MCU (Micturating Cystourethrogram)

MCU (Micturating Cystourethrogram) – Detailed Overview

A Micturating Cystourethrogram (MCU) is a fluoroscopic X-ray study of the bladder and urethra during urination. It is primarily used to diagnose vesicoureteral reflux (VUR), bladder abnormalities, and urethral conditions. The procedure involves injecting a contrast dye into the bladder through a catheter and taking X-ray images before, during, and after urination.

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1. Indications (Why It’s Done?)

✅ Common Indications in Children & Infants

🔹 Recurrent Urinary Tract Infections (UTIs) – To check for vesicoureteral reflux (VUR)
🔹 Congenital Urinary Tract Abnormalities – Posterior urethral valves (PUV), urethral strictures
🔹 Hydronephrosis (Swelling of the Kidneys) – To assess for reflux or obstruction
🔹 Prenatal Diagnosis of Kidney Issues – If abnormalities were detected on antenatal ultrasound
🔹 Bladder Dysfunction – Neurogenic bladder or dysfunctional voiding

✅ Common Indications in Adults

🔹 Urethral Strictures or Obstruction – Due to trauma, infections, or previous surgeries
🔹 Neurogenic Bladder Disorders – In patients with spinal cord injuries or neurological diseases
🔹 Post-Surgical Follow-up – After urethral or bladder surgery
🔹 Bladder Fistulas – Abnormal connections between the bladder and other organs

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2. Procedure & Technique

Patient Preparation

✅ No fasting required
✅ Bladder should be empty before the procedure
✅ Antibiotic prophylaxis may be given in children with recurrent UTIs
✅ Patient is positioned supine on the X-ray table

Step-by-Step Procedure

1️⃣ Sterile catheter insertion – A thin catheter is inserted into the urethra to the bladder
2️⃣ Contrast injection – A radiopaque contrast dye is slowly infused into the bladder
3️⃣ Fluoroscopic X-ray imaging – Images are taken in the filled bladder state
4️⃣ Voiding phase – The catheter is removed, and the patient is asked to urinate while more X-ray images are taken
5️⃣ Post-void images – Final images are taken after urination to check for residual urine

⏳ Duration: About 20-30 minutes

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3. Key Findings in MCU

✅ Normal Findings

• Smooth bladder outline

• No vesicoureteral reflux (VUR)

• Complete emptying of the bladder with no significant residual urine

• Normal urethral caliber and contour

✅ Abnormal Findings & Common Diagnoses

1️⃣ Vesicoureteral Reflux (VUR)

• Urine flows back from the bladder to the ureters/kidneys

• Graded from Grade 1 (mild) to Grade 5 (severe)

• Seen in children with recurrent UTIs and hydronephrosis

2️⃣ Urethral Abnormalities

• Posterior Urethral Valves (PUV) – Congenital obstruction of the urethra in male infants

• Urethral Stricture – Narrowing due to scarring, infections, or trauma

• Urethral Diverticulum – Outpouching of the urethral wall

3️⃣ Bladder Abnormalities

• Neurogenic Bladder – Enlarged bladder with poor emptying

• Bladder Outlet Obstruction – Blockage causing incomplete emptying

• Bladder Fistulas – Abnormal connections to nearby organs

4️⃣ Post-Surgical Complications

• Urethral Leakage – After urethral surgery

• Vesicovaginal or Vesicointestinal Fistulas – Abnormal connections from the bladder to other organs

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4. Advantages of MCU

✔ Gold standard for diagnosing VUR in children
✔ Real-time assessment of bladder and urethral function
✔ Detects urethral strictures, bladder abnormalities, and post-surgical issues
✔ Non-invasive, minimal risk

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5. Limitations & Considerations

❌ Radiation exposure – Though minimal, especially in children
❌ Invasive procedure – Catheter insertion may cause discomfort
❌ Risk of Urinary Tract Infection (UTI) – Due to catheterization
❌ Not useful for soft tissue abnormalities – MRI or ultrasound may be needed for further evaluation

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6. Next Steps After MCU

• Normal Study → No further action needed

• Vesicoureteral Reflux (VUR) Detected → Managed with antibiotics, follow-up imaging, or surgery if severe

• Urethral Stricture or Posterior Urethral Valves (PUV) → May require surgical correction

• Bladder Dysfunction (Neurogenic or Outlet Obstruction) → Further evaluation and management needed