Pulm - Introduction To Chest Radiology

Front 1

Radiograph

Back 1

Images produced by an X-ray beam (electromagnetic radiation) passing through the body and striking a radiographic film contained in a cassette placed behind the subject/object being examined.

Front 2

Radiodensity

Back 2

The radiodensity of an object on a film or image depends on the composition of the object (atomic number), the thickness, and the strength of the X-ray beam. The most radiodense objects are white on the radiograph, while the least radiodense objects are black, with shades of grey in between.

Front 3

Basic radiographic densities

Back 3

Air is black, fat is dark grey, water (soft tissues including organs, muscles, blood vessels, and masses) is grey, calcium is white, and metal is whitest.

Front 4

Computed radiography (CR)

Back 4

CR produces digital radiographic images, which are rapidly replacing film. Instead of film, a phosphor plate is exposed to the X-rays. Then a laser beam scans the phosphor plate and light is released, intensified, and converted into an electron stream that is converted by computer into a digital image. These images can be viewed on a monitor, and transferred via networks.

Front 5

PA chest film

Back 5

This is obtained by placing the X-ray film in front of the patient. X-rays pass through the patient from posterior to anterior. This is a frontal view of the chest. The arms are placed on the hips or elevated and the shoulders are rotated forward to displace the scapulae out of the way.

The PA view gives you much more detail than the AP, and is always preferred over the AP view.

Front 6

AP chest film

Back 6

Usually obtained from patients that are too ill to come to the Radiology Department. A portable X-ray machine is brought to the patient's bedside. The X-ray film is placed behind the patient and X-rays pass through the patient from anterior to posterior. This is also a frontal view of the chest. The heart will look magnified since it is further from the film.

Front 7

Lateral chest film

Back 7

The lateral chest film should accompany the PA view whenever possible for a more complete evaluation of the chest. The lateral view is obtained by placing the x-ray film cassette at the LEFT side of the patient (less magnification of the heart). The arms should be elevated so as not to interfere with passage of the beam through the full thickness of the thorax.

Front 8

Rotation

Back 8

Rotation from the perpendicular placement of the chest film in relation to the X-ray beam is checked by making sure that the medial ends of the clavicles are at equal distances from the spinous processes of the vertebral spine.

Front 9

Inspiration

Back 9

A good inspiratory effort by the patient is present when the lungs are inflated to about the posterior 10th rib. A poor inspiratory effort results in crowding of lung markings, elevation of the hemi-diaphram and a larger appearing heart.

Front 10

Penetration

Back 10

A film can be over-penetrated (too dark) or under-penetrated (too light). This can obliterate or overemphasize structures. A PA chest radiograph is well-penetrated when you can see the thoracic vertebrae through the overlapping density of the heart.

Front 11

Position

Back 11

Analyze the position of the patient on the radiograph as PA, AP, lateral, decubitus, or oblique. Metallic markers should be placed on the film to mark the patient's right or left side. Additional markers are usually placed on the film to label the patient's position. You can tell if the patient is upright by the gastric air bubble or air-fluid levels in small bowel loops under the left hemidiaphragm.

Front 12

Angulation

Back 12

The X-ray beam should be centered onto the film. Angulation occurs if the beam is not centered correctly on the film or if the patient's position is not straight.

Front 13

Systemic approach

Back 13

Approach to reading chest films. For the frontal chest film, the mneumonic ABCDE is the simpliest way to start:

A - airways and lungs
B - bones
C - cardiomediastinal shadow
D - diaphragm
E - everything else

Front 14

Retrosternal clear space

Back 14

Located anterior to the heart on a lateral chest film. It contains air-filled lung from the upper lobes. Anterior mediastinal masses obliterate this space, most commonly due to lymphoma. An enlarged right ventricle can also fill this space.

Front 15

Costophrenic sulci

Back 15

The sulci shoud be well delineated and have sharp points on a lateral chest radiograph. Blunting is an early sign of pleural effusion.

Front 16

Retrocardiac clear space

Back 16

On a lateral radiograph, the position posterior to the heart is composed of the air-filled lower lobes of the lungs. When the posterior border of the heart extends to the anterior surface of the thoracic vertebrae, this is a reliable sign of cardiomegaly.

Front 17

Silhouette sign

Back 17

When two structures of similar density are adjacent to each other, their borders or silhouettes are obscured. For example, the lower lobe of a lung with pneumonia and the diaphragm.

Front 18

Meniscus sign

Back 18

Fluid in the potential pleural space accumulates between the visceral and parietal pleura. At first, the costophrenic sulci become obliterated by increased desity that takes the shape of a meniscus. As fluid increases it continues to track up around the lungs, appearing to rise higher laterally than medially. Sometimes air is introduced into the pleural space at the same time as pleural fluid. The meniscus sign will be destroyed and there will be a straight interface between the air and the fluid. This represents a hyrdropneumothorax.

Front 19

Pneumonia

Back 19

Usually manifests as airspace (alveolar) disease. It is described as fluffy, hazy, cloud-like opacities or consolidations that are confluent with indistinct margins. Air bronchograms may be seen. Pneumonias are usually patchy, segmental or lobar in distribution. There is little or no mass effect on the heart and mediastinum. Aspiration pneumonia usually occurs in the lower lobes or posterior parts of the upper lobes.

Front 20

Air bronchogram

Back 20

Small air filled tubular structures within the white areas of consolidation.

Front 21

Atelectasis

Back 21

Incomplete expansion of a lung or segment of the lung resulting in volume loss. The collapsed lung becomes dense (appears white) as it loses air.

Front 22

Pleural effusion

Back 22

Fluid accumulates between the visceral pleura that lines the lung and the parietal pleura that lines the inside of the thoracic cavity. As fluid accumulates, it fills the most dependent parts - the posterior costophrenic sulci. Then it fills the lateral costophrenic angles, and proceeds to accumulate around the lung as it progresses superiorly.

Front 23

Pneumothorax

Back 23

Occurs when air leaks out of the lung and enters the pleural space. Air surrounds the partly collapsed lung and the visceral pleura becomes visible, because it is outlined by the air in the lung and outside the lung.

Front 24

Pneumomediastinum

Back 24

Air from a pneumothorax leaks out into the mediastinum.

Front 25

Subcutaneous emphysema

Back 25

Air from a pneumothorax leaks into the subcutaneous soft tissues.

Front 26

COPD

Back 26

On chest radiographs, shows hyperinflated, hyperlucent lungs that cause flattening of the hemidiaphragms, increased anteroposterior diameter of the thorax, increase in the retrosternal clear space, and a "barrel chest" deformity of the thoracic cage. The lungs have decreased lung markings and bullous formation. The pulmonary arteries are enlarged due to pulmonary hypertension.