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.