What is the primary imaging modality used to evaluate suspected pulmonary embolism?

The primary imaging modality used to evaluate suspected pulmonary embolism is CT angiography. This technique is highly effective due to its ability to quickly provide detailed images of the pulmonary arteries, allowing for the visualization of blood clots that may be obstructing blood flow. CT angiography is preferred in acute scenarios because it is rapid, widely available, and offers a high sensitivity and specificity for diagnosing pulmonary embolism.

In contrast, while X-rays may be used in the initial evaluation of patients with respiratory symptoms, they are not sensitive enough to detect pulmonary embolism directly. Ultrasound is commonly used for evaluating venous thrombosis, particularly in the legs, but it does not visualize the pulmonary arteries. MRI is generally not utilized for pulmonary embolism due to availability, time constraints in acute settings, and challenges regarding the interpretation of images in this context.