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Cochin Hospital – Port-Royal · AP-HP · Paris Cité University
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Interventional Radiology Cochin
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Radiology A: Imaging

Cochin Hospital · AP-HP · Paris Cité University

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Interventional Radiology›Radiology A›Chest CT
Radiology A · Pulmonary imaging

🫁 Chest CT

Lungs, mediastinum, pleura: how is the examination performed?

Quick answer

Chest CT examines the lungs, mediastinum and pleura, without injection (screening, nodule) or with injection (pulmonary embolism, tumour assessment). It is the reference examination for lung assessment, fast and widely available.

What is it?

Chest CT examines the lungs, mediastinum and pleura. It can be performed without injection (screening, nodule, emphysema) or with injection (pulmonary embolism, tumour assessment). It is the reference examination for lung assessment.

⏱️ Duration: 10 to 20 minutes in total.

How to prepare

1

Fast for 4 hours if an injection is planned. No fasting if there is no injection.

2

Bring your previous examinations (X-rays, CT scans, PET scans) for comparison.

3

Tell us about any allergy to contrast medium.

How does it go?

1

You lie down with your arms raised above your head to clear the chest.

2

Very fast acquisition: 10 to 20 seconds.

3

Breath-holds of a few seconds are requested. Do not move during these breath-holds.

4

If an injection is given: a passing sensation of warmth, which is normal.

After the examination

1

You can resume your activities immediately.

2

If an injection was given: drink plenty of fluids.

3

Report within 2 to 5 working days.

✅ Low-dose chest CT is the reference examination for lung cancer screening in at-risk individuals.

Frequently asked questions

Does a chest CT always require an injection?
No, it depends on the indication: a CT without injection is enough for some conditions (looking for nodules, fibrosis), whereas an injection is needed to study the pulmonary vessels or characterise certain lesions.
Do I have to hold my breath during the examination?
Yes, one or more breath-holds of a few seconds will be requested to obtain sharp images, undisturbed by breathing movements.
Can chest CT be used to screen for lung cancer?
A low-dose chest CT can be offered as part of screening in at-risk patients (notably smokers), according to the criteria defined by your referring doctor.

Do you have a question about your examination?

️ rdv.radioa.cch@aphp.fr Contact us

Why you can trust this page

Written by the Radiology team at Cochin Hospital AP-HP, Paris Cité University. Medical review by a radiologist of the department. Last updated: July 2026.

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