Chest X-ray quality
Artifact
The appearance of anatomical structures may be artifactual because of radiographic technique, patient factors, or the presence of external or internal non-anatomical objects. Artifact is often unavoidable, but some artifact can lead to misinterpretation of the image. Medical equipment may obscure anatomical structures, to the detriment of image interpretation, or conversely may be vital to image assessment.
Artifact is acceptable if the clinical question can still be answered. An image need only be repeated if artifact prevents the clinical question from being answered confidently.
Radiographic artifact
This is spurious or unclear appearance of an anatomical structure due to radiographic technique. As previously discussed, examples include rotation, incomplete inspiration and incorrect penetration. Other radiographic artifact includes clothing or jewelry not removed.
Patient artifact
Artifact may be due to patient factors such as poor co-operation with positioning or movement. Very often obesity exaggerates lung density. Occasionally normal anatomical structures such as hair or skin folds can cause confusion.
Key points
- Some artifacts are unavoidable
- A chest X-ray may be obtained to assess position of medical devices
- Ask yourself if artifact limits image interpretation
- Can the question clinical question still be answered?
Hover over image to show findings
Hair artifact
At first glance the soft tissues at the base of the neck on the right look abnormal. Appearances simulate surgical emphysema. This artifact is due to hair which was draped around the patient's neck.
Click image to align with the top of the page
Medical/surgical artifact
Some chest X-rays are performed solely to assess the position of medical devices. It is a common task of a junior doctor to be asked to assess the position of such devices on a chest X-ray.
External medical devices not part of the X-ray assessment should be removed by radiographers prior to image acquisition, unless it is dangerous to do so.
Hover over image to show findings
Naso-gastric (NG) tube placement
Junior doctors are often required to check the position of a naso-gastric tube. The tube tip should be below the level of the diaphragm (dotted line), and ideally should be at least 10cm beyond the gastro-oesophageal junction (GOJ *).
This tube is only just in the stomach and was advanced prior to using it for feeding.
The tip of a naso-gastric tube should also lie on the left. If it crosses the midline it has entered the duodenum. A tube in this position is correctly termed a naso-enteric tube.