 Diagnosis of PE is challenging because of the nonspecific nature of the clinical presentation, with associated symptoms such as chest pain, shortness of breath, and tachycardia that may mimic other pulmonary or cardiac conditions. The diagnostic challenge of PE is most commonly addressed with clinical scoring algorithms such as the Wells criteria and the Geneva score [6-8], D-dimer testing, and specialized CT angiography (CTA) [9], during which the images are acquired with a timing of the iodinated contrast bolus to best opacify the pulmonary arteries. In hemodynamically stable patients with a low or intermediate clinical likelihood of PE, normal results on D-dimer testing obviates the need for PE imaging. When patients do not fall into these categories, CT pulmonary angiography (CTPA) is commonly performed. There are 3 additional variants covered in this document: patients with a positive D-dimer without a high-risk clinical score (Variant 2), patients with a high pretest probability for PE (Variant 3), and pregnant patients (Variant 4). This document draws on the findings of the joint American College of Cardiology/ACR guideline on chest pain in the emergency room [9] and the American Thoracic Society/Society of Thoracic Radiology Clinical Practice Guideline: Evaluation of Suspected Pulmonary Embolism In Pregnancy [3]. Special Imaging Considerations Chest radiography is very limited in the assessment for PE, but it may diagnose a pneumothorax, pneumonia, or other condition. A chest radiograph is typically used in the interpretation of a ventilation and perfusion (V/Q) lung scan [10]. Because chest radiography is typically performed before advanced imaging is considered, it is not included in the ratings for Variants 1 through 3. aCleveland Clinic, Weston, Florida. bThe University of Texas MD Anderson Cancer Center, Houston, Texas. cPanel Chair, Cleveland Clinic, Cleveland, Ohio. dPanel Chair, Duke University, Durham, North Carolina.
Suspected Pulmonary Embolism PCAs.  Diagnosis of PE is challenging because of the nonspecific nature of the clinical presentation, with associated symptoms such as chest pain, shortness of breath, and tachycardia that may mimic other pulmonary or cardiac conditions. The diagnostic challenge of PE is most commonly addressed with clinical scoring algorithms such as the Wells criteria and the Geneva score [6-8], D-dimer testing, and specialized CT angiography (CTA) [9], during which the images are acquired with a timing of the iodinated contrast bolus to best opacify the pulmonary arteries. In hemodynamically stable patients with a low or intermediate clinical likelihood of PE, normal results on D-dimer testing obviates the need for PE imaging. When patients do not fall into these categories, CT pulmonary angiography (CTPA) is commonly performed. There are 3 additional variants covered in this document: patients with a positive D-dimer without a high-risk clinical score (Variant 2), patients with a high pretest probability for PE (Variant 3), and pregnant patients (Variant 4). This document draws on the findings of the joint American College of Cardiology/ACR guideline on chest pain in the emergency room [9] and the American Thoracic Society/Society of Thoracic Radiology Clinical Practice Guideline: Evaluation of Suspected Pulmonary Embolism In Pregnancy [3]. Special Imaging Considerations Chest radiography is very limited in the assessment for PE, but it may diagnose a pneumothorax, pneumonia, or other condition. A chest radiograph is typically used in the interpretation of a ventilation and perfusion (V/Q) lung scan [10]. Because chest radiography is typically performed before advanced imaging is considered, it is not included in the ratings for Variants 1 through 3. aCleveland Clinic, Weston, Florida. bThe University of Texas MD Anderson Cancer Center, Houston, Texas. cPanel Chair, Cleveland Clinic, Cleveland, Ohio. dPanel Chair, Duke University, Durham, North Carolina.