ABSTRACT
A biomechanical model was built to identify human gallbladder (GB) pain and help diagnose acalculous biliary pain (ABP) based on routine two-dimensional ultrasonic images in emptying phase stimulated with cholecystokinin (CCK) in hospital. The clinical gold standard ellipsoidal geometrical model was adopted for GBs to calculate their bile volume, pressure and peak stress devolved in the GB wall in the emptying phase. The bile pressure in GBs was estimated by using the Windkessel-type model along with human intact GB mean compliance, basal bile pressures in GB and duodenum. The model can predict GB emptying pressure and volume curves, flow resistance across the cystic duct (CD) and common biliary duct (CBD), emptying time at 70% ejection fraction (EF) and the EF for 30 min emptying. Two in-plane principal stresses were calculated based on membrane biomechanical ellipsoidal model. If the peak principal stress is higher than 175 mmHg pain stress threshold, the GB pain is redeemed. The peak in-plane stress exhibits an excellent correlation to clinical GB pain profile of 37 patients observed (78.4% success rate) in comparison with the other factors: peak bile pressure, EF and flow resistance.
