Imaging of the Heart

8/12/2019 Imaging of the Heart

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Imaging of the Heart


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Imaging Modalities

CXR

CT

MRI

Doppler Echocardiography

TOE

Nuclear Imaging incl. PET

Angiography


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What to assess

heart size

relative ventricular wall thickness

atrial dilatation

coronary vessels

heart function

valve patency / insufficiency

anatomical variants congenital anomalies (ASD, VSD, AVSD, PDA, etc)

presence of thrombi in heart / vessels

great vessel anomalies / injury/ disease

viable vs death muscle tissue


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Chest X Ray


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Chest X Ray


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The Cardio Thoracic Ratio

Assess only on PA view

AP projection leads to magnification and a falsely

high CTR

Is a measure of the cardiac silhouette (not the heart

itself)

Good inspiratory effort necessary


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Heart Failure


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Right atrial enlargement


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Left ventricle enlargement


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Left atrial enlargement


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Pericardial Effusion


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Dextrocardia


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CT

Cardiac CT with ECG triggering offers good image quality of the heart

Analyze the heart using cardiac axes

These axes are also used in cardiac CT/MR and must be reconstructed in order to assess the heart properly

Axial slices are useful for a global assessment of the morphology of the heart and its relation to the pericardium


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4-chamber view

Achieved by rotating upwards from the apex of the heart on the axial slices.

In this axis

the right ventricle is projected next to the right atrium

the left ventricle next to the left atrium.

The mitral valve comes into view and - depending on the contrast protocol - the tricuspid valve may also

be visible.

Apex of the heart is well demarcated (note that the apex is formed by the left ventricle)


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3-chamber view

border between the mitral and aortic valves is localized on the axial slices - images are rotated from this point

On this image

left atrium

left ventricle

mitral valve

aortic valve

proximal ascending aorta are visible.


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5-chamber view

similar to the 4-chamber view

additionally displays the aortic valve and left ventricular outflow tract

view achieved by rotating the 4-chamber view more cranially.


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2-chamber view

the 2-chamber view is achieved by rotating the images perpendicularly to the mitral valve and parallel to

the cardiac septum

gives an overview of the left atrium ventricle and mitral valve.


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Cardiac anatomy from right to left


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Right atrium right atrium has an anterolateral position in the heart

lies inferior to the left atrium. superior vena cava enters through the roof of the right atrium.

inferior vena cava enters the right atrium from below near the cardiac septum.

coronary sinus (venous return of the coronaries) enters anterior to, and just to the left of the inferior vena cava

(arrow)


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Coronary sinus

main draining vein of the myocardium. runs in the atrioventricular groove on the posterior surface of the heart and enters the right atrium

in the vicinity of the tricuspid valve.


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Right ventricle

blood leaves the right atrium and enters the right ventricle via the tricuspid valve. shaped differently to the left ventricle

left ventricle is cylindrical in shape and the cavity of the right ventricle is effectively wrapped around it.

has a thinner wall which is more trabecularized, especially towards the apex.

moderator band

runs from the septum to the lateral wall of the right ventricle

plays a key role in the electrophysiological conduction of the right ventricle (blue arrows).


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Pulmonary veins

Oxygen-rich blood enters the left atrium via the pulmonary veins.

In most cases

two pulmonary veins on the left and two on the right

middle pulmonary veins usually drain into the superior pulmonary vein


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Left ventricle

blood enters the left ventricle via the mitral valve

then enters the aortic valve via the left ventricular outflow tract.


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Aortic Valve

cusps of the aortic valves are named according to their relationship with the coronary arteries

the right coronary

left coronary

non-coronary cusp (R, L and N)


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Coronary Arteries on Angiography

Coronary arteries in the anterior projection.

Left Main or left coronary artery (LCA)

Left anterior descending (LAD)

diagonal branches (D1, D2)

septal branches

Circumflex (Cx)

Marginal branches (M1,M2)

Right coronary artery

Acute marginal branch (AM)

AV node branch

Posterior descending artery (PDA)

PA 0 Caud 30


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Coronary Arteries

Coronary arteries in the right anterior obliqueprojection.




septal branches

Circumflex (Cx)

Marginal branches (M1,M2)

Right coronary artery


AV node branch


RAO 20 Caud 20


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Coronary Arteries

Coronary arteries in the lateral projection.




septal branches

Circumflex (Cx)

Marginal branches (M1,M2) Right coronary artery


AV node branch



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Echocardiography

Long axis view provides a reliable picture of the function of the basilar portions of the anterior septum and

posterior walls. motion of the mitral valve opening aortic leaflets shows their rapid systolic opening and a diastolic closed position arising from

position at the base of the anterior mitral leaflet.


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Apical two chamber view permits evaluation of the motion of the anterior and inferior left ventricular myocardial

segments mid-portion of the mitral valve motion is also evident


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Short axis view myocardial segments presented anterior wall and antero-septum presented superiorly and the posterior and

inferior walls in the lower portion of the wedge view. contractile motion should be symmetric toward the mid-portion of the

myocardial cavity


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Short axis view aortic valve three leaflets of the aortic valve are seen left atrium behind the aortic root


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Apical four chamber view symmetric display of the two large atrio-ventricular valves left ventricle is displayed to the viewer's right interventricular septum and interatrial septum form column of tissue in the middle of the

image


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Subcostal view provides nearly a perpendicular view of the interatrial septum permits it to use doppler to interrogate potential shunts between those chambers


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TOE

an invasive echo test

It evaluates

1. heart chamber size

2. pumping action

3. valve appearance and function

4. blood flow through the heart

images taken from the oesophagus

provides superior picture quality

less interference to sound wave travel from the oesophagus into the

heart compared to chest wall and lungs


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MRI

Full 3D capabilities Excellent soft-tissue contrast

Tradeoff: high spatial resolution/short acquisition time

Two main configurations:

1. Spin-echo entire change in magnetization used to create the image

high spatial resolution (0.5mm) very slow (13s for one slice)

2. Gradient-echo only a part of the change in magnetization used to

create the image

lower spatial resolution (1mm)

very fast ( 2s, real time)


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MRI

Pulse sequences:

1. Cardiac Gated T1WI (axial views): anatomical assessment

1. Gradient Echo (GRE) cine in short axis: assesses ventricular function, ejection fraction

1. Phase contrast MRA: estimates ventricular function, regurgitation

1. Gadolinium MRA: to define the anatomy


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Nuclear Imaging

Nuclear imagine evaluates how organs function, unlike other imaging methodsthat assess how organs appear

Small amounts of a radioactive solution is introduced into the body

Gamma detector detects the solution in different parts of the body and a

computer generates a series of images of the areas of interest


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Cardiac SPECT

Single Photon Emission Computed Tomography scans

- also called myocardial perfusion imaging

- non-invasive

- used to

assess the heart's structure and function

measure blood flow through the heart

detect areas of abnormal heart muscle

Information obtained from SPECT scans can be used to:

Identify blockages in the coronary arteries

Determine whether someone has had an MI

Predict those at high risk for MI

Assess a patient's condition after bypass surgery or

angioplasty


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Cardiac PET

Positron Emission Tomography

used to:

look for coronary artery disease by examining how

blood flows through the heart

evaluate damage to heart tissue after an MI


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MUGA

Multiple Gated Acquisition Scan (radionuclide angiography)(RNA)

used to

evaluate heart function

by measuring ejection fraction

Imaging of the Heart

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