Medical Engineering & Physics最新文献_第8页

A compact and cost-effective gait simulator to advance prosthesis development with reduced reliance on human subject testing: Development, validation and application 结构紧凑、成本效益高的步态模拟器，可减少对人体测试的依赖，推动假肢开发：开发、验证和应用

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-11-07 DOI: 10.1016/j.medengphy.2024.104254

S. Sudeesh, M.S. Shunmugam, S. Sujatha

Gait simulators play a crucial role in assessing the performance of physical prototypes of prosthetic knees, validating numerical simulation findings, and reducing dependency on user trials during prosthesis development. However, their practical application is limited because of substantial capital investment required for sophisticated high degrees-of-freedom (DOF) system development on one side and insufficient DOF for accurate simulation on the other. In this study, we evaluated the minimum DOF of thigh segment that a gait simulator should have to test the performance of prosthetic knees in a cost-effective manner. Initially, numerical simulations of swing phase of prosthetic leg with IITM polycentric knee (IPK) using 3D gait data and with different arrested DOF of the thigh were performed to identify the essential DOF of gait simulator. By comparing different cases of arrested DOF with the six-DOF ideal case, it was revealed that only sagittal plane movements, namely flexion-extension, vertical translation, and horizontal translation, are sufficient to test prosthetic knees. Subsequently, a compact and modular gait simulator was developed. Hardware-in-loop simulations of the IPK using the gait simulator were used to demonstrate its effectiveness in assessing the performance of prosthetic knees, which validated the ability of the IPK to extend completely without an extension assist before heel contact. Additionally, it was exposed that the IPK's extension stop needs redesigning to effectively absorb the impact energy when the knee extends completely before heel contact. These findings emphasize the significance of a cost-effective gait simulator in prosthesis development and reduce dependency on user trials.

步态模拟器在评估假肢膝关节物理原型的性能、验证数值模拟结果以及减少假肢开发过程中对用户试验的依赖方面发挥着至关重要的作用。然而，由于一方面复杂的高自由度（DOF）系统开发需要大量资金投入，另一方面用于精确模拟的 DOF 不足，因此其实际应用受到了限制。在这项研究中，我们评估了步态模拟器应具备的大腿部分最小 DOF，以便以经济有效的方式测试假肢膝关节的性能。起初，我们使用三维步态数据和不同的大腿阻尼DOF，对假肢与IITM多中心膝（IPK）的摆动阶段进行了数值模拟，以确定步态模拟器的基本DOF。通过将不同的阻滞 DOF 与六 DOF 理想情况进行比较，发现只有矢状面运动，即屈伸、垂直平移和水平平移，才足以测试假肢膝关节。随后，我们开发了一种紧凑型模块化步态模拟器。使用步态模拟器对IPK进行了硬件在环模拟，以证明其在评估义肢膝关节性能方面的有效性，验证了IPK在脚跟接触前完全伸展而无需伸展辅助的能力。此外，IPK的伸展止挡需要重新设计，以便在膝关节在脚跟接触前完全伸展时有效吸收冲击能量。这些发现强调了具有成本效益的步态模拟器在假肢开发中的重要性，并减少了对用户试验的依赖。

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引用次数: 0

3D bioheat transfer mapping reveals nanomagnetic particles effectiveness in radiofrequency hyperthermia breast cancer treatment comparing to experimental study 与实验研究相比，三维生物传热图揭示了纳米磁性微粒在射频热疗乳腺癌治疗中的有效性

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-11-01 DOI: 10.1016/j.medengphy.2024.104249

Mahsa Kavousi , Erfan Saadatmand , Mahboubeh Masoumbeigi , Rabi Mahdavi , Nader Riyahi Alam

Radiofrequency (RF) hyperthermia has been widely used for tumor ablation since magnetic-fluid-hyperthermia (MFH) can be utilized for increasing temperature in tumor-region as a complementary-method for hyperthermia. In this study, the effectiveness of using the magnetite-nanoparticles (Fe₃O₄) in RF hyperthermia for breast cancer (BC) treatment by determining 3D-temperature-distribution using bioheat-transfer-mapping was evaluated. A breast-phantom with a tumor region was placed in an RF-device with 13.56 MHz frequency in different states (with and without-nanomagnetite). Parallelly, the calculations of the RF-wave and bioheat-equation were accomplished by numerical-simulation and finite-element-method (FEM) in COMSOL-software. The temperature differences were experimentally measured at different points of the phantom with a precision of 0.1 °C, with temperature of 3.6 °C and 6.1 °C in without and with nanomagnetic conditions in tumor area, respectively, and also for normal area with temperature of 1.8 °C and 1.9 °C in non-presence and presence states of 0.05 gr magnetite for both conditions, respectively. Moreover, the difference between the simulation and the experimental results was 0.54–1.1 %. The conformity between temperature measurement in experimental and simulation studies in tumor and normal areas showed the effectiveness of the application of MNPs for RF hyperthermia in tissue equivalent breast phantom. Finally, the positive effect of 0.05 gr of MNPs on BC treatment was confirmed.

射频（RF）热疗已被广泛用于肿瘤消融，因为磁流体热疗（MFH）可作为热疗的补充方法用于提高肿瘤区域的温度。在这项研究中，通过使用生物热传递图确定三维温度分布，评估了在射频热疗中使用磁铁矿纳米颗粒（Fe3O4）治疗乳腺癌（BC）的有效性。在不同状态下（含纳米磁铁矿和不含纳米磁铁矿），将带有肿瘤区域的乳房假体置于频率为 13.56 MHz 的射频设备中。同时，通过 COMSOL 软件中的数值模拟和有限元法（FEM）完成了射频波和生物热方程的计算。通过实验测量了模型不同点的温差，精度为 0.1 °C，肿瘤区域在无纳米磁性和有纳米磁性条件下的温度分别为 3.6 °C和 6.1 °C，正常区域在无和有 0.05 gr 磁铁矿条件下的温度分别为 1.8 °C和 1.9 °C。此外，模拟结果与实验结果的差异为 0.54-1.1%。在肿瘤和正常区域进行的实验和模拟研究的温度测量结果一致，这表明在组织等效的乳房模型中应用 MNPs 进行射频热疗是有效的。最后，0.05 克 MNPs 对 BC 治疗的积极作用得到了证实。

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引用次数: 0

Monitoring focused ultrasound ablation surgery (FUAS) using echo amplitudes of the therapeutic focused transducer 利用治疗性聚焦换能器的回声振幅监测聚焦超声消融手术（FUAS）

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-11-01 DOI: 10.1016/j.medengphy.2024.104247

Yufeng Zhou , Xiaobo Gong , Yaqin You

Objective

B-mode sonography is commonly used to monitor focused ultrasound ablation surgery (FUAS), but has limitations in sensitivity. More accurate and reliable prediction of coagulation is required.

Methods

The focused ultrasound (FUS) transducer was adapted for echo reception. Numerical simulations compared the normalized echo amplitudes from the FUS transducer and imaging probe at varying tissue depths and frequencies with a 3 mm necrosis at focus. An ex vivo experiment then evaluated echo changes from the FUS transducer and ultrasound imaging probe under different settings. Finally, coagulation prediction using FUS echo data was compared to sonography in a clinical ex vivo context.

Results

The echo amplitudes from the FUS transducer exhibit a less pronounced decline with increasing tissue penetration depth compared to the ultrasound imaging probe. In ex vivo bovine liver experiments at depths of 2 cm and 4 cm, the FUS transducer detected normalized echo amplitudes that were significantly larger (i.e., 2∼3 folds) than those received by the ultrasound imaging probe. Moreover, multi-layered ex vivo tissue experiments that replicate clinical conditions revealed that coagulation prediction utilizing the FUS transducer's echo amplitudes achieved superior accuracy (91.2% vs. 60.3 %), sensitivity (92.1% vs. 54.5 %), and negative prediction (78.9% vs. 30.6 %), but similar specificity (88.2% vs. 84.6 %) and positive prediction (95.9% vs. 93.8 %) in comparison to sonography.

Conclusion

The echo amplitude of the FUS transducer serves as a sensitive and dependable metric for monitoring the FUAS outcomes. Its utilization may augment the procedure's safety and efficacy.

目的B型超声造影通常用于监测聚焦超声消融手术（FUAS），但在灵敏度方面存在局限性。方法对聚焦超声（FUS）换能器进行改装，使其能够接收回波。数值模拟比较了 FUS 换能器和成像探头在不同组织深度和频率下的归一化回波振幅，病灶处有 3 毫米坏死。然后进行了一次体内实验，评估了不同设置下 FUS 传感器和超声成像探头的回声变化。结果与超声成像探头相比，随着组织穿透深度的增加，FUS 换能器产生的回声振幅下降不那么明显。在深度为 2 厘米和 4 厘米的体外牛肝实验中，FUS 传感器检测到的归一化回波振幅明显大于超声成像探头接收到的回波振幅（即 2∼3 倍）。此外，复制临床条件的多层体外组织实验显示，利用 FUS 传感器的回波振幅进行凝血预测的准确性（91.2% 对 60.3%）、灵敏度（92.1% 对 54.5%）和阴性预测（78.结论 FUS 传感器的回声振幅是监测 FUAS 结果的灵敏可靠的指标。利用它可以提高手术的安全性和有效性。

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引用次数: 0

Evaluation of a finite state machine algorithm to measure stepping with ankle accelerometry: Performance across a range of gait speeds, tasks, and individual walking ability 评估利用脚踝加速度计测量步速的有限状态机算法：不同步速、任务和个人行走能力下的性能表现

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-11-01 DOI: 10.1016/j.medengphy.2024.104251

Benjamin F Cornish , Karen Van Ooteghem , Matthew Wong , Kyle S Weber , Frederico Pieruccini-Faria , Manuel Montero-Odasso , William E McIlroy

Wearable sensors, including accelerometers, are a widely accepted tool to assess gait in clinical and free-living environments. Methods to identify phases and subphases of the gait cycle are necessary for comprehensive assessment of pathological gait. The current study evaluated the accuracy of a finite state machine (FSM) algorithm to detect strides by identifying gait cycle subphases from ankle-worn accelerometry. Algorithm performance was challenged across a range of speeds (0.4-2.6 m/s), task conditions (e.g., single- and dual-task walking), and individual characteristics. Specifically, the study included a range of treadmill speeds in young adults and overground walking conditions in older adults with neurological disease. Manually counted and algorithm-derived stride detection from acceleration data were evaluated using error analysis and Bland-Altman plots for visualization. Overall, the algorithm successfully detected strides (>96 % accuracy) across gait speed ranges and tasks, for young and older adults. The accuracy of an FSM algorithm combined with ankle-worn accelerometers, provides an analytical approach with affordable and portable tools that permits comprehensive assessment of gait unbounded by setting and proves to perform well in in walking tasks characterized by variable walking. These algorithm capabilities and advancements are critical for identifying phase dependent gait impairments in clinical and free-living assessment.

在临床和自由生活环境中，包括加速度计在内的可穿戴传感器是一种广为接受的步态评估工具。识别步态周期的阶段和子阶段的方法是全面评估病态步态所必需的。目前的研究评估了有限状态机（FSM）算法的准确性，该算法通过识别踝戴式加速度计的步态周期子阶段来检测步幅。该算法的性能在一系列速度（0.4-2.6 米/秒）、任务条件（如单任务和双任务步行）和个体特征中受到了挑战。具体来说，研究包括年轻成年人的一系列跑步机速度和患有神经系统疾病的老年人的地面行走条件。使用误差分析和布兰-阿尔特曼图对加速度数据中手动计数和算法衍生的步幅检测进行了评估。总体而言，该算法在不同步速范围和任务中成功检测到了年轻人和老年人的步幅（准确率达 96%）。FSM 算法的准确性与踝戴式加速度计相结合，提供了一种分析方法，它具有经济实惠、便于携带的工具，可以不受环境限制地对步态进行全面评估，并证明在以步态多变为特征的步行任务中表现良好。这些算法的功能和进步对于在临床和自由生活评估中识别相位依赖步态障碍至关重要。

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引用次数: 0

Understanding vibration exposure in wheelchair users: Experimental insights 了解轮椅使用者的振动暴露：实验启示

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-11-01 DOI: 10.1016/j.medengphy.2024.104253

Delphine Chadefaux , Ophélie Lariviere , Christophe Sauret , Corentin Bosio , Patricia Thoreux

Addressing the complexities of manual wheelchair (MWC) vibrations is crucial for the well-being of users and their integration into society. This study investigates the experimental choices influencing the assessment of vibration exposure, aiming to contribute for enhanced MWC developments and standardized design principles. By conducting a comprehensive full factorial experiment, the impact of various factors, including four MWC loads, two speeds, five floor types, and two MWC models was examined. Notably, findings highlight the predominant influence of floor type on vibration exposure, followed by speed and, to a lesser extent, MWC properties. Furthermore, the study suggests that enlisting an able-bodied participant is more representative than using a dummy when loading the MWC, providing valuable insights into the genuine MWC/user dyad response to vibrations. This research sets the stage for a more informed and standardized approach to address the vibration exposure faced by MWC users.

解决手动轮椅（MWC）振动的复杂性对于用户的福祉及其融入社会至关重要。本研究调查了影响振动暴露评估的实验选择，旨在为加强手动轮椅控制器的开发和标准化设计原则做出贡献。通过进行全面的全因子实验，研究了各种因素的影响，包括四种 MWC 负载、两种速度、五种地板类型和两种 MWC 模型。值得注意的是，研究结果凸显了地板类型对振动暴露的主要影响，其次是速度，其次是 MWC 性能。此外，该研究还表明，在对 MWC 进行加载时，招募一名健全的参与者比使用假人更具代表性，从而为了解 MWC/用户对振动的真实反应提供了宝贵的见解。这项研究为采用更明智、更标准化的方法解决 MWC 用户面临的振动暴露问题奠定了基础。

引用次数: 0

Integrated analysis of clinical indicators and mechanical properties in cancellous bone 松质骨临床指标和机械性能的综合分析

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-10-18 DOI: 10.1016/j.medengphy.2024.104245

Jiapeng He , Zhen Pan , Guowei Zhou , Jiangming Yu , Dayong Li

Cancellous bone plays a critical role as a shock absorber in the human skeletal system. Accurate assessment of its microstructure and mechanical properties is crucial for osteoporosis diagnosis and treatment. However, various methods with different indicators are adopted currently in the clinical and laboratory assessments which lead to confusion and inconvenience for cancellous bone analysis. In the current work, correlations among clinical indicators including CT-derived Hounsfield Unit (HU) & bone mineral density (BMD), laboratory indicators (mass density & volume fraction), and mechanical properties (modulus & strength) are explored. The results show that different indicators can be linearly linked through the HU value which can be adopted as a good microstructure indicator of cancellous bone. Additionally, the impacts of cancellous bone specimen preparation on clinical CT imaging and mechanical properties are also investigated. The results indicate common marrow-removal treatment can lead to decrease in mean HU value, deviation in HU value distribution, while it will increase the modulus and strength. The current work provides a valuable insight into the cancellous properties based on comprehensive analysis on the clinical and laboratory assessments which is critical for accurate diagnosis and personalized treatment.

松质骨在人体骨骼系统中扮演着减震器的重要角色。准确评估松质骨的微观结构和机械性能对骨质疏松症的诊断和治疗至关重要。然而，目前在临床和实验室评估中采用了各种不同指标的方法，导致松质骨分析的混乱和不便。本次研究探讨了临床指标（包括 CT 导出的 Hounsfield 单位（HU）及骨矿物质密度（BMD））、实验室指标（质量密度及体积分数）和机械性能（模量及强度）之间的相关性。结果表明，不同指标可通过 HU 值线性联系起来，HU 值可作为松质骨的良好微观结构指标。此外，还研究了松质骨标本制备对临床 CT 成像和机械性能的影响。结果表明，普通的去髓处理会导致平均 HU 值下降、HU 值分布偏差增大，而模量和强度则会增加。目前的研究基于对临床和实验室评估的综合分析，对松质骨特性提供了宝贵的见解，这对准确诊断和个性化治疗至关重要。

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引用次数: 0

A method of nucleus image segmentation and counting based on TC-UNet++ and distance watershed 基于 TC-UNet++ 和距离分水岭的细胞核图像分割和计数方法

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-10-18 DOI: 10.1016/j.medengphy.2024.104244

Kaifeng Zheng , Jie Pan , Ziyan Jia , Shuyan Xiao , Weige Tao , Dachuan Zhang , Qing Li , Lingjiao Pan

Nucleus segmentation and counting play a crucial role in many cell analysis applications. However, the dense distribution and blurry boundaries of nucleus make nucleus segmentation tasks challenging. This paper proposes a novel segmentation and counting method. Firstly, TC-UNet++ is proposed to achieve a global segmentation. Then, the distance watershed method is used to finish local segmentation, which separate the adhesion and overlap part of the image. Finally, counting method is performed to obtain information on the counting number, area and center of mass of nucleus. TC-UNet++ achieved a Dice coefficient of 89.95% for cell instance segmentation on the Data Science Bowl dataset, surpassing the original U-Net++ by 0.23%. It also showed a 5.09% improvement in counting results compared to other methods. On the ALL-IDB dataset, TC-UNet++ reached a Dice coefficient of 83.97%, a 7.93% increase over the original U-Net++. Additionally, its counting results improved by 16.82% compared to other approaches. These results indicate that our method has a more complete and reasonable nucleus segmentation and counting scheme compared to other methods.

细胞核的分割和计数在许多细胞分析应用中起着至关重要的作用。然而，由于细胞核分布密集且边界模糊，因此细胞核分割任务极具挑战性。本文提出了一种新颖的细胞核分割和计数方法。首先，提出了 TC-UNet++ 来实现全局分割。然后，使用距离分水岭方法完成局部分割，分离出图像的粘连和重叠部分。最后，采用计数法获得细胞核的计数数量、面积和质心等信息。在数据科学碗数据集上，TC-UNet++ 的细胞实例分割 Dice 系数达到 89.95%，比原始 U-Net++ 高出 0.23%。与其他方法相比，TC-Net++ 的计数结果提高了 5.09%。在 ALL-IDB 数据集上，TC-UNet++ 的骰子系数达到 83.97%，比原来的 U-Net++ 提高了 7.93%。此外，与其他方法相比，它的计数结果提高了 16.82%。这些结果表明，与其他方法相比，我们的方法具有更完整、更合理的核分割和计数方案。

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引用次数: 0

Bone ingrowth in randomly distributed porous interbody cage during lumbar spinal fusion 腰椎融合术中随机分布的多孔椎体间笼中的骨生长

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-10-18 DOI: 10.1016/j.medengphy.2024.104248

Rahul Gautam Talukdar , Santanu Dhara , Sanjay Gupta

Porous interbody cages are often used in spinal fusion surgery since they allow bone ingrowth which facilitates long-term stability. However, the extent of bone ingrowth in and around porous interbody cages has scarcely been investigated. Moreover, tissue differentiation might not be similar around the superior and inferior cage-bone interfaces. Using mechanobiology-based numerical framework and physiologic loading conditions, the study investigates the spatial distribution of evolutionary bone ingrowth within randomly distributed porous interbody cages, having varied porosities. Finite Element (FE) microscale models, corresponding to cage porosities of 60 %, 72 %, and 83 %, were developed for the superior and inferior interfacial regions of the cage, along with the macroscale model of the implanted lumbar spine. The implant-bone relative displacements of different porosity models were mapped from macroscale to microscale model. Bone formation of 10–40 % was predicted across the porous cage models, resulting in an average Young's modulus ranging between 765 MPa and 915 MPa. Maximum bone ingrowth of ∼34 % was observed for the 83 % porous cage, which was subject to low implant-bone relative displacements (maximum 50μm). New bone formation was found to be greater at the superior interface (∼34 %) as compared to the inferior interface (∼30 %) for P83 model. Relatively greater volume of fibrous tissue was formed at the implant-bone interface for the cage with 60 % and 72 % porosities, which might lead to cage migration and eventual failure of the implant. Hence, the interbody cage with 83 % porosity appears to be most favorable for bone ingrowth, provided sufficient mechanical strength is offered.

多孔椎体间融合器通常用于脊柱融合手术，因为它允许骨质生长，有利于长期稳定性。然而，关于多孔椎间融合器内和周围的骨质生长程度还鲜有研究。此外，上、下椎体笼-骨界面周围的组织分化可能并不相似。本研究利用基于机械生物学的数值框架和生理加载条件，研究了随机分布的多孔椎间笼内不同孔隙率的进化骨生长的空间分布。研究人员针对椎体笼上、下界面区域以及植入腰椎的宏观模型建立了有限元（FE）微观模型，椎体笼孔隙率分别为 60%、72% 和 83%。从宏观尺度到微观尺度模型映射了不同孔隙率模型的植入物-骨相对位移。根据预测，多孔骨笼模型的骨形成率为 10-40%，平均杨氏模量介于 765 兆帕和 915 兆帕之间。在种植体与骨的相对位移较低（最大 50μm）的情况下，83% 多孔骨笼的最大骨生长量为 34%。与下界面（30%）相比，P83 模型的上界面（34%）有更多的新骨形成。孔隙率为 60% 和 72% 的椎体间骨架在植入物-骨界面形成的纤维组织量相对较大，这可能会导致椎体间骨架移位，最终导致植入物失效。因此，只要有足够的机械强度，孔隙率为 83% 的椎间笼似乎最有利于骨的生长。

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引用次数: 0

Experimental studies on penetration process of high-speed water-jet into ballistic gelatin 高速水射流对弹道明胶渗透过程的实验研究

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.medengphy.2024.104250

Li Liu , XiaoYi Yang , PengFei Wang , Yu Huang , Xing Huang

To reveal the penetration mechanism and present the penetration characteristics of high-speed micro-jet with injection volume larger than 0.3 mL into soft tissue, the present study conducted experimental research on high-speed water-jet penetration into ballistic gelatin. The free jet dynamics of an air-powered needle-free injector that can emit up to 1.27 mL of liquid at once and the penetration dynamics were visualized to reveal the details of the penetration process. In the early unstable stage, the jet is emitted in the form of pulses, and the first jet pulse can rapidly generate an initial slender channel in gelatin in a very short time. In the subsequent stable stage, energy input produces dispersion and further increases the penetration depth slowly. Changing the driving pressure by the power source mainly changes the penetration depth increment by dispersion; while changing the nozzle diameter mainly affects the penetration depth in the initial stage. The central position of the dispersion area in the injection direction was firstly defined in the present work and it was found that an approximate linear relationship between this position and the maximum penetration depth exits for different nozzle diameters and driving pressures when injecting the same liquid dose. These research results can provide a basis for a thorough understanding of the penetration characteristics of high-speed micro-jet with injection volume larger than 0.3 mL into soft tissue, as well as the design and operation of the air-powered needle-free injector.

为了揭示注射量大于 0.3 mL 的高速微射流对软组织的渗透机理并呈现其渗透特性，本研究对高速水射流渗透弹道明胶进行了实验研究。通过对一次性可喷射 1.27 mL 液体的空气动力无针注射器的自由射流动力学和渗透动力学进行可视化研究，揭示了渗透过程的细节。在早期的不稳定阶段，射流以脉冲形式喷出，第一个射流脉冲能在极短的时间内迅速在明胶中生成一个初始细长通道。在随后的稳定阶段，能量输入产生分散，并进一步缓慢增加穿透深度。改变动力源的驱动压力主要是通过分散改变穿透深度的增加；而改变喷嘴直径主要影响初始阶段的穿透深度。本研究首次确定了分散区域在喷射方向上的中心位置，并发现在喷射相同剂量的液体时，不同喷嘴直径和驱动压力下该位置与最大穿透深度之间存在近似线性关系。这些研究成果为深入了解注射量大于 0.3 mL 的高速微射流在软组织中的穿透特性以及气动无针注射器的设计和操作提供了基础。

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引用次数: 0

Methodology to identify subject-specific dynamic laxity tests to stretch individual parts of knee ligaments 确定针对特定对象的动态松弛测试方法，以拉伸膝关节韧带的各个部位

IF 1.7 4区医学 Q3 ENGINEERING, BIOMEDICAL

Medical Engineering & Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.medengphy.2024.104246

Michael Skipper Andersen, Ilias Theodorakos

The mechanical properties of ligaments are important for multiple applications and are often estimated from laxity tests. However, the typical laxity tests are not optimized for this application and, a potential exists to develop better laxity tests in this respect. Therefore, the purpose of this study was to develop a methodology to identify optimal, dynamic laxity tests that isolate the stretch of the individual ligaments from each other. To this end, we applied an existing rigid body-based knee model and a dataset of ∼100.000 random samples of applied forces (0–150 N), moments (0–10 Nm) and knee flexion angles (0–90°) through Monte Carlo Simulations. For each modelled ligament bundle, we identified ten load cases; one producing the highest force and nine equally spaced between the maximal and zero force, where the maximal force in all other ligament bundles were minimized. We compared these novel laxity tests to standard internal/external and varus/valgus laxity tests using an isolation metric.

We found that no laxity test could stretch the anterior part of the posterior cruciate and medial cruciate ligaments (PCL and MCL), whereas for all other ligaments, except the posterior PCL, the new laxity tests isolated the ligament stretch 28 % to 450 % better than standard tests.

From our study, we conclude that it is possible to define better laxity tests than currently exist and these may be highly relevant for determination of mechanical properties of ligaments in vivo. Future studies should generalize our results and translate them to modern laxity measurements technologies.

韧带的机械特性对多种应用都很重要，通常通过松弛测试来估算。然而，典型的松弛测试并没有针对这一应用进行优化，因此有可能在这方面开发出更好的松弛测试。因此，本研究的目的是开发一种方法，以确定最佳的动态松弛测试，从而将单个韧带的拉伸与其他韧带的拉伸隔离开来。为此，我们应用了一个现有的基于刚体的膝关节模型，并通过蒙特卡洛模拟，获得了一个包含 100,000 个随机样本的数据集，这些样本包括外力（0-150 牛）、力矩（0-10 牛）和膝关节屈曲角度（0-90°）。对于每个建模的韧带束，我们确定了十种加载情况：一种是产生最大力的情况，九种是在最大力和零力之间等距加载的情况，其中所有其他韧带束的最大力都被最小化。我们发现，任何松弛测试都无法拉伸后交叉韧带和内侧交叉韧带（PCL 和 MCL）的前部，而对于除后 PCL 外的所有其他韧带，新的松弛测试对韧带拉伸的分离效果比标准测试好 28% 至 450%。从我们的研究中，我们得出结论：有可能定义比现有测试更好的松弛测试，这些测试可能与确定体内韧带的机械性能密切相关。未来的研究应推广我们的结果，并将其转化为现代韧带松弛测量技术。

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引用次数: 0