Chest X-rays

Question 1

In order for a line or an interface to appear between two adjacent structures on a radiograph, . . .

Answer 1

In order for a line or an interface to appear between two adjacent structures on a radiograph, the two structures must differ in density.

Question 2

Two standard radiograph views

Answer 2

• Posteroanterior (source posterior, film anterior)
• Lateral

Question 3

For bedridden patients, it is often necessary to take. . .

Answer 3

. . . an anteroposterior radiograph or a lateral decubitus radiograph (where the patients lies on their side and X-ray beams go horizontally)

Question 4

Decubitus views are particularly useful for identifying. . .

Answer 4

. . . pleural effusion.

Question 5

Atelectasis

Answer 5

Collapse of lung tissue with loss of volume

Question 6

Radiographic lobe identifications

Answer 6

Question 7

Which lobe is this consolidation in?

Answer 7

The left upper lobe

It can only be this lobe based on the lateral distribution, though the apex of the left upper lobe is spared.

Question 8

Features of volume loss due to lobe consolidation

Answer 8

• Displacement of lobar fissures
• Indirect signs of hylum, diaphragm, trachea, or mediastinum displacement

Question 9

Categories of radiographic lung findings

Answer 9

Interstitial and alveolar

These often lack pathologic correlation, but are still useful categories.

Question 10

What is going on with this patient?

Answer 10

Upper R lobe consolidation (in this case it happens to be lung collapse)

Question 11

What radiographic pattern of lung disease is this?

Answer 11

Interstitial lung disease, or reticulonodular.

Consists of an interlacing network of linear and small nodular densities

Question 12

What radiographic pattern of lung disease is this?

Answer 12

Alveolar lung disease, or air bronchogram pattern

Appears fluffy, and the outlines of air-filled bronchi coursing through the alveolar densities are often seen. Due to air in the bronchi being surrounded and outlined by alveoli that are filled with fluid.

Question 13

Nodular pattern

Answer 13

Presence of multiple discrete, typically spherical, nodules on X-ray.

Question 14

Miliary pattern

Answer 14

Uniform pattern of relatively small nodules several millimeters or less in diameter. Associated with hematogenously disseminated tuberculosis.

Question 15

Ground-glass pattern

Answer 15

Used to describe a hazy, translucent appearance to the region of increased density (like that of frosted glass)

Sometimes used to describe X-rays, but more often used to describe CT images.

Question 16

Tradeoff of CT as opposed to X-ray

Answer 16

Compared with the plain chest radiograph, CT of the chest provides greater anatomic detail but is more expensive and exposes patients to a significantly higher dose of radiation

Question 17

How CT scans work

Answer 17

A narrow beam of x-rays is passed through the patient and sensed by a rotating detector on the other side of the patient. The beam is partially absorbed within the patient, depending on the density of the intervening tissues. Computerized analysis of the information received by the detector allows a series of cross-sectional images to be constructed. Use of different “windows” allows different displays of the collected data, depending on the densities of the structures of interest.

Question 18

The best CTs nowadays have a resolution of. . .

Answer 18

. . . 1 to 2 millimeters

Question 19

Computed tomographic angiography

Answer 19

Important in the diagnosis of pulmonary emboli.

The pulmonary arterial system is visualized by helical CT scanning following injection of radiographic contrast into a peripheral vein. More likely to be diagnostic than perfusion scanning, and it is less invasive than traditional pulmonary angiography

Question 20

Virtual bronchoscopy

Answer 20

Three-dimensional view of the airways reconstructed from CT scans

Question 21

Answer 21

Intreaperitoneal air. Indicative of very serious pathology

Question 22

The left diaphragm is generally ___ than the right diaphragm

Answer 22

The left diaphragm is generally 1-2cm lower than the right diaphragm

Question 23

In a CXR obtained at full inflation (at the end of a patient’s maximum inhalational effort), the domes of the right and left diaphragms are normally seen . . .

Answer 23

In a CXR obtained at full inflation (at the end of a patient’s maximum inhalational effort), the domes of the right and left diaphragms are normally seen at the level of the 10th or 11th ribs, posteriorly.

Question 24

Some causes of low, flat diaphragms (with diaphragmatic domes more inferior than the 10th or 11th ribs)

Answer 24

hyperinflation, as in emphysema, or tension pneumothorax

Question 25

Some causes of high diaphragms (domes more superior than the 10th and 11th rib)

Answer 25

diffuse scarring of lungs; diaphragmatic weakness or paralysis; abdominal distention

Question 26

The only pleura visible on a chest X-ray is. . .

Answer 26

. . . the space where layers come together to form the interlobar fissures.

Question 27

Order in which fluid outside the lungs becomes visible

Answer 27

1. The posterior costophrenic sulcus (the costophrenic angle) 2. The lateral costophrenic sulcus Distinguishing between these is best done via a lateral chest X-ray

Question 28

Pneumothorax, when present, will always be visible in . . .

Answer 28

. . . **the apex of the pleural pace**

Question 29

Counting the ribs on a chest X-ray

Answer 29

1. start with the anterior tip of the first rib (typically found just below the medial end of the clavicle) 2. follow it around to the **posterior** portion of the same rib 3. count downward along the **posterior** aspects of each rib

Question 30

When counting ribs on a chest X-ray, it is useful to remember that . . .

Answer 30

. . . **posterior** ribs **descend from medial to lateral**; **anterior** ribs **descend from lateral to medial**

Question 31

On a full inspiration, the domes of the diaphragms overlie the ___ ribs in a normal adult.

Answer 31

On a full inspiration, the domes of the diaphragms overlie the **posterior aspects of the 10th or 11th** ribs in a normal adult.

Question 32

On the PA CXR, the normal right heart and mediastinal border is made up (from bottom to top) of the:

Answer 32

1. Inferior vena cava 2. Right atrium 3. Ascending aorta 4. Superior vena cava

Question 33

On the PA CXR, the normal left heart and mediastinal border consists of (from bottom to top):

Answer 33

1. Left ventricle 2. Left atrium 3. Pulmonary artery 4. Aortic arch 5. L subclavian artery and vein

Question 34

Hila may be enlarged on CXR by. . .

Answer 34

* Dilated pulmonary arteries or veins * Hilar lymphadenopathy * Tumors or masses in the hilar space

Question 35

Examples of excessive radiolucency of lung fields

Answer 35

* Cyst * Bulla * Cavity * Pneumothorax * Emphysematous ring

Question 36

Examples of excessive radiopacity of lung fields

Answer 36

* Focal – tumor, localized pneumonia, aspirated foreign body * Multifocal – pulmonary metastases, multilobar pneumonia, rheumatoid nodules, Ghon-complex of tuberculosis * Diffuse (i.e., generalized throughout all lung fields) – diffuse pneumonia, inhalational lung disease (e.g., asbestosis), pulmonary edema, diffuse pulmonary hemorrhage

Question 37

When identifying a lung problem on CXR, an attempt should always be made to. . .

Answer 37

. . . **localize the problem to the correct lobe.**

Question 38

Pitfalls to CXR interpretation

Answer 38

* **Incomplete inspiration:** High diaphragm, crowding of normal lung markings, leading to the appearance of congestion of anatomic structures and disease. * **Under (too white) - or over (too black)-penetration** of the x-ray beam: Can check by making out the thoracic vertebrae overlying the image of the heart * **Rotation** from the true perpendicular: Proper orientation can be checked by noting equal distances from the vertebral spines (in the midline) to the medial ends of the clavicles.

Question 39

Always check that the trachea is. . .

Answer 39

. . . **midline** If it is not, this could indicate pneumothorax or some pathology of the throat that is pushing it aside.

Question 40

What is going on with this chest x-ray?

Answer 40

Nothing! The patient just had a mastectomy.

Question 41

What's going on with this chest x-ray?

Answer 41

Pneumothorax on the right side.

Question 42

What is the likely diagnosis given this chest x-ray?

Answer 42

Hodgkin's lymphoma

Question 43

What is the defect here?

Answer 43

Pulmonary embolism on right pulmonary artery.