CT Scan for Pulmonary Embolism: The Gold Standard in Diagnosis

At Independent Physicians Medical Center (IPMC) in Northeast Philadelphia, we offer rapid CT imaging with our advanced Siemens scanner to support urgent diagnostic needs.

How Does CT Pulmonary Angiography Work?

CTPA is a specialized type of CT scan that focuses on the blood vessels in the lungs. Iodine-based contrast dye is injected through an IV and timed precisely so that images are captured at the exact moment the contrast fills the pulmonary arteries. On the resulting images, the contrast-filled blood vessels appear bright white, and any blood clots appear as dark filling defects within the vessels.

This technique allows radiologists to identify clots in the main pulmonary arteries, the lobar and segmental branches, and even the subsegmental arteries. The scan also reveals important secondary findings such as right heart strain (an enlarged right ventricle, which indicates the clot is placing significant stress on the heart), pleural effusions (fluid around the lungs), lung infarction (areas of lung tissue that have been damaged by blocked blood flow), and any underlying lung conditions that may complicate treatment.

When Is a CT Scan Needed for Pulmonary Embolism?

Your doctor may order an urgent CTPA if you have symptoms suggestive of a pulmonary embolism, including:

• Sudden shortness of breath that came on without explanation
• Sharp chest pain that worsens with deep breathing or coughing (pleuritic chest pain)
• Rapid heart rate (tachycardia) or heart palpitations
• Coughing up blood (hemoptysis)
• Lightheadedness, dizziness, or fainting
• A recent history of deep vein thrombosis (DVT) — blood clot in the leg — with new respiratory symptoms
• Recent surgery, prolonged immobility, hospitalization, or long travel combined with concerning symptoms
• An elevated D-dimer blood test (a protein fragment produced when blood clots dissolve) in combination with clinical suspicion

CTPA is fast enough to be performed in emergency situations and accurate enough to guide immediate treatment decisions. It can typically be completed in just a few minutes.

What to Expect During the Scan

The scan is fast and noninvasive. An IV will be placed in your arm for contrast dye injection. You’ll lie on a table that slides through the CT scanner. The contrast is injected, and images are captured within seconds as the dye fills your pulmonary arteries.

You may feel a brief warm sensation or metallic taste from the contrast. The actual scan takes only about 5 minutes, making it one of the fastest diagnostic CT exams available. A technologist will be with you throughout.

After Your CT Scan

If a pulmonary embolism is detected, your doctor will discuss treatment options immediately — typically blood-thinning medications (anticoagulants) and, in severe cases, more aggressive interventions. If no clot is found, your doctor will explore other causes for your symptoms.

A board-certified radiologist will interpret the images and provide a detailed report. Results in urgent situations can be available within minutes.