RGU (Retrograde Urethrogram) – Detailed Overview

A Retrograde Urethrogram (RGU) is a fluoroscopic X-ray study of the urethra, primarily used to evaluate urethral strictures, trauma, and congenital abnormalities. The procedure involves injecting a contrast dye into the urethra in a retrograde manner (against the normal flow of urine) and taking X-ray images to visualize the urethral anatomy.

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1. Indications (Why It’s Done?)

✅ Common Indications in Men

🔹 Urethral Stricture Disease – Due to infections, trauma, or surgeries
🔹 Urethral Trauma – Suspected after pelvic fractures or straddle injuries
🔹 Post-Surgical Evaluation – After urethral stricture repair or urethroplasty
🔹 Urethral Fistulas or Diverticula – Abnormal connections or outpouchings
🔹 Congenital Urethral Abnormalities – Such as posterior urethral valves (PUV)

✅ Common Indications in Women

🔹 Urethral Diverticulum – Outpouching of the urethral wall
🔹 Urethral Trauma – Rare but can occur after childbirth or surgery
🔹 Urinary Fistulas – Vesicourethral or urethrovaginal fistulas

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2. Procedure & Technique

Patient Preparation

✅ No fasting required
✅ Bladder should be empty before the procedure
✅ Antibiotics may be given if there’s a risk of infection
✅ Patient positioned supine with legs slightly apart

Step-by-Step Procedure

1️⃣ Sterile cleaning – The urethral opening is cleaned with an antiseptic solution
2️⃣ Contrast injection – A thin catheter or a special syringe is placed at the urethral opening, and a contrast dye is injected slowly in a retrograde manner
3️⃣ Fluoroscopic X-ray imaging – Real-time X-rays are taken to visualize the urethral anatomy
4️⃣ Post-procedure assessment – The patient is monitored for any discomfort, and normal urination is checked

⏳ Duration: About 15-20 minutes

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3. Key Findings in RGU

✅ Normal Findings

• Smooth and continuous urethral outline

• No narrowing, obstructions, or leaks

✅ Abnormal Findings & Common Diagnoses

1️⃣ Urethral Strictures

• Narrowing of the urethral lumen due to scarring or fibrosis

• Causes: Trauma, infections (gonorrhea, STDs), post-catheterization strictures

• Appears as a thin segment with contrast hold-up on imaging

2️⃣ Urethral Trauma

• Seen in pelvic fractures or straddle injuries

• Contrast leakage outside the urethra suggests urethral rupture

• Complete vs. Partial Tear → Determines treatment (catheterization vs. surgery)

3️⃣ Urethral Fistulas

• Abnormal connection between the urethra and surrounding structures

• Seen as contrast extravasation outside the normal urethral tract

4️⃣ Posterior Urethral Valves (PUV)

• Congenital obstruction in male infants causing urinary retention

• Shows dilatation of the posterior urethra with abrupt narrowing

5️⃣ Urethral Diverticulum

• Outpouching of the urethral wall

• Appears as a contrast-filled sac adjacent to the urethra

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4. Advantages of RGU

✔ Gold standard for diagnosing urethral strictures
✔ Non-invasive and quick
✔ Provides real-time visualization of the urethra
✔ Helps in pre-surgical planning

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5. Limitations & Considerations

❌ Mild discomfort during contrast injection
❌ Risk of urinary tract infection (UTI)
❌ Radiation exposure (minimal)
❌ Does not assess bladder function (MCU may be needed for full evaluation)

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6. Next Steps After RGU

• Normal Study → No further action needed

• Urethral Stricture Detected → May require Uroflowmetry, Urethroplasty, or Dilation

• Urethral Trauma → Management based on partial vs. complete rupture

• Fistula or Diverticulum Found → Further imaging (MRI, Cystoscopy) or surgical correction