Helical CT is being increasingly utilized for the evaluation of suspected p
ulmonary embolism (PE). Proper scan interpretation depends on the awareness
of several diagnostic pitfalls that may simulate PE, including normal bron
chovascular structures such as pulmonary veins, bronchi, and lymph nodes, t
echnical considerations such as improper bolus timing and streak artifacts,
and patient-related factors such as motion artifacts, pulmonary arterial c
atheters, and vascular shunts. An understanding of these pitfalls facilitat
es accurate diagnosis.