General Knowledge Flashcards
Understanding the background of echo, how it works, the different modes, normal echo readings, and other features of echo used to analyze valve function.
What is echocardiography and how does it work (generally speaking)?
Echocardiography is a non-invasive cardiac imaging modality that uses piezo-electric crystals that emit and receive ultrasound waves at a rate of 1000 per second.
How do the piezoelectric crystals in echo work to make an image?
The crystals convert electrical oscillations into mechanical oscillations (sound). When the ultrasound waves reach an interface between two different mediums, part of the ultrasound is reflected back towards the probe, which leaves a map of the distance from the probe and the density of the tissue.
How is the distance from the probe calculated in echo?
The distance from the probe is calculated by the time delay between the transmission and reception of the reflected sound wave
How is the density of the tissue calculated in echo?
The density of the tissue is calculated by the intensity of the reflected signal
How is a patient oriented for echo?
A patient is put in the left lateral decubitus position
What echo probe is used for adults? Which one for children?
A 2.25MHz probe is used for adults, and a 5MHz probe is used for children
What affects the quality of echo images?
Any structures between the heart and the probe will affect the quality of the images
Provide three examples that can lead to poor image quality in echo.
- lung disease
- obesity
- chest wall deformities
What is Doppler echo?
Doppler echo uses the principles of the Doppler effect where the relative velocity and direction of a sound source to the observer determines the received frequency of the sound. Velocity over time are plotted to get a map of what direction blood is flowing in relation to the probe (toward or away).
At what frequency does the Doppler probe usually transmit?
2MHz
True or False: The Doppler probe acts as both the transmitter and the reciever.
True, the Doppler probe transmits a frequency and once it bounces off a structure (tissue, bone, etc.) the frequency comes back to the probe for comparison.
What direction is blood moving in relation to a Doppler probe if the ultrasound wave frequency increases?
The blood is moving toward the probe
What direction is blood moving in relation to a Doppler probe if the ultrasound wave frequency decreases?
The blood is moving away from the probe
What does Doppler echo plot on the screen?
Doppler echo images plot velocity against time
What do flows above the line in Doppler echo represent?
Positive values represent blood moving towards the probe
What do flows below the line in Doppler echo represent?
Negative values represent blood moving away from the probe.
How does a normal laminar flow appear on Doppler echo?
Since all the blood cells are travelling at similar velocity, the Doppler flow signal will be represented as a single line.
How does turbulent flow appear on Doppler echo?
Since turbulent flow has a wide range of velocities, it is represented in Doppler as a
“filled in” signal.
What is aliasing in echo imaging?
Aliasing refers to the phenomenon when the Nyquist limit of max velocity is exceeded, resulting in “wrapping around” of the Doppler signal and an abnormally low velocity. This appears as a signal showing up in both the positive and negative directions of the m/s line at the same time.
True or False: Aliasing only occurs with continuous-wave Doppler.
False, the opposite is true where aliasing only occurs with pulse-wave Doppler. For this reason, the recommendation for high velocity jets is to use continuous-wave Doppler to avoid aliasing.
What are the different modes of echo?
What are the 2D applications for ME 4Chamber TEE?
MR etiology, IAS assessment, Presence/absence of mass, RV function, pericardial effusion, visual assessment of LV function, TSP height, and calcification (annular, leaflet, chords)
What are the color doppler applications for ME 4Chamber TEE?
Visual MR and TR assessment
What are the spectral Doppler applications of ME 4Chamber TEE?
MR severity and assessment of MV inflow gradient
What are the 2D Biplane applications for ME Bicommissural TEE view?
Leaflet length in orthogonal LVOT view, flail gap measurement, number of jets
What are the 2D applications for ME Bicommissural TEE view?
Maximum 2D mitral annulus, calcification (annulus, leaflets, and chords), flail/prolapse width, and movement/length of P1/P3
What are the color Doppler applications for ME Bicommissural TEE view?
MR assessment, assessment of commissural jets, location of jet, vena contracta
What are the 2D biplane applications for ME 2Chamber TEE?
Visualization of leaflets, and assessment of LAA (“smoke” or thrombus)
What are the color Doppler applications for ME 2Chamber TEE?
MR assessment, pulmonary vein view (LUPV and RUPV)
What are the Spectral Doppler applications for ME 2Chamber TEE?
Measure LAA emptying velocity (PW only), pulmonary vein view (LUPV and RUPV)
What are the dedicated LVOT view applications for ME Long Axis TEE view?
PML and AML length, MR etiology, mitral valve (P2/A2)
What are the color Doppler applications for ME Long Axis TEE view?
AP vena contracta, MR PISA
What are the 2D biplane applications for the TEE ME bicaval view?
Assessment of IAS and fossa ovalis, LA, RA, RAA, SVC, IVC, recommended for short axis
What are the Color Doppler applications for the TE ME bicaval view?
PFO (patent foramen ovale) assessment, which is a congenital cardiac lesion and can eventually cause stroke
What is the 3D En Face Mitral Valve view good for?
3D zoom, and adjusting ROI around mitral valve