Role of CT in Pyelonephritis: A Comprehensive Pictorial Review.

Pyelonephritis in its various forms represents a urologic emergency that can lead to significant morbidity and requires prompt diagnosis and appropriate management. While clinical assessment and laboratory findings remain the cornerstone for diagnosis, imaging studies play a crucial role in evaluating the extent of infection, identifying complications, and guiding therapeutic interventions. Computed tomography (CT) has emerged as the imaging modality of choice for evaluating the severity of patients with pyelonephritis, offering superior sensitivity and specificity compared to other imaging modalities.Through illustrative cases and a systematic approach to image interpretation, this pictorial essay aims to comprehensively review the CT imaging features of various forms of pyelonephritis, highlighting characteristic imaging features of each entity, potential complications, and key differential diagnoses that help in differentiating them from their mimics, thus enhancing radiologists' and clinicians' ability to recognize the diverse CT appearances of this common but potentially serious infection.