B P3 C16 Echocardiography Flashcards
Early ultrasound equipment projected a single beam of ultrasound,which resulted in a single scan line that could be “painted” across a moving paper or screen,with depth being depicted on the vertical axis and time on the horizontal axis. This method, known as _____ echocardiography
M-mode (for motion)
Proper interpretation of returning signals is physically limited by the speed of sound in tissues (approximately ___m/ sec) and the depth of the tissues being interrogated, both of which dic
1540 m/s
Nevertheless, improvements in processing speed have allowed “frame” rates, a major determinant of temporal resolution, to reach speeds higher than _____ image frames per second.
100
The _____ of the ultrasound used, which is inversely related to ultrasound frequency, is the principal determinant of axial imaging resolution, which equals approximately half the wavelength.
Wavelength
The higher the ultrasound frequency (i.e., shorter the wavelength), the higher is the _____
Spatial Resolution
Most TTE machines operate across frequencies of _____ MHz.
2.5 to 5 MHz
Higher frequencies up to _____ MHz can be used in pediatric imaging,
7 to 10 MHz
The speed of ultrasound through body tissues averages _____ meters per second (m/sec), essentially the speed of sound through water, but varies minutely as ultrasound waves traverse various body constituents.
1540 m/s
These slight differences in ultrasound speed through different media (e.g., blood, muscle, fat, air) result in impedance mismatches at the tissue interfaces, which produces the _____ that mark the boundaries between different tissues.
Specular reflections
When ultrasound encounters inhomogeneous tissue regions, such as myocardium, liver, or other tissues, _____, occurs and results in speckled-appearing images.
Multidirectional reflection, or backscatter
In ______ Doppler, discrete pulses of ultrasound reflect off moving structures (i.e., red blood cells moving through the heart) and return to the transducer.
Pulsed-wave
With _____ Doppler a dedicated piezoelectric element continuously emits ultrasound, and a separate element simultaneously continuously receives the returning signals.
Continuous-wave
This refers to the maximum velocity that can be accurately quantified within a given sample volume and is directly related to the PRF (the numeric value equals 1⁄2 the PRF)
Nyquist limit
_____ Doppler is primarily used to assess flow with relatively low velocity (typically ≤1.5 m/sec) present at a specific location
Pulsed-wave
_____ Doppler is used to assess higher velocities (typically ≥1.5 m/sec) along the transducer beam, but cannot specify at what location the highest velocity occurs.
Continuous-wave
____ Doppler is a PW Doppler–based technique in which the velocities in a region of interest are encoded with colors that represent both mean velocities and directionality of the flow, which are superimposed on a 2D image in the region of interest
Color Flow Doppler
By convention, flow moving away from the transducer is encoded in _____, and flow toward the transducer is encoded in _____.
Away: Blue; Toward: Red
_____ flow, in which a wide range of velocities exist, appears as a multicolored mosaic pattern (usually green and yellow).
Turbulent
Blood flow through the normal heart and great vessels is predominantly _____, meaning that the direction and velocity of flow are streamlined and uniform, even across valves.
Laminar
_____ echocardiography provides greater temporal resolution than standard 2D imaging and was traditionally the method of choice for certain linear measurements, particularly those that are collinear with the ultrasound beam.
M-mode
Estimates the pressure gradient (ΔP) between two chambers separated by an orifice based on the velocity of flow through the orifice.
Bernoulli equation
P1 − P2 = 4V2
It is important to appreciate that Doppler echocardiography measures _______ but neither pressure nor flow direction.
Velocity
The magnitude of flow can also be inferred by multiplying the ________ by the cross-sectional area (CSA) of the region being interrogated
Velocity-time integral (VTI; i.e., integrated velocity throughout the cardiac interval)
The _________ is based on conservation of mass and states that flow in one region of the heart should be equivalent to flow in another region (assuming no intervening shunt or valve regurgitation).
Continuity principle
Since velocities through stenotic valves are usually too high to assess with PW Doppler, ________ is usually used, assuming that the highest attained velocities correspond to the narrowest region along the ultrasound beam.
CW Doppler
Identify the M-mode image
Normal M-mode across the base of the left ventricle at the level of the mitral leaflet tips.
Note the E and A waves corresponding to the anterior mitral leaflet motion in early diastole (E) and with atrial contraction (A), respectively.
Identify the M-mode image
Mitral valve prolapse
There is late systolic posterior bowing (arrow) of the mitral leaflets on M-mode.
Identify the pathology
Rheumatic mitral stenosis
Thickened mitral leaflets that move parallel to each other, straightening of the slope after the E wave (E-F slope), and reduced leaflet opening in diastole
Identify the pathology
Hypertrophic obstructive cardiomyopathy
Very thickened interventricular septum and systolic anterior motion of the mitral valve leaflets
For all LV geometries, the _______ has been demonstrated and recommended as the most accurate method
Modified biplane Simpson method of discs
Normal LVMI for Men and Women
Men - 49 - 115
Women - 43 - 95
Pathologically, LV hypertrophy is defined as __________
Increased overall LV mass
Identify the pattern of LV remodelling
RWT .30
LVMI 130
Male diagnosed with MVP Severe MR
Eccentric hypertrophy
The most common method of assessment of systolic function is ______
Formula?
Left ventricular ejection fraction (LVEF),
Difference between end-diastolic volume and end-systolic volume divided by end-diastolic volume
Stroke volume can be determined from 2D or 3D images by subtracting _______
End-systolic volume from end-diastolic volume
The __________, also known as the Tei index, is defined as the sum of isovolumic relaxation time (IVRT) and isovolumic contraction time divided by ejection time, and this method takes into account both systolic and diastolic performance
Myocardial performance index (MPI)
A higher index is associated with worse function.
In adults, values of LV MPI greater than _____ and RV MPI greater than _____ are considered abnormal.
LV MPI > 0.40
RV MPI > 0.43
_________ refers to the percent deformation between two regions, such as shortening of myocardial muscle in systole or lengthening in diastole.
Strain
The maximal deformation of the LV myocardium at peak systole averaged over the entire ventricle), has emerged as an important measure of cardiac performance that adds incremental predictive value to standard measures such as the LVEF
Global longitudinal strain
This measure also appears to predict survival or the development of heart failure in patients following MI.
Global strain measurements are also useful in assessing the effect of cardiotoxic chemotherapies on individual patients over time, and may be useful in identifying acute subclinical rejection in cardiac transplant patients.
Both regional timing, reflecting synchrony, and myocardial peak strain, reflecting contractile function, have prognostic significance in patients undergoing _________
Cardiac resynchronization therapy (CRT)
Utilizing regional strain data during CRT placement to help guide optimal lead position may be a more effective approach
A pattern in which strain is preserved apically relative to that at the midventricular and basal levels is suggestive of ________
Amyloid cardiomyopathy.
The _______ is equal to the sum of these grades divided by the number of segments visualized, so a normally contracting ventricle should have a score of 1.0.
Wall motion score index (WMSI)
A WMSI of 1.7 or higher is usually associated with the physical examination findings of heart failure.
Ultrasound cannot easily distinguish between old and new wall motion abnormalities, although ______ and _______ would be suggestive of chronic infarction and scar tissue.
Local myocardial thinning and increased echo-brightness
______ used to assess flow from the left atrium to the left ventricle during diastole
Mitral inflow Doppler
_____ occurs during early diastole when the ventricle is filling passively
E wave
_______ represents the velocity of blood flow during late diastole during atrial contraction
A wave
E wave velocity is dependent on the transmitral pressure gradient and is thus directly related to _______ and inversely related to _______
LA pressure
LV compliance
The height of the A wave is additionally dependent on the strength of _________
Atrial contraction.
E/A ratio for younger individuals less than 65 years old
1.0 or higher
E wave height is greater than A wave
LV compliance declines with _______, and so the E wave generally diminishes. Simultaneously, the A wave typically increases as atrial contraction augments to compensate for the reduced LV compliance.
Age
The _________ of the E wave increases as compliance worsens initially
Deceleration time (DT)
However, as diastolic function continues to worsen and LA pressures rises, the E wave will heighten again, and the size of the A wave declines as LV pressure rises and LA function begins to worsen, so the E/A ratio may revert to relatively normal (_______).
Pseudonormalization
Further worsening of diastolic function leads to the so-called ______, in which the descending slope of the E wave becomes very steep (rapid DT) because of abrupt cessation of mitral inflow. T
Restrictive pattern
Identify the transmitral inflow pattern
E/A ratio > 1.5
DT < 150
Restrictive Pattern
Three distinct waveforms are seen in TDI:
Systolic contraction (the S′ wave) toward the relatively fixed apex, followed by early (e′) and late relaxation (a′) signals in diastole
The timing of the e′ and a′ waves is coincident and a gous in many ways to standard Doppler of mitral inflow, but the movement is in the ______ and of much lower velocity.
Opposite direction to blood flow
DTI e′ in principle is a measure of ______
LV compliance
An E/e′ ratio ________ is considered abnormally high at any age and is usually indicative of elevated LVEDP.
Greater than 14
Pulmonary vein flow has three components:
(1) the S wave, which consists of forward flow from the pulmonary veins to the left atrium during ventricular systole
(2) the D wave, which consists of passive flow during ventricular diastole
(3) the AR wave, which is the slight flow reversal into the pulmonary veins during atrial contraction.
Findings in PV Doppler flow pattern in Impaired LV relaxation
Blunting of the S wave relative to the D wave
Greater flow into the p monary veins during atrial contraction (broader A wave)
