Can an ultrasound of the testicle show gas in the tissue in a patient with a suspected necrotizing infection, such as Fournier's gangrene?

Can Ultrasound Detect Gas in Testicular Tissue?

Yes, ultrasound can definitively show gas in the tissue of the testicle and surrounding structures, appearing as subcutaneous gas with characteristic findings including marked scrotal skin thickening, soft tissue inflammation, and collections/abscesses. 1

Ultrasound Capabilities for Gas Detection

Ultrasound reliably demonstrates subcutaneous gas in necrotizing infections like Fournier's gangrene, which affects the scrotum and perineal tissues. 1 The specific ultrasonographic findings include:

• Marked thickening of the scrotal skin 1
• Soft tissue inflammation 1
• Collections and abscesses 1
• Subcutaneous gas (the key finding) 1
• Paratesticular fluid, which appears before clinical crepitus develops 1

Clinical Context: When Gas Indicates Emergency

Gas formation in testicular/scrotal tissue is present in nearly half of all Fournier's gangrene cases and is highly specific (94%) for necrotizing infection. 1 This finding represents a surgical emergency requiring immediate intervention.

The World Journal of Emergency Surgery guidelines emphasize that ultrasound has emerged as a particularly valuable bedside tool when:

• CT scan is unavailable 1
• Patient transport to radiology is unsafe due to hemodynamic instability 1
• Acute renal failure contraindicates CT contrast 1

Advantages of Ultrasound in This Setting

Ultrasound offers multiple critical advantages for detecting gas in scrotal/testicular tissue:

• Can be performed immediately at bedside 1
• Evaluates scrotal contents and Doppler blood flow 1
• Requires no radiation or intravenous contrast 1
• Demonstrates paratesticular fluid before clinical crepitus appears 1

Critical Limitation: Do Not Delay Surgery

Imaging—including ultrasound—should NEVER delay surgical intervention when necrotizing infection is clinically suspected. 1, 2 The World Journal of Emergency Surgery provides a strong recommendation (1B) that in patients with obvious clinical findings or hemodynamic instability, proceed directly to surgery without waiting for any imaging. 1, 2

Comparison to Other Imaging Modalities

While ultrasound can detect gas, CT scan remains superior for evaluating disease extent, with sensitivity approaching 90% and specificity of 93.3% for necrotizing soft tissue infections. 1, 2 However, ultrasound is the preferred modality when CT is not feasible or would delay treatment. 1

Plain radiographs can also demonstrate gas in soft tissue planes but lack the detail of ultrasound or CT. 1

Clinical Pitfall to Avoid

The presence of gas on ultrasound in scrotal/testicular tissue indicates necrotizing fasciitis (Fournier's gangrene) until proven otherwise—this requires immediate broad-spectrum antibiotics and emergent surgical debridement. 3, 2 Do not mistake this for simple cellulitis or abscess; gas in tissue represents a life-threatening emergency with mortality rates of 20-50% even with optimal treatment. 2, 4