CT renal angiography shows the arteries to the kidneys. Learn when it is used for uncontrolled blood pressure, kidney artery narrowing and kidney donor planning.
CT renal angiography is a contrast CT scan that shows the arteries supplying the kidneys. It is used to find narrowing of the renal arteries (renal artery stenosis), a cause of high blood pressure that is hard to control, to plan surgery or stenting, and to map kidney arteries in potential kidney donors.
Why the Kidney Arteries Matter
When a kidney artery is narrowed, the kidney senses low blood flow and releases hormones that raise blood pressure. The result can be severe or hard-to-control hypertension and kidney damage. Young women with fibromuscular dysplasia and older people with plaque are two typical groups. See CT angiography of the aorta for a related scan.
ReasonWhat CT renal angiography showsHard-to-control high blood pressureNarrowing of a kidney arterySudden drop in kidney function on certain medicinesPossible bilateral stenosisKidney donor evaluationNumber, size and branching of arteries and veinsFibromuscular dysplasiaBeaded pattern in the arteryAfter stent or surgeryPatency and complicationsWhen Is It Advised?
- High blood pressure starting before age 30 or after age 55, or not controlled on several medicines
- Sudden worsening of kidney function after starting certain blood pressure medicines
- A kidney that is smaller than the other
- Flash pulmonary oedema (sudden breathlessness) with high blood pressure
- Evaluation of a living kidney donor
Kidney Safety With Contrast
This is a special concern: the test uses contrast, and the person may already have kidney problems. A creatinine and eGFR test is needed. Doctors weigh the benefit, use the lowest dose and ensure hydration. MR angiography or Doppler ultrasound can be used in some people with poor kidney function. See kidney function and contrast and CT vs MR angiography.
Preparation and Procedure
Fast for 4 to 6 hours and drink water as advised. Tell the staff about diabetes, metformin, allergy and kidney disease. The scan takes seconds with a short breath-hold, and the visit under an hour. See CT scan preparation.
A Practical Example
Anjali, 27, has high blood pressure not controlled on three medicines. Doppler is unclear, and a CT renal angiography shows a beaded pattern of fibromuscular dysplasia in the right renal artery. A vascular specialist treats it with balloon angioplasty, and her blood pressure falls, so she can reduce medicines.
Care Tips and Key Facts
- Take blood pressure medicines on time
- Check blood pressure at home and keep a record
- Limit salt and avoid tobacco
- Avoid anti-inflammatory painkillers unless advised
After the Scan and Next Steps
Take the report to a nephrologist, cardiologist or vascular specialist. Mild narrowing is treated with medicines. Severe narrowing with uncontrolled blood pressure or kidney damage may need angioplasty or stenting. Kidney donor candidates will discuss the findings with the transplant team. Keep monitoring blood pressure and kidney function.
Questions to Ask Your Doctor
- Is my blood pressure caused by kidney artery narrowing?
- Do I need angioplasty or only medicines?
- Is my kidney function safe for contrast?
- Which medicines should I avoid?
Common Mistakes to Avoid
- Stopping blood pressure medicines on your own.
- Ignoring sudden worsening of kidney function.
- Skipping the creatinine report.
Booking, Timing and Report
Book a morning slot if possible, since fasting is easier. Carry your doctor's prescription, previous heart and blood reports, a recent creatinine report and a medicine list. Allow 45 to 90 minutes at the centre. Reports are usually ready within 24 to 48 hours, because vessel images need careful review.
Understanding Your Report
The report may grade narrowing as mild, moderate or severe, describe a beaded pattern and compare the size of the two kidneys. Not every narrowing causes high blood pressure, so your doctor will match the findings with your blood pressure, kidney function and any kidney size difference before deciding on treatment.
Frequently Asked Questions
What is renal artery stenosis?
Narrowing of the artery to a kidney.
Can it cause high blood pressure?
Yes.
Is CT renal angiography safe for the kidneys?
It uses contrast, so kidney function is checked first.
Can Doppler replace it?
Doppler is a first test; CT gives more detail.
Do I need fasting?
Yes, 4 to 6 hours.
Is it used for kidney donors?
Yes, to map arteries and veins.
Do all narrowings need treatment?
No.
How long does it take?
The scan takes seconds.
When is the report ready?
Usually within 24 hours.
Book Your Test at Ganesh Diagnostic
Ganesh Diagnostic & Imaging Centre in Rohini, Delhi offers this test with trained radiology staff and clear reports. You can book an appointment online, check our branches across Delhi NCR, contact us for current rates, or explore all our services. Reports can be downloaded online through our patient portal, so you do not need to make a second trip just to collect them.
This article is for general information only. It does not replace advice from your doctor. Always follow your doctor's instructions for your test.
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