform.
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ct measurement of main pulmonary Artery Diameter
British Journal of Radiology, 1998Co-Authors: P D Edwards, R K Bull, Richard CouldenAbstract:The aim of this study was to determine the upper limit of the normal main pulmonary Artery Diameter using a modern CT system. This was measured at the level of the pulmonary Artery bifurcation in 100 normal subjects using unenhanced contiguous 10 mm CT slices viewed at fixed mediastinal window settings (400/20). These normal subjects were then compared with similar unenhanced 10 mm images from 12 patients with proven pulmonary arterial hypertension (mean pulmonary Artery pressure > 20 mmHg). The main pulmonary Artery Diameter in normal subjects was 2.72 cm (SD = 0.3). Main pulmonary Artery Diameter in patients with pulmonary arterial hypertension was significantly greater (p < 0.01) at 3.47 cm (SD = 0.33). A pulmonary Artery Diameter of 3.32 cm (main pulmonary Artery Diameter + 2 SD) had a 58% sensitivity and 95% specificity for the presence of pulmonary arterial hypertension. It is concluded that, using unenhanced axial 10 mm CT sections, the upper limit of normal main pulmonary Artery Diameter is 3.32 cm. Pulmonary arterial hypertension should be considered in patients with values above this level.
