CT Renal Angio

• What the test does: Uses X-rays and contrast dye to create high-resolution maps of the renal arteries.
• Why kidneys need special imaging: These arteries are only a few millimetres wide; early narrowing can raise blood pressure or damage kidney tissue long before symptoms appear.

A renal angiogram is a specialised vascular imaging study that reveals the size, shape, and flow of the renal artery and its branches.

1. Conventional catheter angiography Gold-standard for intervention (angioplasty or stent placement).
2. CT renal angiogram Combines speed, comfort, and 3-D detail; no overnight stay.
3. MR renal angiogram Uses magnetic fields and gadolinium; great for children or pregnant patients when essential.

• Artery diameter (normal: 4–6 mm)
• Stenosis percentage (mild <50 %, moderate 50–70 %, critical >70 %)
• Blood-flow velocity measured with Doppler if catheter study is done

• Detect renal artery stenosis before kidneys lose function
• Evaluate hypertension causes when medication fails
• Pre-surgical planning for kidney transplant or tumour removal

Symptoms that signal testing

• Sudden, severe high blood pressure (especially under 40 or over 60)
• Unexplained drop in kidney function
• Abnormal whooshing sound (bruit) heard over the abdomen

Age and risk factors

• Adults 18-80 with hypertension resistant to 3+ medications
• Smokers, diabetics, or those with a family history of vascular disease

• Early detection: Catch vessel disease before dialysis is needed
• Minimally invasive: Only an IV line for CT renal angi
• Guides precise treatment like stenting or medication changes

• Renal artery stenosis (plaque build-up or fibromuscular dysplasia)
• Fibromuscular dysplasia (web-like narrowing in younger women)
• Aneurysms and fistulas (ballooning or abnormal connections)

• Fasting guidelines: Nothing by mouth 4-6 hours before
• Medication adjustments: Hold metformin 48 h; bring insulin plan if diabetic
• Consent process: Written form plus verbal explanation in English, Hindi, or Kannada

• Kidney function tests (Creatinine, eGFR) within 30 days
• Allergy screening: Previous contrast or shellfish reactions noted

• Morning appointments for easy fasting
• Schedule around contrast clearance: If dialysis is needed, same-day slot can be arranged

• Adults with hypertension or kidney issues who meet lab criteria
• Contra-indications: Pregnancy (unless urgent), severe contrast allergy uncontrolled by pre-medication

1. Change into gown; vitals checked
2. IV line inserted for CT renal angi (or groin prep for catheter study)
3. Contrast injection—warm feeling for 10–15 seconds
4. Scan lasts 5–10 minutes; hold breath when asked
5. Recovery and monitoring for 30 minutes

• Inform about allergies (iodine, drugs, latex)
• Diabetic medication alerts: Resume metformin only after kidney function review

• Contrast reactions: Rare (1 in 1,000) itching, rash, or in very few cases anaphylaxis
• Radiation exposure: Equivalent to ~6 months of natural background; dose kept ALARP at Cadabams Diagnostics
• Not suitable for patients with very poor kidney function without dialysis planning