Diagnostic Test
CT Scan (CAT Scan)
A fast, detailed X-ray scan that creates 3D "slices" of your kidneys and bladder. It is the gold standard for spotting kidney cancer, kidney stones and investigating blood in the urine.
Key Takeaways
- A fast, detailed X-ray scan that creates 3D "slices" of your kidneys and bladder. It is the gold standard for spotting kidney cancer, kidney stones and investigating blood in the urine.
- We offer specialist interpretation and related treatments. Book a consultation to discuss your options.
Overview
About CT Scan (CAT Scan)
A CT scan (sometimes called a CAT scan) is a sophisticated type of X-ray. While a normal X-ray takes a flat, 2D picture, a CT scan rotates around your body to take hundreds of images from different angles. A computer then joins these together to create highly detailed "slices" of your internal organs. In urology, this gives your consultant an incredibly clear view of your kidneys, ureters, and bladder.
Test Information
Understanding Your Test
A detailed guide to your diagnostic procedure — from essential preparation and the purpose of the test to safety considerations and what to expect during the process.
You will lie on a flat, narrow bed that slides into the scanner, which looks like a large, brightly lit doughnut. Unlike an MRI, the CT scanner is much shorter and open at both ends, so most people don't feel "closed in."
The scanner rotates rapidly around you (you might hear a "whirring" sound) and you may be asked to hold your breath for a few seconds. If you are having a CT Urogram, a contrast dye will be injected into a vein in your arm during the scan. This dye is essential for highlighting the kidneys and bladder on the X-ray.
The scan itself is completely painless. However, the contrast dye can cause some "unusual" sensations that are worth knowing about:
A warm flush: You may feel a wave of heat spreading through your body.
Metallic taste: You might notice a strange, metallic taste in your mouth.
A "full" feeling: Some people feel a warm sensation in their pelvis that makes them feel—just for a few seconds—as if they have accidentally urinated.
These feelings are completely normal and pass within a minute or two.
CT scans are the most effective way for doctors to find kidney or ureteric stones, as even tiny stones show up clearly. You may also be booked for a "CT Urogram". This is a specific type of scan where a special dye (contrast) is used to highlight the entire lining of your urinary system. It is often the first-line investigation if you have found blood in your urine, as it helps rule out tumours or other abnormalities in the "drainage" system.
At a glance
Preparation required
- Fasting: If your scan requires contrast dye, you may be asked not to eat for a few hours beforehand.
- Blood Test: You must have a recent blood test (to check your eGFR or kidney function) before the scan. This ensures your kidneys are healthy enough to "flush out" the contrast dye.
- Hydration: You might be asked to drink a few glasses of water just before the scan to help fill your bladder.
- Clothing: Wear comfortable clothes without metal zips or buttons. You may be asked to change into a hospital gown to prevent metal from interfering with the images.
Risks or considerations
- Radiation: CT scans use X-rays. While the dose is low, it is higher than a standard chest X-ray. We only perform CT scans when the benefit of an accurate diagnosis outweighs the small risk.
- Contrast Allergy: A small number of people are allergic to the dye. Please tell the staff if you have any known allergies or asthma.
- Kidney Health: If your kidney function is low, the team may decide to perform the scan without the dye or suggest a different test.
- Pregnancy: CT scans are generally avoided during pregnancy due to the risk of radiation to the baby.
What it can help diagnose
- Kidney and Ureteric Stones: Pinpointing exactly where a stone is and how large it is.
- Kidney Cysts and Tumours: Distinguishing between simple fluid-filled sacs and more serious growths.
- Urothelial Cancer: Identifying issues in the lining of the kidney or the tubes (ureters).
- Obstructions: Finding narrowings or "kinks" in the tubes that might be blocking urine flow.
- Congenital Issues: Checking if you were born with any unusual kidney shapes or positions.
- Trauma: Assessing any damage after an accident or injury.
Our Commitment
Care you can trust
Every test is delivered to the same standard: senior consultants, a personalised plan, and the safety of an accredited private hospital behind you.
Consultant-Led Excellence
Receive evidence-based treatments delivered by senior NHS consultants in a professional, specialist setting.
Personalised Care Plans
Your consultant will design a bespoke treatment plan tailored to your specific health goals and lifestyle.
Hospital-Grade Safety
We operate within leading private hospitals, adhering to strict CQC safety and technology standards.
A Heritage of Trust
Our partners bring decades of NHS and private experience, successfully managing thousands of patient cases.
Patient Guidance
Frequently Asked Questions
Common questions about this test and what to expect
3 questions
If your scan requires contrast dye (an 'IVP' or Urogram), the dye is filtered out of your body by your kidneys. We perform a blood test beforehand to check your kidney function (eGFR) to ensure your kidneys are healthy enough to process the dye safely without risk of damage.
Reviewed 2 Mar 2026
Was this helpful?
When the dye is injected, most people feel a sudden wave of warmth spreading through their body. Many patients also experience a metallic taste in their mouth or a strange sensation in their lower abdomen that makes them feel like they've had a small 'accident.' This is a completely normal reaction to the dye and passes in less than a minute.
Reviewed 2 Mar 2026
Was this helpful?
A CT scan uses X-rays and is much faster (minutes), making it better for looking at bones and hard structures like kidney stones. An MRI uses magnets, takes longer (30-45 mins), and provides better detail for soft tissues like the prostate gland. CT is generally preferred for a 'whole-picture' look at the urinary plumbing.
Reviewed 2 Mar 2026
Was this helpful?