The Clinical Study On CT Three-dimensional(3D) Reconstruction Of Renal Collecting System To Decide Anterior And Posterior Calyces

Objective:CT three-dimensional reconstruction of renal collecting system was performed to accurately distinguish the anterior and posterior calyx according to the 3D image.This method provided guidance in pre-judgement of posterior renal calyx before PCNL and provided anatomical basis for percutaneous nephrolithotomy.Method:Patients with renal calculi and upper ureteral calculi underwent CTU at the Second Affiliated Hospital of Kunming Medical University from January 2015 to April 2018.Patients who meet the inclusion and exclusion criteria underwent CT three-dimensional reconstruction of renal collecting system.There were 200 cases totally,in which 130 were male and 70 were female.70 cases were left renal calculi,4 cases were left ureteral calculi,72 cases were right renal calculi,6 cases were right ureteral calculi,and 48 cases were bilateral renal calculi.The patients were aged from 4-80 years old,with an average of 48 ± 37 years.In totally 226 kidneys,111 left kidney cases and 115 right kidney cases were studied.CT three-dimensional reconstruction was performed on the workstation.The anatomy of renal collection system was observed by rotating the 3D image of the collection system,distribution of the calyx and the axial information of the calyx were observed from different angle.From the midline of the renal hilum to the most convex part of the lateral renal margin,which is located on the dorsal side of the baseline,is defined as the posterior renal calyx.The calyx at the ventral side of the baseline toward the ventral side is defined as the anterior renal calyx,the calyx which is located on the baseline and oriented to the outer side of renal axial is defined as the lateral renal calyx.First,the posterior calyx is marked in posterior view with CT post-processing system,then posterior renal calyx was_transformed into the maximum intensity projection(MIP)image,specific position of the posterior renal calyx is observed to determine the anatomical distribution of the posterior renal calyx in the kidney and whether the posterior calyx is near the Central Line(spine)or near the outer kidney.Results:In 226 kidneys,there are 134 renal posterior calyx are close to the midline(59.29%);among them 83 cases are on the left side(61.94%)and 51 cases(38.06%)are on right side,;In other 62 renal calyx,one have multiple posterior calyx located laterally,and others have posterior calyx close to the midline(27.43%),Among them 17 cases are on the left side(27.42%),45 cases are on the right side(72.58%);23 kidney's anterior and posterior calyx overlap together(10.18%)which is difficult to distinguish on MIP,among them 9 cases are on the left side(39.13%),14 cases are on the right side(60.87%).7(3.1%)cases only have lateral and anterior calyx but no clear-cut posterior calyx,among them 2(28.57%)cases in left side and 5(71.43%)on right side.Conclusion:Using CT three-dimensional reconstruction of the renal collecting system,The anatomical position of the anterior and posterior renal calyx is accurately determined,anatomical basis for the planning of percutaneous nephrolithotomy and the selection of target renal calyx is provided.This will help to further improve the efficacy of PCNL.