What is the diagnostic approach for a bladder diverticulum?

Diagnostic Approach for Bladder Diverticulum

Cystography, ultrasound, or CT are the preferred initial imaging modalities for diagnosing bladder diverticulum, with CT retrograde cystography offering the highest diagnostic accuracy. 1

Initial Evaluation

When suspecting a bladder diverticulum, the diagnostic approach should focus on:

• Clinical presentation: Recurrent UTIs (present in 30-50% of cases), voiding difficulties, incomplete emptying, or pelvic pain
• Physical examination: Palpable mass in some cases, possible findings of bladder outlet obstruction

Diagnostic Imaging Algorithm

First-Line Imaging Options:

1. CT Imaging:

   • CT retrograde cystography is the most accurate diagnostic method, with superior sensitivity and specificity 2
   • Shows detailed information about size, location, shape, and opening of the diverticulum
   • Can identify complications such as stones, tumors, or infection within the diverticulum
   • Can differentiate diverticulum from other pelvic masses

2. Ultrasound:

   • Transabdominal ultrasound can detect larger diverticula
   • Less invasive but lower sensitivity compared to CT
   • Useful for initial screening, especially in patients where radiation exposure is a concern
   • Can evaluate for post-void residual volume to assess emptying of the diverticulum

3. Fluoroscopic Cystography:

   • Traditional method that can delineate bladder diverticula
   • Voiding cystourethrography (VCUG) is particularly useful when the diverticulum is near a ureteral orifice to evaluate for vesicoureteral reflux 1
   • Has been largely supplanted by CT at most institutions

Second-Line Imaging:

1. MRI:

   • Not typically used as first-line imaging for bladder diverticula
   • May be considered when CT is contraindicated or for complex cases
   • Provides excellent soft-tissue contrast but less sensitive for small diverticula

2. Cystoscopy:

   • Direct visualization of the diverticular opening
   • Allows assessment of the bladder mucosa and potential pathology within the diverticulum
   • Complementary to imaging studies rather than a replacement

Special Considerations

• In women: Bladder diverticula are unusual and typically associated with neurogenic or postoperative bladder; they are rarely congenital 1
• Complicated cases: When a diverticulum presents with complications such as recurrent infections, stones, or suspected malignancy, contrast-enhanced CT is recommended
• Diagnostic pitfalls: Large bladder diverticula can occasionally appear as complex pelvic masses not obviously connected to the bladder, leading to diagnostic confusion 3

Management Implications of Imaging

Imaging findings directly impact management decisions:

• Small diverticula with minimal symptoms may be managed conservatively
• Larger or symptomatic diverticula often require surgical intervention
• Imaging helps determine if outlet obstruction correction alone is sufficient or if diverticulectomy is needed 4

The diagnostic approach should be tailored based on the clinical presentation, with CT retrograde cystography offering the highest diagnostic accuracy when available.