Magnetic Resonance Imaging Features of Hepatic Hydatid Disease: A Pictorial Review with Emphasis on Atypical Presentations and Differential Diagnosis.

Hepatic echinococcosis, caused by Echinococcus species, remains a significant global health concern, with cystic echinococcosis (CE) being widespread and alveolar echinococcosis (AE) representing a rarer but more aggressive form. CE generally demonstrates characteristic imaging features, allowing straightforward diagnosis, whereas atypical presentations can closely mimic other hepatic lesions, leading to diagnostic uncertainty. AE poses an even greater diagnostic challenge due to its infiltrative, tumor-like growth pattern. Magnetic resonance imaging (MRI), with its superior soft-tissue contrast and multiplanar capabilities, plays a crucial role in the evaluation of AE and atypical CE cases. This pictorial review summarizes MRI features of hepatic echinococcosis, detailing both typical and atypical appearances, and emphasizes key criteria for differentiating hydatid cysts from other cystic or solid hepatic lesions. By consolidating imaging findings and discussing relevant differential diagnoses, this review aims to improve diagnostic accuracy, guide clinical management, and increase radiologists' awareness of echinococcosis in both endemic and non-endemic regions.