Clot or Not? Mimics of Acute Pulmonary Embolism on CT

Abstract

Diagnosis of acute pulmonary embolism (PE) can be challenging for both clinicians and radiologists. CT angiography (CTA) has emerged as the most practical imaging modality to ensure accurate and prompt recognition of acute PEs. Thus, radiologists are positioned as the first physicians able to confirm a diagnosis of acute PE in clinically suspected cases. However, in addition to identifying acute PE on CTA, radiologists also must be aware of its mimics. Misdiagnosis of PE can result in detrimental patient outcomes, exposing patients unnecessarily to the risks of anticoagulation and delaying recognition of any true underlying pathology. In this article, we discuss entities that can be mistaken for acute PE on CTA. These mimics include artifacts, nonvascular abnormalities, and various causes of filling defects in the pulmonary vasculature, both thrombotic and nonthrombotic. The objectives of this article are to familiarize the reader with mimics of acute PE and to review the characteristic features that differentiate them from acute PE on CT.