You are in Tuesday morning trauma rounds after a night shift. The room is warm, and the senior’s voice is monotonous. You begin to drift off to sleep when you hear your name called to go to the front of the room to read a chest x-ray. You know nothing about the patient. Where do you start?
1. What is the first thing you should do with the chest x-ray?
2. What is an easy acronym you can use to recall all of the important parts of the chest x-ray?
How to Read a Chest X-ray
The key to reading a chest x-ray is to develop a system that you will be able to replicate time after time. This will ensure that you evaluate every important aspect of the chest x-ray consistently. If you are not looking for it, you are not going to see it! What follows is an example of such a system. It is by no means the only way to look at a chest x-ray, and you should develop your own system that works for you.
Make sure that it is hung (or displayed) correctly and that it is a chest x-ray of the correct patient. Sometimes images get mixed up or the side is incorrectly marked. Look for the heart on the left side of the chest (unless, of course, the patient has dextrocardia). Make sure that it has appropriate exposure and that you can see everything that you need to see (ie, apices of lungs, costophrenic angles). On a properly exposed film, the lungs are not too black and you can see the vertebral bodies through the heart. Ideally, patients are imaged straight on, rather than being rotated, which can distort the appearance of the mediastinum. Additionally, adequate inspiration is essential to good technique. In adults, approximately 9 posterior ribs should be identified. Low lung volumes mimic pulmonary edema.
Just like a trauma evaluation, ABCDE can be used to note each important part of the radiograph. This method takes advantage of the fact that all you want to do when you look at a chest x-ray is look at the lungs—which is why it saves the lungs for last.
- A—Abdomen. Look for free air under the abdomen on an upright film.
- B—Bones. Examine all of the ribs, clavicles, and vertebrae for fractures or dislocations.
- C—Cardiac. Trace the cardiac silhouette starting from the right base, along the right atrium, and examine the mediastinum for any tumors or deviation. Evaluate the aortic arch on the left and trace the silhouette down to the left ventricle. On a PA CXR you can measure the width of the heart and compare it with the width of the chest. A ratio greater than 1:2 is evidence of cardiomyopathy. This rule does not apply to a portable ...