Echo Parameters Flashcards
Normal RA volume for men
25 +/- 7 mL/m2
Normal RA volume for women
20.5 +/- 6mL/m2
How is RA size measured?
Dedicated apical 4C to measure RA volume by single plane area-length
HTN causes dilation of what portion of the aorta?
distal aortic segments, little effect on SoV
What coronary cusps are seen in PS long axis view?
RCC above NCC
What aortic annular axis (minor or major) is measured in PS long axis
Minor
What part of the cardiac cycle do you measure aortic annulus and LVOT diameter? How to measure?
Mid-systole
inner -edge to inner-edge
What part of the cardiac cycle do you measure SoV, aortic root, STJ? How to measure?
End-diastole
leading edge to leading edge
What is the concern with IVC diameter in athletes?
Does not correlate well with RAP, they typically have dilated IVC with normal collapse
When should you measure IVC?
End expiration and end diastole using M-mode
How does RV EF compare to LVEF?
RVEF is normally smaller than LVEF, but RV EDV is larger than LV EDV, so stroke volume is similar.
RV EF is slightly higher in women compared to men.
Normal RV EF
> /= 45%
Normal RV fractional area change?
> /= 35%
Normal TAPSE?
1.8 or greater
Normal RV base diameter? mid?
Normal = 41mm for base
Normal = 35mm for mid
Normal Tissue doppler-derived tricuspid lateral annular systolic velocity
> 9.5cm/s
Normal RIMP (PW)
<0.43
Normal RIMP (TD)
<0.54
Normal LV EDV volume for men/women?
Men <74 mL/m2
Women < 61mL/m2
Normal LV ESV volume for men/women?
Men 31 mL/m2
Women 24 mL/m2
Regional wall motion 4 grade scheme?
- Normal or hyperkinetic
- Hypokinetic or reduced thickening
- Akinetic or absent/negligible thinning
- Dyskinetic or systolic thinning/stretching
The current generation of fully sampled matrix array transducers typically containes how many crystals?
3,000 piezoelectric crystals
What causes stitch artifact?
Any sort of non-regular movement during a multibeat acquisition: respiration, arrhythmia, patient/operator movement, esophageal motility
What LAA filling velocity is associated with CVA?
<20cm/s
What tricuspid leaflet has the longest radial length?
Anterior
Methemoglobinemia suspected if? Consequences? Treatment?
Cyanosis, low SpO2, normal pO2
Circulatory collapse, neurologic depression, death
Methylene blue
Coronary cusp closest to atrial septum on TEE?
NCC
Why is the RCA most at risk for air embolization during surgery?
It is the most anterior when a patient is supine and air floats.
What should you do if a patient needs intraop TEE but has an esophageal stricture?
Epicardial echo
Intraoperative TEE is useful in LVAD placement because ?
Evaluation of AI, as this may make LVAD ineffective
Most specific criterion for severe MR?
EROA >0.4cm2 or VC > 7mm
What happens to ESV and EF in a hypovolemic patient?
Decreased ESV, increased EF
EF on TEE is higher or lower while on cardiopulm bypass?
Either: tends to be underfilled, so EF is higher but metabolic changes/transient ischemia can cause decreased as well
Hoe to get PHT from DT?
PHT = DT x 0.29
MVA using PHT?
MVA = 220/PHT
How to estimate PADP with PI?
PADP = 4[PV (EDP)]2 + RAP
Use PV END-DIASTOLIC PRESSURE, not early peake diastolic.
PAWP by Vp?
PAWP = 4.6 + 5.27(E/Vp)
What is Vp? Normal?
Flow propagation velocity.
Rate at which RBCs reach the LV apex from the MV leaflet during early diastole. Measure of LV relaxation (diastolic function).
Normal: >55cm/s in young, >45cm/s in middle-aged and elderly
E/e’ is directly proportional to what?
LAP.
LAP = 1.9 + 1.24(E/e’) or 4 + E/e’
E/e’ medial>15 = elevated LAP
E/e’ lateral>12 = elevated LAP
Peak to peak gradient equation?
P2P = (LVSP + LAP) - SBP
LVSP can be calculated by peak MR velocity using bernoulli
P1/2t of severe AI?
<200
What would preclude ASD closire?
Elevated PVR
How to calculate PVR on echo?
PVR = change in pulmonary pressure/pulmonary flow PVR = MPAP-LAP/pulmonary flow (Qp)
MPAP = PADP + 1/3(PASP-PADP)
Answer in woods units, normal 1-2
RVSP equation using VSD?
RVSP = SBP - 4(VSD)2
*no need for RAP if VSD used
RVSP - PS gradient = PASP
LAP equation
LAP = LVSP - (pressure change using Vmr jet)
Mean aortic gradient is about __%of peak gradient?
60%
E wave deceleration time that would point towards restrictive (G III)?
<160ms
What atrial reversal velocity would indicate elevated LVEDP? What about AR-a duration?
> 35cm/s.
The atrium is contracting, which propels blood into atrium (A wave on MV inflow) and backwards into PV (no valves). The higher the LVEDP, the more blood that will be pushed backwards and the higher the AR wave will be.
if AR duration is >30ms longer than a wave (AR-a), this also implies LVEDP is elevated.
How does inspiration affect ventricular interdependence?
Ventricular interdependence refers to diastolic filling of one ventricle at the expense of the other.
In constriction, inspiration leads to decreased systemic vein pressure, which leads to increased SV-RA-RV gradient, leading to increased RV filling and decreased LV filling.
So you will see increased HV forward flow during inspiration and increased retrograde flow with expiration.
This will occur in BOTH constriction and tamponade
When doe flow across the AV occur?
Only during ET, whether normal or abnormal.
Systole consists of IVCT and ET. TR/MR will be holosystolic, AS will start later because it will not happen during IVCT.
Triphasic MV inflow is consistent with what diagnosis?
Cor triatrium, can present similar to MS.
How do you calculate LAV index?
LAV = 0.85 x (A1xA2/L)
LAVindex = LAV/BSA
How to differentiate tamponade from constriction using E:A ratio?
Constriction does not impede early diastolic filling, so E>A. Tamponade impedes diastolic filling, so A>E.
Tissu doppler filters are used to excllude __ velocities.
high
What is strain rate?
The change in velocity between two points divided by their distance.
Subendocardial fibers are __ and mid-myocardial fibers are __.
- Longitudinal, this is why the detection of subendocardial disease uses global longitudinal strain.
- Circumferential
GLS is dependent on __, __, and __.
Vendor, age, and gender.
Tell me about radial strain rates.
Positive radial strain rates represent active contraction. So negative strain rates are either relaxation (if during diastole) or hypokinetic/dyskinetic (if during systole).
How would you define subclinical LV dysfunction?
GLS reduction in 15% compared to baseline.
In asymmetric septal HCM, the tissue doppler e’:
Has an inverse relationship with septal thickness. You can use this to differentiate HCM from athlete’s heart.
HgbA1c correlates with
E/e’, so elevated A1c is associated with diastolic dysfunction, even if asymptomatic.
What change in US contrast led to improved LV opacification?
Using higher-molecular weight gases instead of room air.
Allergy to __ is a contraindication to Optison.
blood products
__ is a contraindication to all contrast agents.
ASD, though can be used with PFO
What is contractility?
How can you measure this?
Systolic function independent of loading conditions. So if EF changes with constant HR, conduction velocity, preload, and afterload: contractility has changed.
Can measure with systolic strain rate (always) or LV dP/dT (if MR present but not severe)
What is the most reliable measure of RV function?
None are reliable, though 3DE is up and coming.
Wall stress is proportionate to __.
transmural pressure and chamber size.
How do you define a WMA?
<50% wall thickening or <5mm excursion
5 year mortality of postinfarct patient with mild LV dysfunction and ESV <95mL?
10%
5 year mortality of postinfarct patient with mild LV dysfunction and ESV >95mL?
30%
How would decreased preload affect strain?
Decreased preload would decrease strain due to decreased LV cavity size.
Decreased HR (increased filling) and decreased afterload (decreased impedance) would increase strain.
LV mass equation?
LV mass = 1.04([LVd+IVS+PW]3 - LVd3) -13.6
hypertrophy >131 men, >100 women
What anomalies are associated with subaortic membrane?
PDA, PS, coarctation of Ao, and VSD
How to differentiate constriction from restriction via e’?
MEDIAL e’ >8cm/s heavily favors constriction over restriction. <6cm/s favors restriction.
What will you see on HV doppler in constriction?
HV end-diastolic reversal velocity/flow flow velocity >0.8
Pulmonary inflow pattern. What are the S1, S2, and D waves related to?
S1: LA relaxation
S2: Stroke volume and PA pressure
D: LV relaxation
How do you estimate PCWP in atrial fibrillation?
E/e’ >11, MV DT <150ms, and PV diastolic velocity <220ms are all associated with elevated filling pressures.
If large V-wave on Cath and no MR on echo?
LA has lost reservoir function. Severe loss of LA compliance.
LVEDP given AI?
End diastolic AI velocity can be used to determine LVEDP if systolic DBP is known.
LVEDP = DBP - LVEDP
WHat are the components of the Wilkins score?
Leaflet mobility, leaflet calcifications, leaflet thickening, subvalvular thickening
Most likely to give a false negative on stress echo?
Isolated LCx disese. Sensitivity of stress echo increases as the number of vessels involved increases.
Myxoma characteristics?
Usually in the LA and attached to the atrial septum by a narrow stalk
Fibroma characteristics?
almost always single and located in the ventriculary myocardium, commonly the ventricular septum.
Fibroelastoma characteristics?
well-circumscribed oval mass that is often attached to the leaflet of a valve by a narrow stalk
Indications for PV balloon valvuplasty?
Peak gradient >60, mean >40 or symptomatic with peak gradient>50.
Effective orifice area indexed to BSA fro PPM in aortic position? severe?
PPM <0.85, severe <0.65
Risk factors for coronary obstruction during TAVR?
LM height >10mm above aortic annulus
Female (83% were women)
Small aortic root diameter
Mitral clip inclusion criteria?
A2-P2
Copatation length between 2mm and 11mm
Flail gap <10mm and flail width <15mm
Before releast of mitral clip, what should sonographer do?
Ensure proper clip capture
Measue MV gradient to ensure no MS (must be <6mmHg)
planimeter MVA (should be >2.0cm2)
Importantly, once above is performed mitral clip release does not need to be performed under echo guidance. Every other step should be.
Contraindication to LAA occlusion?
Valvular Afib
Most common potential complication of Watchman?
Serious pericardial effusion
What defines LVOT obstruction?
Peak instantaneous gradient of >30mmHg, and >50mmHg meet the conventional threshold for surgical or percutaneous intervention
What defines success in alocohol septal ablation?
Reduction in gradient by at least 50%, Myocardial contrast echo is important to define vascular distribution of septal wall.
ASA should be avoided if septal wall thickness >30mm
Contraindication to mitral clip?
MVA <4.0cm2
What defines success of MV valvuloplasty?
Increase in MVA by 50%.
thinning of the anterior, basal septum is highly specific for what disease?
Cardiac sarcoidosis
What is the definition of chemo-induced cardiac toxicity?
Reduction in EF by 10% with EF <53%.
*GLS is not currently in the definition, but >15% drop may predict a reduction in LVEF
Septal thickness in HCM that is an indication for ICD?
30mm
RVOT diameter to make you think of ARVC?
3.6cm or greater
Apical HCM measurement?
Apical thickness >15mm. End-diastolic dimension usually normal. Important to note that no LVOT obstruction/SAM occur in isolated apical HCM
Most important predictor of mortality in amyloidosis?
Increased LV wall thickness. >15mm predicts CHF and death.
What treatment for AI would not be recommended prior to LVAD? Why?
Mechanical, because of risk of thrombus
Definition of RV failure after LVAD?
Implantation of RVAD or 14 days of inotropic support
Does negative bubble study exclude PFO?
No, should have them valsalva, as well.
Should be closed at time of LVAD surgery.
Acute RV failure during or immediately after LVAD or other cardiac surgery should make you think of __.
RCA air embolism
Heartmate II speed range?
6,000 - 15,000
HVAD speed range?
1,800 - 4,000
For an LVAD, what is a suction event?
When the LVAD decompresses the LV to an abnormally small size. Will cause abnormal septal shift into the LV. Can cause ventricular arrhythmias due to cannula irritation.
Best views to interrogate LVAD cannula?
Parasternal long and short axis
For LVAD, what needs to be the case for a speed test echo to be performed?
Patient must be on therapeutic anticoagulation, as a thrombus can embolize. Thrombus may form in aortic root if AV continuously closed.
How do you differentiate cor triatrium from supravalvular mitral ring?
By the location of the LAA.
If LAA in the distal/MV/apical portion, cor triatrium.
If LAA in basal/PV portion, supravalvular ring.
Annual risk of CVA in patient with AF and MS?
7-15%
Smallest vegetation that can be detected by TTE? TEE?
TTE 5mm
TEE 1mm
How does persistence of vegetation after abx therapy affect outcomes?
It doesn’t. Persistence of vegetation after abx therapy without significant regurgitation. Persistence only affects outcomes if the valve continues to degenerate.
After healing from endocarditis, what percentage of valves will regain normal structure and function?
<10%
How to identify eustachian valve vegetation?
RVOT view or parasternal short axis.
> 5mm thick (normal <2mm) with high-frequency motion independent of the underlying structure.
MV aneurysm is usually due to __.
Endocarditis and surgical repair is usually indicated due to high rate of perforation.
What is a “ghost”?
Tubular, mobile mass in the path of an intracardiac lead following lead extraction. Almost always occurs after removal for infectious reasons and may persist after abx treatment. Prognostic significane is uncertain.
How does severe prosthetic mitral regurgitation affect gradients?
Peak gradient increased more than mean gradient.
Attenuation is the combined result of __ ,__, and __?
What aims to correct for this?
Ultrasound scattering, absorption, and scattering.
Time gain compensation
What controls the strength of a transmitted ultrasound wave?
Pawer control
The spatial resolution of an ultrasound image is equal to the:
What is spatial resolution?
Size of a pixel in the relevant direction
Smallest distal between two objects that allows distinction between them.
What is temporal resolution?
Temporal resolution is equal to __.
Smallest time between two events that allows distinction between the two.
Temporal resolution is equal to the inverse of the FRAME rate. For example, if frame rate is 20frames/second. Temporal resolution = 1/20 = .05seconds = 50ms
The dynamic range of echoes displayed on the screen is adjusted by the __.
Compression control, this control can be used to include or suppress weak echoes.
What control can best compensate for image losses due to attenuation?
Gain, which amplifies the return signal.
How does filtering eliminate ghosting artifacts?
By removing low-velocity signals.
With time gain compensation, the machine __ signal in near field and __ signal in far field.
Decreases near
Increases far
What is persistance?
A tool used to smooth out an image. Images are averaged to create this smoothing effect. This comes at the expense of temporal resolution, so increased persistence can cause structures to appear to be moving in slow motion.
What is the difference between read and write zoom?
Read zoom simply magnifies an image.
Write zoom improves image resolution by increasing both the line density and number of pixels.
What is harmonic imaging?
Imaging that uses ultrasound reflections that have twice (for second harmonic) the frequency of the transmitted waves.
How does decreasing depth affect frame rate?
Hoe does reducing sector width affect frame rate?
BOTH will allow increased rape rate.
How does echo contrast work?
Added gas-liquid interface of the microbubbles augment reflection.
How can you improve shadowing with echo contrast?
Use less contrast.
Eustachian valve, crista terminalis, chiari network are all structures that are seen in the __.
Right atrium
Where is the moderator band?
RV
Rhabdomyoma
Benign cardiac tumor. Usually small and lobulated with diameter of 2mm-2cm. Usually multiple and are strongly associated with tuberous sclerosis.
Common primary cancers that met to the heart?
RCC - IVC to the R heart
Breast- heme/lymph spread, pericardial effusion common
Lung - direct extension, pericardial effusion common
Melanoma - intracavitary/myocardial involvement
Lymphoma - lymphatic spread
Carcinoid - TV and PV
Common myxoma symptoms?
Dyspnea, syncope, palpitations, fevers/weight loss (IL-6 production)
Fibroelastomas
90% are single and can occur on any valve. Valve dysfunction is rare.
Leiomyosarcomas
are derived from smooth muscle tissue and can originate from the cells lining the PV. Usually occur in the LA, as opposed to most other cardiac tumors, terrible prognosis. Usually present in their 30s.
Angiosarcoma.
Terrible prognosis, usually metastasized by diagnosis. 3:1 M:F ratio. R>L heart. Can be intracavitary or infiltrative.
Synovial sarcoma
Transposition between Ch 18 and X. Malignant primary cardiac tumor, very rare.
What is likely if cardiac mass does not opacify at all with echo contrast?
Cyst
Chiari network
congenital remnant of sinus venosus. RA, 2-3% prevalence. Usually incidental
What is the most common valve-associated tumor?
Papillary fibroelastoma, 85% (though overall third most common tumor after myxoma and lipoma). Can embolize. All symptomatic patients should get surgery, as should those with large or mobile masses (>1cm)
What three vitamin/minerals can lead to a reversible CM?
Thiamine (beriberi) - seen in alcoholics, causes high-output failure
Selenium - TPN patients, LV dilation and systolic CHF
Carnitine - TPN, genetic, liver, renal disease. Systolic CHF
Echo of hemochromatosis?
Mild LV dilation with decreased systolic function. Normal valves, maybe some mildly increase wall thickness. Usually in late stage of disease, so other organ systems will also be involved.
Friedreich’s ataxia?
AR disease. Severe, concentric LVH. Global decrease in function. May mimic HCM. Suspect if young patient with neuro/ataxic complaints.
Most common echo abnormality in HIV?
Pericardial effusion
Most common associated lesion with sinus venosus ASD?
Anomalous R PV connection
Describe hallmarks of AVSD?
Cleft anterior MV leaflet, lateral rotation of the LV papillary muscles, TV/MV attached at same level, LV inflow shortened due to absent of AVS (LV inlet:outlet ratio <1). AV “sprung” anteriorly due to no longer being wedged between TV and MV.
Other name for outlet VSD? Most common acquired lesion?
Supracristal or Subpulmonary
Aortic regurgitation due to prolapse of the aortic cusp into the VSD.
Most common type of VSD associated with coarctation?
Perimembranous.
What percentage of small trabecular VSDs in neonates will close spontaneously?
80-90%
Direction of atrial level shunting is primarily related to __.
Compliance of the ventricles or the ventricular EDP
Most common site of aortic coarctation?
Just opposite the insertion site of the ductus arteriosus (juxtaductal).
Valve lesion associated with Noonan?
Pulm stenosis.
RAP as determined by JVP?
RAP = JVP * 0.7
Primum ASD associated with?
VSD, cleft MV, LVOT obstruction.
Holt-Oram congenital heart defect?
Secundum ASD
What is the cause of cyanosis in most congenital patients?
Decreased pulmonary blood flow
Tricuspid atresia is always seen with __.
Atrial connection to relieve RA overload.
Mean gradient for severe TS? PHT for severe severe PS?
Gradient >7mmHg
190
Mean gradient for PS? Peak velocity?
Peak gradient >64mmHg
Peak velocity >4m/s
Single most prognostic factor in determining pHTN severity?
Presence of pericardial effusion. RV size, function and LV size are also important.
PAP are not too important, just need to determine high vs low.
What measure of RV function is not applicable in acute PTE?
RIMP, will be abnormally low (normal).
What best describes the cyclic changes in pressure waves responsible for the creation of sound waves?
Rarefactions and compressions
Propagation speed of sound in tissue?
1540m/s
How do you resolve aliasing in PW Doppler?
- Use CW
- Increase PRF (scale) to the maximum setting for depth
- Switch to high pulse repetition frequency
- Utilize a lower frequency transducer
- Adjust baseline to allow for imaging the maximum velocity
What is an ultrasound period?
Time to complete one cycle
What does aliasing look like?
Light red to light blue
What crystal produces the narrowest far field beam?
Largest diameter crystal and higher frequency
Larger crystals create less divergence. Higher frequencies create less divergence.
Equation relating PRF (pulse repetition frequency) and Doppler shift?
The Nyquist limit or frequency is the highest Doppler velocity before aliasing occurs and is equal to half of the PRF.
PRF = 2NL
What has a higher NL, PW or CW?
CW, since it is continuously sending and receiving signals (very high PRF).
Variance map?
Green is added to normal red/blue to show turbulent flow.
You see something you think is an artifact, what’s the first thing you can do?
Change the depth setting, artifact will change with depth. Real will not.
What artifact results in a hyperintense signal behind a low attenuating structure, such as a fluid filled structure?
Enhancement.
What artifact results in the placement of echogenic lines, equally spaced apart from each other, in a fluid filled structure?
Reverberation
What artifact results in the misplacement of a structure in an image due to a change in direction at non-perpendicular boundaries with a difference in tissue impedance.
refraction
What artifact results in ghost images of high contrast structures, off axis to the sound beam?
Grating lobes.
Lateral resolution is best where the beam is __.
Narrowest
What term most accurately defines the percentage of time that an echo machine is actually transmitting a pulse into the body?
Duty factor
The percentage of time that an echo machine is actually transmitting a pulse into the body is very short and is called the duty factor. Most ultrasound machines while imaging in 2D spend approximately 0.2% of the time transmitting and 99.8% of the time “listening” for returning signals.
What is the highest Doppler velocity before aliasing starts and is equal to half of the pulse repetition frequency (PRF).
The Nyquist limit
What is propagation speed?
The propagation speed is how far (distance) a sound wave travels through a medium in one second. The speed of sound varies depending on the medium. Propagation speed in soft tissue is 1,540 m/sec or 1.54 mm/μsec
How do you calculate duty factor? What is the maximum DF?
DF = (pulse duration / PRF) x 100
Maximum is 100%. For example, in CW there are two crystals (one that sends and one that receives). The sending crystal has a DF of 100%.
What influences PV S1 wave?
LA relaxation
As LV chamber stiffness increases, what happens to mitral inflow velocity?
E wave velocity increases and deceleration time decreases.
What are the components of an endocardial cushion defect?
Most common operative problem?
Inlet VSD
Primum ASD
Abnormal MV (often cleft)
Widened anteroseptal tricuspid commissure
MR
Congenitally corrected TGA is associated with what other defect?
VSD
Fetal echo is not useful for defining what congenital defect?
ASD, because PFO is normal
Parameters for aortic prosthetic stenosis?
Normal: >0.85cm2/m2
Mild to moderate: 0.65 - 0.85
Severe: <0.65cm2/m2
PPM is not necessarily validated in what population?
Obese, i.e. PPM may not have same detrimental effects in high BMI patient since obese patients may require less cardiac output than non-obese patients of the same BSA
When is the risk of dissection in pregnancy the highest?
Third trimester.
Paravalvular leak >__% will typically cause rocking and will need surgery rather than device closure.
25%
Areas of 3D echo drop-out suspected to be paravalvular defects should be confirmed with color Doppler mapping
Normal EF and decreased SV in setting of prosthesis points to what?
Prosthetic stenosis
Normal SV = 60-100
Normal SVI >35
Weirdly, PAU is rarely associated with __.
Dissection.
IS associated with intramural hematoma, pseudoaneurysm, stroke, aneurysm, or rupture.
How does VC correlate with anatomic orifice?
VC is slightly smaller.
The vena contracta is characterized by high velocity, laminar flow.
VC is relatively independent of flow and driving pressure and eccentricity.
For prosthetics:
Thrombus causes __.
Flail/structural issue causes __.
Thrombus causes stenosis.
Flail/structural issue causes regurgitation.
How doe you calculate PA pressures?
Systolic PAP = 4(TR)2 + RAP
Mean PAP = 4(Early-diastolic PR)2 + RAP
End-diastolic PAP = 4(end-diastolic PR)2 + RAP
Near zone length equation?
NZL = D2f/4c
What is a transducer?
Any device that transforms one kind of energy into a different form is called a transducer. The energy type is not limited to sound but in ultrasound piezoelectric crystals convert electrical current into vibrations (sound) and also on the receive side convert vibrations (sound) back to electrical signals.
As LV sphericity index becomes closer to one, what happens to the papillary muscles?
Move laterally and apically.
True - The normal left ventricle has an elongated, ellipsoid or bullet-like shape. The long axis is normally 1.5X to 2X that of the short axis. The index is therefore ≥ 1.5
B. True - Short axis diameter of the ventricular short axis is usually measured simultaneously to the long axis in the apical 4-chamber view, but can be measured in the parasternal short axis view if necessary.
C. True - The index represents the ratio between long and short axis lengths, and is therefore a unitless number
D. True — The long axis diameter is measured from apex to the mitral annular plane in the apical 4-chamber view.
E. False - As the ventricle becomes more spherical, the short axis diameter increases more than the long axis length. The Index approaches 1. There is displacement of the papillary muscles laterally, but also APICAL displacement (not basal).
What post-stress E/e’ is suggestive of elevated filling pressures?
13
New inferior WMA while on CPB (intraoperative TEE) is suggestive of what?
Air embolism to the RCA.
Pre-pump TEE: what parameter is predictive of SAM of MV after repair?
A mitral valve coaptation point to septal distance of less than 15mm
Speed of sound in tissue?
1,540 m/s
Speed of sound in Starr-Edwards mechanical valve ball is __ (higher/lower) than surrounding tisse.
Slower, this makes it look larger and more oval-shaped.
Called propagation speed error artifact.
What is a useful tool to determine whether aortic images are artifact or flap?
What type of artifact is this?
M-mode.
Reverberation artifact. There is sometimes a linear artifact in the aorta at twice the distance of LA wall. This is why this artifact typically appears when the aorta is larger than the LA (so that doule the LA distance falls within the aorta). If moves with aortic posterior wall, most likely artifact. If independent movement, likely real.
__ results from repeated reflections off the transducer or other strong reflectors.
Reverberation artifacts, Intensity will decrease with distance travelled. Equally spaced and parallel to the main sound beam.
What are comet tail artifacts?
Reverberation-type artifact that results in a solid hyperechoic beam of ultrasound distal to the object. Similar to reverberation but does not have equally spaced lines of decreasing intensity. Violation of time of flight and speed of sound assumptions.
Seen commonly with mechanical valves.
Where do beam width artifacts occur?
Distal to the focal zone where lateral resolution is the least optimal.
Snell’s Law
Describes the principle by which refraction of ultrasound occurs and contributes to the development of reverberation-type artifacts.
SL = sin(transmission angle)/sin(incident angle) = speed of medium 2/speed of medium 1
Side lobe artifact
Artifact that appears lateral to the real object. Caused by some of the ultrasound beam being to the side of the central beam. These weak signals will return to the transducer if they hit a strongly reflective object. Will falsely appear within the central beam of the transducer.
Refraction artifact
Produced when the transmitted ultrasound beam is deviated from its straight path line due to crossing a boundary between two media with different propagation velocities. Will result in a duplicate structure displayed in the wrong location.
How does range ambiguity occur?
Occurs when echoes from deep structures created by a first pulse arrive AFTER the second pulse has been emitted.
Mirror-image artifact
occurs when doppler gains are set too high and causes a flow signal (usually less intense than real) on the opposite side of the baseline.
Ring-down artifact
Occurs when the sound beam hits a strong reflector that causes multiple reverberations with distal echogenic lines. Often caused by gas particles. Looks similar to comet-tail, tbh.
Difference between shielding and shadowing?
Shielding refers to the presence of bright beam ultrasound that obscures the visualization of tissue beyond.
Shadowing refers to attenuation and black echoes after a strong reflector.
Ghosting artifact
Develops with color doppler, refers to color doppler that is distorted beyond anatomic borders due to multiple reflections.
