5. Imaging Flashcards
Equation for Nyquist limit?
PRF/2
What is the Nyquist limit?
Maximal frequency shift that can be determined by PW Doppler
*Equal to 1/2 the pulse repetition frequency
What can extend the Nyquist limit?
Using lower frequency transducers
What does the simplified Bernoulli equation ignore?
Flow acceleration
Viscous friction
What is an appropriate use of the simplified Bernoulli equation?
Isolated valvar stenosis
Should you use the simplified Bernoulli equation if you have multiple obstructions in series?
No… need to account for flow acceleration proximal to and distal to the sites of obstruction
Ex. AS and CoA
Why shouldn’t you use the simplified Bernoulli equation for a PDA or BT shunt?
It doesn’t account for viscous friction… the Doppler velocities will be underestimated
*Also difficulties with proper US beam alignment
What is seen on the pulmonary vein Doppler tracing in Grade 1 diastolic dysfunction?
Systolic predominance, more prominent a-wave reversal
What grade of diastolic dysfunction do you see E/A reversal?
Grade 1
What is the expanded Bernoulli euqation?
P1-P2 = 4(V2^2-V1^2)
Coarctation, PW Doppler has a peak velocity of 2M/sec proximal to the coarctation. A CW Doppler across the coarctation reveals a peak Doppler velocity of 4M/sec. What is pressure gradient across coarctation?
4(4^2-2^2) = 48mmHg
What does the presence of holodiastolic flow reversal in the abdominal aorta indicate?
Severe AR
What is used in echo that passes through the pulmonary circulation to opacify LA/LV?
Contrast agents
What size are typical contrast agents?
1-10 microns
Which has lower acoustic impedance, blood or contrast?
Contrast
How long do contrast agents effects persist?
3-5 minutes
When are agitated saline injections used in echo?
- Unexplained cyanosis
2. Stroke
What size are microbubbles in agitated saline?
10-100 microns
How does an agitated saline injection work?
- Don’t pass through the pulmonary capillary bed
- Microbubbles opacity the RA and RV, but not the left heart structures in the absence of an intracardiac or intrapulmonary shunt
- Helpful to identify an intracardiac right to left shunt
How many cardiac cycles for microbubbles to appear in the left heart in an intrapulmonary shunt?
3-5
How many cardiac cycles for microbubbles to appear in the left heart in an intracardiac shunt?
1-2
True or False: A negative bubble study rules out an intracardiac R-L shunt?
False- Negative bubble study doesn’t definitively exclude presence of an intermittent R-L shunt
Name 2 quantitative measures to grade AI
- Width of regurgitant jet (vena contracta)
2. Ratio of vena contracta dimension to aortic annulus dimension
Name a semi-quantitative measure of AI severity?
LV dilation
*Consistent with duration of AI and severity of AI
What factors can influence the length of a regurgitant jet into the LV besides the severity of AI?
- LVEDP
2. Eccentricity of jet
What non-aortic valve measure is an excellent predictor of the regurgitation degree?
Degree of Doppler flow reversal in abdominal aorta
*Forward to reverse flow TVI ratio in distal transverse arch
What is the equation for MPI or Tei index?
[ICT + IRT] / ET
*Distance between end of A wave and beginning of E wave minus ejection time divided by ejection time
What is the ratio of total time spent in isovolumic activity (isovolumic contraction and isovolumic relaxation times) divided by the time spend in ventricular ejection?
Myocardial performance index
What echo window is best for a secundum ASD?
Subcostal
Imaging plane should be what in relation to the cardiac structure of interest?
Perpendicular
Most common associated cardiac defect with a sinus venosus ASD?
Anomalous right pulmonary venous connection
*Either a single right upper pulmonary vein or the right upper and middle pulmonary veins insert anomalously to the SVC or SVC-RA junction
Where are sinus venosus defects most commonly found?
Superior portion of the atrial septum creating a “biatrial” insertion of the SVC
What is characterized by increased respiratory variation in mitral inflow Doppler velocities by >25%
Constrictive pericarditis
What is seen in the transmitral Doppler in constrictive pericarditis?
Increased E:A ratio and a shortened E-wave deceleration time
True or False: The lateral mitral TDI velocities are usually normal in constrictive pericarditis?
True
What is seen in the hepatic venous Doppler in constrictive pericarditis?
Increased atrial systolic flow reversal during expiration
List the echo hallmarks of restrictive LV physiology in adults
- Increased mitral inflow Doppler E:A ratio > 2.0
- Shortened mitral E-wave deceleration time <160msec
- Decreased lateral mitral Ea velocity
- Increased E/E’ ratio >15
What does the pulmonary venous Doppler show in restrictive LV physiology?
Decreased systolic to diastolic pulmonary venous filling wave ratio with significant increased atrial reversal wave velocity and duration
What associated congenital heart lesion most common in patient with Down syndrome and AVSD?
ToF
What is % incidence of CHD in T21?
50%
Most common cardiac anomaly in T21?
AVSD
Most common constellation of cardiac anomalies in Down?
AVSD + ToF
Most common anatomic finding in complete AVSD?
LVOT “sprung” anteriorly
Anatomic hallmarks of AVSD?
- Cleft in anterior leaflet of left AV valve
- Lateral rotation of left ventricular papillary muscles
- Attachments of left and right AV valves at the same level as cardiac crux
- LVOT “sprung” anteriorly
Goose-neck deformity?
- AVSD
- Absence of AV septum, LV inflow is shortened and LV outflow is elongated
- Creates a ratio of LV inlet to LV outlet <1
- Common AV valve, aortic valve is no longer “wedged” between tricuspid and mitral valves and is pushed anteriorly (“sprung”)
What imaging modality had excellent temporal resolution and a high fixed PRF?
M-mode
What is on X and Y axis for M-mode?
X-axis: Time
Y-axis: Distance from transducer
What is used in M-mode?
Single imaging crystal
What is the smallest distance between 2 points distinguishable as separate points?
Spatial resolution
What is axial resolution?
- Ability to differentiate points along the US beam
- Equal to wavelength
What is lateral resolution?
- Ability to resolve points perpendicular to the US beam
- Dependent on beam width (best resolution found where beam narrowest)
What is better, axial or lateral resolution?
Axial
What is the most likely source of error in calculation of Doppler flow velocity?
Angle of incidence of US beam
[c(fd)]/[2focostheta]
Doppler velocity
- Speed of sound (c)
- Transmitted US frequency (fo)
- Frequency shift (fd)
- Angle of incidence (theta)
Under what angle of incidence will Doppler velocity not be significantly underestimated?
<20 degrees
What type of Doppler has no limit to max velocity measured?
CW
How does CW Doppler work?
- Utilizes 2 crystals
* One is continuously transmitting and one is continuously receiving
What is a disadvantage of CW Doppler?
No range gating leads to lack of range resolution… the max velocity can be anywhere along the US beam path
True or False: CW and PW are equally dependent on the angle of incidence for accurate velocity determination
True
How does PW Doppler work?
Utilizes 1 crystal that intermittently transmits and receives
True or False: PW has excellent range resolution?
True…1 crystal transmits and receives and the time between transmission and reception allows determination of depth of signal which provides excellent range resolution
Why does PW have a lower Nyquist limit than CW?
The max detectable frequency shift is limited
Which has higher PRF, Color or Spectral Doppler?
Spectral
What does PRF vary with in PW Doppler?
Depth of sample volume
*Higher PRF with shallower sample volume
What represents the highest frequency shift that can be unambiguously detected and displayed?
Nyquist limit
What is the maximal frequency shift detectable by PW Doppler?
Nyquist limit
What is the Nyquist limit equal to?
1/2 PRF
Is the Nyquist limit lower or higher with PW Doppler?
Lower
Is the Nyquist limit lower or higher with a lower frequency transducer at a shallower depth of interrogation?
Lower
What does color Doppler represent?
Mean velocity of blood flow
How does color Doppler work?
Utilizes multiple sampling sites along multiple US beams to generate frequency shifts that are converted into a digital format and autocorrelated into a color scheme
What does the intensity of color represent in color Doppler?
Mean Doppler flow velocities
The nyquist limit is lower with what compared to spectral Doppler?
Color Doppler
What happens to the 2D images color Doppler is superimposed onto?
Less resolution
What is the optimal echo view to show a subpulmonary VSD?
PSSA
*Can also see in subcostal/apical views angled into RVOT
Where are subpulmonary VSDs located?
Adjacent to the PV and AV
What are other names for a subpulmonary VSD?
- Supracristal
- Doubly committed defect
What is most characteristic acquired cardiac lesion resulting from a subpulmonary VSD?
AI
What causes AI in a subpulmonary VSD?
Prolapse of the aortic cusp into the VSD
What is an indication for surgical closure of subpulmonary VSd with a trivial-small L-R shunt?
- Significant or progressive AI
- Prolapse of aortic tissue may limit size of VSD and lessen L-R shunt, but progression of AI due to distortion of AV seen
- In this case, close VSD regardless of size of L-R shunt
What is the most characteristic physiologic effect of a large VSD?
Equal RV/LV pressures
A large VSD results in what change in ventricular pressure?
- Equalized RV/LV pressures
- Also elevated PASP
Which chambers become volume overloaded with a large VSD?
LA/LV
-L-R ventricular shunting causes increase in PBF and return to left heart
True or False: Overall systemic blood flow isn’t significantly increased in a large VSD?
True
What is the best morphologic marker of RA?
Broad based triangular appendage
*Also connections of IVC and CS (SVC connections can have anatomic variability)
The valve of the fossa ovalis (septum primum) is a structure in which atria?
LA
AV valves are a hallmark of what?
Ventricular morphology
The atrial septum is best imaged in which scan plane?
Subcostal
-This is perpendicular to septum… can get false dropout in imaging planes more parallel
What is the best anatomic hallmark of the morphologic RV?
Connection of the tricuspid valve with a more apical insertion at the cardiac crux as compared to the morphologic MV
List some anatomic features of a morphologic RV
- More apical insertion point of AV valve
- Septophilic (tricuspid valve attachments to the ventricular septum)
- Crescent shaped
- Prominent trabeculations
What is a typical feature of the morphologic LV?
Lack of AV valve septal chordal attachments
List some anatomic features of a morphologic LV?
- Lack of AV valve septal chordal attachments (septophobic)
- Higher insertion of morphologic MV at cardiac crux
- Ellipsoid
- Fine trabeculations (mainly towards apex
Modified Bernoulli equation?
Velocity^2 * 4
What estimate does the modified Bernoulli equation give?
Max instantaneous Doppler gradient
What is the most common anatomic type of subaortic stenosis?
Discrete membrane proximal to AV within LVOT
*Most often circumferential and can be adherent to AV and anterior leaflet of MV
LVOT obstruction in HCM is related to what?
- Asymmetric septal hypertrophy
- SAM of MV chordal/leaflet tissue
What issue with the mitral valve can cause LVOT?
Anomalous chordal insertions in the LVOT
*Can be isolated or found in association with CHD
What is the most common associated cardiac abnormality in someone with CoA?
Bicuspid AoV
*As high as 80% occurrence in patients with CoA
In patients with CoA, systemic arterial pressure begins to be significantly affected when the overall aortic lumen is narrowed by how much?
50%
*Lumen must be narrowed by at least 50% to significant affect systemic arterial pressure… 50% narrowing = 10mmHg gradient
What is the most diagnostic echo finding in pericardial effusion with cardiac tamponade?
Diastolic RV wall collapse
When does cardiac tamponade occur?
When increasing fluid in the pericardial space causes a rise in intrapericardial pressure (typically > intracardiac pressure) compromising systemic venous return to RA
When does diastolic RA/RV collapse occur in tamponade?
When intrapericardial pressure exceeds intracardiac pressure
What is most sensitive to identify tamponade physiology on echo?
Diastolic RV collapse
How can pulse-wave Doppler help identify cardiac tamponade?
> 30% change in Doppler flow across the tricuspid valve or >25% change in Doppler flow across the mitral valve with respiratory cycle
What causes the inflow variation seen across the AV valves in tamponade physiology?
Ventricular interdependence
What has the most effect on intrapericardial pressure in the setting of tamponade?
How quickly the fluid accumulates (versus overall size of effusion)
*Due to relative compliance of pericardium in acute/chronic setting
Which method of assessing LV systolic function is most independent of loading conditions?
Stress-velocity index
*EF, SF and MPI are all impacted by preload/afterload
True or False: The relationship between velocity of circumferential fiber shortening and end systolic wall stress (Stress-velocity index) is independent of HR and preload
True
*Also incorporates afterload making it a quantitative measure of ventricular contractility
Normal LV shortening fraction is maximal at what age?
2 weeks
*Maximal during 1st month of life (35-45)
Equation for SF?
(LVEDD-LVESD) / LVEDD
The mean LV shortening fraction in children is what?
36% (ranges 28-40%)
The presence of holodiastolic Doppler flow reversal is consistent with what?
Significant runoff from teh descending Ao
What could cause holodiastolic Doppler flow reversal?
- Large PDA
- Severe AI
- Systemic-PA shunts
- Large AV fistula
What is the most common type of VSD associated with CoA?
Perimembranous
- Can see possterior malalignment with severe CoA or IAA
- Can see muscular or inlet (unbalanced RV dominant AVSD)
Although less common than perimembranous, what type of VSD can result in severe CoA or IAA?
Posterior malalignment
What is the Coanda effect?
- Doppler finding often seen in patients with supravalvar AS
- High-velocity post-stenotic jet that hugs the aortic wall and preferentially transfers kinetic energy into the right innominate artery
- Marked discrepancy in arm BP (Right arm > Left arm)
What should you consider with a upper extremity BP gradient (R > L) in a patient with supravalvar AS?
Coanda effect
*The systolic jet in patients with supravalvar AS propagates further than the jet originating with aortic valvar stenosis and has a tendency to be entrained along the aortic wall thereby transferring its kinetic energy into the right innominate artery
What component of the complete Bernoulli equation isn’t ignored in the simplified version?
Convective acceleration
What component of the complete Bernoulli equation is ignored in the simplified version?
Flow acceleration
Viscous friction
To utilize the simplified Bernoulli equation, what must be negligible?
Proximal Doppler velocity
How do you determine which ventricle an overriding AV valve is committed to?
Whichever ventricle that >50% of the orifice is directed
What is the definition of an overriding AV valve?
Empties into 2 ventricles
An overriding AV valve is always associated with what?
Malalignment VSD
True or False: Valves that override can also straddle?
True- Can straddle by having chordal attachments to the contralateral ventricle
What type of AV valve has anomalous chordal insertions or papillary muscles in the contralateral ventricle?
Straddling
True or False: Straddling and overriding AV valves can coexist?
True
What is a straddling AV valve associated with?
VSD
*Doesn’t have to be malalignment
Interruption of the intrahepatic portion of the IVC with azygous vein continuation to the SVC is a common feature of what?
Polysplenia (LA isomerism)
Describe abdominal anatomy in polysplenia (LA isomerism)?
Variable- Can be ambiguous, inversus or solitus
- Usually multiple spleens that are on the same side
- Single gallbladder (can occasionally get biliary atresia though)
How are the great arteries positioned in a levocardia (normal) heart?
Aorta is rightward and posterior relative to the PA
How are the great arteries positioned in a d-TGA heart?
Aorta is typically anterior and rightward relative to PA
How are the great arteries positioned in a l-TGA heart?
Aorta is typically anterior and leftward relative to PA
How are the great arteries positioned in DILV?
Aorta is most commonly anterior and leftward relative to PA
What is an example of a single inlet atrioventricular valve connection?
Tricuspid atresia
Where does a Type A interrupted aortic arch occur?
Distal to the origin of the left subclavian artery
Where does a Type B interrupted aortic arch occur?
Between the left common carotid and left subclavian arteries
Where does a Type C interrupted aortic arch occur?
Between the right innominate and left common carotid arteries
When a persistent left SVC drains to the CS, the size of the CS is inversely proportional to what?
Size of the bridging innominate vein
Describe the innominate or brachiocephalic vein when the CS is severely dilated?
Very small or absent
When the IVC is interrupted, how does venous return get to the heart?
From the azygous vein to the SVC
Interrupted IVC is more common in polysplenia or asplenia?
Polysplenia
True or False: The SVC connection is an anatomic hallmark of the morphologic RA?
True
Which sided pulmonary veins more commonly merge as they connect to the LA?
Left
What is the most reliable feature that distinguishes a mitral valve from a tricuspid valve?
Level of attachment to the AV valve at the cardiac crux
True or False: The AV valves are invariably associated with their appropriate morphologic ventricle (tricuspid to RV and mitral to LV) and are the best marker for atrioventricular connection and ventricular morphology
True
What are some features that distinguish the AV valves from each other?
- Shape of the orifice
- Atrioventricular valve-semilunar valve continuity
- Presence of septal chordal attachments
- Level of attachment of the atrioventricular valve at cardiac crux
- # of leaflets
- Which morphologic ventricle it is associated with
What organ systems are characterized by situs or sidedness?
Cardiac, Pulmonary GI
Cardiac sidedness is determined by what?
Position of RA
Pulmonary situs is determined by what?
Positions of morphologic right and left lungs
Abdominal situs is characterized by what?
Location of liver and stomach
Where is the defect in a sinus venosus ASD?
Superior/posterior portion of the atrial septum adjacent to the SVC
Which veins are often anomalous in a sinus venosus ASD?
Right upper and middle pulmonary veins
Where do the right upper and middle pulmonary veins connect to most often in a sinus venosus ASD?
SVC
Large primum septum, AV valves inset at same level at the cardiac crux, inlet ventricular septum intact, MR from cleft mitral valve?
Partial AVSD
What defects could be present if you see a large anterior malalignment VSD with 50% aortic override of the VSD?
ToF, PA-VSD, Truncus
Significant aortic root dilation and MVP should make you think of…?
Marfan
AVSD and VSD should make you think of…?
Down
Aortic arch anomalies and conotruncal defects should make you think of…?
DiGeorge
RVOT/PA anomalies, ASD and HCM should make you think of…?
Noonan
Supravalvar AS and supravalvar/branch PS should make you think of…?
Williams
What is the most common adult cardiac tumor?
Myxoma
What is the 2nd most common childhood cardiac tumor?
Myxoma
Where are myxomas typically located?
LA (75%) often attached to the fossa ovalis
What can happen if a myxoma in the LA is very large?
Can obstruct AV valve inflow leading to positional dyspnea, syncope, death
Name some symptoms associated with a myxoma
- Weight loss
- Malaise
- Arthralgias
- Myalgias
- Positional dyspnea
- Syncope
- Death
What is a familial form of myxoma that is associated with lentigines and endocrine abnormalities?
Carney syndrome
What should you consider with a large homogenous echogenic mass in the posterior wall of the LV?
Fibroma
Describe a fibroma
Firm, white, non-encapsulated tumor
Where are fibromas typically found?
LV within posterior wall or septum and commonly at apex
What is the problem with fibromas?
- Often large and can result in cavitary obstruction or impair AV valve function
- Risk of SCD due to ventricular arrhythmias
Doppler flow studies in human fetus have shown that the ratio of R-L ventricular combined output is about what?
RV: 50-55%
LV: 40-45%
*CO increases during gestation, but relative amounts from 2 parallel circulations stay same
What is the best management for a fetus with tachycardia and hydrops?
Sotalol
*Dig has poor maternal fetal transfer for a hydropic fetus (isn’t 1st line)
What is maternal lupus associated with?
Fetal heart block and bradycardia
A fetal 4C view is inadequate to exclude which lesion?
D-TGA
*Need to look at outflow tracks… 4C view often normal in these babies
True or False: HLHS, tricuspid atresia, AVSD and Ebstein can all be diagnosed by a 4C view on fetal echo?
True
What is the normal range for fetal CT area ratio?
25-35% (about 1/3)
What is the most common fetal arrhythmia?
PACs
*Next is PVC
Fetal arrhythmias occur in what % of pregnancies?
1-3%
Fetal SVT, atrial flutter and complete heart block account for what % of reported fetal arrhythmias?
<10%
How do you measure a mechanical PR interval on echo?
Measure from beginning of atrial inflow (mitral A-wave) to beginning of ventricular ejection
What change in ductal flow would you see in PA + IVS?
Flow reversal in the ductus arteriosus
*No antegrade flow across atretic pulmonary valve, so flow reversal into hypoplastic MPA/branch PAs
What lesion would you expect to see flow retrograde flow into the aortic arch?
Critical AS
*Have limited antegrade blood flow across the critically stenotic aortic valve, so arch is supplied retrograde via duct
Normal fetal HR ranges?
120-180bpm
Normal fetal cardiac axis?
30-60 degrees
*Left axis of fetal heart relative to midline
What % of fetal CO at term perfuses the lungs?
10%
*Remainder of deoxygenated blood is directed through ductus to descending Ao/Placenta for oxygenation
Fetal CHD with indomethacin?
Ductal constriction
Fetal CHD with fetal alcohol syndrome?
VSD
*Septal defects (ASD/VSD), less common CoA and conotruncal
Fetal CHD with fetal hydantoin syndrome?
CoA
*Also LVOTO
Fetal CHD with lithium?
Ebstein
*Also ASD and AV valve atresia
Fetal CHD with isotretinoin?
d-TGA
*Also septal defects and conotruncal anomalies
CHD with Turner (XO)?
CoA
- Most common CoA/AS with bicuspid AoV
- Less common ASD/VSD
CHD with DiGeorge (22q11)?
IAA, conotruncal defects (Truncus arteriosus)
CHD with T21?
AVSD
*Also secundum ASD, VSD, ToF and arch obstruction
CHD with T13?
VSD
*Also HLHS, ToF, AVSD
CHD with Williams Syndrome?
Supravalvar AS
*Supravalvar AS and branch PS, septal defects, arch anomalies
Maternal SLE, umbilical cord compression, heterotaxy and L-TGA can all cause what in a fetus?
Bradycardia
- SLE: Complete heart block
- Umbilical cord compression: Transient bradycardia or brief asystole
- Heterotaxy/L-TGA: Heart block, bradycardia
What congenital heart lesion should be excluded in a fetus with SVT?
Ebstein
Ebstein is associated what % incidence of rhythm abnormalities?
15-20%
What rhythm issues are associated with Ebstein?
WPW/SVT
How do you calculate pulsatility index in the umbilical artery?
(Peak systolic velocity-End Diastolic velocity)/Mean Velocity
*(s-d)/mean
What do Doppler velocities within the umbilical artery reflect?
Downstream resistance within the placenta
Peak systolic velocity minus end diastolic velocity divided by mean velocity
Pulsatility index
List some findings associated with heart failure in a fetus?
- Decreased pulsatility index in MCA
- Increase in pulsatility index in UA
- Pulsations within umbilical vein
- Flow reversal in ductus venosus
- AVVR
Why do you see decreased pulsatility index in the MCA in fetuses with CHF?
Cerebral resistance falls (“brain-sparing” effect)
What finding would be common to a fetus in the following circumstances:
- Recipient twin in twin-twin transfusion
- Poorly controlled maternal DM
- Fetal HCM
- Noonan
Ventricular hypertrophy
True or False: Fetuses with ToF will have RVH on echo?
False- RVH develops secondary to RVOT obstruction and develops post-natally
What is the incidence of CHD in maternal DM?
4-10%
What is the incidence of CHD in FHx of CHD?
2-4%
Which has a higher incidence of CHD… Maternal DM history or FHx of CHD?
Maternal DM (4-10%)
FHx 2-4%
What are the most common cardiac lesions in fetuses of diabetic mothers?
- D-TGA
- Truncus arteriosus
- ToF
What is the risk of CHD in a fetus of a diabetic mother directly associated with?
Maternal Hgb A1C levels during early gestation
True or False: HCM associated with poor maternal glucose control is most often reversible within weeks or months post-delivery?
True
What cardiac devices are a relative contraindication for CMR?
AICD
- Most implanted metallic objects, coils, clips, pacemaker leads, occluder devices, are weakly ferromegnetic and relatively immobile after implantation
- Now, many pacemakers/AICDs are CMR compatibile
What type of objects cause the most prominent imaging artifact with CMR?
Stainless steel (like a PDA coil)
- Occluder devices including the Amplatzer ASD device also cause significant imaging artifact
- Pacemaker leads, PDA vascular clip and nonferromagnetic stents cause less artifact with MRI
Blood appears black in which CMR techqniue?
Spin echo
Describe spin echo sequencing on CMR
- Relatively long time period between spin excitation and data sampling resulting in blood flow leaving the imaging plane when the signal is sampled
- Produces an image where blood appears black and surrounding cardiac tissue is encoded in shades of gray or white
What type of images to spin echo sequences provide on CMR?
Still images for anatomy and tissue characterization
Blood appears bright in what types of CMR images?
- Gradient echo
- Steady-state free precession
- Contrast-enhanced images
What is the optimal technique to calculate Qp:Qs by CMR in someone with a large ASD?
Velocity-encoded cine (VEC) images
What is VEC MRI?
- Velocity-encoded cine images
- Gradient echo sequence that can measure blood flow velocity and quantify blood flow
True or False: SPAMM, contrast-enhanced MRA, myocardial perfusion study and spin echo don’t provide any quantifiable flow or velocity information?
True
What CMR technique produces an image where the blood pool is black and surrounding cardiac tissue is gray or white?
Spin echo
What are some spin-echo applications?
- Myocardial and blood vessel walls
- Cardiac masses and tumors
- Pericardium
What sequences in spin echo imaging can help with tissue characterization?
T1/T2 weighted sequences
How is signal acquisition performed in CMR?
Over several cardiac cycles
True or False: Spin echo CMR produces high tissue contrast and has less imaging artifact with metallic implants compared to other CMR techniques?
True
What kind of images does gradient echo CMR produce?
Bright blood
Describe gradient echo sequences in CMR
- Gradient echo sequences have less time between spin excitation and signal detection resulting in a faster acquisition than spin echo sequences
- Gradient echo technique results in high imaging speed with multiple images acquired during each cardiac cycle
Describe CMR signal from slower moving tissue?
Gray with less contrast (compared to spin echo images)
What type of CMR images are more susceptible to imaging artifact?
Signal from slower moving tissue
Faster moving blood has a stronger signal which results in what?
Bright blood images
What is the best cardiac MRI technique to assess myocardial viability?
Myocardial delayed enhancement
Describe myocardial delayed enhancement
- Washout of gadolinium contrast agents is delayed in necrotic myocardium and areas of fibrotic tissue
- Nonviable myocardium appears bright when compared to viable myocardium
What is effective in determining presence, size and transmurality of MI as well as identification of presence and extent of myocardial fibrosis in patients with HCM?
Myocardial delayed enhancement
What CMR sequences can be done without IV contrast?
Phase-contrast (velocity-encoded) cine images
What is phase-contrast (or velocity encoded) cine imaging used for?
Flow quantification
*Doesn’t require contrast administration
True or False: IV contrast is needed in CMR for myocardial perfusion, delayed enhancement and TRICKS?
True
What CMR sequence allows the best assessment of myocardial edema?
T2 weighted black blood imaging
What sequences are fluid sensitive and can best detect myocardial edema (like in myocarditis)?
T2 weighted sequences
True or False: First pass perfusion imaging may or may not show a hypo-attenuated filling defect in the area of myocardial edema?
True
What test is best to establish a diagnosis of anomalous origin of the LCA from right sinus of Valsalva with intramural course?
CTA with ECG gating
- MRI doesn’t have the spatial resolution needed
- CTA without ECG gating doesn’t allow assessment of coronaries
- Coronary angiography can’t assess the intramural course
- Thallium scan can only show myocardial areas of hypoperfusion
What advanced imaging modality is best to assess CoA?
MRA or CTA (don’t need ECG gating)
What kind of CTA has the highest dose of radiation?
Retrospective ECG-gated
True or False: The CMR magnet is always on
TRUE
Ferromagnetic objects brought into room can act as projectiles
True or False: Distribution of delayed myocardial enhancement can help distinguish infarction from myocarditis?
True
Where is delayed myocardial enhancement seen in myocarditis?
- Subepicardial or midmyocardial
- Patchy
Where is delayed myocardial enhancement seen in infarction?
-Subendocardial or transmural
Myocardial edema is best seen on what type of imaging?
T2-weighted black blood images
Fatty infiltrates can be seen on what type of imaging?
T1 weighted images
In myocarditis, what is early myocardial enhancement due to?
Hyperemia of inflamed areas
What is the best test to assess pericardial calcification in someone with pericardial construction?
Non-contrast CT
*Don’t need contrast or ECG gating
What CMR sequences allows assessment of myocardial iron overload in patients with thalassemia or other chronic blood transfusion recipients?
Myocardial T2* quantification
What is seen on CMR for a patient with pericarditis?
- Thickened pericardium on T1 weighted double inversion recovery sequence
- Pericardia edema and effusion on T2-weighted sequence
- Diffuse post-contrast delayed enhancement
What type of surgery was done if you see the MPA anterior to the aorta with the branch PAs draped over the aorta?
ASO- LeCompte maneuver
Why is it so important to delineate coronary arteries in a ToF patient?
If there is a single coronary or other anomaly where a branch crosses anterior to the pulmonary valve, may need a RV-PA conduit to avoid damage to the coronary artery
Surgical shunt from right subclavian to PA?
Modified BTT
Surgical shunt with direct end-to-side anastomosis of subclavian artery to PA?
Classic BTT
Surgical shunt with direct side-to-side anatomosis of ascending aorta to RPA?
Waterston shunt
Surgical shunt with direct side-to-side anatomosis of descending aorta to LPA?
Potts shunt
Small conduit from aorta to PA?
Central shunt
Aortic arches on both sides of trachea?
Double aortic arch
What is the typical branching pattern for a double aortic arch?
Separate origin of 4 arch branches
- Right common carotid and right subclavian from right arch
- Left common carotid and left subclavian from left arch
What happens with time to the coronary arteries in anomalous origin of the LCA from PA?
They become dilated due to increased flow from RCA to LCA via collaterals + Chronic run-off of blood from the LCA to PA
What is common in Fontan patients who received a conduit made of biologic material (like an aortic homograft)?
Fontan conduit stenosis
What are the 2 most common coexisting diagnoses in patients with CoA?
VSD and Bicuspid AoV
