Imaging in chest disease

Imaging is critically important in the diagnosis and management of patients with chest disease, and the chest X-ray remains the most commonly performed imaging examination in medicine. Its correct interpretation is important in not only the diagnosis and exclusion of disease, but also in the choice of the next imaging investigation performed. As picture archiving and communication systems increase more doctors will have access to images and will need improved skills in their interpretation. The variety of chest imaging techniques available for patient investigation continues to increase, most importantly with the advent of positron emission tomography and computerized tomography (PET-CT), and there has also been a substantial improvement in pre-existing techniques. The decision on which technique to employ in disease investigation requires knowledge of their benefits and disadvantages, and information on how successfully these tests have been employed. Additionally, there is increasing evidence that clinician-performed imaging (ultrasound) provides substantial benefit to patients, with improved speed of access and safety. This chapter will provide information on the normal chest X-ray and its differential diagnosis when abnormal, and will discuss the use of a variety of imaging techniques in investigating common diseases.