Diagnostic Imaging of the Heart

Imaging the heart, why use radiography?

Visualization of overall size

Visualization of shape

Location

Evidence of congestive heart failure (pulmonary edema, pleural effusion, etc.)

Imaging the heart, why use ultrasound?

Visualize chamber size

Myocardial function

Blood flow and leakage through valves

Disease of internal cardiac structures

Less useful for evidence of congestive heart failure

Full assessment of the heart requires

Both radiography and echocardiography

What cannot be visualized on radiography in regards to the heart?

Internal structures

Myocardial function

Valve incompetence

What is indicated by the red arrow?

The aorta (image, lateral)

What is indicated by the white arrows?

Trachea (image, lateral)

What is indicated by the yellow arrows?

Large bronchi (image, lateral)

What is indicated by the blue arrows?

Pulmonary vessels (image, lateral)

What is indicated by the orange arrows?

Caudal vena cava (image, lateral)

What is indicated by the red arrow?

Aorta (image, dorsoventral)

What is indicated by the black arrow?

Trachea, usually deviates to the right of midline (image, dorsoventral)

What is indicated by the yellow arrows?

Large bronchi (image, dorsoventral)

What is indicated by the blue arrow?

Pulmonary vessels (image, dorsoventral)

What is indicated by the orange arrow?

Caudal vena cava

What is indicated by the white arrow?

Mediastinum (image, dorsoventral)

What structure(s) are not typically seen on a lateral radiograph?

Esophagus

Mediastinum

What should you note while assessing normal and abnormal findings called Roentgen signs?

Size

Shape

Opacity

Margins

Location

Number

What position is best to assess the heart?

Right lateral recumbency and Dorsoventral radiographs

How many intercostal spaces should the heart cover in a dog?

3-3.5

How many intercostal spaces should the heart cover in a cat?

2-3

The height of the heart relative to the height of the thorax should be about ____ in dogs and cats

2/3

The width of the heart relative to the width of the thorax should be about ____ in dogs and cats

1/2-2/3

Position of the heart should be within/near the

Middle mediastinum, 4th-6th intercostal space

Degree of sternal contact of the heart depends on

Breed

What condition is visualized here?

Cardiomegaly

How would you quantify a canine heart being enlarged? (ie cardiomegaly)?

Heart with >2-3 height of thorax

Heart >3.5 intercostal spaces covered

Heart shape: RLR view: What is seen at 12-3?

Left Atrium (lateral view)

Heart shape: RLR view: What is seen at 3-5?

Left Ventricle (lateral view)

Heart shape: RLR view: What is seen at 5-8?

Right ventricle (lateral view)

Heart shape: RLR view: What is seen at 8-10?

Right Atrium (lateral view)

Heart shape: RLR view: What is seen at 10-12?

Great Vessels (lateral view)

Heart shape: DV view: What is seen at 11-1?

Aortic arch (Ventral view)

Heart shape: DV view: What is seen at 1-2?

Pulmonary artery (ventral view)

Heart shape: DV view: What is seen at 2-3?

Left auricle (ventral view)

Heart shape: DV view: What is seen at 3-5?

Left Ventricle (ventral view)

Heart shape: DV view: What is seen at 5-9?

Right ventricle (ventral view)

Heart shape: DV view: What is seen at 9-11?

Right Atrium (ventral view)

Complete assessment via echocardiography requires the following

B-Mode

M-Mode

Doppler

Integrated ECG

What does B-mode show?

“Slice” of anatomy

What does M-mode show?

Functional measurements

Shows movement or contraction of structures over time

Measurements of myocardial contractility

What does Doppler show?

Quantitative and qualitative assessment of blood flow

How does M-mode ultrasound work?

Echoes from a single line of ultrasound are plotted against time

What is the benefit of having integrated ECG?

Allows synchronization of ultrasound images with known heart beat patterns at a given time

How does Doppler imaging work?

Reflection of sound from moving object → change in frequency

If doppler imaging has color flow, what color means flow is away from transducer?

Blue

If doppler imaging has color flow, what color means flow is towards transducer?

Red

What type of measurement is color flow doppler imaging considered?

Qualitative blood flow

What type of measurement is pulsed-wave or continuous wave doppler imaging considered?

Quantitative blood flow

When scanning the heart, how should the patient be positioned?

In R and L lateral recumbency

Where is the best position to place the transducer when scanning the heart?

Beneath the patient, nearest the dependent wall of thorax (ideally via a hole in ultrasound table), between the ribs

Why should sedation be avoided when scanning the heart?

It can affect myocardial contraction

Right parasternal approach is the

most widely used scanning approach

What does the Right parasternal approach give you information on?

Chamber sizes

Myocardiac function

Valve function

What is a limitation of the right parasternal approach?

Difficult to image all chambers together

What direction are the planes of view when doing the right parasternal approach?

Ventral to dorsal, labelled A-F

What structure(s) are visible when looking at slice A on a right parasternal short axis scan?

LV and a little of RV

What structure(s) are visible when looking at slice B on a right parasternal short axis scan?

LV, more of RV, and papillary muscles

Mushroom slice is a view to visualize which structures?

Left ventricle is the characteristic shape, some of Right ventricle

What structure(s) are visible when looking at slice C on a right parasternal short axis scan?

LV, RV, and CH?

What structure(s) are visible when looking at slice D on a right parasternal short axis scan?

LVO, RVO, PM, PMV, AMV

“Fish mouth” appearing structure is what structure within the heart?

Mitral valve

What structure(s) are visible when looking at slice E on a right parasternal short axis scan?

LA, RV, pulmonary valve, TV, Aorta and aortic valve

What structure(s) are visible when looking at slice F on a right parasternal short axis scan?

RA, R auricle, Caudal vena cava, R and L pulmonary artery, aorta

What view is being shown in this image?

Right parasternal long axis - LA/MV

What view is best for viewing vegetative growth on the mitral valve?

Right parasternal long axis L atrium view

What view is being shown in this image?

Right parasternal long axis - Aorta

How should the patient and transducer be oriented for left apical views of the heart?

Patient: L lateral recumbency

Scan from dependent left thoracic wall

Why are L apical views beneficial?

Good “end-on” views through the mitral and tricuspid valves (four chamber) and aortic outflow (five chamber)

Good for accurate measurements of blood flow velocities

What view is being shown in this image?

Left apical Four-Chamber view

What are common classes of cardiac diseases?

Myocardial disease

Valvular disease

Pericardial disease

Describe Myocardial disease: Dilated cardiomyopathy

Reduced myocardial contractility

Decreased cardiac output and dilation of chambers

Describe Myocardial disease: Hypertrophic cardiomyopathy

Decreased capacity of ventricles

Reduced cardiac output

Describe Valvular disease aetiologies

Dysplasia, infection, etc.

Leakage of valves and chamber dilation

Ex endocardiosis

Describe Pericardial disease

Prevents proper fulling of heart chambers (esp. RV) and reduces cardiac output

M Mode ultrasound, is this normal or an example of dilated cardiomyopathy?

Normal

M Mode ultrasound, is this normal or an example of dilated cardiomyopathy?

Dilated Cardiomyopathy

What is shown in this image?

M mode ultrasound of a dog with DCM

What is shown in this image?

B mode ultrasound of a dog with DCM

How can you identify a cat having hypertrophic cardiomyopathy?

“Valentine’s heart” or atrial enlargement on DV view

What is shown in this image?

Cardiomegaly with LA enlargement

What is shown in this image?

Pericardial effusion