You have probably seen a chest x-ray (chest radiograph),or might even have had one taken.Have you ever wondered how to read a chest x-ray? When looking at a radiograph,remember that it is a 2-dimensional representation of a 3-dimensional object.Height and width are maintained,but depth is lost.The left side of the film represents the right side of the individual,and vice versa.Air appears black,fat appears gray,soft tissues and water appear as lighter shades of gray,and bone and metal appear white.The denser the tissue,the whiter it will appear on x-ray.Denser tissues appear radiopaque,bright on the film; less dense tissues appear radiolucent,dark on the film.

1.Check the patient's name.Above all else,make sure you are looking at the correct chest x-ray first.This sounds obvious,but when you are stressed and under pressure you can skip some of the basics.If you have the wrong x-ray you will be wasting time not saving it.

2.Look up the patient's history.When you are preparing to read an x-ray make sure you have all the information on the patient,including age and sex,and their medical history.Remember to compare with old x-rays if there are any.

3.Read the date of the radiograph.Make special note of the date when comparing older radiographs (always look at older radiographs if available).The date the radiograph is taken provides important context for interpreting any findings.

4.Check if the film was taken under full inspiration.Chest x-rays are generally taken when the patient is in the inspiratory phase of the respiration cycle,in layman's termed having breathed in.This has an important effect on the quality of the x-ray.When the x-ray beams pass through the anterior chest onto the film,it is the ribs closest to the film,the posterior ribs,that are the most apparent.You should be able to view ten posterior ribs if it was taken under full inspiration.

5.Check the exposure.Overexposed films look darker than normal,and fine details are very difficult to see.Underexposed films look whiter than normal,and cause the appearance of areas of opacification.Look for intervertebral bodies in a properly penetrated chest x-ray.

6.Check for rotation.If the patient was not completely flat against the cassette,there may be some rotation evident on the x-ray.If this has happened the mediastinum can look very unusual.You can check for rotation by looking at clavicular heads and thoracic vertebral bodies.