Chest X-ray interpretation: Clinical sciences

Chest radiograph, or chest X-ray, is one of the most commonly performed imaging studies, and can provide a large amount of useful information. So understanding how to approach and interpret a chest X-ray is an incredibly important clinical skill.

So the most common indications for a chest X-ray include chest pain, shortness of breath, or cough. It is also often used as a part of trauma and preoperative evaluation, and after placement of monitoring and support devices. 

While there are no absolute contraindications for a chest X-ray, and the radiation dose is small, you do want to ensure it is truly necessary, especially if your patient is pregnant.

Now, let’s discuss a systematic approach to interpreting a chest X-ray. This is going to involve checking the patient and study details, then assessing the quality of the study. Next, you want to scan the chest X-ray systematically and completely. You are looking to identify any abnormalities. Finally, you want to get a radiologist’s review of the film. Let’s go through each of these steps in more detail.

The first step in interpreting a chest X-ray is to check the name and date of birth on the image to confirm it’s the right patient, and the date and time to confirm it’s the right study.

Once you’ve done that, you are going to assess the quality of the chest X-ray. You’ll look at six main factors: projection, orientation, rotation, angulation, penetration, and inspiration. Remember, a good quality image gives you a lot of information, and a bad quality image could cause you to misinterpret findings. 

Begin with projection. Look to see how the film was taken. Is it a PA, or posterior to anterior, AP, or anterior to posterior, or a lateral study? The standard chest x-ray is PA. However, AP films are often seen when the patient needs a portable machine, like when they’re bedbound. Lateral films can be obtained with both.

Next, look at the orientation of the chest X-ray. Check the left and right markings. You’ll see a “L” or left marker on the right side of the image. Also the position of the patient is important. Supine means they’re laying down facing upward; lateral is when they’re laying on their side; semi upright is when their upper body is elevated 45 to 60 degrees from the bed; and upright is when they are sitting up at 90 degrees.

You then need to assess whether the patient is rotated toward their left or right. To do this, look at the relationship between the clavicles and the spine. If the medial ends of the clavicles are equidistant from the thoracic spinous process, the patient is not rotated.