title: Shadow or substance.
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D004380:Duodenal Obstruction / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008638:Mesenteric Arteries; D010488:Polyarteritis Nodosa / Q000000981:diagnostic imaging*; D011859:Radiography