Interpreting Chest X-rays
PA – Upright Lateral – Upright Portable – AP Supine
AP – Upright or Supine Lateral Decubitus Portable – AP “erect”
Portable – Lateral Decubitus
Develop a system to look at all important areas in order to avoid “tunnel vision”
N – Name, date, study
O – Orientation
- PA / AP
- Upright / supine / decubitus
- ? rotation
A – Appliances: lines and tubes
B – Bones: fractures?, destruction?
C – Cardiovascular: heart, great vessels, pulmonary vasculature
Center of Chest = mediastinum: contours?, shift?
D – Diaphragms – degree of inspiration
- free intraperitoneal air?
E – Extrathoracic tissues: abdomen and chest wall
- free intraperitoneal air?
- bowel gas, calcifications?
- subcutaneous emphysema?
F – Fluid: pleural effusion (meniscus)
- check patient position!
- air-fluid levels?
G – Gas
- lungs: lobar anatomy, asymmetry
- odd air?
H – History
- clinical (H&P)
- radiographic (prior films)
- clinical questions to be answered
- Check patient’s name, date and Right/Left marker on the x-ray
- A “good” inspiratory result usually exposes the sixth rib anteriorly, and the tenth posteriorly, at the mid right hemidiaphragm.
- The spinous process of a vertebra should be equidistant from the heads of the clavicles on the PA film. This confirms the patient is not rotated on the image.
- Evaluate the soft tissue and bony shadows outside and inside the rib cage for asymmetry, masses, air, and foreign bodies.
- Note the shape and height of the diaphragms; the right is normally higher by one interspace.
- Examine the mediastinum, its position and contents; note the air column, the carina, any lymph nodes, the heart shadow and great vessels.
- On the PA film, the right atrium forms the right heart border and, from top to bottom, the left heart border is made up of the aortic knob, main pulmonary artery, left atrial appendage, and left ventricle.
- On the lateral film, below the aortic arch, the left pulmonary artery lies posterior to the right and the left upper lobe bronchus lies inferior to the right. The right ventricle forms the anterior heart border and, from top to bottom, the left atrium and left ventricle form the posterior heart border.
- Observe the hilar shadows for symmetry left to right (the left is up to one interspace higher) and up and down. Look for asymmetric size and density.
- Examine the pleral surfaces, including the lateral and posterior costophrenic angles and the lung apices.
- Examine the lung parenchyma, looking for symmetry, increased or decreased density, calcification and cavitation.
- Air space disease replaces normal alveolar air with fluid density, is more homogeneous, and has air bronchograms.
- Interstitial disease can be reticular (branching lines), nodular, or both together
- On the lateral film, density should normally decrease as one proceeds down the spine. That is, the spine should get darker as one proceeds down the spine to the diaphragm.
Although abdominal x-rays will not be covered on the UNC Medicine Exam, here is a good series from the Student BMJ website on interpreting abdominal x-rays: