The Collaborative International Dictionary of English v.0.48:
Duodenal \Du`o*de"nal\, a. [Cf. F. duod['e]nal.] Of or pertaining to the duodenum; as, duodenal digestion. [1913 Webster]WordNet (r) 3.0 (2006):
duodenal adj 1: in or relating to the duodenum; "duodenal ulcer"