Measurement of blood flow by ultrasound: Accuracy and sources of error

Gill, R.W.

doi:10.1016/0301-5629(85)90035-3

Cited by 726 publications

(408 citation statements)

References 40 publications

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“…This method is described in more detail elsewhere. 21 The peak velocity of the systolic flow (V ps ) was assessed for 3 to 4 consecutive heart cycles. The mean blood flow velocity (V mean ) over 1 heart cycle was calculated by the computer program of the ultrasound system and the regional blood flow over 1 heart cycle was calculated by multiplying the time velocity integral by the diastolic carotid lumen area.…”

Section: Blood Flow Measurementsmentioning

confidence: 99%

Structural, Functional, and Hemodynamic Changes of the Common Carotid Artery With Age in Male Subjects

Schmidt‐Trucksäss

Grathwohl

Schmid

et al. 1999

ATVB

124

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Abstract-Aging of the common carotid artery (CCA) is associated with different principal structural, functional, and hemodynamic changes, which are often influenced by several atherosclerotic risk factors, so that it is difficult to estimate the exclusive effect of aging on this process. Studies dealing with vascular aging of the CCA usually assess only single, dimensional, or functional parameters, although it is likely that there are interactions and probably differences between them. Moreover, regional vascular blood flow characteristics are often not taken into consideration. Therefore, the aim of the study was to assess the age-related multiparametric changes of the CCA properties with ultrasound in 69 male subjects between the ages of 16 and 75 (42.4Ϯ16.5 years), who were screened for the absence of major atherosclerotic risk factors or existing vascular disease. As a result, the intima media thickness (0.052 mm/10 y) and diastolic diameter (0.17 mm/10 y) increased nearly linearly with age (rϭ0. 60, PϽ0.001; and rϭ0.46, PϽ0.001, respectively). The absolute diastolic/systolic diameter change diminished by 0.10 mm/10 y (rϭϪ0.73, PϽ0.001) and peak expansion velocity dropped by 0.12 cm/s per 10 years (rϭϪ0.62, PϽ0.001) highly significantly with age. The peak blood flow velocity decreased continuously with age (rϭϪ0.67, PϽ0.00) by 9.3 cm/s per 10 years. According to multiple regression analysis, peak blood flow velocity seems to reflect the changes of several structural and functional parameters in one; intima-media thickness was determined by diastolic arterial diameter and age as independent variables. The data indicate that a multiparametric assessment may contribute to a better understanding of vascular aging and might be the basis for further studies to evaluate the association of atherosclerotic risk factors and/or major vascular disease with local changes in the CCA. Key Words: carotid artery Ⅲ aging Ⅲ arterial stiffness Ⅲ ultrasound V ascular aging is associated with different principal structural and functional changes; ie, intima-media thickening, 1,2 arterial dilation, 3,4 and the deterioration of elastic wall properties with vascular stiffening 5-7 belong to this process. Each of these has an impact on vascular blood flow and the local and/or systemic hemodynamics interact with the structure and function of the artery. For example, both the elevation of blood pressure and stroke volume increase the wall shear rate and may thus lead to a midterm increase in the thickness of the intima-media 8 or structural adaptation in the form of a greater vascular diameter. 9 Although these interactions are known, very few studies take all these structural, functional, and hemodynamic parameters into consideration, which might be of interest to enable a better understanding of the relation of aging to the named arterial changes. Furthermore, only little data exist on the differences in the progression of these alterations.It is well known that atherosclerotic risk factors such as a high cholesterol level, hyperten...

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Section: Blood Flow Measurementsmentioning

confidence: 99%

Structural, Functional, and Hemodynamic Changes of the Common Carotid Artery With Age in Male Subjects

Schmidt‐Trucksäss

Grathwohl

Schmid

et al. 1999

ATVB

124

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“…Advantages of both Doppler ultrasound and pcMRI are no need for using ionizing irradiation or administration of intravenous agents, and the possibility of repeated measurements on a short-term basis. However, limitations of Doppler ultrasound are its operator dependency and overestimation of total blood flow in a given vessel due to the fact that only the highest flow in the center of the vessel is assessed (1). Using pcMRI, total CBF can be assessed by simultaneously measuring flow in the internal carotid arteries and the basilar artery.…”

mentioning

confidence: 99%

Reproducibility of total cerebral blood flow measurements using phase contrast magnetic resonance imaging

Spilt

Box

Geest

et al. 2002

Magnetic Resonance Imaging

146

150

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Purpose: To evaluate reproducibility of total cerebral blood flow (CBF) measurements with phase contrast magnetic resonance imaging (pcMRI). Materials and Methods:We repeated total CBF measurements in 15 healthy volunteers with and without cardiac triggering, and with and without repositioning. In eight volunteers measurements were performed at two different occasions. In addition, measurement of flow in a phantom was performed to validate MR measurements. Results:A difference of 40.4 ml/minute was found between CBF measurements performed with and without triggering (P Ͻ 0.05). For repeated triggered measurements, the coefficient of variation (CV) was 7.1%, and for nontriggered measurements 10.3%. For repeated measurements with repositioning, the CV was 7.1% with and 11.2% without triggering. Repeated measurements at different occasions showed a CV of 8.8%. Comparing measured with real flow in the phantom, the triggered differed 4.9% and the nontriggered 8.3%. Conclusion:The findings of this study demonstrate that pcMRI is a reliable method to measure total CBF in terms of both accuracy and reproducibility. METHODS THAT CURRENTLY ARE USED to assess total cerebral blood flow (CBF) can be divided into two groups based on the underlying concepts. On the one hand, total CBF can be estimated based on information generated by flow in the capillaries; on the other hand, total CBF can be assessed by measuring flow in the supplying vessels of the brain. Methods that are based on measurements of flow in the capillaries are single positron emission computed tomography (SPECT), xenon-computed tomography (Xe-CT), and perfusion magnetic resonance imaging (MRI). Blood flow in the supplying vessels of the brain can be measured using Doppler ultrasound and phase contrast MRI (pcMRI). Advantages of both Doppler ultrasound and pcMRI are no need for using ionizing irradiation or administration of intravenous agents, and the possibility of repeated measurements on a short-term basis. However, limitations of Doppler ultrasound are its operator dependency and overestimation of total blood flow in a given vessel due to the fact that only the highest flow in the center of the vessel is assessed (1). Using pcMRI, total CBF can be assessed by simultaneously measuring flow in the internal carotid arteries and the basilar artery. As compared to Doppler ultrasound, pcMRI has the advantage of being operator independent and involving straightforward flow quantification. In addition, pcMRI can be added to morphologic MRI sequences, offering the option to correlate flow to morphology based on data generated during one examination.In vitro and in vivo studies have demonstrated that pcMRI provides reliable flow data (2-4). However, data on short-term and long-term reproducibility are scarce. Furthermore, there is an ongoing discussion whether total CBF should be measured using a cardiac-triggered or a nontriggered pcMRI technique (4 -6). Finally, using pc-MRI, considerable differences in total CBF have been found between healthy volunteers (7,8). ...

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“…This method is unlimited in terms of the number of repeated measurements that can be performed, and therefore CBF can be followed continuously. The limitations of Doppler ultrasound are operator dependency and inaccuracy of measurement, which results from the fact that the total blood flow in a given vessel is not directly measured but rather is estimated based on measurements of the highest flow in the center of the vessel, and the diameter of that vessel (4).…”

mentioning

confidence: 99%

MR assessment of cerebral vascular response: A comparison of two methods

Spilt

Boom

Kamper

et al. 2002

Magnetic Resonance Imaging

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Purpose:To compare the results and reproducibility of two MR-based methods of measuring the cerebrovascular response (CVR). Materials and Methods:In eight volunteers, CVR was assessed with two MR-based methods upon a challenge with acetazolamide. CVR was assessed by measuring changes in total cerebral blood flow (TCBF) using phase contrast (PC) MRI, and by measuring perfusion MRI. To assess reproducibility the measurements were repeated after 1 week. Results:The average CVR with the PC-MRI method was 46% (SD ϭ 16%), and for perfusion MR the measured CVR was 44% (SD ϭ 16%). The coefficient of variation (COV) for PC-MRI was 28%, while perfusion MR had a COV of 26%. The limits of agreement between the two methods were -49% and 45%, demonstrating a lack of agreement between the two methods in terms of CVR estimation. Conclusion:CVR estimates based on PC-MRI and perfusion MRI showed reproducibility but a lack of agreement in healthy volunteers. This lack of agreement can be attributed to the different aspects of the CVR reflected by these methods: TCBF reflects changes in CBF, whereas our perfusion MRI method reflects cerebral blood volume (CBV).

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Measurement of blood flow by ultrasound: Accuracy and sources of error

Cited by 726 publications

References 40 publications

Structural, Functional, and Hemodynamic Changes of the Common Carotid Artery With Age in Male Subjects

Structural, Functional, and Hemodynamic Changes of the Common Carotid Artery With Age in Male Subjects

Reproducibility of total cerebral blood flow measurements using phase contrast magnetic resonance imaging

MR assessment of cerebral vascular response: A comparison of two methods

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