The document discusses various types and diagnostic criteria for cholecystitis, highlighting conditions like gangrenous, emphysematous, and acalculous cholecystitis, along with their clinical presentations and CT findings. It emphasizes the importance of imaging techniques in diagnosis and treatment strategies, especially in life-threatening scenarios. Additionally, other related conditions, such as Bouveret syndrome and parasitic cholecystitis, are briefly described, showcasing their complexities and required interventions.