Toward a highly‐detailed 3D pelvic model: Approaching an ultra‐specific level for surgical simulation and anatomical education

The surgical anatomy of the pelvis is highly complex. Anorectal and urogenital dysfunctions occur frequently after pelvic oncological surgery and are mainly caused by surgical damage of the autonomic nerves. A highly‐detailed 3D pelvic model could increase the anatomical knowledge and form a solid basis for a surgical simulation system. Currently, pelvic surgeons still rely on the preoperative interpretation of 2D diagnostic images. With a 3D simulation system, pelvic surgeons could simulate and train different scenes to enhance their preoperative knowledge and improve surgical outcome. To substantially enrich pelvic surgery and anatomical education, such a system must provide insight into the relation between the autonomic network, the lymphatic system, and endopelvic fasciae. Besides CT and MR images, Visible Human Datasets (VHDs) are widely used for 3D modeling, due to the high degree of anatomical detail represented in the cryosectional images. However, key surgical structures cannot be fully identified using VHDs and radiologic imaging techniques alone. Several unsolved anatomical problems must be elucidated as well. Therefore, adequate analysis on a microscopic level is inevitable. The development of a comprehensive anatomical atlas of the pelvis is no straightforward task. Such an endeavor involves several anatomical and technical challenges. This article surveys all existing 3D pelvic models, focusing on the level of anatomical detail. The use of VHDs in the 3D reconstruction of a highly‐detailed pelvic model and the accompanying anatomical challenges will be discussed Clin. Anat., 2013. © 2012 Wiley Periodicals, Inc.     

Acetabular fractures,anatomy and implications for treatment

Acetabular fractures are relatively uncommon and their definitive treatment tends to be focused on specialist major trauma centres. This can make both accurate diagnosis and management challenging, particularly in hospitals where they are rarely seen. Contemporary management of these injuries owes a lot to the work of Judet and Letournel undertaken in the 1970s. The key to understanding these injuries is to know the embryology and development of the pelvis and then be able to appreciate its three-dimensional structure from two-dimensional X-rays. This can then be overlaid with the Judet classification and the action of force vectors encountered in various mechanisms of injury. It is also important to realise the ageing demographics of this group of patients and the complexities this adds to classification and ultimately treatment. Finally, the presence of an acetabular fracture is often seen in association with a number of other injuries. It is imperative that these are appropriately and contemporaneously diagnosed so that a comprehensive management plan may be instituted to give the best outcomes. However, even with optimal management the prognosis is guarded with a majority of patients suffering some degree of functional loss and this must be made clear to the patient from the outset.     

MDCT在肾盂癌和肾癌鉴别诊断中的价值

目的探讨多层螺旋CT(MDCT)三期增强扫描在肾盂癌和肾癌鉴别诊断中的价值,以期提高术前诊断的准确性。方法回顾性分析经病理证实的11例[男9例,女2例;平均年龄(70.2±11.7)岁]肾盂癌及26例[男21例,女5例;平均年龄(67.3±11.7)岁]肾癌,所有病人术前均行64层螺旋CT平扫及三期增强扫描。分析病人的CT表现,测量并计算病人各期肿瘤/皮质CT比值及肿瘤-皮质CT差值,并采用独立样本t检验比较2组间各期CT参数值的差异。结果肾盂癌病人动脉期及实质期的肿瘤/皮质CT比值均低于肾癌病人(均P0.05),2组病人平扫及排泄期的肿瘤/皮质CT比值差异均无统计学意义(均P0.05)。肾盂癌病人实质期的肿瘤-皮质CT差值低于肾癌病人(P0.05),而2组病人平扫、动脉期及排泄期的肿瘤-皮质CT差值差异无统计学意义(均P0.05)。结论肾盂癌及肾癌的三期增强扫描CT参数存在明显差异。肿瘤/皮质CT比值对两者具有更好的鉴别诊断能力。     

Pelvic Periprosthetic Bone Mineral Density Measurement Around Cemented vs Cementless Acetabular Prostheses

We compared the short-term precision of pelvic periprosthetic bone mineral density (BMD) measurement around a cementless acetabular prosthesis (n = 29) vs a cemented all-polyethylene acetabular prosthesis (n = 19) in patients after total hip arthroplasty. Two dual-energy x-ray absorptiometry scans of the pelvis were made on the same day in each subject with subject repositioning between scans and analyzed independently with a 4-region of interest model. Precision was expressed as coefficient of variation (CV%). The measured BMD around the cemented prostheses was greater than the cementless prostheses p < 0.004, all analyses). The net CV for pelvic BMD measurements around the cementless prosthesis was 1.9% vs 3.6% around the cemented prosthesis (F-test p < 0.001). The CVs of individual regions of interest was between 2.8% and 4.8% for the cementless prosthesis vs 4.4% to 8.4% for the cemented prosthesis (F-test; p < 0.05, all comparisons). Prospective studies would require 57 subjects to detect a 10% change in net pelvic BMD around a cementless prosthesis and 122 to detect a similar change around a cemented prosthesis with 90% power and with an alpha error of 0.05. In conclusion, the precision of pelvic BMD measurements made around cementless prostheses are better vs those for cemented prostheses. Dual-energy x-ray absorptiometry studies of cemented prosthesis require approximately double the number of subjects vs cementless prostheses to achieve a similar level of power.     

基于人体骨盆运动轨迹的康复辅助机构设计

针对临床康复医师提出在下肢行走障碍患者康复训练过程中,患者身体重心缺乏在左右两脚之间的横向移动能力,从而影响行走甚至导致跌倒的问题,本文通过健康人步态行走过程的骨盆运动特征,对复杂的骨盆运动学和运动轨迹进行分析,提炼出骨盆侧向移动的轨迹和范围。根据人体工学分析,设计辅助骨盆侧向移动的机构,配合康复机器人应用在下肢行走训练,使得康复训练更接近健康人的自然状态,有利于训练过程中机械设备和人的相互作用。此方法获得医生和治疗师们的高度评价,并通过仿真试验做出了验证。     

Renal Squamous Cell Carcinoma-related Polymyositis in a Patient with Autosomal Dominant Polycystic Kidney Disease

A 74-year-old Japanese woman diagnosed with autosomal dominant polycystic kidney disease (ADPKD) was admitted to our institute for the further examination of right-side groin pain developing in the past week. The patient was diagnosed with polymyositis (PM). Diagnostic imaging showed a mass lesion measuring 8 cm and a renal stone in the right kidney. Immediately following surgical resection of the right kidney, the patient''s serum CK decreased to the normal range. A histopathological analysis showed well-differentiated squamous cell carcinoma. In conclusion, this case showed a close relationship between the occurrence of squamous cell carcinoma and the development of PM in an ADPKD patient.     

基于循环一致性生成对抗网络的盆腔伪CT生成方法

目的:基于循环一致性生成对抗网络（CycleGAN）,利用非配对患者盆腔部位数据,实现MRI和CT图像之间的相互转换,并对基于该模型生成的盆腔伪CT（sCT）进行精度和剂量性能的评估。方法:该CycleGAN网络包含两个生成器和两个判别器。先基于全卷积网络（FCNs）构建两个生成器,一个将2D盆腔MRI转换为2D盆腔sCT图像,另一个将CT图像转换为伪MRI（sMRI）图像。再基于FCNs构建两个判别器,用于对真实图像和生成的伪图像进行判别,提升生成图像的质量。为保证sCT图像与MRI图像的一致性,引入归一化互信息作为相似性约束损失项,对模型进行改进。训练集包括35例患者盆腔部位的T1-MRI图像和另外36例患者盆腔部位的CT图像,测试集包括10例盆腔部位患者的MRI和CT图像,评估方法包括sCT与CT图像的误差和放疗剂量伽马通过率。结果:对于测试集中所有病例,生成的sCT与真实CT图像之间的平均绝对误差（MAE）为35.537（±4.537） HU;基于体素的平均剂量差异最大为0.49%;以3%/3 mm、2%/2 mm和1%/1 mm为标准的平均伽马通过率分别高于99%、98%和95%。结论:使用CycleGAN网络和非配对患者训练数据可以生成准确且符合临床剂量精度要求的盆腔部位sCT图像。     

Anterior fracture dislocation of sacroiliac joint: A rare type of crescent fracture

Crescent fractures of the pelvis are usually described as posterior sacro iliac fracture dislocations. Rarely anterior displacement of the fractured iliac fragment along with dislocation has been reported in crescent fractures. Four cases of anterior fracture dislocation of the sacro iliac joint managed in the last two years by a single surgeon are presented. The injury mechanism, radiological diagnosis, management protocol along with functional outcomes of all the four patients have been discussed. CT scan is essential in the diagnosis and preoperative planning of this injury pattern. Early fixation along with proper reduction leads to excellent functional outcome in this subset of lateral compression injuries of the pelvis.