Diagnosing acute pulmonary embolism with computed tomography: imaging update.

Acute pulmonary embolism is recognized as a difficult diagnosis to make. It is potentially fatal if undiagnosed, yet increasing referral rates for imaging and falling diagnostic yields are topics which have attracted much attention. For patients in the emergency department with suspected pulmonary embolism, computed tomography pulmonary angiography (CTPA) is the test of choice for most physicians, and hence radiology has a key role to play in the patient pathway. This review will outline key aspects of the recent literature regarding the following issues: patient selection for imaging, the optimization of CTPA image quality and dose, preferred pathways for pregnant patients and other subgroups, and the role of CTPA beyond diagnosis. The role of newer techniques such as dual-energy CT and single-photon emission-CT will also be discussed.