Advances in Imaging and Diagnosis of Emphysematous Cholecystitis.

Emphysematous cholecystitis is a rare but severe variant of acute cholecystitis characterized by gas-forming organisms within the gallbladder wall or lumen. It progresses rapidly and carries substantial mortality, making early and accurate recognition essential. Although its pathogenesis involves gallbladder wall ischemia with superimposed infection by gas-producing bacteria-most commonly Clostridium species-the clinical presentation is often nonspecific, particularly in patients with diabetes mellitus or immunosuppression. Imaging therefore serves as the cornerstone of diagnosis. Abdominal radiographs may demonstrate intraluminal or intramural gas, while ultrasound can reveal echogenic foci with reverberation artifacts, though overlying bowel gas and diagnostic mimics may limit sensitivity. Computed tomography remains the most accurate modality, precisely delineating gas within the gallbladder wall, lumen, or adjacent tissues and facilitating urgent surgical or percutaneous intervention. Magnetic resonance imaging offers complementary soft tissue characterization when computed tomography is contraindicated. This review synthesizes traditional imaging findings and emerging diagnostic innovations by critically comparing modality-specific strengths, limitations, and pitfalls. Dual-energy and photon-counting computed tomography enhance tissue contrast and gas conspicuity, while artificial intelligence-assisted image analysis enables earlier detection and expedited triage in emergency settings. By integrating evolving technologies with established radiologic principles, this article provides a forward-looking framework for improving diagnostic precision and ultimately enhancing outcomes for patients with emphysematous cholecystitis.