This document discusses the basics of echocardiography and Doppler ultrasound principles. It begins by explaining why a basic understanding is necessary and provides an overview of ultrasound, including its frequency range, advantages, and disadvantages. It then covers topics such as attenuation, reflection, field of view, scan lines, frames, depth, zoom, freeze, and two-dimensional imaging controls including transmit power, gain, time gain compensation, focus, frequency, dynamic range, and compression. The document provides explanations of how these various controls and settings impact the ultrasound image quality.
This document discusses various types of artifacts that can occur in echocardiography and their causes. It describes artifacts related to ultrasound properties like reflection, refraction, scattering, attenuation and beam width. Common artifacts include reverberation between two reflective surfaces, ring down from gas bubbles, shadowing from highly attenuating structures, mirror images from multiple reflections, and refraction artifacts from structures acting as lenses. Side lobe and grating lobe artifacts result from secondary beams around the main ultrasound beam. Near field clutter and blooming/color bleed can obscure structures. Pseudoflow shows motion of non-blood fluids. Twinkling artifacts can mimic abnormal flow near reflective surfaces. Figure of 8 artifacts can occur around intracardiac devices
This document discusses the echocardiographic assessment of atrial septal defects (ASDs). It describes the main types of ASDs and notes that 80% are secundum defects. Echocardiography is used to identify and characterize ASDs, detect associated anomalies, diagnose complications, and guide treatment. Transthoracic echocardiography is the initial study, while transesophageal echocardiography provides better views of the atrial septum. Key measurements include ASD size, location, rim dimensions, and quantifying shunt severity with Qp/Qs. Echocardiography guides decisions about ASD device closure or surgery.
Echo Differentiation of Restrictive Cardiomyopathy and Constrictive PericarditisJunhao Koh
1. The document compares and contrasts constrictive cardiomyopathy (CP) and restrictive cardiomyopathy (RCMP), discussing their definitions, etiologies, pathophysiology, and echocardiographic findings.
2. Key differences include CP presenting with thickened pericardium while RCMP presents with stiff myocardium. CP shows ventricular interdependence and respiratory variation on echo, while RCMP shows restrictive physiology from diastolic dysfunction.
3. Optimizing the echo exam is important for evaluating CP, including adjusting the respirometer waveform, Doppler sweep speed, and positions like upright to increase respiratory variation. Hepatic vein and SVC Doppler also help differentiate the conditions.
Echo assessment of aortic valve diseaseNizam Uddin
This document discusses the echocardiographic assessment of aortic valve diseases. It describes how aortic stenosis is classified based on its location as valvular, subvalvular, or supravalvular. It outlines the etiology of valvular aortic stenosis and discusses echocardiographic methods for assessing the severity of aortic stenosis including peak transvalvular velocity, mean transvalvular gradient, and aortic valve area using the continuity equation. The document also discusses the assessment of aortic regurgitation severity using measurements such as vena contracta width, regurgitant jet width and area, pressure half time, diastolic flow reversal, and regurgitant volume and fraction. Methods for
This document summarizes dobutamine stress echocardiography (DSE). Key points include:
- DSE uses the drug dobutamine to simulate exercise and increase heart rate, contractility, and myocardial oxygen demand to detect ischemia.
- It is useful for evaluating ischemia, viability, and valvular dysfunction in patients unable to exercise.
- The document reviews the DSE protocol, interpretation of wall motion abnormalities, indications, side effects, and applications for assessing ischemic heart disease, viability, valvular stenosis like mitral and aortic stenosis, and pulmonary hypertension.
This document discusses strain and strain rate imaging techniques used to quantify regional myocardial function. It describes various methods to measure strain, including tissue Doppler, 2D speckle tracking, and cardiac MRI. It outlines normal values and patterns of strain in healthy individuals and how strain is altered in various cardiac diseases, such as coronary artery disease, heart failure, cardiomyopathies, and congenital heart disease. Strain imaging can identify myocardial scar, viability, dysfunction, and response to treatments.
Nuclear imaging techniques have various applications in cardiology, including assessing coronary artery disease, left ventricular function, cardiomyopathy, valvular heart disease, cardiac shunts, pulmonary hypertension, and more. Myocardial perfusion imaging can accurately diagnose and assess the prognosis of coronary artery disease, viability after myocardial infarction, and effectiveness of revascularization procedures. Gated SPECT allows evaluation of both cardiac function and perfusion simultaneously. Other nuclear techniques help evaluate conditions like myocarditis, pulmonary embolism, and secondary causes of hypertension.
This document discusses various types of artifacts that can occur in echocardiography and their causes. It describes artifacts related to ultrasound properties like reflection, refraction, scattering, attenuation and beam width. Common artifacts include reverberation between two reflective surfaces, ring down from gas bubbles, shadowing from highly attenuating structures, mirror images from multiple reflections, and refraction artifacts from structures acting as lenses. Side lobe and grating lobe artifacts result from secondary beams around the main ultrasound beam. Near field clutter and blooming/color bleed can obscure structures. Pseudoflow shows motion of non-blood fluids. Twinkling artifacts can mimic abnormal flow near reflective surfaces. Figure of 8 artifacts can occur around intracardiac devices
This document discusses the echocardiographic assessment of atrial septal defects (ASDs). It describes the main types of ASDs and notes that 80% are secundum defects. Echocardiography is used to identify and characterize ASDs, detect associated anomalies, diagnose complications, and guide treatment. Transthoracic echocardiography is the initial study, while transesophageal echocardiography provides better views of the atrial septum. Key measurements include ASD size, location, rim dimensions, and quantifying shunt severity with Qp/Qs. Echocardiography guides decisions about ASD device closure or surgery.
Echo Differentiation of Restrictive Cardiomyopathy and Constrictive PericarditisJunhao Koh
1. The document compares and contrasts constrictive cardiomyopathy (CP) and restrictive cardiomyopathy (RCMP), discussing their definitions, etiologies, pathophysiology, and echocardiographic findings.
2. Key differences include CP presenting with thickened pericardium while RCMP presents with stiff myocardium. CP shows ventricular interdependence and respiratory variation on echo, while RCMP shows restrictive physiology from diastolic dysfunction.
3. Optimizing the echo exam is important for evaluating CP, including adjusting the respirometer waveform, Doppler sweep speed, and positions like upright to increase respiratory variation. Hepatic vein and SVC Doppler also help differentiate the conditions.
Echo assessment of aortic valve diseaseNizam Uddin
This document discusses the echocardiographic assessment of aortic valve diseases. It describes how aortic stenosis is classified based on its location as valvular, subvalvular, or supravalvular. It outlines the etiology of valvular aortic stenosis and discusses echocardiographic methods for assessing the severity of aortic stenosis including peak transvalvular velocity, mean transvalvular gradient, and aortic valve area using the continuity equation. The document also discusses the assessment of aortic regurgitation severity using measurements such as vena contracta width, regurgitant jet width and area, pressure half time, diastolic flow reversal, and regurgitant volume and fraction. Methods for
This document summarizes dobutamine stress echocardiography (DSE). Key points include:
- DSE uses the drug dobutamine to simulate exercise and increase heart rate, contractility, and myocardial oxygen demand to detect ischemia.
- It is useful for evaluating ischemia, viability, and valvular dysfunction in patients unable to exercise.
- The document reviews the DSE protocol, interpretation of wall motion abnormalities, indications, side effects, and applications for assessing ischemic heart disease, viability, valvular stenosis like mitral and aortic stenosis, and pulmonary hypertension.
This document discusses strain and strain rate imaging techniques used to quantify regional myocardial function. It describes various methods to measure strain, including tissue Doppler, 2D speckle tracking, and cardiac MRI. It outlines normal values and patterns of strain in healthy individuals and how strain is altered in various cardiac diseases, such as coronary artery disease, heart failure, cardiomyopathies, and congenital heart disease. Strain imaging can identify myocardial scar, viability, dysfunction, and response to treatments.
Nuclear imaging techniques have various applications in cardiology, including assessing coronary artery disease, left ventricular function, cardiomyopathy, valvular heart disease, cardiac shunts, pulmonary hypertension, and more. Myocardial perfusion imaging can accurately diagnose and assess the prognosis of coronary artery disease, viability after myocardial infarction, and effectiveness of revascularization procedures. Gated SPECT allows evaluation of both cardiac function and perfusion simultaneously. Other nuclear techniques help evaluate conditions like myocarditis, pulmonary embolism, and secondary causes of hypertension.
Doppler echocardiography uses the Doppler effect to analyze the velocity and direction of blood flow. There are several Doppler modalities used in cardiac evaluation including continuous wave Doppler, pulsed wave Doppler, and color flow Doppler. Continuous wave Doppler measures very high velocities, pulsed wave Doppler samples local low velocities, and color flow Doppler visually displays velocities using color scales. The Nyquist limit defines the maximum detectable velocity and avoiding aliasing. Tissue Doppler also evaluates myocardial velocities. The Bernoulli equation relates velocity and pressure gradients which allows Doppler to estimate valve pressures.
Ultrasound imaging relies on pulses of sound waves being emitted into the body and reflected echoes being received. The timing and amplitude of echoes are used to determine the position and brightness values of pixels in the ultrasound image. Image resolution depends on factors like wavelength, pulse length, beam width, and sweep speed, with shorter/smaller values allowing better separation of objects. Axial resolution relates to separation along the beam axis, lateral resolution to separation perpendicular to the beam, and temporal resolution to locating moving structures over time.
M-mode echocardiography uses ultrasound to evaluate cardiac structures through motion over time. It can be used to assess morphology, movement, velocity and timing of valves and walls. Specific measurements are made of amplitudes, slopes, and time intervals which provide information on cardiac function. M-mode views of the mitral valve, aortic valve and left ventricle allow evaluation of values, wall motion, and calculation of ejection fraction, fractional shortening and left ventricular mass. Abnormal findings provide clues to conditions like valve disease, hypertrophy and ischemia.
No reflow and slow flow phenomenon during pcirahul arora
This document discusses strategies and prevention of slow flow and no-reflow phenomenon during percutaneous coronary intervention (PCI). It defines no-reflow as inadequate myocardial perfusion through a coronary artery without mechanical obstruction. No-reflow occurs in 8-11% of primary PCIs and is associated with worse clinical outcomes. The pathophysiology involves distal embolization, ischemic injury, reperfusion injury, and individual patient susceptibility. Preventing no-reflow requires reducing thrombus burden, ischemia time, reperfusion injury through anti-inflammatory drugs, and addressing risk factors like diabetes.
The document provides an overview of right ventricular assessment using echocardiography. It discusses normal RV anatomy, segmental nomenclature, and coronary supply. Key metrics for evaluating RV size, wall thickness, function, and pressures are outlined. Normal values and technical aspects of measuring RV dimensions, area/fractional area change, tricuspid annular plane systolic excursion, myocardial velocity, and diastolic function are summarized. Hemodynamic assessment of pulmonary pressures is also reviewed.
Three sentences:
The document provides details on the anatomy and evaluation of aortic stenosis using echocardiography. It describes the normal aortic valve anatomy and how various types of aortic stenosis like calcific, rheumatic, bicuspid and subvalvular present on echo. Quantitative assessment of aortic stenosis severity is done using Doppler ultrasound to measure the maximum jet velocity and calculate the pressure gradient across the stenotic valve.
Doppler echocardiography is the main method used to evaluate ventricular function in children. It provides important information not available from adult assessments due to differences in myocardial maturation and the effects of congenital heart disease. Echocardiography allows assessment of ventricular dimensions, ejection fraction, wall motion, and Doppler indices of systolic and diastolic function. Newer techniques like Doppler tissue imaging and strain rate imaging provide enhanced evaluation of regional myocardial function. Comprehensive echocardiography is crucial for understanding the complex effects of pediatric heart conditions on ventricular performance.
This book provides a practical introduction to echocardiography (echo) for medical students and doctors in training. It explains basic echo techniques and what a normal echo looks like. New sections in this second edition cover topics like cardiac resynchronization therapy for heart failure and the use of echo in special hospital settings. The aim is to help readers use, request, and interpret echo in a clinical context without being an exhaustive textbook on the topic.
Tissue Doppler Imaging (TDI) provides low velocity, high amplitude signals from the myocardium that can be used to assess systolic and diastolic function. TDI utilizes pulsed wave and color Doppler techniques to measure peak myocardial velocities. The E/E' ratio, where E is transmitral early diastolic velocity and E' is early diastolic mitral annular velocity, correlates well with left ventricular filling pressures and can help distinguish normal from elevated pressures. TDI parameters are useful for evaluating global and regional systolic function, diastolic function, ischemia, and viability as well as distinguishing between restrictive cardiomyopathy and constrictive pericarditis.
Speckle tracking echocardiography (STE) is an echocardiographic imaging technique that analyzes the motion of tissues in the heart by using the naturally occurring speckle pattern in the myocardium or blood when imaged by ultrasound.
This document discusses low flow, low gradient aortic stenosis. It begins by introducing aortic stenosis and its prevalence. It then outlines the different types of low flow, low gradient aortic stenosis, including those with low ejection fraction and those with normal ejection fraction. For those with low EF, the document discusses the pathophysiology, importance of distinguishing true from pseudo-severe stenosis, and role of dobutamine stress echocardiography in making this distinction. It provides details on dobutamine stress echo protocol and parameters used to identify true severe stenosis versus pseudosevere stenosis.
This document discusses M-mode echocardiography, including its physics, applications, and findings. M-mode provides high temporal resolution to evaluate cardiac structure movement and timing. It can be used to assess valves, walls, intervals, and morphology. Examples are given of M-mode findings in various cardiac pathologies at the mitral, aortic, pulmonary, and tricuspid valves as well as the left ventricle. Measurements like fractional shortening and ejection fraction are also reviewed.
Stress echocardiography combines echocardiography with physical, pharmacological, or electrical stress to effectively evaluate for myocardial ischemia. It is used to screen for coronary artery disease and identify affected coronary territories. Stress echocardiography can also differentiate viable myocardium from scarred tissue and provides important prognostic information after myocardial infarction and before noncardiac surgery. Dobutamine stress echocardiography is widely used to assess viable myocardium while exercise stress echocardiography is preferred when possible due to its safety. Stress echocardiography techniques are safe and relatively inexpensive options for evaluating myocardial ischemia and viability.
The document discusses the history, anatomy, angiographic views, variations, and clinical relevance of coronary arteries. It provides a detailed overview of the typical anatomy and branches of the left main, left anterior descending, left circumflex, and right coronary arteries. It also describes common anatomical variations and anomalies seen in coronary arteries and their clinical implications. Angiographic classification methods for different coronary artery segments are presented.
Hepatic veins - The Doppler interrogation Praveen Nagula
Doppler interrogation of the hepatic veins can provide information about underlying cardiovascular disorders by assessing changes in hepatic venous flow patterns related to cardiac cycle, respiration, and right heart pressures and function. Abnormal flow patterns seen on hepatic vein Doppler include increased systolic and diastolic waveforms with inspiration in constrictive pericarditis, prominent diastolic reversals with inspiration in restrictive cardiomyopathy, an enlarged and prolonged A wave in conditions with elevated right ventricular filling pressures, blunting of the S wave in right ventricular systolic dysfunction, and loss of the A wave with atrial fibrillation or arrhythmias causing atrioventricular dissociation.
This document discusses contrast echocardiography, including the mechanism by which microbubble contrast agents improve echocardiographic imaging. Ideal contrast agents are described as being safe, metabolically inert, long-lasting, strong sound reflectors that are small enough to pass through capillaries. Several FDA-approved second generation contrast agents are mentioned along with their shell materials and gases. Optimal echocardiographic settings for contrast imaging are outlined. Clinical applications of contrast echocardiography include assessing shunts, venous anomalies, and leaks. Examples of its use in specific cases are provided.
A lecture on the echocardiographic evaluation of hypertrophic cardiomyopathy. Starts with an overview of the topic then a systematic approach to diagnosis and then a differential diagnosis followed by take-home messages and conclusion.
The document discusses various techniques for assessing myocardial viability, including stress echocardiography, single photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance imaging (MRI). Stress echocardiography evaluates contractile reserve through techniques like dobutamine stress echocardiography. SPECT assesses viability by detecting thallium or technetium uptake, which relies on intact cell membranes. PET detects FDG uptake indicating active glucose metabolism. MRI evaluates viability through detection of late gadolinium enhancement, indicating scar tissue, and can also assess contractile reserve with stress MRI. A combined approach utilizing multiple techniques can provide complementary information on viability.
This document discusses the physics and instrumentation of ultrasound. It describes how sound waves propagate through tissue and how ultrasound is generated and detected using piezoelectric transducers. Key parameters like frequency, wavelength, resolution and depth of penetration are defined. The interactions of ultrasound with tissue including reflection, scattering, refraction and attenuation are covered. The document also discusses the various controls available on ultrasound machines to optimize image quality including gain, depth, focus and dynamic range.
This document discusses key concepts regarding ultrasound physics and instrumentation relevant to echocardiography. It covers topics such as sound wave properties, factors that influence ultrasound velocity, reflection and attenuation, transducer characteristics related to resolution, and optimization of 2D, Doppler, and TEE imaging. The key points are that ultrasound is used to image cardiac structures, transducer properties like frequency affect image quality, and proper adjustment of controls optimizes the ultrasound information obtained.
Doppler echocardiography uses the Doppler effect to analyze the velocity and direction of blood flow. There are several Doppler modalities used in cardiac evaluation including continuous wave Doppler, pulsed wave Doppler, and color flow Doppler. Continuous wave Doppler measures very high velocities, pulsed wave Doppler samples local low velocities, and color flow Doppler visually displays velocities using color scales. The Nyquist limit defines the maximum detectable velocity and avoiding aliasing. Tissue Doppler also evaluates myocardial velocities. The Bernoulli equation relates velocity and pressure gradients which allows Doppler to estimate valve pressures.
Ultrasound imaging relies on pulses of sound waves being emitted into the body and reflected echoes being received. The timing and amplitude of echoes are used to determine the position and brightness values of pixels in the ultrasound image. Image resolution depends on factors like wavelength, pulse length, beam width, and sweep speed, with shorter/smaller values allowing better separation of objects. Axial resolution relates to separation along the beam axis, lateral resolution to separation perpendicular to the beam, and temporal resolution to locating moving structures over time.
M-mode echocardiography uses ultrasound to evaluate cardiac structures through motion over time. It can be used to assess morphology, movement, velocity and timing of valves and walls. Specific measurements are made of amplitudes, slopes, and time intervals which provide information on cardiac function. M-mode views of the mitral valve, aortic valve and left ventricle allow evaluation of values, wall motion, and calculation of ejection fraction, fractional shortening and left ventricular mass. Abnormal findings provide clues to conditions like valve disease, hypertrophy and ischemia.
No reflow and slow flow phenomenon during pcirahul arora
This document discusses strategies and prevention of slow flow and no-reflow phenomenon during percutaneous coronary intervention (PCI). It defines no-reflow as inadequate myocardial perfusion through a coronary artery without mechanical obstruction. No-reflow occurs in 8-11% of primary PCIs and is associated with worse clinical outcomes. The pathophysiology involves distal embolization, ischemic injury, reperfusion injury, and individual patient susceptibility. Preventing no-reflow requires reducing thrombus burden, ischemia time, reperfusion injury through anti-inflammatory drugs, and addressing risk factors like diabetes.
The document provides an overview of right ventricular assessment using echocardiography. It discusses normal RV anatomy, segmental nomenclature, and coronary supply. Key metrics for evaluating RV size, wall thickness, function, and pressures are outlined. Normal values and technical aspects of measuring RV dimensions, area/fractional area change, tricuspid annular plane systolic excursion, myocardial velocity, and diastolic function are summarized. Hemodynamic assessment of pulmonary pressures is also reviewed.
Three sentences:
The document provides details on the anatomy and evaluation of aortic stenosis using echocardiography. It describes the normal aortic valve anatomy and how various types of aortic stenosis like calcific, rheumatic, bicuspid and subvalvular present on echo. Quantitative assessment of aortic stenosis severity is done using Doppler ultrasound to measure the maximum jet velocity and calculate the pressure gradient across the stenotic valve.
Doppler echocardiography is the main method used to evaluate ventricular function in children. It provides important information not available from adult assessments due to differences in myocardial maturation and the effects of congenital heart disease. Echocardiography allows assessment of ventricular dimensions, ejection fraction, wall motion, and Doppler indices of systolic and diastolic function. Newer techniques like Doppler tissue imaging and strain rate imaging provide enhanced evaluation of regional myocardial function. Comprehensive echocardiography is crucial for understanding the complex effects of pediatric heart conditions on ventricular performance.
This book provides a practical introduction to echocardiography (echo) for medical students and doctors in training. It explains basic echo techniques and what a normal echo looks like. New sections in this second edition cover topics like cardiac resynchronization therapy for heart failure and the use of echo in special hospital settings. The aim is to help readers use, request, and interpret echo in a clinical context without being an exhaustive textbook on the topic.
Tissue Doppler Imaging (TDI) provides low velocity, high amplitude signals from the myocardium that can be used to assess systolic and diastolic function. TDI utilizes pulsed wave and color Doppler techniques to measure peak myocardial velocities. The E/E' ratio, where E is transmitral early diastolic velocity and E' is early diastolic mitral annular velocity, correlates well with left ventricular filling pressures and can help distinguish normal from elevated pressures. TDI parameters are useful for evaluating global and regional systolic function, diastolic function, ischemia, and viability as well as distinguishing between restrictive cardiomyopathy and constrictive pericarditis.
Speckle tracking echocardiography (STE) is an echocardiographic imaging technique that analyzes the motion of tissues in the heart by using the naturally occurring speckle pattern in the myocardium or blood when imaged by ultrasound.
This document discusses low flow, low gradient aortic stenosis. It begins by introducing aortic stenosis and its prevalence. It then outlines the different types of low flow, low gradient aortic stenosis, including those with low ejection fraction and those with normal ejection fraction. For those with low EF, the document discusses the pathophysiology, importance of distinguishing true from pseudo-severe stenosis, and role of dobutamine stress echocardiography in making this distinction. It provides details on dobutamine stress echo protocol and parameters used to identify true severe stenosis versus pseudosevere stenosis.
This document discusses M-mode echocardiography, including its physics, applications, and findings. M-mode provides high temporal resolution to evaluate cardiac structure movement and timing. It can be used to assess valves, walls, intervals, and morphology. Examples are given of M-mode findings in various cardiac pathologies at the mitral, aortic, pulmonary, and tricuspid valves as well as the left ventricle. Measurements like fractional shortening and ejection fraction are also reviewed.
Stress echocardiography combines echocardiography with physical, pharmacological, or electrical stress to effectively evaluate for myocardial ischemia. It is used to screen for coronary artery disease and identify affected coronary territories. Stress echocardiography can also differentiate viable myocardium from scarred tissue and provides important prognostic information after myocardial infarction and before noncardiac surgery. Dobutamine stress echocardiography is widely used to assess viable myocardium while exercise stress echocardiography is preferred when possible due to its safety. Stress echocardiography techniques are safe and relatively inexpensive options for evaluating myocardial ischemia and viability.
The document discusses the history, anatomy, angiographic views, variations, and clinical relevance of coronary arteries. It provides a detailed overview of the typical anatomy and branches of the left main, left anterior descending, left circumflex, and right coronary arteries. It also describes common anatomical variations and anomalies seen in coronary arteries and their clinical implications. Angiographic classification methods for different coronary artery segments are presented.
Hepatic veins - The Doppler interrogation Praveen Nagula
Doppler interrogation of the hepatic veins can provide information about underlying cardiovascular disorders by assessing changes in hepatic venous flow patterns related to cardiac cycle, respiration, and right heart pressures and function. Abnormal flow patterns seen on hepatic vein Doppler include increased systolic and diastolic waveforms with inspiration in constrictive pericarditis, prominent diastolic reversals with inspiration in restrictive cardiomyopathy, an enlarged and prolonged A wave in conditions with elevated right ventricular filling pressures, blunting of the S wave in right ventricular systolic dysfunction, and loss of the A wave with atrial fibrillation or arrhythmias causing atrioventricular dissociation.
This document discusses contrast echocardiography, including the mechanism by which microbubble contrast agents improve echocardiographic imaging. Ideal contrast agents are described as being safe, metabolically inert, long-lasting, strong sound reflectors that are small enough to pass through capillaries. Several FDA-approved second generation contrast agents are mentioned along with their shell materials and gases. Optimal echocardiographic settings for contrast imaging are outlined. Clinical applications of contrast echocardiography include assessing shunts, venous anomalies, and leaks. Examples of its use in specific cases are provided.
A lecture on the echocardiographic evaluation of hypertrophic cardiomyopathy. Starts with an overview of the topic then a systematic approach to diagnosis and then a differential diagnosis followed by take-home messages and conclusion.
The document discusses various techniques for assessing myocardial viability, including stress echocardiography, single photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance imaging (MRI). Stress echocardiography evaluates contractile reserve through techniques like dobutamine stress echocardiography. SPECT assesses viability by detecting thallium or technetium uptake, which relies on intact cell membranes. PET detects FDG uptake indicating active glucose metabolism. MRI evaluates viability through detection of late gadolinium enhancement, indicating scar tissue, and can also assess contractile reserve with stress MRI. A combined approach utilizing multiple techniques can provide complementary information on viability.
This document discusses the physics and instrumentation of ultrasound. It describes how sound waves propagate through tissue and how ultrasound is generated and detected using piezoelectric transducers. Key parameters like frequency, wavelength, resolution and depth of penetration are defined. The interactions of ultrasound with tissue including reflection, scattering, refraction and attenuation are covered. The document also discusses the various controls available on ultrasound machines to optimize image quality including gain, depth, focus and dynamic range.
This document discusses key concepts regarding ultrasound physics and instrumentation relevant to echocardiography. It covers topics such as sound wave properties, factors that influence ultrasound velocity, reflection and attenuation, transducer characteristics related to resolution, and optimization of 2D, Doppler, and TEE imaging. The key points are that ultrasound is used to image cardiac structures, transducer properties like frequency affect image quality, and proper adjustment of controls optimizes the ultrasound information obtained.
Ultrasound uses high-frequency sound waves to produce images of structures inside the body. It has several advantages over other imaging techniques as it is noninvasive, painless, and does not use radiation. The document discusses key ultrasound concepts like frequency, wavelength, speed of sound and how ultrasound images are formed using the pulse-echo principle. It also describes various ultrasound imaging modes like B-mode, M-mode, Doppler and 3D/4D imaging. Factors affecting image quality and different ultrasound transducer types are explained.
01 basic principles of ultrasound & basic termJuan Alcatruz
Ultrasound uses sound waves above 20 kHz to produce images. It can be directed in a beam and obeys reflection and refraction laws. Higher frequencies have better resolution but poorer penetration. The document defines ultrasound terms like cycle, wavelength, velocity and discusses transducer components, instrumentation settings, and Doppler modes. Pulsed wave Doppler has range resolution while continuous wave Doppler can measure higher velocities but lacks range information.
01 basic principles of ultrasound & basic termJuan Alcatruz
This document provides an overview of basic ultrasound principles and terminology. It defines ultrasound as sound waves with a frequency over 20 kHz. Ultrasound can be directed in a beam and obeys the laws of reflection and refraction. The document describes ultrasound properties such as wavelength, velocity, frequency, and acoustic impedance. It also discusses ultrasound imaging techniques including pulsed wave and continuous wave Doppler, and how settings like depth, focal zone, and filter affect the image.
This document summarizes the key components and functioning of an ultrasound machine. It discusses how ultrasound machines use piezoelectric transducers to both transmit sound waves into the body and receive echoes. The echoes are processed by the machine's central processing unit and converted into images that are viewed on a monitor. Proper use of time gain compensation is important to produce images with uniform brightness from near to far field regions.
This document provides an overview of ultrasound physics, instrumentation, and techniques. It discusses how acoustic waves propagate in tissue, the principles of ultrasound transducers and imaging, factors that influence image quality like attenuation and impedance, and advanced techniques like elastography. The key topics covered are the longitudinal propagation of sound waves in tissue, piezoelectric transducers, the basic components of ultrasound machines, and how beamforming and different transducer arrays are used to generate images.
The document provides details about a training internship at Doordarshan Kendra Lucknow. It describes the three main divisions of Doordarshan Kendra Lucknow - the studio, transmitter, and earth station. The studio is where various television programs and serials are recorded. The transmission section modulates and transmits both audio and video signals. The earth station communicates with satellites to downlink and uplink signals over long distances.
MRI image quality is affected by several factors including signal-to-noise ratio, receive bandwidth, noise sources, and spatial resolution. A higher signal-to-noise ratio provides better image quality. Receive bandwidth determines the range of frequencies received and affects chemical shift artifact and readout time. Noise in MRI comes from electronic noise and fluctuations in body tissues. Spatial resolution is influenced by receive bandwidth, matrix size, slice thickness, and field of view. Contrast resolution depends on tissue T1 and T2 values and the timing of pulse sequences. Motion contrast methods like diffusion weighting and flow weighting provide additional tissue information.
This document summarizes key aspects of ultrasound imaging as presented by Dr. A.M. Ehab Mahmoud. It discusses how B-mode images are reconstructed based on echo amplitude and travel time. It then describes the various processing steps involved in ultrasound imaging systems, including amplification, time gain compensation, and post-processing techniques. Finally, it evaluates imaging system performance based on spatial and temporal resolution, contrast, and artifacts that can occur due to assumptions made in image formation.
This document discusses various topics related to ultrasound imaging including goals, early pioneers, transducer types, Doppler instrumentation and physics, harmonic imaging, spatial compounding, extended field of view, fusion imaging, 3D and 4D ultrasound, and contrast enhanced ultrasound. It provides details on transducer selection, control settings, tissue harmonic imaging principles, spatial compounding benefits, fusion imaging steps, and contrast agent interactions.
Usg transducer and basic principles of ultrasound Doppler, this slide describe the basic physics of ultrasound transducer and Doppler , must know thing is given in this presentaion. Good review for radiology resident. Thanks.
This document discusses ultrasound and its use in diagnostic radiology. It begins by defining sound and describing the different categories of sound including infrasound, audible sound, and ultrasound. It then explains that ultrasound is an imaging technology used in diagnostic radiology to examine internal body structures using high frequency sound waves without using ionizing radiation. The document goes on to describe the piezoelectric effect and pulse echo principle, which are the physical principles that allow ultrasound to generate and receive sound waves. It also discusses the different components of an ultrasound machine including transducers, pulsers, amplifiers, beamformers, and displays. Finally, it describes different types of transducers and their applications.
Ultrasound uses high frequency sound waves to visualize internal structures. It works by transmitting sound waves into the body using a transducer probe, which detects the echoes as they bounce off tissues and organs. The echoes are processed to form images on the ultrasound machine screen in real-time. Common applications include obstetrics, cardiology, and urology. The Philips HD11 is an ultrasound system with curvilinear, linear, and phased array probes for different exams. It provides grey scale, Doppler, and color imaging modes. Ultrasound has benefits of being non-invasive, portable, and having no radiation, but has limitations of being operator dependent and unable to penetrate bone.
Here are quick answers to the review questions:
1. Ultrasound is high frequency sound waves that travel well through soft tissues like muscles, organs and fat. It travels poorly through gas pockets or bones.
2. Higher frequency ultrasound has better resolution but poorer penetration. Lower frequency has poorer resolution but better penetration.
3. Pros of ultrasound include lack of radiation, quick exams, ability to see different tissue planes, portability and lower cost compared to other imaging modalities.
4. Probes come in linear, convex, sector and endocavity shapes. Linear probes have a rectangular footprint for long superficial structures. Convex probes have a curved footprint for abdominal exams. Sector probes have a wedge shape for
The document discusses the basic components and functioning of an ultrasound machine. It describes the transmitter/pulser, transducer, receiver and processor, display, and recording components. The transducer is made of piezoelectric crystals and converts electrical energy to ultrasound energy and vice versa. Different controls like gain, zoom, and Doppler are used by the radiographer to optimize the ultrasound image.
This document discusses non-thermal effects of diagnostic ultrasound, specifically radiation force and its potential biological effects. It outlines ultrasound basics and physics, defines key terms, and explores mechanical effects not related to heating, including cavitation, acoustic radiation force, and acoustic streaming which can cause fluid movement. Observations of effects on bone, lung, heart, perception, and development are provided, such as ultrasound accelerating bone healing and potentially altering neural migration through radiation force.
Ultrasound imaging uses high frequency sound waves to create images of internal organs and structures. It provides a non-invasive way to visualize anatomy and diagnose conditions. The document discusses how ultrasound works, including how transducers convert electrical signals to sound waves and receive echo signals. It also covers the factors that affect image quality and resolution. Overall, ultrasound is a valuable medical imaging tool when properly operated by a skilled clinician.
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significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
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তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
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This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
2. WHY THE BASIC UNDERSTANDING IS
NECESSARY?➤ To get full advantage of this technique
➤ Appreciate its strengths and limitations
3. ULTRASOUND
➤ Sound waves have frequency in the range of 20 to 20,000 Hz.
➤ Ultrasound are in the range of > 20,000 Hz (or 20 KHZ)
➤ Medical ultrasound typically use frequency of 2.5 MHZ to 15
MHZ
➤ Advantages
Can be directed as a beam
Obeys laws of refection and refraction.
Gets reflected by small objects as well
➤ Disadvantages
Propagates poorly through gas medium
47. Field of view
The field of view (FOV) is the plane or area scanned by the ultrasound transducer.
Sector
The sector is a fan-shaped image with the narrow end displaying objects closer to the
transducer and the wider section showing the more distant structures . The region of
interest (ROI) should be kept as close as possible to the TEE probe. 2-D imaging is
displayed on a gray scale, with the high amplitude signals being ascribed a white color
and low amplitude a black color. The shades of gray form a picture of the heart in a
sector.
Scan lines
Each piezoelectric element of the transducer transmits a US pulse along a line. All
echoes from the structures along this line are received, thus producing a scan line
whose length is the image depth. [12] The ultrasound beam then moves on to the next
scan line position where the process is repeated [Figure 5]. Increased scan lines
improve the resolution of the image.
49. Frame
Each frame represents a total sweep of the US beam and is made up of a complete set
of scan lines depending on the number of individual piezoelectric elements in the
transducer. [12]
Frame rate
The frame rate (number of images recorded every second, i.e., Hertz) provides a
seamless, continuous, moving 'real time' display. [13] The highest frame rate possible
should be sought as a lower frame rate lends a 'swimmy' quality to the moving image.
In order to maintain a higher frame rate, the smallest FOV that allows the display of the
region of interest, should be employed. [14]
Depth
This control alters the vertical FOV of the image, and is used to get the ROI into view.
Increasing the depth increases the time taken for the signal to return back to the
transducer, thereby decreasing the frame rate, and vice versa.
50. Zoom
Zoom is used to magnify and improve the resolution of the selected ROI, by
decreasing the sector size and increasing line density. The entire FOV is used to
display the enlarged ROI image. This function is invaluable in the investigation of
valvular morphology, pathology, and relatively small pathological masses, such as,
vegetations. It can also be employed to improve measurement accuracy, when
measuring smaller structures. [14]
Most ultrasound scanners feature one or more zoom modes. In a receive zoom mode,
the ROI is selected via trackball control and then magnified. Receive zoom is a post-
processing function that simply enlarges the pixels within a selected ROI, without
improving the fundamental resolution, akin to a magnifying glass. [15] An acoustic or
transmit zoom is a pre-processing function that digitizes the image data in the selected
region at a higher density, by increasing the data bandwidths, to provide a higher
resolution zoom image. [
51. Freeze
The freeze button freezes the real-time display and retains it in the digital memory, in a
sequence of the immediately preceding frames. Scrolling the frames will allow
selection of the appropriate image for study, annotation, and archiving. [15] Freezing the
image also stops the transmission of the ultrasound and prevents the probe from
overheating and possible tissue damage.
Trackball
This control is a stationary pointing device that contains a movable ball rotated with the
fingers or palm, similar to using a mouse on the PC. It is used for moving Doppler
boxes to the desired location and for measuring and annotating.
52. TWO-DIMENSIONAL CONTROLS
Preprocessing versus Postprocessing Controls
Preprocessing controls adjust the transmission and acquisition of the
ultrasound signals. Preprocessing settings control the formatting of
the ultrasound signal for conversion into an electric signal. Changes
in the preprocessing controls affect the information that the scanner
will access to create an image, and this formatted information is the
basis on which an image is created.
Postprocessing settings affect the manner in which the formatted
information is displayed on the monitor.
Simply put, postprocessing defines the "cosmetic appearance" of the
ultrasound data displayed on the monitor
53. System controls
Power is the rate of energy delivered in a sound wave. Intensity is the concentration of power within the
cross-sectional area of the US beam. [20] There are several system controls that can be used to obtain a
good image by using minimal acoustic intensity. These controls can be divided into three categories:
Direct controls
The Power control has a direct impact on acoustic intensity and is used to select the minimal intensity
levels required to produce an optimal image.
Indirect controls
The controls of imaging mode, pulse repetition frequency (PRF), focus depth and frequency have an
indirect effect on acoustic intensity. 2D imaging mode disperses energy over the entire scanned area but
Doppler concentrates energy in a particular area. Increasing the rate and time of the ultrasound signals
increases the time-averaged intensity value.
Receiver controls
Receiver controls such as gain, dynamic range and image processing influence ultrasound without
affecting the intensity output. Hence they should be optimized first before increasing the power.
Another classification of these controls can be based on the time of modification of the signal.
Preprocessing controls modify the analog and digital signal prior to storage in the computer memory
whereas postprocessing controls manipulate the image after its entry into memory. [21]
54. Transmit power
Most machines describe power in terms of decibels (dB). An increase of 3 dB increases power or
intensity by twice the original and a decrease of 3 dB will halve the power- the 3 dB
rule. [23] Minimum power which is consistent with good image quality should be used.
Thermal Index (TI) is an estimate of risk from thermal effects of US and is defined as the ratio of
total acoustic power to that required to raize the temperature by 1°C under defined
assumptions. [9]
Mechanical Index (MI) is an estimate of risk from the non-thermal effects and is the amount of
negative acoustic pressure within an ultrasonic field. It is defined as the peak negative pressure
divided by the square root of the ultrasound frequency. Values of indices less than 1 are generally
considered safe and though a high index reading is not proportional to a bioeffect, every effort
must be made to reduce the chances of a high index. [5]
55. Transmit Power
Transmit power controls the amplitude (acoustic power) of the transmitted
ultrasound signal.
Modern echocardiography systems default to a high-power setting to
maximize the signal-to-noise ratio.
A theoretic concern is that high-power ultrasound can have deleterious
effects on tissue, particularly in fetal echocardiography.
Federal standards restrict the maximal intensities allowed for transmit power
settings on commercially available ultrasound systems.
Typically, echocardiography systems default to the maximum transmit power,
however, proper adjustment of transmit power becomes critical when echo
contrast studies are performed.
56. Gain
Gain is the degree of amplification of
the returning US signal. [20] The gain
button alters the "brightness" of the
whole image by adjusting the
amplification of all returning echo
signals. Minimal gain should be used
to provide an optimal image with good
quality without dropout or blooming of
signals [14] [Figure 7]. As a rule of thumb, fluid
and blood should appear black,
myocardium a medium grey and the
pericardium and calcification, a bright
white color on the grey scale.
Figure 7: Mid-esophageal AV short axis view. In the image the a arrow highlights a low gain setting of 20; and the coaptation line between NCC and LCC is
not visualized. In image b, the gain is set too high at 100. LCC - Left coronary cusp; NCC - Non coronary cusp; RCC - Right coronary cusp
57. Gain
Increasing the gain increases the amplitude of the electric signal generated by
returning ultrasound signals received at all depths.
Unfortunately, any noise present is also amplified.
Setting the gain too high or too low affects the ability to read the image correctly.
When the gain is set too high, the image appears quite bright, and linear structures,
such as the mitral valve, appear thickened. Increases in the gain also increase the
amount of visible noise.
For instance, with moderately excessive gain settings, the left ventricular (LV)
cavity acquires a speckled appearance, which can make it difficult to differentiate
the LV cavity from the myocardium.
With further increases in the gain, the entire LV takes on a whitened appearance,
and the ability to differentiate structures is lost.
58. When the gain is set too low, only bright signals, such as those from
the pericardium, are visible, and very low-amplitude signals, such as
the signal from an LV thrombus or "smoke" in the LV, are lost.
Therefore, the gain should be adjusted to obtain an image with a
gray scale ranging from low-amplitude (dark gray) to high-amplitude
(white) signals.
The gray scale, displayed as a bar graph on the right side of the
image, is useful for guiding adjustments.
59.
60. Clinical pearl
The bright ambient lighting of the operating room often misleads the
echocardiographer to use excessive gain settings. This problem can be
overcome by eliminating the operating room lights briefly during the
examination or shielding the screen with a hood.
61. Time Gain Compensation
Because the amplitude of the reflected ultrasound depends on the distance
traveled (depth) and the echogenicity of the tissue, the ability to adjust the gain
setting selectively at each depth is essential to optimize the image.
Time gain compensation allows the operator to adjust the gain at specific
depths. For example, the echocardiographer can use the time gain
compensation to amplify the weaker signals returning from the far field more
than the signals returning from shallower depths (near field).
The echocardiographer should be careful when adjusting the time gain
compensation. If it is set too low, the elimination of true tissue signals is a risk.
The time gain compensation should be used to eliminate gain-related artifacts
and optimize far field structures. The effects of time gain compensation settings
on image quality are shown in .
62. Time gain compensation (TGC)
As the US beam passes deeper through tissue, there is a steady loss of transmitted
intensity caused by attenuation of ultrasound. TGC toggles amplify the weak
returning signal proportionately to the time delay and increase the gain for that
particular depth . Near field gain is usually set low and the farfield gain is set high to
compensate for the energy loss. Therefore the primary function of TGC is to ensure
signals of similar magnitude at different depth are displayed at same amplification. [20]
Figure 8: In this mid-esophageal four-chamber view, the TGC toggles at the level of the ventricles have been manipulated to illustrate the high gain at that
particular depth (arrow)
63.
64. Clinical pearl.
In a normal examination, the time gain compensation controls are set
lower in the near field and higher in the far field. However, for imaging
pathology in the near field with low echogenicity (e.g., thrombus in the
aorta or left atrium), the near field time gain compensation should be
increased.
65. igure 9: Transgastric mid-papillary short axis
view. In panel A the septal and lateral wall
areas are poorly defined. In panel B both
wall regions are adequately imaged by
increasing the lateral gain. PPM-
Posteromedial papillary muscle and APM -
Anterolateral papillary muscle
Lateral gain compensation (LGC)
LGC is similar to TGC except they alter image gain at specific
angle sectors in a direction perpendicular to TGC. It is useful to
image hypoechoic images caused by suboptimal positioning.
66. Depth
This control selects the maximal distance to be displayed. Increasing depth
beyond the structure of interest has several negative consequences.
1. The image size is reduced. The most obvious consequence is that the
image size is reduced because a larger area of the cardiac anatomy
must be displayed on a screen of fixed size. The display of the cardiac
structure of interest will be smaller and thus more difficult to evaluate.
2. The frame rate is lower. In addition, as the depth is increased, the frame
rate of the two-dimensional ultrasound is slowed because the system
must wait longer for signals to be received. Doubling the depth of
penetration doubles the wait time before another pulse can be sent, so
that the pulse repetition frequency and subsequently the frame rate are
decreased.
67. Thus, to optimize image display and temporal resolution, the depth
should be set just beyond the structure of interest.
68. It also must be appreciated that the lateral resolution of the ultrasound
system is inversely proportional to the depth. Therefore, it is practical
to have the position of the probe as close as possible to the structure
of interest. For example, when the leaflets of the aortic valve are being
evaluated, the ME aortic valve short-axis view is preferable to the deep
transgastric (TG) long-axis view because the probe is closer to the
aortic valve and lateral resolution is improved.
70. Focus
The focus control enables the operator to focus the ultrasound beam at a selected
distance from the transducer.
This is achieved by altering the sequences of electric impulses sent to the
transducer elements.
The goal of focusing is to have the beam narrowest at the location of the structure
being evaluated because a thinner beam improves lateral resolution.
The user must be cognizant of the focus depth of the system, which is typically
marked on the edge of the sector. If the focal zone is located too far from the area
of interest, the image resolution may not be sufficient for proper evaluation.
When the atrial septum is being evaluated for a patent foramen ovale, the focus
should be placed at this level. Remember that structures distal to the focal point lie
in the far field and may appear "fuzzy" or abnormally thick. Avoid evaluating small
structures distal to the focal point until the focal point is moved to that level.
71. Clinical pearl.
Adjust the focus point to the level of the structure of interest for high-
resolution imaging.
72. Frequency
A feature of modern TEE systems is that they are capable of multiple
frequencies, so that the transmitted ultrasound frequency can be
adjusted.
This can be especially important in TEE applications. When the
structures being evaluated are in close proximity to the transducer
(atria, aorta), higher frequencies are used to optimize resolution.
When the structures being evaluated are farther from the transducer
(deep TG views), higher frequencies may not be adequate because
penetration is poor. In these situations, the frequency should be
reduced until a satisfactory image is produced.
73. Clinical pearl.
Use higher frequencies when evaluating shallow structures and lower
frequencies when evaluating deep structures (i.e., TG views).
74. Dynamic Range
Modern ultrasound transducers are capable of detecting reflected
ultrasound signals with amplitudes over a range of approximately
100 dB.
Unfortunately, the monitors used in these systems are capable of
displaying only a much smaller range (30 dB).
Therefore, to display the range of ultrasound signals detected by the
transducer, the dynamic range control allows the wide spectrum of
ultrasound amplitudes to be compressed.
The compressed signals are then displayed on the monitor as
varying shades of gray.
75. Ultrasound systems have both a fixed dynamic range, which is limited
by the hardware of the system, and a selectable dynamic range, which
can be changed according to the echocardiographer's preference.
➤ Increasing the dynamic range of the system increases the number of
shades of gray between black and white within the image and
therefore increases image detail, so that a smoother image appears
on the display screen.
➤ Decreasing the dynamic range of the system increases the contrast
of the image, with more black and white areas than shades of gray.
The effect of dynamic range on image quality.
76.
77. POST PROCESSING TOOL
Compression
Compression is a postprocessing tool that in conjunction with the preprocessing
dynamic range control setting alters the range of the displayed gray scale.
The compression control changes how the given dynamic range of ultrasound data is
displayed.
➤ When the compression control is reduced, the given dynamic range is displayed
with the largest range of allowable shades of gray. The lowest-intensity signal is
displayed as black, and the highest-intensity signal is displayed as white.
➤ As the compression control is increased, the range of shades of gray used to
produce the image is reduced to produce a softer, smoother image. The gray
scale is therefore compressed by eliminating the display of shades of gray at each
end of the spectrum. Compression settings are a personal preference of the
echocardiographer.
78. Reject
In the early stages of ultrasound development, it was discovered that ultrasound transducers
detect many sources of low-level interference from within the body. Examples include movement
artifacts, the electronic noise of equipment, such as ventilators, and aberrant ultrasound resulting
from refraction of the ultrasound signal. These low-level signals are detected by the scanner and
displayed in the image as “noise."
➤ To eliminate such signals, all ultrasound systems have a fixed or default "filter" that removes
any signal below a certain amplitude threshold (the lower limit of the displayed dynamic range).
Sometimes, the default filter is not enough to remove the noise in an image.
➤ The reject control is an adjustable control that enables the user to eliminate a greater number
of low-intensity signals. The reject control is used to eliminate signals that are usually located in
blood pools and are a result of artifacts.
➤ When the reject control is adjusted, care must be taken not to eliminate important low-intensity
echoes from certain pathologic conditions. Specifically, fresh thrombi within a cardiac chamber
or vessel have a low-intensity (dark) signal that may be eliminated from the image if the reject
is set too high.
79. Clinical pearl.
Increase the reject control to eliminate noise (random echoes often
found in blood pools and other low-intensity areas). Do not use
excessive reject because low-intensity echoes such as thrombi may be
removed from the image.
80. Persistence
Persistence is a postprocessing control that can best be described as signal averaging or
image blending.
As incoming signals are processed by the system, images are displayed as they are created
in their purest form (no persistence), or the system can average one image with the next and
display the averaged image.
➤ Persistence is used to smooth the appearance of the heart in motion.
➤ As the persistence control is increased, more images are used to create the averaged
image, and temporal and spatial resolution is decreased.
➤ If the persistence is set too high, the image is often described as appearing to be in "slow
motion.”
➤ Because valvular structures move rapidly, persistence is usually set low in
echocardiographic applications to retain temporal resolution and a real-time appearance.
81. Sector Size
Sector size controls the angle of the sector displayed on the monitor.
Most ultrasound scanners can display sectors with angles ranging from 15 to 90 degrees.
Wide angles allow the operator to survey a broad array of cardiac structures in a single view.
The most important effect of the sector size is on the frame rate. The wider the sector size, the
lower the frame rate and the temporal resolution.
For a proper evaluation of fast-moving structures, the sector size should be kept small to allow
for higher frame rates. Some scanning systems do not depend on sector size for high frame
rates and can achieve adequate frame rates with a full 90-degree sector.
Clinical pearl.
Larger sector sizes result in lower frame rates and a lower level of temporal resolution. When
valvular structures are evaluated, it is helpful to decrease the sector size (or use M-mode) to
improve the frame rates.
82. COLOR CONTROLS
Region of Interest
The region of interest is the area that defines where the color will be displayed. There are certain
limitations to setting the size of the region of interest. As the width of the region of interest
increases, the frame rate decreases. The goal is to optimize the frame rate to improve temporal
resolution and the assessment of blood flow. The depth also affects the color frame rate. As the
depth increases, the system must wait longer for the returning signal; therefore, the frame rate is
slower.
Color Gain
Color gain is similar to two-dimensional gain in that it increases or amplifies the signal generated
by the returning echoes. It is very important to have the color gain set properly. If the gain is set
too low, a small jet, such as a small atrial septal defect or patent foramen ovale, can be missed. If
the gain is set too high, the size of a regurgitant jet is frequently overestimated. The color gain is
adjusted simply by increasing the color gain control until speckles of color lay outside the blood
pools and then decreasing the gain one to two settings until the speckles go away.
83.
84. Color Scale
The color scale is the range of color velocities displayed. To optimize the color scale, one
must be cognizant of the general velocities of the blood flow being evaluated. For example,
when lower-flow velocities in the pulmonary veins are evaluated, one must decrease the color
scale. Adjusting the scale will affect the Nyquist limit. Velocities sampled outside this range
cause aliasing within the color display. In certain applications, such as when the proximal
isovelocity surface area (PISA) is calculated, adjusting the color scale to produce aliasing is
required to create an adequate flow convergence hemisphere for measurement.
Variance
The variance color flow map displays the range of velocities in any given sample volume. The
variance in flow is displayed as shades of green, whereas normal flows are displayed with the
standard red-blue color flow map. In laminar flow, the range of velocities in a given sample
volume is relatively small, and laminar flow appears color-coded as red or blue. In turbulent
flow, the number of velocities is increased (i.e., increased variance) such that turbulent flow is
color-coded as green. A variance map may help to identify a small turbulent jet by tagging it
with a different (i.e., green) color.
85. STORAGE SYSTEMS: ANALOG VIDEOTAPE VERSUS DIGITAL STORAGE
The advantages of videotape storage are its availability and reasonable cost. It is the most
common storage format used today. A patient's study can be reviewed anywhere a
videocassette recorder is available.
A shortcoming is that it is difficult to archive and retrieve studies, and to directly compare
different studies of the same patient.
Current digital technology also allows the study data to be manipulated.
The reviewer can adjust the postprocessing controls, including contrast, brightness, and two-
dimensional and Doppler gain. It is also possible to make measurements from stored images
without having to recalibrate the system. Finally, optical storage media make it practical to house
large databases in minimal space.
In sum, digital storage offers major advantages for archiving, retrieving, and sharing
echocardiographic studies.
SUMMARY
The extensive control options of modern full-platform echocardiography systems provide the
echocardiographer with tools for reliably obtaining high-quality images under a broad range of
conditions. With a firm understanding of the control settings available, the examiner can optimize
image acquisition and display and detect pathology that might otherwise be missed.
86. Two-dimensional imaging
2D imaging helps to image the heart motion in real-time enabling
detailed morphological and functional assessment .
It also helps quantitative assessment of cardiac dimensions and
provides the framework for M-mode and Doppler imaging. The
various control buttons used to get an optimal image are
described in.
Figure 6: Mid-esophageal AV short axis view. LA- Left atrium; NCC- Non-coronary cusp; LCC- Left coronary cusp; RCC- Right coronary cusp; TV- Tricuspid valve; P
88. M-mode imaging
Motion mode imaging is one of the basic forms of imaging. One scan
line provides a single dimensional "ice-pick" view of the heart and the
signal is plotted as brightness mode against time on the X-axis. The
amplitude of movement of an object and its distance from the
transducer is displayed on the Y-axis.
The short sampling time ensures a higher sampling frequency and
frame rate, which allows for extremely accurate measurement and
timing of events.
M-mode is typically used for measurements of the aortic and mitral
valve, ventricle cavity size and thickness during systole and diastole
and timing of flow patterns in combination with color flow mapping.
89. Doppler Imaging
The Doppler shift is defined as the change in frequency of sound
reflected by a moving object and is determined by the Doppler
equation [28] [Figure 12]. Doppler shift caused by red blood cells reflecting
ultrasound can be used to assess the trajectory and speed of normal
and abnormal blood flow by determining flow velocity, direction and
turbulence. The two main types of Doppler imaging techniques are
pulsed wave Doppler (PWD) and continuous wave doppler (CWD) [Table 1].
Figure 12: The Doppler frequency shift (fd) depends on the transmitted frequency (ft) and the velocity (V) of the moving blood and the angle (θ) between the ultraso
90. Pulse wave Doppler
PWD measures low-velocity flows at a specific point along the beam axis.
The beam axis should be parallel to the blood flow to maintain accuracy. For practical
purposes, if the angle between the US beam and the blood flow is greater than 20°, there is an
unacceptable degree of error in estimating the velocity.
PWD is used to diagnose diastolic dysfunction from mitral valve and pulmonary vein inflow
patterns, estimate aortic valve area and calculate stroke volume. [27]
Sampling
PWD uses a single piezoelectric crystal which acts both as a transmitter and receiver to measure
blood velocity intermittently at a particular area called as sample volume.
Adjusting the gate control can increase or decrease the size of the sample volume. The
trackball is used to place the sample volume at the area of interest.
91. Depth
The ROI should be as near the transducer as possible. This is because as imaging depth
increases, there is a decrease in the pulse repetition frequency.
Gain
Gain is used to amplify the returning Doppler signals. The audio volume can be used to
hear the Doppler shift to optimize the spectral waveform.
Display
The velocity is displayed as a spectral waveform on the vertical axis with time
displayed on the horizontal axis .
By convention, blood flowing towards the probe is displayed above the baseline and
blood flowing away from the probe is displayed below the baseline. The baseline
should be adjusted to accommodate the complete waveform.
92. Figure 13: PWD applied across the mitral valve inflow. Tracing the typical hollow velocity envelope is used to calculate Velocity Time Integral, peak, and mean gra
93. Aliasing
The major limitation of PWD is the maximum velocity (2 m/sec) that can be
measured. A velocity higher than half of pulse repetition frequency (Nyquist
limit) will appear as an ambiguous signal on the other side of the baseline. This
is known as aliasing.
High PRF Doppler imaging is a technique that combines features of both PWD
and CWD imaging which can be used to prevent aliasing. [20]
Frequency
Since Doppler shift is proportional to ultrasound frequency, lower frequency
transducers are more useful as there is less chance of reaching the Nyquist limit.
94. Reject
Reject function is used to eliminate low-velocity signals near the
baseline by filtering the lower frequencies and trace a sleek
waveform.
Invert
The invert button is used to reverse the direction of the signal
display above or below the baseline irrespective of the direction
of flow.
95. Continuous wave Doppler
Continuous wave Doppler (CWD) can accurately measure high-velocity flows (<9
m/second) along the beam axis, provided it is parallel to the blood flow. It is used to
calculate the grade of stenotic valve lesions and estimates pulmonary artery
pressure. [27]
Sampling
The CWD uses two separate piezoelectric crystals to transmit and receive signals in
order to measure all the different blood velocities along the beam axis, continuously.
This makes it difficult to accurately know the depth of the reflected signal. The main
disadvantage of CWD is its lack of depth discrimination (Range ambiguity).
Display
The CWD is displayed as a waveform with a filled-in spectrum caused by the different
velocities being measured along the scan line [Figure 14]. A turbulent flow, caused by
obstruction, results in spectral broadening and increased velocities.
96. Figure 14: The transgastric long axis view and the CW Doppler applied through the stenosed calcific aortic valve displays a typical 'filled-in' velocity envelope. By tr
97. ➤ Scale factor
➤ The scale control adjusts the range of velocity that can be displayed, and
should be set so that the highest velocity spectral trace can be displayed
without cutting off the peak of the trace.
➤ Sweep speed
➤ This control indicates how fast the spectral waveform can sweep across
the screen.
➤ Increasing the sweep speed decreases the number of cycles and
increases the width of the waveform.
➤ A low sweep speed shows more waveforms on the screen and is useful
to demonstrate waveform variations caused by respiration and
arrhythmias
98. Wall filters
All Doppler systems have a variable wall filter control that sets a threshold
beyond which frequency signals can be removed from the display.
Angle correction
This control changes the angle calculation in the Doppler equation by
adjusting the beam axis to the direction of assumed flow, thereby minimizing
the error. This does not actually change the direction of the Doppler beam
nor does it alter the quality of the spectral recording. It is preferable to adjust
the transducer to position the beam axis parallel to the blood flow rather than
count on angle correction.
Compression, and the Reject and Invert buttons can be used as for the pulse
wave Doppler.
99. Color flow Doppler
The Color Flow Doppler (CFD) provides a striking display of both
blood flow and the cardiac anatomy by superimposing the PWD
flow data on 2D images [29] [Figure 15]. It is useful in diagnosing the
abnormal flow as well as confirming the normal structures.
Figure 15: A mid esophageal, four-chamber view superimposed with color flow doppler showing mitral regurgitation. The vena contracta (VC) depicts the regurgita
100. Color maps
The PWD used for color mapping, records the mean velocity data
from multiple sample volumes - color packets along each scan line.
This velocity data is then color-coded; blue indicates flow away
from the transducer and red is the flow toward the transducer.
The color bar on the screen provides a reference frame for
interpreting the colors.
The color flow maps are then integrated with 2-D imaging to
provide a real-time display.
101. Sampling and depth — Color sector size and placement
The size, position, and trackball controls are used to change the width,
length, and position of the color box.
The color box, while enclosing the ROI, should be narrow and as close to
the transducer as possible. This prevents aliasing, lower frame rates, and
'swimmy images' caused by the longer time taken to interrogate pulses
that are far away from the transducer. [19]
Gain
Excessive 2-D gain before superimposing the CFD should be avoided, as
it may obscure the flow.
Optimal adjustment of the color gain setting is essential, as too much gain
will result in noise and impair the image quality and interpretation.
A low gain setting will attenuate sensitivity and make the image appear
smaller than the flow jet.
102. Velocity scale
The adjustable velocity scale is calculated by the machine depending on the depth of the
image.
When the blood-flow velocity exceeds the velocity scale of the color legend, the machine
will continue to represent the velocity of the blood flow, but in the opposite direction. This
means that once the velocity of blood flow in one direction exceeds the brightest red, the
color will instantaneously change to the brightest blue, then gradually darken.
➤ The velocity scale must be set to around 50 - 60 cm/second usually.
➤ Lower scales increase sensitivity, but promote aliasing.
➤ When the flow is turbulent, some of the velocities will be depicted as a multicolored
mosaic signal.
103. Baseline
The baseline button helps to shift the zero baseline of the velocity
scale.
Smoothing
Smoothing determines the grade at which the color packets
merge into the adjacent packets.
➤ A low smoothing setting will create a speckled flow pattern
and
➤ a high setting will blend the color packets together.
104. Tissue Doppler echocardiography
Tissue doppler echocardiography (TDE) uses the Doppler frequency shift to calculate
low myocardial velocity, to objectively quantify regional myocardial motion.
Pulsed TDE is similar to PWD, while the color-coded TDE display is based on
assigning colors to different velocities.
Lower velocity colors tend to be darker colors, while higher velocities are
represented by brighter colors.
This modality has been applied in the assessment of regional and global left
ventricular systolic and diastolic function.
TDE is limited by its reliance on the angle of interrogation.
This problem can be solved by 2D Speckle Tracking Echocardiography which
tracks tissue movement by offline analysis of acquired ECG triggered image loops.
Speckles are small areas of different brightness and shape contained within the 2D
gray-scale. By tracking the velocity, direction of movement and spatial relationship
of speckle clusters during a cardiac cycle, strain and strain rate can be measured to
quantify myocardial wall deformation.
105. Figure 16: Tissue Doppler image of the lateral mitral annular motion showing early diastolic filling E', atrial contraction A', and movement in systole S'
106. Three-dimensional (3D) echocardiography
The 3D technology enables us to view the cardiac structures
from different perspectives. Real-time (RT) 3D TEE, using a
matrix array probe, interrogates a volume of tissue and produces
pyramidal-shaped ultrasound datasets. [31] The 3D image quality
depends on the quality and number of 2D images used, limiting
motion artifacts and achieving adequate ECG, and respiratory
gating. [32]
107. Three-dimensional live mode
This displays a live narrow angle RT 3D volume of the selected
2D view for single or multiple heart beats with a frame rate of 20 -
30 Hz. The maximum sector dimensions are 60°×30° in the
lateral and elevational planes, respectively, which can be
changed using trackball controls. Using physical movements of
the probe, this mode can be used to rapidly scan the heart and
guide RT interventional procedures. [33]
108. Three-dimensional zoom mode
This provides a magnified RT 3D image, with sector dimensions
of 90° × 90° and a lower frame rate of 10 - 15 Hz. Selecting a 3D
zoom displays two orthogonal 2D images, which can be modified
in the lateral and elevational planes, to accommodate the ROI
within the box. The acquired dataset can then be cropped and
orientated to provide excellent spatial resolution for structures
such as mitral valves, intraoperatively [Figure 17].
109. Figure 17: A 3D zoom mode image rotated to display the surgeons view from the left atrium onto the mitral valve, with a P2 prolapse and ruptured chordae tendin
110. Three-dimensional full-volume mode
Although this mode is not an RT imaging modality, it provides a large volume image, with
sector dimensions of 75°×75°. Selecting 'Full volume' displays two orthogonal 2D images
that can be modified in the lateral and elevational planes, to accommodate the ROI. Small
sub-volumes are acquired over four to seven cardiac cycles, synchronized, and then
'stitched' together to display the 'blob view'. The frame rate varies between 20 and 50 Hz,
depending on the number of cardiac cycles. The dataset can then be cropped and
orientated. The 3D color flow Doppler can be superimposed on a 3D full volume, using
seven cardiac cycles, but it reduces the frame rate to <10 Hz.
Arrhythmias, electrocautery artifacts, and probe movements cause a demarcation line,
termed as a stitch artifact, which is seen between the sub-volumes, distorting the
anatomy. [34] Offline analysis of digitally recorded cine loops using specialist software allows
manipulation, rotation and cropping of an image to display details in a surgical orientation
including measurements of distance, area and volume.
111. Conclusion
Echocardiography is an important technology, widely used for the
evaluation of cardiac anatomy and physiology. Despite the recent
advances of 3D TEE, a sharp, optimized 2D image is pivotal for the
reconstruction. The low degree of invasiveness and the capacity to
visualize and assimilate dynamic information that can change the course
of the surgery is an important advantage of TEE. An understanding of the
fundamental principles of cardiac ultrasound and knowledge of ultrasound
instrumentation and settings is necessary for the proper acquisition and
interpretation of the echocardiographic data.