Dual-energy subtraction chest radiography: what to look for beyond calcified nodules.

Dual-energy subtraction chest radiography is a robust and powerful tool that improves the ability to detect and accurately diagnose a wide variety of thoracic abnormalities on posteroanterior-lateral chest images. Dual-energy subtraction chest radiography has many advantages over conventional chest radiography that facilitate image interpretation. The major advantage of this imaging technique is that it more clearly depicts calcification, which greatly aids in characterizing pulmonary nodules. Dual-energy subtraction images are also helpful in the recognition of hilar and mediastinal masses; the detection of tracheal narrowing and vascular disease; the identification of bone, pleural, and chest wall abnormalities; and the localization of indwelling devices such as stents and catheters. However, dual-energy subtraction imaging also has some limitations of which the radiologist should be aware and requires a somewhat higher radiation dose than does conventional radiography.