Acute pulmonary embolism: visualization of high attenuation clot in the pulmonary artery on noncontrast helical chest CT

Helical CT of the thorax is frequently utilized for the evaluation of chest pain or shortness of breath affecting the emergency patient. To improve diagnostic accuracy, thoracic CT examinations are frequently tailored to address specific conditions. Although tailored protocols may enhance diagnostic accuracy, implementing the wrong protocol could result in a misdiagnosis. The proper protocol choice may particularly difficult in the emergency patient due to the nonspecific nature of many chest pain syndromes. Recently, helical CT has been used for the evaluation of suspected pulmonary embolism (PE). Demonstration of an intravascular filling defect surrounded by contrast-enhanced blood is diagnostic of PE. However, because the clinical presentation of PE is frequently nonspecific, awareness of the many potential imaging manifestations of PE is important. Therefore, we present the rare circumstance of high-attenuation clot visible within the pulmonary arteries on noncontrast helical CT; PE was confirmed after the administration of iodinated contrast medium.