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Diagnostic Ultrasound Imaging And Blood Flow Measurements Pdf

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Medical ultrasound also known as diagnostic sonography or ultrasonography is a diagnostic imaging technique, or therapeutic application of ultrasound. It is used to create an image of internal body structures such as tendons , muscles , joints, blood vessels, and internal organs. Its aim is often to find a source of a disease or to exclude pathology.

Medical ultrasound

OBJECTIVE: To evaluate the inter-observer agreement between Doppler ultrasonography and magnetic resonance imaging in the quantification of portal blood flow in healthy individuals, as well as evaluating the reproducibility of both methods.

Interobserver and intermethod agreements were calculated using the intraclass and Pearson's correlation coefficients. Mean values for the portal blood flow measured by Doppler ultrasonography and magnetic resonance imaging were respectively 0. Interobserver agreement for quantification of the portal blood flow by Doppler ultrasonography and magnetic resonance imaging was respectively reasonable intraclass coefficient: The intermethod agreement was low. Keywords: Portal blood flow; Magnetic resonance imaging; Ultrasonography.

Portal hypertension is a hemodynamic disorder characterized by persistent increase in the venous pressure in the portal system, clinically translated into collateral circulation and ascites. This is a frequent and severe complication of several chronic hepatopathies 1. Among the several measurable parameters, the portal blood flow measured by Doppler-US has been utilized for predicting the response to treatment in patients with portal hypertension 9.

The evaluation of the portal vein caliber, its alteration with the inspiration and expiration, flow velocity and direction, as well as volume measured in the portal vein and presence of collateral circulation are other parameters considered in the characterization of portal hypertension 7,10, Ready availability, relatively short procedure time and low cost may be mentioned as the main advantages of Doppler-US 2.

These limitations may lead to the utilization of other more accurate diagnostic methods, such as magnetic resonance imaging MRI. MRI angiography, for example, allows the evaluation of the blood flow within the vessel without the Doppler-US inconveniences 2 ; however it is highly expensive and is not widely available.

However, these studies have been developed with obsolete equipment in low magnetic field and with outdated techniques, besides not evaluating the MRI reproducibility interobserver agreement. The reproducibility of a diagnostic method measures its accuracy and is essential for validating the usefulness of this method in the clinical practice.

The present study is aimed at evaluating the intermethod Doppler US and MRI agreement in the measurement of the portal blood flow in healthy individuals, as well as the reproducibility of these diagnostic methods. The study was approved by the Committee for Ethics in Research of the institution and all of the volunteers signed a term of free and informed consent. They were considered as healthy for being asymptomatic, denying previous history of alcoholism ingestion of more than g of ethanol per week , with negative serology for hepatitis B and C viruses, and no previous history of proved autoimmune disease that might course with autoimmune hepatitis, denying use of hepatotoxic drugs, and originating from areas endemic for schistosomiasis.

Additionally, all of them denied possible contraindications for MRI such as cardiac pacemaker, cochlear implant or claustrophobia. US and MRI examinations were performed at up to day intervals and preferably at the same day. All of the patients were examined after four to six-hour fasting. Caliber and area of the portal vein were measured on the same topography of the dopplerfluxometric sampling for the flow calculation. Following the spectral curve acquisition, a sample of at least four seconds was obtained for measurement of the portal vein diameter which was utilized by the software package of the US equipment for calculating the vessel section area.

The value for mean flow velocity was measured by the equipment itself in the selected interval, finally providing the mean flow in the segment evaluated during this period. Portal vein localization was determined by coronal true fast imaging with steady precession TRUFI sequences. The imaging plane for blood flow mapping was adjusted perpendicularly to the portal vein Figure 1 and the phase-contrast technique was utilized for images acquisition. The parameters utilized are shown on Table 1.

Two independent observers with more than three years of experience in Doppler US and abdominal MRI after completing medical residency in imaging diagnosis and specific training for portal blood flow measurement by both methods performed and evaluated all the US Doppler and MRI studies.

The classification proposed by Fleiss 22 was utilized for interpreting the results, as shown on Table 2. Also, the Pearson's correlation coefficient was utilized for calculating the linearity degree between measurements obtained by the two observers. The same patients had their portal blood flow evaluated at US by two independent observers observer 1 and observer 2.

These same portal blood flows at MRI were also evaluated by other two observers, one of them being the same who had performed the US examinations observer 1 and observer 3. The analysis of agreement between US Doppler and MRI measurements performed by the observer 1 was ruled out to avoid any bias. Also, the mean value for the portal blood flow measured by the observers was calculated for each study.

The US reproducibility in the evaluation of the portal blood flow demonstrated a merely regular interobserver agreement intraclass correlation coefficient: Figure 2 presents a dispersion graphic with values for portal flow obtained by these two observers, where data seem not approximating a straight line. As regards the MRI reproducibility in the evaluation of the portal blood flow, a good interobserver agreement was observed intraclass correlation coefficient: Figure 3 presents a dispersion graphic with values for portal flow obtained by these two observers, where data seem to approximate a straight line, i.

A low intermethod agreement was observed in the evaluation of MRI and US results depending on the observers, the intraclass correlation coefficient ranged between 1. Notwithstanding, mean values for portal blood flow found a US and MRI were similar, respectively corresponding to 0. Morphological and hemodynamic studies in cases of portal hypertension play a significant role in the attempt to better understand a clinical condition that frequently leads to severe complications, for example, high digestive hemorrhage For this reason, the imaging evaluation of the portal system for quantifying the portal venous flow and analyzing the hemodynamics of this venous system in patients with chronic hepatopathy is aimed at the early diagnosis of portal hypertension in a poorly symptomatic phase of the disease 23,24 and identifying cirrhotic or schistosomal patients with a higher risk for hemorrhage from esophageal varices 11,12, The diagnostic accuracy of a method is an essential parameter for definition of it usefulness and can be determined by the evaluation of its reproducibility or interobserver agreement.

The present study demonstrated that the Doppler US reproducibility in the evaluation of the portal blood flow was merely regular and lower than the MRI reproducibility, coherently with the method limitations. Similar results have been found in previous studies approaching the role of Doppler US in the evaluation of patients with portal hypertension The measurement of the blood flow by MRI is an objective technique for evaluating the portal blood flow. This method presents the advantages of providing spatial and temporal information on the blood flow in different phases of the cardiac cycle 18 and not requiring breath-hold acquisition, which could affect the hemodynamic parameters 13,14, Major MRI disadvantage is related to the cost of this method, besides the lesser availability and higher complexity for evaluating the images acquired.

In the present study, a good interobserver agreement was found in the evaluation of the portal blood flow by MRI. However, no other study has been found in the literature about the reproducibility of this method in the evaluation of the portal blood flow in healthy individuals. It is important to note the poor intermethod agreement observed in the quantification of the portal blood flow by Doppler US and MRI. The higher MRI accuracy, and the fact of this method being considered as a reference standard in the evaluation of the blood flow lead to a tendency towards considering the results of this method as the closest to the actual values 2,13,14,16, Further studies with larger samples and utilizing specific phantoms are necessary to validate the results of the present study.

Similarly to the results of the present study, mean values for the portal blood flow in healthy individuals at MRI in previous studies have presented a high variability, ranging from 0. On the other hand, few studies were found in the literature with mean values for portal blood flow measured by Doppler US in healthy individuals. Differently from the present study, Kashitani et al. It is important to note, in the present study, the high variability in normal values of measurements by US 0.

The results of the present study were based on the evaluation of a limited population of asymptomatic volunteers, with a limited presumed variability. Notwithstanding, a high variation was observed in normal values, which does not allow an approach in terms of normality interval. Further studies with larger samples will be necessary for determining a narrower range of normality values.

The present study demonstrated that phase-contrast MRI presents an excellent reproducibility and is superior to Doppler US in the measurement of the portal blood flow. On the other hand, the intermethod agreement is low, and the authors could not determine a reliable interval corresponding to normality values for the portal blood flow.

Further studies will be necessary for determining the value of these methods. Mincis M. Evaluation of the portal venous system: complementary roles of invasive and noninvasive imaging strategies.

Um estudo centrado em necropsias. J Bras Patol Med Lab. Diagnostic value of Doppler assessment of the hepatic and portal vessels and ultrasound of the spleen in liver disease. Eur J Gastroenterol Hepatol.

Portal blood flow in the presence or absence of diffuse liver disease: measurement by phase contrast MR imaging. Abdom Imaging. Radiol Bras. Abnormal portal venous flow at sonography predicts reduced survival after transjugular intrahepatic portosystemic shunt creation. J Vasc Interv Radiol. Ultra-sonografia abdominal. Interobserver and interequipment variability of echo-Doppler examination of the portal vein: effect of a cooperative training program.

Hepatic flow parameters measured with MR imaging and Doppler US: correlations with degree of cirrhosis and portal hypertension. Volumetric flow rates in the portal venous system: measurement with cine phase-contrast MR imaging. Inter-observer and intra-observer variability in hepatology. Quantitative measurement of portal blood flow by magnetic resonance phase contrast: comparative study of flow phantom and Doppler ultrasound in vivo.

Acta Med Okayama. Portal venous flow while breath-holding after inspiration or expiration and during normal respiration in controls and cirrhotics. J Gastroenterol. J Hepatol. Portal blood flow: measurement with MR imaging. MR angiography and dynamic flow evaluation of the portal venous system. Fleiss JL.

Statistical methods for rates and proportions. New York: Wiley; Ultrasonography in the diagnosis of portal hypertension: diminished response of portal vessels to respiration. Endoscopic, ultrasonographic, and US-Doppler parameters as indicators of variceal bleeding in patients with schistosomiasis.

Dig Dis Sci. Mailing address: Dr. Received August 24, Accepted after revision October 23, All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License. Services on Demand Journal.

How to cite this article.

Diagnostic Ultrasound: Imaging and Blood Flow Measurements

Biomarkers in Cardiovascular Disease pp Cite as. The cardiovascular system is singular among the physiological systems in the combination of its continuous, unceasing functionality, very rapid response to external and internal stimuli, and potential for bodily harm if either of the first two is dysfunctional. Therefore, the ability to quickly and accurately monitor blood flow is an important tool for clinicians. Ultrasound has proved to be uniquely suitable for blood flow monitoring for several reasons, including its relatively low expense, safety due to the use of nonionizing radiation, and ease of portability. However, the most important feature is its real-time feedback, which matches the rapidity with which cardiovascular conditions may change. Ultrasound may be used to measure blood flow velocities within most physiological systems noninvasively with immediate visual and aural feedback.

OBJECTIVE: To evaluate the inter-observer agreement between Doppler ultrasonography and magnetic resonance imaging in the quantification of portal blood flow in healthy individuals, as well as evaluating the reproducibility of both methods. Interobserver and intermethod agreements were calculated using the intraclass and Pearson's correlation coefficients. Mean values for the portal blood flow measured by Doppler ultrasonography and magnetic resonance imaging were respectively 0. Interobserver agreement for quantification of the portal blood flow by Doppler ultrasonography and magnetic resonance imaging was respectively reasonable intraclass coefficient: The intermethod agreement was low. Keywords: Portal blood flow; Magnetic resonance imaging; Ultrasonography. Portal hypertension is a hemodynamic disorder characterized by persistent increase in the venous pressure in the portal system, clinically translated into collateral circulation and ascites.

What was wrong with this picture. I heard you mention wine and my ears perked up. This is done using color-coded maps called color Doppler imaging. Doppler ultrasound is commonly used to determine whether plaque build-up inside the carotid arteries is blocking blood flow to the brain. Instead she tossed her red hair and laughed.

Ultrasonic Measurement of Blood Flow Velocity and Applications for Cardiovascular Assessments

Medical ultrasound also known as diagnostic sonography or ultrasonography is a diagnostic imaging technique, or therapeutic application of ultrasound. It is used to create an image of internal body structures such as tendons , muscles , joints, blood vessels, and internal organs. Its aim is often to find a source of a disease or to exclude pathology.

Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Shung Published Physics. Save to Library. Create Alert.

Haynes ManualsThe Haynes Author : K. Kirk Shung Description:Ultrasound imaging is one of the most important and widely used diagnostic tools in modern medicine, second only to the conventional x-ray. Although considered a mature field, research continues for improving the capabilities and finding new uses for ultrasound technology while driving down the cost of newer, more complicated procedures such as intravascular ultrasound.

Ultrasonic Measurement of Blood Flow Velocity and Applications for Cardiovascular Assessments

Diagnostic ultrasound: imaging and blood flow measurements [1ed.]0824740963, 9780824740962

Haynes ManualsThe Haynes Author : K. Kirk Shung Description:Ultrasound imaging is one of the most important and widely used diagnostic tools in modern medicine, second only to the conventional x-ray.

For children who do not like reading books here I have the most interesting book. If you are curious about the book Diagnostic Ultrasound: Imaging and Blood Flow Measurements, Second Edition you can download as you please we also have provided the latest book. All books are in clear copy here, and all

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It seems that you're in Germany. We have a dedicated site for Germany. Medical applications of ultrasound range from therapy, foetal monitoring, diagnostic imaging and blood flow measurement, to surgery and lithotripsy. Ever since the earliest developments of medical ultrasound there has been an interest in the measurement and characterisation of the ultrasonic fields generated in these applications, either for assessment of performance of equipment or for safety. Until recently, procedures for acoustic output measurements were ill-defined, but standards are now being developed internationally by the International Electrotechnical Commission 1EC and reliable commercial measuring equipment is becoming more widely available. The aim of this book is to introduce acoustic output measurement techniques and to provide an insight into the measurement methods.

Skip to Main Content. A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. Use of this web site signifies your agreement to the terms and conditions. Estimation of Three-dimensional Blood Flow with Ultrasound - Continuity Equation on Multiplane Dual-angle Doppler Imaging Abstract: Atherosclerosis plays the major role in myocardial infarction and stroke and its pathophysiology is closely related to blood flow. Among clinical imaging modalities, ultrasound has the highest temporal resolution. Doppler ultrasound has been clinically applied for blood flow measurement and several parameters obtained with Doppler have been considered as essential for diagnosis. However, conventional Doppler method merely measures one-dimensional component of the blood flow along the ultrasonic beam.

Direct measurement of volumetric flow rate in the cardiovascular system with ultrasound is valuable but has been a challenge because most current 2-D flow imaging techniques are only able to estimate the flow velocity in the scanning plane in-plane. Our recent study demonstrated that high frame rate contrast ultrasound and speckle decorrelation SDC can be used to accurately measure the speed of flow going through the scanning plane through-plane. The volumetric flow could then be calculated by integrating over the luminal area, when the blood vessel was scanned from the transverse view. However, a key disadvantage of this SDC method is that it cannot distinguish the direction of the through-plane flow, which limited its applications to blood vessels with unidirectional flow. Physiologic flow in the cardiovascular system could be bidirectional due to its pulsatility, geometric features, or under pathologic situations. In this study, we proposed a method to distinguish the through-plane flow direction by inspecting the flow within the scanning plane from a tilted transverse view. This method was tested on computer simulations and experimental flow phantoms.

Diagnostic Ultrasound Imaging provides a comprehensive introduction to and a state-of-the-art review of the essential science and signal processing principles of diagnostic ultrasound. The progressive organization of the material serves beginners in medical ultrasound science and graduate students as well as design engineers, medical physicists, researchers, clinical collaborators, and the curious. This it the most comprehensive and extensive work available on the core science and workings of advanced digital imaging systems, exploring the subject in a unified, consistent and interrelated manner. From its antecedents to the modern day use and prospects for the future, this it the most up-to-date text on the subject.

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