Multimodality CT and MRI evaluation of para-aortic arch lesions: a diagnostic review of congenital and acquired mimics

Lesions in the para-aortic arch region span a broad spectrum of congenital anomalies, vascular variants, cystic malformations, and mass-like entities that may closely mimic one another on imaging. Accurate distinction among these conditions is essential to avoid diagnostic errors, unnecessary interventions, and delays in appropriate management. The aim of this review is to provide a comprehensive and clinically oriented evaluation of para-aortic arch lesions using a multimodality imaging approach. Relevant literature and representative institutional cases were synthesized to illustrate key diagnostic features, with emphasis on computed tomography (CT) and magnetic resonance imaging (MRI) findings, anatomic relationships, and characteristic cross-sectional appearances. A mechanism-based diagnostic matrix is introduced to facilitate systematic lesion classification according to location, morphology, and radiologic attributes. This overview underscores imaging hallmarks that aid differentiation of congenital, vascular, cystic, and neoplastic entities. In conclusion, this review consolidates practical imaging criteria that enhance diagnostic accuracy, strengthen radiologists’ confidence, and support safe clinical decision-making in the evaluation of para-aortic arch abnormalities.