The ultrasound image shows echogenic foci with dirty shadowing and reverberation artifacts within the gallbladder wall and lumen. These features are characteristic of emphysematous cholecystitis, a severe, life- threatening variant of acute cholecystitis caused by gas-forming organisms (e.g., Clostridium or E. coli) infecting the gallbladder wall.
Sonographic features of emphysematous cholecystitis:
* Echogenic gas within the gallbladder wall or lumen
* Reverberation or "dirty" shadowing artifacts
* May show intramural gas bubbles or "ring-down" artifact
* Often seen in diabetic or immunocompromised patients
* No gallstones may be present ("acalculous cholecystitis")
Clinical context:
* More common in elderly men and diabetics
* Presents with right upper quadrant pain, fever, and leukocytosis
* Surgical emergency due to risk of perforation and sepsis
Differentiation from other options:
* A. Adenomyomatosis: Involves gallbladder wall thickening with "comet tail" artifacts due to Rokitansky-Aschoff sinuses, not intramural gas.
* B. Porcelain gallbladder: Shows curvilinear calcification of the gallbladder wall - dense echogenic rim with posterior shadowing.
* C. Gangrenous cholecystitis: May show wall irregularity, intraluminal membranes, and absence of Doppler flow but lacks intramural gas.
References:
Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th Edition. Elsevier, 2018.
Chapter: Gallbladder and Biliary System, pp. 155-160.
American College of Radiology (ACR). Appropriateness Criteria for Right Upper Quadrant Pain, 2022.
Radiopaedia.org. Emphysematous cholecystitis: https://radiopaedia.org/articles/emphysematous-cholecystitis