Chest X-rays Flashcards
In order for a line or an interface to appear between two adjacent structures on a radiograph, . . .
In order for a line or an interface to appear between two adjacent structures on a radiograph, the two structures must differ in density.
Two standard radiograph views
- Posteroanterior (source posterior, film anterior)
- Lateral
For bedridden patients, it is often necessary to take. . .
. . . an anteroposterior radiograph or a lateral decubitus radiograph (where the patients lies on their side and X-ray beams go horizontally)
Decubitus views are particularly useful for identifying. . .
. . . pleural effusion.
Atelectasis
Collapse of lung tissue with loss of volume
Radiographic lobe identifications
Which lobe is this consolidation in?
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.
Features of volume loss due to lobe consolidation
- Displacement of lobar fissures
- Indirect signs of hylum, diaphragm, trachea, or mediastinum displacement
Categories of radiographic lung findings
Interstitial and alveolar
These often lack pathologic correlation, but are still useful categories.
What is going on with this patient?
Upper R lobe consolidation (in this case it happens to be lung collapse)
What radiographic pattern of lung disease is this?
Interstitial lung disease, or reticulonodular.
Consists of an interlacing network of linear and small nodular densities
What radiographic pattern of lung disease is this?
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.
Nodular pattern
Presence of multiple discrete, typically spherical, nodules on X-ray.
Miliary pattern
Uniform pattern of relatively small nodules several millimeters or less in diameter. Associated with hematogenously disseminated tuberculosis.
Ground-glass pattern
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.
Tradeoff of CT as opposed to X-ray
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
How CT scans work
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.
The best CTs nowadays have a resolution of. . .
. . . 1 to 2 millimeters
Computed tomographic angiography
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
Virtual bronchoscopy
Three-dimensional view of the airways reconstructed from CT scans
Intreaperitoneal air. Indicative of very serious pathology
The left diaphragm is generally ___ than the right diaphragm
The left diaphragm is generally 1-2cm lower than the right diaphragm
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 . . .
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.
Some causes of low, flat diaphragms (with diaphragmatic domes more inferior than the 10th or 11th ribs)
hyperinflation, as in emphysema, or tension pneumothorax
Some causes of high diaphragms (domes more superior than the 10th and 11th rib)
diffuse scarring of lungs; diaphragmatic weakness or paralysis; abdominal distention
The only pleura visible on a chest X-ray is. . .
. . . the space where layers come together to form the interlobar fissures.
Order in which fluid outside the lungs becomes visible
- The posterior costophrenic sulcus (the costophrenic angle)
- The lateral costophrenic sulcus
Distinguishing between these is best done via a lateral chest X-ray
Pneumothorax, when present, will always be visible in . . .
. . . the apex of the pleural pace
Counting the ribs on a chest X-ray
- start with the anterior tip of the first rib (typically found just below the medial end of the clavicle)
- follow it around to the posterior portion of the same rib
- count downward along the posterior aspects of each rib
When counting ribs on a chest X-ray, it is useful to remember that . . .
. . . posterior ribs descend from medial to lateral;
anterior ribs descend from lateral to medial
On a full inspiration, the domes of the diaphragms overlie the ___ ribs in a normal adult.
On a full inspiration, the domes of the diaphragms overlie the posterior aspects of the 10th or 11th ribs in a normal adult.
On the PA CXR, the normal right heart and mediastinal border is made up (from bottom to top) of the:
- Inferior vena cava
- Right atrium
- Ascending aorta
- Superior vena cava
On the PA CXR, the normal left heart and mediastinal border consists of (from bottom to top):
- Left ventricle
- Left atrium
- Pulmonary artery
- Aortic arch
- L subclavian artery and vein
Hila may be enlarged on CXR by. . .
- Dilated pulmonary arteries or veins
- Hilar lymphadenopathy
- Tumors or masses in the hilar space
Examples of excessive radiolucency of lung fields
- Cyst
- Bulla
- Cavity
- Pneumothorax
- Emphysematous ring
Examples of excessive radiopacity of lung fields
- 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
When identifying a lung problem on CXR, an attempt should always be made to. . .
. . . localize the problem to the correct lobe.
Pitfalls to CXR interpretation
- 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.
Always check that the trachea is. . .
. . . midline
If it is not, this could indicate pneumothorax or some pathology of the throat that is pushing it aside.
What is going on with this chest x-ray?
Nothing! The patient just had a mastectomy.
What’s going on with this chest x-ray?
Pneumothorax on the right side.
What is the likely diagnosis given this chest x-ray?
Hodgkin’s lymphoma
What is the defect here?
Pulmonary embolism on right pulmonary artery.
