目的 探讨CT仿真内镜（CT virtual endoscopy，CTVE）在低位直肠癌术前分期中的价值。方法 收集我院2008年8月1日至2011年3月1日期间的直肠癌患者57例，术前行直肠CTVE检查，详细记录患者直肠癌周围组织浸润和淋巴结转移的情况；患者术后常规进行病理检查，比较两者结果的差异。结果 术前直肠CTVE检查与术后石蜡病理检查对直肠癌周围淋巴结转移的判断经四格表χ2检验，差异无统计学意义（χ2=2.5，P＞0.05），其对直肠癌周围淋巴结转移预测的敏感性为66.67%，特异性为93.94%。术前直肠CTVE预测直肠癌周围组织浸润和术后病理检查结果经四格表χ2检验，差异有统计学意义（χ2=4.4，P＜0.05），其对直肠癌周围组织浸润判断的敏感性为27.78%，特异性为42.86%。结论 CTVE在术前评估直肠癌周围淋巴结转移有较高的可信性，但对直肠癌周围组织浸润的评价较差。
Pulse waves contain rich physiological and pathological information of the human vascular system. The pulse wave diagnosis systems are very helpful for the clinical diagnosis and treatment of cardiovascular diseases. Accurate pulse waveform is necessary to evaluate the performances of the pulse wave equipment. However, it is difficult to obtain accurate pulse waveform due to several kinds of physiological and pathological conditions for testing and maintaining the pulse wave acquisition devices. A pulse wave generator was designed and implemented in the present study for this application. The blood flow in the vessel was simulated by modeling the cardiovascular system with windkessel model. Pulse waves can be generated based on the vascular systems with four kinds of resistance. Some functional models such as setting up noise types and signal noise ratio (SNR) values were also added in the designed generator. With the need of portability, high speed dynamic response, scalability and low power consumption for the system, field programmable gate array (FPGA) was chosen as hardware platform, and almost all the works, such as developing an algorithm for pulse waveform and interfacing with memory and liquid crystal display (LCD), were implemented under the flow of system on a programmable chip (SOPC) development. When users input in the key parameters through LCD and touch screen, the corresponding pulse wave will be displayed on the LCD and the desired pulse waveform can be accessed from the analog output channel as well. The structure of the designed pulse wave generator is simple and it can provide accurate solutions for studying and teaching pulse waves and the detection of the equipments for acquisition and diagnosis of pulse wave.
Numerical simulation of stent deployment is very important to the surgical planning and risk assess of the interventional treatment for the cardio-cerebrovascular diseases. Our group developed a framework to deploy the braided stent and the stent graft virtually by finite element simulation. By using the framework, the whole process of the deployment of the flow diverter to treat a cerebral aneurysm was simulated, and the deformation of the parent artery and the distributions of the stress in the parent artery wall were investigated. The results provided some information to improve the intervention of cerebral aneurysm and optimize the design of the flow diverter. Furthermore, the whole process of the deployment of the stent graft to treat an aortic dissection was simulated, and the distributions of the stress in the aortic wall were investigated when the different oversize ratio of the stent graft was selected. The simulation results proved that the maximum stress located at the position where the bare metal ring touched the artery wall. The results also can be applied to improve the intervention of the aortic dissection and the design of the stent graft.
Sudden cardiac arrest is one of the critical clinical syndromes in emergency situations. A cardiopulmonary resuscitation (CPR) is a necessary curing means for those patients with sudden cardiac arrest. In order to simulate effectively the hemodynamic effects of human under AEI-CPR, which is active compression-decompression CPR coupled with enhanced external counter-pulsation and inspiratory impedance threshold valve, and research physiological parameters of each part of lower limbs in more detail, a CPR simulation model established by Babbs was refined. The part of lower limbs was divided into iliac, thigh and calf, which had 15 physiological parameters. Then, these 15 physiological parameters based on genetic algorithm were optimized, and ideal simulation results were obtained finally.
The pulse amplitude of fingertip volume could be improved by selecting the vascular dense area and applying appropriate pressure above it. In view of this phenomenon, this paper used Comsol Multiphysics 5.6 (Comsol, Sweden), the finite element analysis software of multi-physical field coupling simulation, to establish the vascular tissue model of a single small artery in fingertips for simulation. Three dimensional Navier-Stokes equations were solved by finite element method, the velocity field and pressure distribution of blood were calculated, and the deformation of blood vessels and surrounding tissues was analyzed. Based on Lambert Beer's Law, the influence of the longitudinal compression displacement of the lateral light surface region and the tissue model on the light intensity signal is investigated. The results show that the light intensity signal amplitude could be increased and its peak value could be reduced by selecting the area with dense blood vessels. Applying deep pressure to the tissue increased the amplitude and peak of the signal. It is expected that the simulation results combined with the previous experimental experience could provide a feasible scheme for improving the quality of finger volume pulse signal.
The mechanical behavior modeling of human soft biological tissues is a key issue for a large number of medical applications, such as surgery simulation, surgery planning, diagnosis, etc. To develop a biomechanical model of human soft tissues under large deformation for surgery simulation, the adaptive quasi-linear viscoelastic (AQLV) model was proposed and applied in human forearm soft tissues by indentation tests. An incremental ramp-and-hold test was carried out to calibrate the model parameters. To verify the predictive ability of the AQLV model, the incremental ramp-and-hold test, a single large amplitude ramp-and-hold test and a sinusoidal cyclic test at large strain amplitude were adopted in this study. Results showed that the AQLV model could predict the test results under the three kinds of load conditions. It is concluded that the AQLV model is feasible to describe the nonlinear viscoelastic properties of in vivo soft tissues under large deformation. It is promising that this model can be selected as one of the soft tissues models in the software design for surgery simulation or diagnosis.
背景 基于仿真研究（simulation-based research，SBR）的数量迅速增加，但是这类研究的报告质量却需亟待提高。为使读者能够批判性地评估研究，研究报告的要素需要在文章中清晰地报告出来。我们旨在通过扩展试验报告的统一标准（Consolidated Standards of Reporting Trial，CONSORT）和加强流行病学观察性研究报告（Strengthening the Reporting of Observational Studies in Epidemiology，STROBE）声明来制定卫生保健仿真研究的报告规范。 方法 在制定报告规范的建议步骤基础上，使用迭代的多步共识法建立流程。多步共识法包括以下内容：① 建立指导委员会；② 定义报告规范的范围；③ 确定共识小组参与者；④ 通过在线会前调查生成拟讨论项目清单；⑤ 召开共识会议；⑥ 起草报告规范及解释与说明文件。 结果 对 CONSORT 的 11 个条目进行了扩展，包括条目 1（文题和摘要），条目 2（背景），条目 5（干预措施），条目 6（结局指标），条目 11（盲法），条目 12（统计方法），条目 15（基线数据），条目 17（结果和估计值），条目 20（局限性），条目 21（可推广性）和条目 25（资金来源）。对 STROBE 的 10 个条目进行了扩展：条目 1（文题和摘要），条目 2（背景/原理），条目 7（变量），条目 8（数据来源/数据测量），条目 12（统计方法），条目 14（描述性数据），条目 16（主要结果），条目 19（局限性），条目 21（可推广性）和条目 22（资金来源）。工作组已创建详细说明文档，提供每个扩展条目的示例和说明。 结论 制订基于 CONSORT 和 STROBE 声明的仿真研究扩展版，可帮助提高仿真研究的报告质量。
The subpulmonary ventricular exclusion (Fontan) could effectively improve the living quality for the children patients with a functional single ventricle in clinical. However, postoperative Fontan circulation failure can easily occur, causing obvious limitations while clinically implementing Fontan. The cavopulmonary assist devices (CPAD) is currently an effective means to solve such limitations. Therefore, in this paper the in-silico and in-vitro experiment coupled model of Fontan circulation failure for the children patients with a single ventricle and CPAD is established to evaluate the effects of CPAD on the Fontan circulation failure. Then a sensorless feedback control algorithm is proposed to provide sufficient cardiac output and prevent vena caval suction due to CPAD constant pump speed. Based on the CPAD pump speed-an intrinsic parameter, the sensorless feedback control algorithm could accurately estimate the cavopulmonary pressure head (CPPH) using extended Kalman filter, eliminating the disadvantage for pressure sensors that cannot be used in long term. And a gain-scheduled, proportional integral (PI) controller is used to make the actual CPPH approach to the reference value. Results show that the CPAD could effectively increase physiological perfusion for the children patients and reduce the workload of a single ventricle, and the sensorless feedback control algorithm can effectively guarantee cardiac output and prevent suction. This study can provide theoretical basis and technical support for the design and optimization of CPAD, and has potential clinical application value.
The purpose of this paper is to report the research and design of control system of magnetic coupling centrifugal blood pump in our laboratory, and to briefly describe the structure of the magnetic coupling centrifugal blood pump and principles of the body circulation model. The performance of blood pump is not only related to materials and structure, but also depends on the control algorithm. We studied the algorithm about motor current double-loop control for brushless DC motor. In order to make the algorithm adjust parameter change in different situations, we used the self-tuning fuzzy PI control algorithm and gave the details about how to design fuzzy rules. We mainly used Matlab Simulink to simulate the motor control system to test the performance of algorithm, and briefly introduced how to implement these algorithms in hardware system. Finally, by building the platform and conducting experiments, we proved that self-tuning fuzzy PI control algorithm could greatly improve both dynamic and static performance of blood pump and make the motor speed and the blood pump flow stable and adjustable.