目的 评价基于CT影像三维重建胆囊体积计算方法的准确性,并研究胆囊运动中的生物力学变化,探索胆囊动力学变化与胆结石形成的关系。方法 提出一种基于CT影像三维重建胆囊模型来计算胆囊体积的方法,并与椭球体法进行比较；构建胆囊有限元模型并进行流体力学分析,模拟胆囊出口胆囊管与胆总管汇合不同角度下及伴有结石状态下的胆囊运动功能变化。结果 比较50位患者的特异性胆囊模型体积和椭球体法体积,对应平均误差分别为7.26%和25.35%。梨形胆囊再充盈期最大压力、最大变形和最大流速都明显大于葫芦形胆囊。胆囊管与胆总管之间的夹角对胆汁流型影响不大,夹角为120°时胆汁流速最大。伴有结石胆囊的胆汁流速小于无结石胆囊,且在结石附近产生漩涡。结论 基于CT影像三维重建计算胆囊体积较传统椭球体法更准确。相对于梨形胆囊,葫芦形胆囊的胆囊壁收缩和胆汁流速较小,运动功能差。伴结石胆囊的胆汁流速较慢,更易导致结石增大或新结石形成。
Objective To evaluate the accuracy of three-dimensional reconstruction of gallbladder volume based on CT images, and to study the biomechanical changes of gallbladder movement, to explore the relationship between gallbladder dynamics and gallstone formation. Methods A method of calculating gallbladder volume based on CT three-dimensional reconstruction of gallbladder model is proposed, and compared with ellipsoid method. Construct a finite element model of the gallbladder and perform fluid dynamics analysis to simulate the functional changes in gallbladder motility under different angles of convergence between the cystic duct and common bile duct, as well as in the presence of gallstones. Results The mean error of specific gallbladder model volume and ellipsoid volume of 50 patients was 7.26% and 25.35%. The maximum pressure, maximum deformation and maximum flow velocity of pear-shaped gallbladder during the refill period were significantly greater than those of gourd-shaped gallbladder. The angle between the gallbladder duct and the common bile duct had little effect on bile flow pattern, and the maximum bile flow rate was reached when the Angle was 120°. The bile flow velocity of gallbladder with calculus is smaller than that of gallbladder without calculus, and there is a vortex near the calculus. Conclusion The calculation of gallbladder volume based on CT 3D reconstruction is more accurate than ellipsoid method. Compared with pear-shaped gallbladder, gourd-shaped gallbladder has lower gallbladder wall contraction and bile flow rate, and poor motor function. The bile flow rate of the gallbladder is slow, which is more likely to lead to the enlargement of stones or the formation of new stones.