The purpose of this exhibit is to present a graphical review of the anatomy of the duodenum and a series of compelling cases depicting the pathology of the duodenum (congenital, inflammatory, neoplastic, vascular, and iatrogenic disease) with their imaging characteristics at computed tomography (CT) studies. This exhibit intends to be a helpful tool for radiology residents and radiologists.

Although the duodenum is not the primary concern when evaluating the gastrointestinal tract in a CT study, the duodenum is a source of ample pathology, some conditions arising primarily from the duodenum and some conditions secondary to processes that involve neighboring organs. The duodenum, the first portion of the small bowel, is a C-shaped structure that lies at the level of the L1 to L3 vertebrae and extends from the gastric pylorus to the ligament of Treitz. The duodenum is mostly retroperitoneal in location, except...

ANATOMIC LANDMARKS OF THE DUODENUM Anatomical landmarks of the duodenum: the duodenum is divided into four segments and extends to both retro and intraperitoneal spaces. And has two flexures, the superior and the inferior duodenal flexures. [Fig 1] Anatomic relationships of the first duodenal segment [Fig 2] Anatomic relationships of the second duodenal segment [Fig 3] Anatomic relationships of the third duodenal segment [Fig 4] Anatomic relationships of the fourth duodenal segment [Fig 5] Common duodenal conditions by duodenal segment. [Fig 6] CONGENITAL ANOMALIES Annular...

It is important for the radiologist to have thorough knowledge about the anatomy of the duodenum, its anatomical relationships, and the most frequently seen anatomical anomalies; and also the radiologist should be aware that in duodenal pathology some findings are subtle and a good knowledge of the most common duodenal pathologies is essential for an optimal and complete reading of an abdominal CT.

M. S. Paez Alvarez: Nothing to disclose X. Aragón: Nothing to disclose A. Calero Ortega: Nothing to disclose E. F. Berríos: Nothing to disclose M. J. Risco Fernández: Nothing to disclose A. M. H. Hernández García-Calvo: Nothing to disclose C. Ruiz De Castañeda Zamora: Nothing to disclose I. Cifuentes García: Nothing to disclose M. M. Merideño: Nothing to disclose

Gosangi, B., Rocha, T. C., & Duran-Mendicuti, A. (2020). Imaging spectrum of duodenal emergencies. Radiographics, 40(5), 1441–1457. https://doi.org/10.1148/rg.2020200045 Del Cura JL, Gutiérrez Pedraza S, Gayete Á. Radiología Esencial. Madrid: Editorial Médica Panamericana; 2019. Jayaraman, M. v, Mayo-Smith, W. W., Movson, J. S., Dupuy, D. E., & Wallach, M. T. (2001). CT of the Duodenum: An Overlooked Segment Gets Its Due. In RadioGraphics (Vol. 21). Barat, M., Dohan, A., Dautry, R., Barral, M., Boudiaf, M., Hoeffel, C., & Soyer, P. (2017). Mass-forming lesions of the duodenum:...