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Module 4

Circulatory System - Ch 10

Lymphatic System - Ch 11

Cardiovascular System - Ch 12

Respiratory System - Ch 13

Circulatory system may not seem as important to radiographers who have not specialized in angiography and sonography but it is still important to understand the basic anatomy and conditions that will be visualized on a radiographic image.

Those that continue on to do NM or CT or MR will need to know anatomy, physiology, and pathologies of the circulatory system in great detail to determine what images should be obtained to demonstrate the pathologic process

Two atria/ventricles

Septum

Four main valves

Three layers of the wall

Anatomy—Circulatory—Heart

Two atria/ventricles: the two atria are at the base of the heart at the top and the two ventricles are at the apex, which is the pointed end. Both are divided by a thick muscular wall known as the septum.

Four main valves that should be known by the technologist: the right AV is also called the tricuspid because it has three flaps to close it. The left AV is known as the bicuspid (for two valves) but is also known as the mitral valve. The valve that protects the pulmonary trunk artery is the pulmonary valve and the valve that protects the aortic arch is the aortic semilunar valve. Both valves that lead to the arteries have three flaps.

There are three layers of the wall. The lining is the endocardium, the muscle wall is the myocardium, and the outer lining is the pericardium.

The heart is held in a sac known as pericardial sac like the lungs.

Arteries to arterioles

Arterioles become capillaries

Gas exchange

Capillaries to venules

Venules become veins

Superior and inferior vena cava

Anatomy—Blood Vessels

Arteries carry blood from the heart to the arterioles.

From the arterioles the blood vessels get smaller and become capillaries.

Exchange of gases in the lungs and from the body takes place here.

Blood starts its journey back to the heart through larger vessels called venules.

Finally, the venules become larger and are called veins. The veins drain into the superior and inferior vena cava.

Spleen, thymus, tonsils, adenoids

Spleen stores red corpuscles and macrophages

Thymus is large in infants

Tonsils and adenoids are lymph tissue

Anatomy—Lymphatic System

The four lymphatic organs of the body are spleen, thymus, tonsils, and adenoids.

Spleen stores red corpuscles and macrophages.

Thymus is large in infants which is normal as can be seen in this figure. It will atrophy by the age of 40 and will no longer be of use in the lymphatic system and immunity.

Tonsils and adenoids are lymph tissues but can’t be relied upon for immunity because most youngsters have removed both when they are young. Adenoids also shrink as the person grows older.

Physiology & Function

Pulmonary circulation

Systemic circulation

Portal

Cardiac

Pulmonary circulation is obviously required to take blood from the heart to the lungs and back to the heart after it has given off carbon dioxide and picked up oxygen.

As you can see in the figure here, the pulmonary system starts in the right atria, through the tricuspid into the right ventricle through the pulmonary valve and 60% going to the right and 40% going to the left. Why the difference in blood amount? (Left lung is smaller). The blood does its gas exchange in the alveoli of the lungs and brings oxygenated blood from the lungs back through the pulmonary veins into the left atria and once it hits the left atria the systemic circulation begins.

We will see the systemic circulation in the next slide. It takes oxygenated blood to the body to give off oxygen and pick up carbon dioxide. There are two parts to the systemic circulation. The portal goes through the liver to have the blood detoxified. The cardiac circulation is the blood flow to the walls of the heart (not through the chambers).

Systemic Circulation

Aortic arch

Brachiocephalic

Left common carotid

Left subclavian

As the blood goes into the aortic arch some of the blood will go through these three branches to supply blood to the upper body (arms and brain). The branches from left to right are:

Brachiocephalic also known as the innominate artery. The right common carotid branches off this artery.

Left common carotid is the middle branch.

Left subclavian flows down the left arm. This is why it is good to take the blood pressure on this arm because the blood comes directly off the aortic arch. It is a true pressure reading.

Physiology & Function of the Lymph

Immunity

Lymph fluid in a closed circuit

Lymphocytes and antibodies

Absorbs fat and fat-soluble substances

Phagocytosis

Manufactures blood if it has to

Because we are looking at just the anatomy and physiology/function of the lymph system, we have this slide to show you how important that system really is.

As a whole, it has a major role in immunity.

It moves lymph fluid in a closed circuit.

Lymphocytes and antibodies are produced here.

This system absorbs fat and fat-soluble substances from the intestinal tract.

Phagocytosis is initiated as appropriate.

Manufactures blood when other sources are compromised.

Congenital Pathology

This 21-year-old patient was brought into the ED approximately 1am. A chest radiograph was ordered. The technologist marked the image with his initials, the date, the fact that it was an upright image and a 40L next to the upright arrow. The radiologist read this as a GSW to the right axillary area. It was discovered the next morning the report was incorrect. The patient had been shot on the left side.

If the patient was truly shot on the left side (as was confirmed by visual inspection of the patient in the operating room) then this patient has the condition known as situs inversus.

Let’s talk about this case study

How should it have been marked? It would be best to have only the side letter marker on one side with nothing else, if the technologist knows there is dextrocardia (heart is displaced to the right side of the body), cardiac heterotaxia (heart is reversed so that it is a mirror image of a normal heart), or situs inversus (all organs of body are reversed from normal and on the opposite side of the body).

Is the image “hung” correctly? While the heart is on the viewers right side and this would be a normal position to view a chest image. In this case, the image should be reversed. We know from the history in the text that the physician did read it incorrectly.

If the gunshot is on the left, and the heart apex is on the right, what would this be? This is cardiac heterotaxia.

What is below the diaphragm below the heart? You can see the air in the stomach below the diaphragm leading us to a diagnosis of situs inversus.

Congenital Pathology

Localized

Adult (old term)

Rib notching

Tubular

Long section

Cardiac anomalies

Coarctation is severe narrowing of the aorta as you can see here on the right.

It causes the left ventricle to work harder to try to push blood past the obstruction and to the body. Results in hypertension in upper extremities and hypotension in the lower extremities. Coarctation can be removed by surgery or by balloon dilation done in the cardiac catheterization lab. If done as a newborn, it is common for the coarctation to return. As an adult, with equal pressure in the upper and lower extremities, it is unlikely that the aorta will become obstructed again.

Two varieties: localized used to be called adult. It occurs in men more than in women and is rarely seen in African Americans. The classic radiographic sign is rib notching caused by dilated vessels that rub against the ribs and erode the bone. Anastomotic vessels enlarge under their increased volume and cause pressure erosions on the ribs.

Tubular is the second variety. Rather than a short section like in localized, tubular is a long section of the aorta. There are cardiac anomalies common with this type but not with the localized.

Congenital Pathology

Shunts

Allow pulmonary and systemic blood to mix

High pressure to low pressure

Two are septal defects

One defect between arteries

Shunts are congenital holes in the heart wall or between two arteries that allows pulmonary and systemic blood to mix.

Blood will flow from high pressure to low pressure (systemic to pulmonary).

Two are septal defects are between the two atria or between the two ventricles.

The defect between the arteries is between the aortic arch and the pulmonary trunk.

Congenital Pathology

Shunts

ASD

VSD

The image on the left is the most common congenital defect of the heart. In large atrial septal defects, a large amount of oxygen-rich blood leaks from the left side back to the right side and then back to the lungs. This is left-to-right shunt because the pressure is higher in the left atrium than it is in the right atrium. Pulmonary blood flow in increased because of this type of shunt. In addition to overloading the pulmonary bed, the right ventricle experiences an overload. This produces a radiographic appearance of enlargement of the right ventricle and right atrium.

The image on the right is more serious than the ASD because the pressure is greater between the ventricles than between the atria. There is enlargement of the left side of the heart. The radiographic image shows enlargement of the left side of the heart. In small openings, there is no strain on the heart, and patients are usually asymptomatic except for a heart murmur in the first weeks of life. If the opening is large, the symptoms can be severe: breathing is rapid, growth is retarded, and the infant has feeding difficulties.

Small defects often close in childhood; however, if opening is large, closing the hole before age 2 is necessary to prevent future problems. Surgically corrected by sewing a patch over the hole. Repairing the VSD restores the blood circulation to normal and the long-term outlook is good.

Congenital Pathology

Shunts - PDA

Patent arterial duct (PAD)

Located at the aorta and pulmonary trunk

Lungs and heart are overworked

Patent ductus arteriosis or patent arterial duct either way is correct.

Notice on the drawing on the right that there is a passageway between the aortic arch and the pulmonary trunk right at the bifurcation of the right and left arteries.

The arterial duct in a newborn fails to close after birth. Failure of closing is quite common in premature infants, but is somewhat rare in full-term babies. Arterial duct is a vessel that extends from the bifurcation of the PA to join the aorta just distal to the left subclavian artery. It serves to shunt blood from the PA into the Systemic circulation during intrauterine life. If it does not close soon after birth, blood will continue to flow through the duct during systole and diastole. Oxygenated blood is continuously shunted from the aorta to the PA and back to the lungs instead of going through the aorta to the body. The heart will be overworked in an attempt to balance the supply with the demand for oxygen. Lungs become overworked in their effort to keep pace with oxygen demands and breathing becomes dyspneic on light exertion, with resultant fatigue.

Chest radiographs demonstrate enlargement of the left atrium and left ventricle and increased vascular congestion. A large opening will cause a child to tire quickly, grow slowly, and be more susceptible to things like pneumonia. If opening doesn’t close within a few weeks of birth, it must be surgically tied off.

Congenital Pathology

Right to Left Shunt

Tetralogy of Fallot

Pulmonary stenosis

Ventricular septal defect

Right ventricle hypertrophy

Overriding aorta

Blue baby

‘Coeur en sabot’

Only right to left shunt:

Tetralogy of Fallot means four conditions exist.

Pulmonary stenosis: narrowing of the pulmonary valve decreasing the amount of blood to the lungs.

Ventricular septal defect: opening between the septum between the ventricles.

Right ventricle hypertrophy: enlargement of the right ventricle heart muscle.

Overriding aorta which is really a displacement of the aorta to the right. Aorta arises from a VSD which results in hypertrophy of right ventricle

Because the blood isn’t getting to the lungs for oxygen, it causes the baby to be cyanotic (most common cause of blue baby).

The right ventricle pushes the left ventricle horizontal, causing the coeur-en-sabot sign (wooden shoe). That can really be seen here on this image.

Complete repair tends to be done early in life but usually after the age of 1 year. If the infant is extremely small and cyanotic, a temporary operation may be done first to provide adequate blood flow to the lungs. This allows the baby to grow big enough to have a full repair. Unfortunately, it is being proven that 20-30 years after the repair, pulmonary regurgitation is common. Because the valves put into the pulmonary main truck have a point in which it will wear out, there is a need for valve replacement. MRI is extremely helpful in determining the time for replacement.

Inflammatory Processes

Aneurysm

Saccular: berry; cerebral

Fusiform: abdominal; long bulging on both sides

Dissecting; tearing into the walls of the vessel

False: palpable hematoma

AAA

Aneurysm is a permanent dilation of all the layers of a weakened but intact vessel wall.

Saccular: localized out pouching on one side usually in the cerebral arteries and is known as a Berry.

Fusiform: uniform dilation of an entire portion of the distal abdominal aorta.

Dissecting: tearing into the walls of the vessel.

False: palpable hematoma that pulsates. – clot outside the arterial wall

AAA: the triple A; any aneurysm that is in the abdomen (abdominal aortic aneurysm).

Inflammatory Processes

A – normal artery

B – false aneurysm: clot is outside arterial wall

C – true aneurysm with one, two, or all three layers of the wall involved

D – fusiform aneurysm

E – saccular aneurysm

F – dissecting aneurysm: layers of arterial wall have been split

Atherosclerosis

Major cause of vascular disease

Characterized by irregularly distributed fat deposits (lipids)

Causes narrowing of the vessel to build these lipids

Caused by smoking and high cholesterol

Arteriosclerosis occurs when the artery wall hardens

Major cause of vascular disease.

Characterized by irregularly distributed fat deposits (lipids).

Causes narrowing of the vessel due to build up of these lipids.

Caused by smoking and high cholesterol.

These plaques can occlude the entire vessel lumen and block the blood flow.

If this occurs in a coronary artery, the patient will have a myocardial infarct.

Once the vessel walls become hard due to calcification in the lipids, the process is arteriosclerosis.

When arteriosclerosis occurs in the coronary arteries, it is arteriosclerotic heart disease.

Arteriosclerotic Heart Disease

AKA: cardiovascular disease

Leading cause of death

CABG

Hypertension

AKA: cardiovascular disease.

Leading cause of death but has been declining.

CABG stands for coronary artery bypass graft and is used to provide a new means for arteries to get blood to the heart walls.

Hypertension is found in association with AHD because it accelerates the formation of plaque which causes the arteriosclerosis to begin with.

Congestive Heart Failure

CHF

Heart is not supplying enough blood

Caused by heart attach, cardiovascular disease, hypertension, and infection

Right or left side of heart is affected

Accompanied by pleural effusion

Classic radiographic sign: diffuse cardiomegaly, cephalization

Congestive heart failure results when the heart is not supplying enough blood to supply the needs of the tissues of the body.

Caused by heart attack, cardiovascular disease, hypertension, or infection.

Right or left side of the heart is affected. When one side fails, the other one continues its normal output. This makes pressure in the pulmonary or systemic veins or both. Blood will “back up” in the vessels. This creates pleural effusion.

Classic radiographic sign: diffuse cardiomegaly. In right-sided failure, there will be larger pulmonary vessels in the upper zone than the lower which is the reverse of normal. This is known as cephalization (toward the head).

Hypertensive Heart Disease

Most common cause of CHF

Hypertension is major cause

Apex of heart is pushed down

Most common cause of CHF in the older adult.

Hypertension is major cause (duh!) because high blood pressure over a long period of time causes narrowing of the systemic blood vessels. This causes the left ventricle to work harder and enlarge.

As the left ventricle enlarges, it will push the apex of the heart downward, elongating the heart shadow.

Apex of the heart is pushed down.

Hypertrophy

Enlargement of the atria or the ventricles

Right atrial enlargement

Right ventricular enlargement

Left atrial enlargement

Left ventricular enlargement

When any of the chambers of the heart becomes enlarged, it helps to diagnose a problem that has not yet been made obvious.

For example:

Right atrial enlargement is not common but if there is no malrotation of the patient, then there may be subacute bacterial endocarditis or an atrial septal defect that has gone unnoticed.

Right ventricular enlargement: the right ventricle is not a good indicator that there is something else going on because the size of the ventricle varies so greatly from person to person. If the ventricle is enlarged the atrium is probably enlarged as well.

Left atrial enlargement: this will enlarge with rheumatic heart disease with mitral stenosis or insufficiency.

Left ventricular enlargement: aortic stenosis and hypertension are two things that can make the LV enlarge

Imaging Modalities

Ultrasound

Computed Tomography (CT) & Magnetic Resonance Imaging (MRI)

Nuclear Medicine

Interventional

Angiography

PTA

Endovascular stent repair

Sonography

Echocardiography: heart chambers; valves; septal defects, pericardial effusion

Carotid duplex: blood flow through carotid artery

Echocardiography is used to see the contraction and relaxation of the heart chambers, to see the valves for prolapse, and to see right-to-left shunts; pericardial effusion can be assessed as you saw on that slide.

Carotid duplex scanning will demonstrate blood flow through carotid artery and show any narrowing.

CT & MRI

CT is best for:

Aorta or other arteries

Size and shape of aneurysms

Obstruction of lymph system

MRA: (type of MRI after contrast injection)

Blood vessels for aneurysms

Both are excellent to visualize thoracic or abdominal aneurysms and obstructions in the lymph systems.

CT is an excellent method to show the obstruction of the lymph system that causes edema.

In MRA, the blood vessels are studied after the patient is injected with contrast media.

Nuclear Medicine

Complement study

Gated heart scan

Demonstrates myocardial infarction, myocardial ischemia, pericardial effusion, and shunts

Nuclear medicine is a complement study.

A gated heart scan studies the motion of the wall of the heart.

It can assess regional blood flow to the myocardium.

It can detect necrosis of the myocardium.

Interventional

Angiography: study of all blood vessels

Arteriography: study of all arteries

Aortography: study of aorta

Venography: study of all veins

All of these except venography require a catheter inserted into a major blood vessel (femoral artery, for example) and contrast injected near the area of interest and then watching and imaging the flow of blood through the systemic circulation. Angiography will take longer because the full phase of blood flow will be imaged.