Common causes of such biliary pain include the following: Microscopic stones—not detected by routine abdominal ultrasonography Abnormal gallbladder emptying (gallbladder dyskinesia) Biliary tract hypersensitivity Sphincter of Oddi dysfunction (including papillary stenosis and functional gallbladder, biliary sphincter, or pancreatic sphincter disorders [1]) Hypersensitivity of the adjacent duodenum Gallstones that have spontaneously passed Diagnosis of Acalculous Biliary Pain Unclear Usually ultrasonography and sometimes cholescintigraphy and / or endoscopic retrograde cholangiopancreatography (ERCP) with sphincter of Oddi manometry The best diagnostic approach remains unclear.