If you can see 6 anterior ribs, then the film is of a very high standard.
An under-penetrated chest x-ray cannot differentiate the vertebral bodies from the intervertebral spaces. It is under penetrated if you can’t see the thoracic vertebrae. An over-penetrated film shows the intervertebral spaces very distinctly.
Check that the thoracic spine aligns in the centre of the sternum and between the clavicles. Check if the clavicles are level.
If there are old films available you should hang these adjacent. The term posteroanterior (PA) refers to the direction of the x-ray traversing the patient from posterior to anterior, from back to front. The term antero-posterior (AP) refers to the direction of the x-ray traversing the patient from anterior to posterior, from front to back. The lateral chest radiograph is taken with the patient’s left side of chest held against the x-ray cassette. An oblique view is a rotated view in between the standard front view and the lateral view. It is useful in localizing lesions and eliminating superimposed structures.
Since AP radiographs are taken from shorter distances, they appear more magnified and less sharp compared to standard PA films. An AP film can show magnification of the heart and a widening of the mediastinum. [5] X Research source
The dependant lung should increase in density. This is due to atelectasis from the weight of the mediastinum putting pressure on it. If this doesn’t happen it is an indicator of air trapping. [6] X Research source
Assess the amount of gas and location of the gastric bubble. Normal gas bubbles may also be seen in the hepatic and splenic flexures of the colon.
Examine the lung fields for any infiltration, fluid, or air bronchograms. If fluid, blood, mucous, or tumor, etc. fills the air sacs, the lungs will appear radiodense (bright), with less visible interstitial markings.
A lucent bone lesion is an area of bone with a decreased density (appearing darker); it may appear punched out compared to surrounding bone. [9] X Research source A sclerotic bone lesion is an area of bone with an increased density (appearing whiter). [10] X Research source At joints, look for joint spaces narrowing, widening, calcification in the cartilages, air in the joint space, and abnormal fat pads.
Look at the size of the cardiac silhouette (white space representing the heart, situated between the lungs). [12] X Expert Source Ni-Cheng Liang, MDBoard Certified Pulmonologist Expert Interview. 18 June 2021. A normal cardiac silhouette occupies less than half the chest width. A heart with a diameter greater than half thoracic diameter is an enlarged heart. Note the lymph nodes, look for subcutaneous emphysema (air density below the skin), and other lesions. Look for water-bottle-shaped heart on PA plain film, suggestive of pericardial effusion. Get an ultrasound or chest Computed Tomography (CT) to confirm. [13] X Research source
The right diaphragm is normally higher than the left, due to the presence of the liver below the right diaphragm. [16] X Research source Also look at the costophrenic angle (which should be sharp) for any blunting, which may indicate effusion (as fluid settles down). [17] X Research source
Look for calcified lymph nodes in the hilar, which may be caused by an old tuberculosis infection. [18] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source
