Peripheral pulmonary embolism on multidetector CT pulmonary angiography.

Nowadays CT pulmonary angiography (CTPA) has been established a widely accepted technique for the diagnosis of pulmonary embolism (PE), based on its high accuracy and ability to provide alternative diagnoses such as pulmonary, pleural or mediastinal diseases. Since its introduction in 1992, the sensitivity and specificity of CTPA increased due to reduced collimation and faster rotation time. The main limitation of single-detector row CTPA was diagnosis of PE at the subsegmental level, similar to other diagnostic techniques, such as pulmonary angiography, V/Q lung scan and MR. The advent of multi-detector row CT technology has increased the analysability of pulmonary vessels distal to the segmental level. Multi-detector row CTPA detects more subsegmental PE than single-detector row CTPA. The incidence of isolated subsegmental PE is between 5-15%, depending of the population investigated. Currently there is no straightforward admitted guidelines for treatment of subsegmental PE. Indications for treatment of isolated subsegmental PE are reviewed.