Respiratory motion

Imaging description Acute and chronic pulmonary emboli (PE) on contrast-enhanced CT chest are recognized as intraluminal filling defects within opacified pulmonary arteries. The filling defects may be complete or partial. The interface with intravenous contrast material should be sharp. Respiratory motion artifact may result in apparent termination of vessels or result in volume averaging with surrounding air-filled lung, mimicking an intraluminal filling defect [1]. and could be misinterpreted as a pulmonary embolus (Figure 85.1). Importance Annually, as many as 300 000 people in the United States die from acute pulmonary embolism [2]. Most of the deaths from PE result from failure of diagnosis rather than from treatment failure [3]. However, overdiagnosis of PE should also be avoided as there can be complications associated with the treatment of PE. Anticoagulation is the main therapy for acute PE. It is estimated that major bleeding (intracranial hemorrhage, retroperitoneal hemorrhage, or bleeding that led directly to death, hospitalization, or transfusion) occurs in fewer than 3% of patients receiving intravenous unfractionated heparin or oral warfarin to treat PE or deep vein thrombosis [4]. Heparin-induced thrombocytopenia (HIT) is another complication of heparin therapy.