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Hôpital Cochin – Port-Royal · AP-HP · Université Paris Cité
Interventional Radiology Hôpital Cochin rdv.radioa.cch@aphp.fr
Radiologie Interventionnelle
Hôpital Cochin Port-Royal AP-HP AP-HP
Radiologie Cochin
Radiologie A — Imagerie

Hôpital Cochin · AP-HP · Université Paris Cité

️ rdv.radioa.cch@aphp.fr 01 58 41 24 69
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Radiology A · Urinary imaging

🩻 Uro-CT (CT urography)

CT scan of the kidneys and urinary tract — how does the examination work?

What is it?

Uro-CT (CT urography) is a reference examination to assess the kidneys, ureters and bladder. It combines several acquisitions before and after injection of iodinated contrast, including a delayed phase that opacifies the urine. It is used to look for a stone, a tumour of the kidney or urinary tract, a malformation, an infection or the cause of blood in the urine (haematuria).

⏱️ Duration: 15 to 30 minutes. Uses X-rays and, in most cases, a contrast injection.

Uro-CT — At a glance

A uro-CT (CT urography) is a specialised CT scan of the kidneys, ureters and bladder, often with contrast injection, used to investigate blood in the urine, kidney stones, or urinary tract tumours.

Criterion Data
IndicationsBlood in the urine (haematuria), suspected kidney stones, urinary tract tumours
DurationAbout 15–20 minutes
PreparationFasting may be required before contrast injection; blood test to check kidney function
RadiationOptimised low-dose protocols used where clinically appropriate
CostCovered by French national health insurance at Cochin AP-HP — no out-of-pocket fees

Data validated by the team of Prof. Anthony Dohan, Department of Interventional Radiology, Cochin Hospital AP-HP, Université Paris Cité.

How to prepare

1

A few hours of fasting may be requested depending on the protocol indicated when booking.

2

Bring a recent creatinine level (kidney function), required before iodinated contrast injection.

3

Report any allergy to iodinated contrast, kidney impairment, diabetes or use of metformin.

4

Good hydration before the examination is advised. Bring your previous reports and imaging.

5

Report any possible pregnancy: uro-CT uses X-rays.

How does it work?

1

You lie on your back on the CT table. The examination is painless.

2

A venous catheter is placed in the arm to inject the iodinated contrast.

3

Several acquisitions are performed: without injection, then at the arterial, venous and delayed phases (urinary excretion) to image the whole urinary tract.

4

You are asked to hold your breath briefly at each pass. A warm sensation is possible during injection.

After the examination

1

You can resume your usual activities immediately.

2

Drink plenty of fluids to flush out the contrast.

3

The report is sent to your doctor or urologist within 2 to 5 working days.

✅ Reference examination for stones, haematuria and urinary tract tumours. No additional fees.
⚠️ Iodinated contrast injection may be contraindicated in case of severe allergy or advanced kidney impairment. Report your situation before the examination.

Questions fréquentes

What is a uro-CT?
It is a CT scan dedicated to the kidneys and urinary tract, performed in several phases after contrast injection. It assesses stones, tumours, malformations and the cause of blood in the urine.
Uro-CT or ultrasound: what is the difference?
Ultrasound uses no X-rays and is useful as a first step. Uro-CT is more accurate for stones, tumours and full assessment of the urinary tract, but uses X-rays and a contrast injection.
Is the contrast injection mandatory?
In most cases yes, as it allows assessment of the kidneys and opacification of the urinary tract. A recent kidney function test is checked beforehand. If contraindicated, an adapted protocol is offered.
Does uro-CT involve radiation?
Uro-CT uses X-rays, so a dose of radiation. Protocols are optimised to keep the dose to the necessary minimum. In pregnant women, the examination is only performed when absolutely necessary, and other tests (ultrasound, MRI) may be preferred.
When are the results available?
The images are analysed by the radiologist and a detailed report is sent to your doctor or urologist within 2 to 5 working days. In an emergency, results can be communicated more quickly.

See also

Have a question about your examination?

️ rdv.radioa.cch@aphp.fr 01 58 41 24 69

Why this page is trustworthy

Written by the Interventional Radiology team at Cochin Hospital AP-HP, Université Paris Cité. Medically reviewed by an interventional radiologist of the department. Last updated: August 2026.