肾部分切除术前CT三维可视化评估标准的初步探究

目的: 探索并构建肾肿瘤行肾部分切除术的CT三维可视化术前评估系统及其应用价值。方法: 回顾性收集北京大学第一医院泌尿外科因肾肿瘤行肾部分切除术患者的临床资料做初步探究,同时收集我国16家临床中心因肾肿瘤行肾部分切除术患者的同质化标准数据,应用CT三维可视化系统(IPS系统,Yorktal)评估肿瘤解剖结构、血供等信息,通过归纳和总结构建评估系统,完成虚拟手术设计及术中辅助导航,指导临床手术。结果: 基于泌尿系增强CT建立三维可视化图像,评分系统纳入肿瘤最长径和体积、肿瘤侵入实质内体积占比、肿瘤侵入实质最大深度、肿瘤与肾实质接触面积、肿瘤肾实质接触面平整度、肿瘤所在肾脏分段位置、肾血管变异情况及肾周脂肪。肿瘤平均二维直径为(2.78±1.43) cm,平均三维最大径为(3.09±1.35) cm,术后病理平均大小(3.01±1.38) cm。三维重建肿瘤最大径与术中肾动脉阻断时间延长、术中出血量显著相关(r=0.502,P=0.020;r=0.403,P=0.046)。三维重建及病理肿瘤体积分别为(25.7±48.4) cm³、(33.0±36.4) cm³(P=0.229),三维重建肿瘤体积与术中出血量显著相关(r=0.660,P<0.001),肿瘤侵入肾实质内体积占比与术中肾动脉阻断时间延长、术后并发症的发生显著相关(r=0.410,P=0.041;r=0.587,P=0.005)。肿瘤与肾实质接触面积及是否存在血管变异与围手术期指标及术后并发症未见相关性。完成术前评估的同时,重建后的三维影像可在Touch Viewer系统上进行缩放、旋转、组合显示、颜色调整、透明化、长度体积自动测量及模拟裁切等操作,满足术前虚拟手术规划及术中辅助导航的要求。结论: 三维图像可提供更加直观的解剖结构,清晰显示肿瘤解剖参数及血供、脂肪等信息,CT三维重建肾肿瘤评价系统可帮助预测肾部分切除术手术难度、围术期并发症等。重建的三维可视化图像导入指定程序或机器人操作系统即可完成虚拟手术及术中辅助导航,帮助手术医师更好地把握手术过程。评分系统所包含的指标及各项指标的分值权重需要通过多中心大样本的研究来证实及完善。

Three dimensional nephrometry system for partial nephrectomy:Our initial explora-tion

Objective: To construct a preoperative evaluation system for partial nephrectomy using CT three-dimensional visualization technology and to explore its practical value. Methods: The clinical data of the patients who underwent partial nephrectomy for renal tumors in Department of Urology, Peking University First Hospital were collected retrospectively. At the same time, the homogenized standard data of patients who underwent partial nephrectomy for renal tumors were collected in 16 clinical centers in China. The CT three-dimensional visualization system was applied (IPS system, Yorktal) to evaluate tumor anatomy, blood supply, perirenal fat and other information. The parameters were summarized to build a three-dimensional nephrometry system, on the basis of which virtual surgery design and intraoperative navigation were completed. Results: A three-dimensional visualization image was established based on the enhanced CT urography. The nephrometry system included the longest diameter and volume of the tumor, proportion volume of tumor invading the parenchyma, maximum depth of the tumor invading the parenchyma, contact surface area, flatness of the tumor surface, renal segment where the tumor was located, vascular variation, and perirenal fat. The average two-dimensional diameter of the tumor was (2.78±1.43) cm, the average three-dimensional maximum diameter was (3.09±1.35) cm, and the average postoperative pathological size was (3.01±1.38) cm. The maximum tumor diameter in the three-dimensional image was significantly related to the prolonged renal artery clamping time and intra-operative blood loss (r=0.502, P=0.020; r=0.403, P=0.046). The three-dimensional and pathological tumor volume were (25.7±48.4) cm³ and (33.0±36.4) cm³, respectively (P=0.229). The tumor volume was significantly related to the intraoperative blood loss (r=0.660, P<0.001). The proportion volume of the tumor invading into renal parenchyma was significantly related to the prolongation of renal artery clamping and the occurrence of postoperative complications (r=0.410, P=0.041; r=0.587, P=0.005). The tumor contact surface area and the presence of vascular variation did not show correlation with the perioperative data and postoperative complications. While the preoperative evaluation was completed, the reconstructed three-dimensional image could be zoomed, rotated, combined display, color adjustment, transparency, and simulated cutting on the Touch Viewer system. The process generally consisted of showing or hiding the tissue, adjusting the transparency of the interested area, rotating and zooming the image to match the position of the surgical patient. Together, these functions met the requirements of preoperative virtual surgery plan and intraoperative auxiliary navigation. Conclusion: Three-dimensional images can provide a more intuitive anatomical structure. The CT three-dimensional visua-lization system clearly displays tumor anatomical parameters, blood supply and perirenal fat. The three-dimensional nephrometry system for renal tumors can help predict the difficulty of partial nephrectomy and perioperative complications. Importing the reconstructed three-dimensional visualization image into the specified program or robot operating system can complete virtual surgery and intraoperative navigation, helping the surgeon to better grasp the surgical process. The indexes included in the nephrometry system and the score weights of each index need to be confirmed and perfected by multi-center study with large samples.