Multidetector computed tomography findings of dense pulmonary emboli in oncologic patients

Pulmonary embolism is a frequent condition for which multidetector computed tomography (MDCT) plays an important role in its detection. Occasionally, on MDCT studies, dense linear branching opacities may be found within the pulmonary vessels. They represent dense emboli within the pulmonary arteries (DEPA). These may occur in oncologic patients that undergo specific treatments or interventional procedures, such as cement embolus from vertebroplasty, catheter or coil migration after embolization procedures, radioactive seed embolus in patients treated with local brachytherapy for prostate, lung, or liver cancer, and also in chronic pulmonary embolism. Usually DEPA does not have any clinical significance but may be fatal when massive or when in patients with impaired cardiopulmonary function. Being familiar with their radiologic appearance and knowing about the good clinical outcome of these patients will avoid unnecessary imaging testing. In this article, we describe some examples of DEPA. Based on the MDCT imaging findings, these emboli have very few or no side effects on the underlying lung parenchyma. We would like to stress the need for using bone window values for identifying these emboli. We provide examples of dense linear nonvascular images (pulmonary calcification secondary to tuberculosis (TBC) or radiotherapy, calcified mucous plugs, lung sutures, etc) that may mimic DEPA.