Digital tomosynthesis of the chest: current and emerging applications

Digital tomosynthesis (DTS) of the chest is a technique whose basic components are similar to those of digital radiography, but that also provides some of the benefits of computed tomography (CT). The major advantages of DTS over conventional chest radiography are improved visibility of the pulmonary parenchyma and depiction of abnormalities such as pulmonary nodules. Calcifications, vessels, airways, and chest wall abnormalities are also much more readily visualized at DTS than at chest radiography. DTS could potentially be combined with chest radiography to follow up known nodules, confirm or rule out suspected nodules seen at radiography, or evaluate individuals who are at high risk for lung cancer or pulmonary metastases. DTS generates coronal "slices" through the chest whose resolution is superior to that of coronal reconstructed CT images, but it is limited by its suboptimal depth resolution and susceptibility to motion; consequently, potential pitfalls in recognizing lesions adjacent to the pleura, diaphragm, central vessels, and mediastinum can occur. However, the radiation dose and projected cost of chest DTS are lower than those of standard chest CT. Besides pulmonary nodule detection, specific applications of DTS that are under investigation include evaluation of pulmonary tuberculous and nontuberculous mycobacterial disease, cystic fibrosis, interstitial lung disease, and asbestos-related thoracic diseases. A basic understanding of chest DTS and of the emerging applications of this technique can prove useful to the radiologist. Online supplemental material is available for this article.