The recent increase in the adoption of total ankle arthroplasty(TAA)reflects the improvements in implant designs and surgical techniques,including the use of preoperative navigation system and patient-specific instrum...The recent increase in the adoption of total ankle arthroplasty(TAA)reflects the improvements in implant designs and surgical techniques,including the use of preoperative navigation system and patient-specific instrumentation(PSI),such as custom-made cutting guides.Cutting guides are customized with respect to each patient's anatomy based on preoperative ankle computed tomography scans,and they drive the saw intra-operatively to improve the accuracy of bone resection and implant positioning.Despite some promising results,the main queries in the literature are whether PSI improves the reliability of achieving neutral ankle alignment and more accurate implant sizing,whether it is actually superior over standard techniques,and whether it is cost effective.Moreover,the advantages of PSI in clinical outcomes are still theoretical because the current literature does not allow to confirm its superiority.The purpose of this review article is therefore to assess the current literature on PSI in TAA with regard to current implants with PSI,templating and preoperative planning strategies,alignment and sizing,clinical outcomes,cost analysis,and comparison with standard techniques.展开更多
Objective:To observe the clinical efficacy and advantages of 3D printed patient-specific instrumentation(PSI)assisted distal tibial tuberosity-high tibial osteotomy in the treatment of medial compartment knee osteoart...Objective:To observe the clinical efficacy and advantages of 3D printed patient-specific instrumentation(PSI)assisted distal tibial tuberosity-high tibial osteotomy in the treatment of medial compartment knee osteoarthritis.Methods:75 patients with medial compartment knee osteoarthritis were included in the study performed DTT-HTO in our hospital from August 2017 to August 2019.The patients were divided into the PSI group(n=39)and conventional group(n=36)According to whether PSI was used in surgery.The differences of lateral cortical fracture rate,time of intraoperative X-ray exposure,intraoperative blood loss,operative time,weight bearing line(WBL),Posterior tibial slope(PTS)and Caton-Deschamps index(CDI)were compared between the two groups.Visual analogue scale(VAS)scores and Hospital for Special Surgery(HSS)scores were recorded to evaluate knee pain and function before surgery and after surgery at 3 months and 12 months.Results:All 75 patients were followed up for more than 12 months,the ranged from 12-26(18.74±6.21)months.Three lateral cortical fractures in the conventional group and no fracture in PSI group.The lateral cortical fracture rate,time of intraoperative X-ray exposure,intraoperative blood loss,operative time in PSI group were lower than those in conventional group(p敿0.05).WBL in two groups were significantly improved after surgery(p敿0.05),and PTS,CDI were no statistically improved after surgery(p>0.05).While there was no statistically significant difference with WBL,PTS and CDI between two groups(p>0.05).At 1 months,3 months and 12 months after surgery;VAS and HSS scores in both groups were significantly improved compared with that before surgery(p0.05),and were no statistically significant difference between two groups.Conclusion:3D printed patient-specific instrumentation assisted DTT-HTO has significant clinical efficacy,and effectively standardized surgical procedures,meanwhile reduced the time of intraoperative X-ray exposure,intraoperative blood loss and risk of lateral cortical fracture.展开更多
AIM: To summarise and compare currently available evidence regarding accuracy of pre-operative imaging, which is one of the key choices for surgeons contemplating patient-specific instrumentation(PSI) surgery.METHODS:...AIM: To summarise and compare currently available evidence regarding accuracy of pre-operative imaging, which is one of the key choices for surgeons contemplating patient-specific instrumentation(PSI) surgery.METHODS: The MEDLINE and EMBASE medical literature databases were searched, from January 1990 to December 2013, to identify relevant studies. The data from several clinical studies was assimilated to allow appreciation and comparison of the accuracy of each modality. The overall accuracy of each modality was calculated as proportion of outliers > 3% in the coronal plane of both computerised tomography(CT) or magnetic resonance imaging(MRI). RESULTS: Seven clinical studies matched our inclusion criteria for comparison and were included in our study for statistical analysis. Three of these reported series using MRI and four with CT. Overall percentage of outliers > 3% in patients with CT-based PSI systems was 12.5% vs 16.9% for MRI-based systems. These results were not statistically significant. CONCLUSION: Although many studies have been undertaken to determine the ideal pre-operative imaging modality, conclusions remain speculative in the absence of long term data. Ultimately, information regarding accuracy of CT and MRI will be the main determining factor. Increased accuracy of pre-operative imaging could result in longer-term savings, and reduced accumulated dose of radiation by eliminating the need for post-operative imaging and revision surgery.展开更多
Serous Purpose: There is limited information in the literature surrounding the use of patient-specific instrumentation (PSI) by a large number of surgeons. This prospective observational study was therefore designed t...Serous Purpose: There is limited information in the literature surrounding the use of patient-specific instrumentation (PSI) by a large number of surgeons. This prospective observational study was therefore designed to evaluate the logistics of using PSI for total knee arthroplasty (TKA) in a multi-surgeon environment, as well as its accuracy in positioning components. Methods: Of 73 patients enrolled in this study, 3 were excluded after the surgeon decided intraoperatively to switch to conventional instrumentation. Results: Mean operative time was 77.6 minutes. The component size had to be changed in 19 patients and bone cuts corrected in 12. In 65 of the 70 cases (92.9%), mechanical alignment was within the optimal range from 3° varus to 3° valgus, with the remaining 5 cases considered outliers (7.1%). Mean overall mechanical alignment was 0.3° varus (standard deviation, ±2°). There was a distinct variance with regard to the position of the tibial component in the sagittal plane. Conclusions: PSI can be effectively incorporated in larger, multisurgeon practices. Although high accuracy was observed for overall mechanical alignment and component positioning in the frontal and sagittal planes, further attention must be paid to the tibial slope. We highly recommend the use of the extramedullary alignment rod to the proper position of the tibial block, as well as double-checking the slope before performing bone cuts.展开更多
Background： Restoring good alignment after total knee replacement （TKR） is still a challenge globally, and the clinical efficiency of patient-specific instruments （PSIs） remains controversial. In this study, we a...Background： Restoring good alignment after total knee replacement （TKR） is still a challenge globally, and the clinical efficiency of patient-specific instruments （PSIs） remains controversial. In this study, we aimed to explore the value and significance of three-dimensional printing PSls based on knee joint computed tomography （CT） and full-length lower extremity radiography in TKR. Methods： Between June 2013 and October 2014, 31 TKRs were performed using PSIs based on knee joint CT and full-length lower extremity radiography in 31 patients （5 males and 26 females; mean age： 67.6 ± 7.9 years, body mass index [BMI]： 27.4 ±3.5 kg/m2）. Thirty-one matched patients （4 males and 27 females; mean age： 67.4± 7.2 years; mean BM 1：28.1 ± 4.6 kg/m2） who underwent TKR using conventional instruments in the same period served as the control group. The mean follow-up period was 38 months （31-47 months）. Knee Society Score （KSS）, surgical time, and postoperative drainage volume were recorded. Coronal alignment was measured on full-length radiography. Results： Twenty-three （74.2%） and 20 （64.5%） patients showed good postoperative alignment in the PSI and control groups, respectively, without significant difference between the two groups （χ2 = 0.68, P = 0.409）. The mean surgical time was 81.48± 16.40 rain and 72.90 ± 18.10 min for the PSl and control groups, respectively, without significant difference between the two groups （t = 0.41, P = 0.055）. The postoperative drainage volume was 250.9 ± 148.8 ml in the PSI group, which was significantly less than that in the control group （602. 1± 230.6 ml, t = 6.83, P 〈 0.001）. No significant difference in the KSS at the final follow-up was found between the PSI and control groups （91.06 ± 3.26 vs. 90.19±3.84, t= 0.95, P=0.870）. Conclusions： The use of PSls based on knee joint CT and standing full-length lower extremity radiography in TKR resulted in acceptable alignment compared with the use of conventional instruments, although the marginal advantage was not statistically different. Surgical time and clinical results were also similar between the two groups, However, the PSI group had less postoperative drainage.展开更多
Reconstruction of a traumatic distal femur defect remains a therapeutic challenge.Bone defect implants have been proposed to substitute the bone defect,and their biomechanical performances can be analyzed via a numeri...Reconstruction of a traumatic distal femur defect remains a therapeutic challenge.Bone defect implants have been proposed to substitute the bone defect,and their biomechanical performances can be analyzed via a numerical approach.However,the material assumptions for past computational human femur simulations were mainly homogeneous.Thus,this study aimed to design and analyze scaffolds for reconstructing the distal femur defect using a patient-specific finite element modeling technique.A three-dimensional finite element model of the human femur with accurate geometry and material distribution was developed using the finite element method and material mapping technique.An intact femur and a distal femur defect model treated with nine microstructure scaffolds and two solid scaffolds were investigated and compared under a single-leg stance loading.The results showed that the metal solid scaffold design could provide the most stable fixation for reconstructing the distal femur defect.However,the fixation stability was affected by various microstructure designs and pillar diameters.A microstructure scaffold can be designed to satisfy all the biomechanical indexes,opening up future possibilities for more stable reconstructions.A three-dimensional finite element model of the femur with real bone geometry and bone material distribution can be developed,and this patient-specific femur model can be used for studying other femoral fractures or injuries,paving the way for more comprehensive research in the field.Besides,this patient-specific finite element modeling technique can also be applied to developing other human or animal bone models,expanding the scope of biomechanical research.展开更多
Low-visibility phenomena strongly impact the environment,as well as transportation,aviation and other fields that are closely related to people's livelihoods;thus,they represent important ecological issues of soci...Low-visibility phenomena strongly impact the environment,as well as transportation,aviation and other fields that are closely related to people's livelihoods;thus,they represent important ecological issues of social concern.Based on observation data concerning low-visibility phenomena derived from 105 national meteorological stations in Xinjiang,China over the past 20 years,we systematically analyzed the differences between manual and instrument observations for six types of low-visibility phenomena,with a focus on exploring their spatiotemporal distribution characteristics using instrument data.The results revealed that low-visibility phenomena were dominated by fog-and haze-related events(mist,fog,and haze)in northern Xinjiang and dust-related events(dust storms,blowing sand,and floating dust)in southern Xinjiang,with transitional characteristics observed in eastern Xinjiang.Compared with manual observations,the instrument measurements significantly improved the fine-scale low-visibility phenomenon identification process.On the basis of the instrument observation data,spatial-dimension analysis results indicated that low-visibility phenomena in Xinjiang were significantly influenced by terrain factors.Constrained by the Tianshan Mountains,haze-like phenomena formed a core agglomeration area in northern Xinjiang,whereas dust-and sand-related phenomena radiated outward,with the Taklimakan Desert at the center.Moreover,the gripping effect of the terrain promoted dust transmission along low-altitude channels.Temporally,fog-and haze-related phenomena occurred mainly during autumn and winter,and the proportion of these events decreased from 76.7%to 55.1%.The fog-and haze-related phenomena demonstrated a U-shaped rebound trend,while the proportion of mist phenomena decreased by 34.2%.Dust storms occurred during spring,accounting for 23.3%to 44.9%of all storms.Instrument measurement technology has the advantages of high spatial and temporal resolutions and multiparameter coordination but provides a limited dust-haze mixed-pollution identification capacity.This study provides crucial reference data for enhancing the understanding of low-visibility events in Xinjiang and the potential responses while improving the accuracy of pollution source tracking and meteorological process diagnosis tasks.展开更多
Scientific instruments serve as foundational pillars for both scientific progress and industrial innovation,enabling deep exploration and driving technological breakthroughs.Their independent controllability and conti...Scientific instruments serve as foundational pillars for both scientific progress and industrial innovation,enabling deep exploration and driving technological breakthroughs.Their independent controllability and continuous innovation are indispensable for sustaining a competitive advantage in technological development,thereby securing national scientific capacity and long-term strategic growth.At present,however,China faces substantial risks of technological"stranglehold"in the high-end scientific instrument domain.The underlying causes are multifaceted,arising not only from insufficient accumulation of core technologies but also from entrenched systemic and ecosystem-level barriers that impede the application,scaling,and promotion of domestic instruments.This paper provides a systematic analysis of the challenges hindering the widespread adoption of domestically developed scientific instruments and proposes practical pathways to build a new,integrated"R&D-application-promotion"ecosystem.This ecosystem is anchored in trust,driven by user demand,and shaped through collaborative innovation.Key initiatives include organizing user visits to instrument manufacturers,convening seminars on domestic alternatives to imported equipment,establishing demonstration centers for application and promotion,and involving end-users directly in the R&D and iterative upgrading of domestic instruments.Together,these efforts aim to close the final critical gap,advancing domestic instruments from merely"functional"to genuinely"user-friendly",and ultimately to"widely implemented".By doing so,this framework offers both theoretical grounding and practical guidance for achieving high-level scientific and technological self-reliance and sustained innovation capacity.展开更多
Chinese video game Black Myth:Wukong has been a h it among gaming enthusiasts worldwide since its release in 2024, its breakout success demonstrating the potential global appeal of traditional Chinese culture. Based o...Chinese video game Black Myth:Wukong has been a h it among gaming enthusiasts worldwide since its release in 2024, its breakout success demonstrating the potential global appeal of traditional Chinese culture. Based on the 16th-century classic novel Journey to the West, the game not only introduces international audiences to Chinese literature but has also become a far-reaching platform for traditional Chinese music.展开更多
Patient-specific instrumentation(PSI)enables a more accurate alignment of the lower limbs in a high tibial osteotomy(HTO)than in traditional surgery;however,the current design of commercial PSIs is not perfect.Therefo...Patient-specific instrumentation(PSI)enables a more accurate alignment of the lower limbs in a high tibial osteotomy(HTO)than in traditional surgery;however,the current design of commercial PSIs is not perfect.Therefore,we designed a new patient-specific surgical guide to improve the accuracy of the osteotomy and verified its reliability through a clinical operation.Here,we describe a patient with isolated medial-compartment bilateral knee osteoarthritis,accompanied by a varus deformity of the proximal tibia.The patient was treated with HTO using a patient-specific 3D-printed surgical guide.We concluded that the patient-specific 3D-printed surgical guide improved the accuracy of the osteotomy and the alignment of the lower limb.展开更多
The automatic detection of cardiac arrhythmias through remote monitoring is still a challenging task since electrocardiograms(ECGs)are easily contaminated by physiological artifacts and external noises,and these morph...The automatic detection of cardiac arrhythmias through remote monitoring is still a challenging task since electrocardiograms(ECGs)are easily contaminated by physiological artifacts and external noises,and these morphological characteristics show significant variations for different patients.A fast patient-specific arrhythmia diagnosis classifier scheme is proposed,in which a wavelet adaptive threshold denoising is combined with quantum genetic algorithm(QAG)based on least squares twin support vector machine(LSTSVM).The wavelet adaptive threshold denoising is employed for noise reduction,and then morphological features combined with the timing interval features are extracted to evaluate the classifier.For each patient,an individual and fast classifier will be trained by common and patient-specific training data.Following the recommendations of the Association for the Advancements of Medical Instrumentation(AAMI),experimental results over the MIT-BIH arrhythmia benchmark database demonstrated that our proposed method achieved the average detection accuracy of 98.22%,99.65%and 99.41%for the abnormal,ventricular ectopic beats(VEBs)and supra-VEBs(SVEBs),respectively.Besides the detection accuracy,sensitivity and specificity,our proposed method consumes the less CPU running time compared with the other representative state of the art methods.It can be ported to Android based embedded system,henceforth suitable for a wearable device.展开更多
The complex meniscus tissue plays a critical role in the knee. The high susceptibility to injury has led to an intense pursuit for better tissue engineering regenerative strategies, where scaffolds play a major role. ...The complex meniscus tissue plays a critical role in the knee. The high susceptibility to injury has led to an intense pursuit for better tissue engineering regenerative strategies, where scaffolds play a major role. In this study, indirect printed hierarchical multilayered sca ffolds composed by a silk fibroin (SF) upper layer and an 80/20 (w/w) ratio of SF/ionic-doped β-tricalcium phosphate (TCP) bottom layer were developed. Furthermore, a comparative analysis between two types of sca ffolds pro- duced using di fferent SF concentrations, i.e., 8% (w/v) (Hi8) and 16% (w/v) (Hi16) was performed. In terms of architecture and morphology, the produced sca ffolds presented homogeneous porosity in both layers and no di fferences were observed when comparing both sca ffolds. A decrease in terms of mechanical performance of the sca ffolds was observed when SF concentration decreased from 16 to 8% (w/v). Hi16 revealed a static compressive modulus of 0.66 ± 0.05 MPa and dynamical mechanical properties ranging from 2.17 ± 0.25 to 3.19 ± 0.38 MPa. By its turn, Hi8 presented a compressive modulus of 0.27 ± 0.08 MPa and dynamical mechanical properties ranging from 1.03 ± 0.08 MPa to 1.56 ± 0.13 MPa. In vitro bioactivity studies showed formation of apatite crystals onto the surface of Hi8 and Hi16 bottom layers. Human meniscus cells (hMCs) and human primary osteoblasts were cultured separately onto the top layer (SF8 and SF16) and bottom layer (SF8/TCP and SF16/TCP) of the hierarchical sca ffolds Hi8 and Hi16, respectively. Both cell types showed good adhesion and proliferation as denoted by the live/dead staining, Alamar Blue assay and DNA quanti fication analysis. Subcutaneous implantation in mice revealed weak in flammation and sca ffold’s integrity. The hierarchical indirect printed SF sca ffolds can be promising candidate for meniscus TE sca ffolding applications due their suitable mechanical properties, good biological performance and possibility of being applied in a patient-speci fic approach.展开更多
Craniomaxillofacial reconstruction implants,which are extensively used in head and neck surgery,are conventionally made in standardized forms.During surgery,the implant must be bended manually to match the anatomy of ...Craniomaxillofacial reconstruction implants,which are extensively used in head and neck surgery,are conventionally made in standardized forms.During surgery,the implant must be bended manually to match the anatomy of the individual bones.The bending process is time-consuming,especially for inexperienced surgeons.Moreover,repetitive bending may induce undesirable internal stress concentration,resulting in fatigue under masticatory loading in v iv o and causing various complications such as implant fracture,screw loosening,and bone resorption.There have been reports on the use of patient-specific 3D-printed implants for craniomaxillofacial reconstruction,although few reports have considered implant quality.In this paper,we present a systematic approach for making 3D-printed patientspecific surgical implants for craniomaxillofacial reconstruction.The approach consists of three parts:First,an easy-to-use design module is developed using Solidworks®software,which helps surgeons to design the implants and the axillary fixtures for surgery.Design engineers can then carry out the detailed design and use finite-element modeling(FEM)to optimize the design.Second,the fabrication process is carried out in three steps:0 testing the quality of the powder;(2)setting up the appropriate process parameters and running the 3D printing process;and (3)conducting post-processing treatments(i.e.,heat and surface treatments)to ensure the quality and performance of the implant.Third,the operation begins after the final checking of the implant and sterilization.After the surgery,postoperative rehabilitation follow-up can be carried out using our patient tracking software.Following this systematic approach,we have successfully conducted a total of 41 surgical cases.3D-printed patient-specific implants have a number of advantages;in particular,their use reduces surgery time and shortens patient recovery time.Moreover,the presented approach helps to ensure implant quality.展开更多
To improve aneurysm treatment,this study examined the influence of clip locations on hemodynamic factors in patient-specific anterior communicating artery(ACoA)aneurysms with different aneurysmal angle.We proposed a s...To improve aneurysm treatment,this study examined the influence of clip locations on hemodynamic factors in patient-specific anterior communicating artery(ACoA)aneurysms with different aneurysmal angle.We proposed a simplified classification of ACoA aneurysms using aneurysmal angle,defined by the angle of pivot of the aneurysmal dome and the virtual two-dimensional plane created by both proximal A2 segments of anterior cerebral artery(ACA).ACoA aneurysms with three different aneurysmal angles,which are 15°,80°and 120°,were analyzed in our study.In this work,we obtained hemodynamics before and after clipping surgery with three clip locations based on clinical clipping strategies in three ACoA aneurysms with different aneurysm angles.Results showed that local high pressure occurs at impingement region of the ACoA aneurysm before clipping and new impingement region close to the clipping location after clipping treatment.For clipping the aneurysm with aneurysmal angle 15°and a wide neck,wall shear stress(WSS)distribution is more uniform when the clipping angle of two clips close to 180°comparing with other two angles.In addition,for clipping the aneurysm with aneurysmal angle 80°and 120°,local high pressure appears on new impingement region and high WSS distributes around the clipping location when the clip plane is normal to the direction of inflow of aneurysm from the dominance of A1 segment of ACA.Hence,we should avoid the impingement of inflow from the A1 segment and choose a favorable clipping location for the fastness of clip.The results of our study could preoperatively give a useful information to the decision of surgical plan.展开更多
Radiochromic film for spot-scanning QA provides high spatial resolution and efficiency gains from one-shot irradiation for multiple depths. However, calibration can be a tedious procedure which may limit widespread us...Radiochromic film for spot-scanning QA provides high spatial resolution and efficiency gains from one-shot irradiation for multiple depths. However, calibration can be a tedious procedure which may limit widespread use. Moreover, since there may be an energy dependence, which manifests as a depth dependence, this may require additional measurements for each patient. We present a one-scan protocol to simplify the procedure. A calibration using an EBT3 film, exposed by a 6-level step-wedge plan on a Proteus®PLUS proton system (IBA, Belgium), was performed at depths of 18, 20, 24 cm using Plastic Water®(CIRS, Norfolk, VA). The calibration doses ranged from 65 - 250 cGy (RBE) (relative biological effectiveness) for proton energies of 170 - 200 MeV. A clinical prostate + nodes plan was used for validation. The planar doses at selected depths were measured with EBT3 films and analyzed using one-scan protocol (one-scan digitization of QA film and at least one film exposed to a known dose). The gamma passing rates, dose-difference maps, and profiles of 2D planar doses measured with EBT3 film and IBA MatriXX-PT, versus the RayStation TPS calculations were analyzed and compared. The EBT3 film measurement results matched well with the TPS calculation data with an average passing rate of ~95% for 2%/2 mm and slightly lower passing rates were obtained from an ion chamber array detector. We were able to demonstrate that the use of a proton step-wedge provided clinically acceptable results and minimized variations between film-scanner orientation, inter-scan, and scanning conditions. Furthermore, for relative dosimetry (calibration is not done at the time of experiment), it could be derived from no more than two films exposed to known doses (one could be zero) for rescaling the master calibration curve at each depth. The sensitivity of the calibration to depth variations has been explored. One-scan protocol results appear to be comparable to that of the ion chamber array detector. The use of a proton step-wedge for calibration of EBT3 film potentially increases efficiency in patient-specific QA of proton beams.展开更多
Introduction Trabeculae carneae are irregular structures that cover the endocardial surfaces of both ventricles of human heart and account for a significant portion of the ventricular mass.However,the role of trabecul...Introduction Trabeculae carneae are irregular structures that cover the endocardial surfaces of both ventricles of human heart and account for a significant portion of the ventricular mass.However,the role of trabeculae carneae in left ventricular(LV)function is not well understood.Previous reports suggested that trabeculae help squeeze blood from the apical region during systole[1].Our recent study suggests that trabeculae carneae hypertrophy and fibrosis contribute to increased LV stiffness in patients with diastolic heart failure,and severing free-running trabeculae carneae may improve diastolic compliance of the LV[2].Objective To understand the role of trabeculae carneae in the left ventricular diastolic and systolic functions using anatomically detailed patient-specific finite element models of the human LV.Methods(1)Image acquisition An explanted human heart was collected from a 63 year old female donor with a history of stroke and congestive heart failure within 24 hours postmortem from South Texas Blood and Tissue Center(San Antonio,TX).The heart was de-identified in accordance with Institutional Review Board(IRB)requirements and informed consent for research was obtained from the donor’s family.Three-dimensional MRI scanning was conducted on a 3T(128 MHz)MRI system(TIM Trio,Siemens Medical Solutions),comprised of a superconducting magnet with a 60 cm diameter accessible bore,when the heart was submerged in a saline filled plastic container.(2)Finite element analysis Three distinct LV models were derived from the MR images.The first model was the intact trabeculated model(TM)which contained all trabeculae carneae and papillary muscles.This high-resolution anatomically detailed 3D model of the LV was segmented from 2D MR images in DICOM format using Mimics(Materialise NV,Leuven,Belgium).The second model was the papillary model(PM),in which the papillary muscles remain intact but most of the trabeculae carneae were excluded in the smoothing process.The third model was the smooth model(SM)in which the trabeculae carneae and papillary muscles were excluded during image segmentation.Finite element(FE)models of the TM,PM and SM were created by meshing 3D reconstructions of the acquired MR images using tetrahedral elements(ICEM,Ansys Inc.,Canonsburg,PA).The mesh size was selected after a pilot study on mesh sensitivity.The passive cardiac muscle was characterized as a hyperelastic,incompressible,transversely isotropic material with a Fung exponential strain energy function.The material constants were determined by matching the end-diastolic pressure-volume relationship with the empirical Klotz relation[3].A rule-based myocardial fiber algorithm was adopted to generate the myofiber directions[4].The active contraction(i.e.,systolic contraction)was modeled by the time varying'Elastance'active contraction model.The contractile parameter Tmax was determined and calibrated so that the FE predicted ejection fraction(EF)of TM matched the EF of a normal human heart at the specified end-systolic pressure[3].The analysis of the TM,PM,and SM models were implemented using the open-source finite element package FEBio(www.febio.org).In all models,the rigid body motion was suppressed by constraining the base from moving in all directions.The end-diastolic and end-systolic pressure-volume relationships(EDPVR and ESPVR)were obtained and characterized by an exponential function and the slope,respectively.Results Our simulation results showed that independent of the material model,the EDPVR curve shifts to the right in PM and SM compared to TM.However,the ESPVR curve may shift to the right or left in PM compared to TM,while shifting tothe right in SM for all material models.EDPVR was steeper in TM compared to PM and SM;however,ESPVR was found to be steeper in PM than in TM and SM.The predicted parameters of EDPVR and ESPVR showed lower average exponential term in PM and SM compared to TM,indicating a significant improvement in the compliance and global diastolic function of less trabeculated LV models(P<0.01).Similarly,the higher average elastance EEs and lower volume intersect in PM compared to TM,suggests that mild cutting of trabeculae carneae slightly improves the global systolic function of the LV(P=0.89).However,cutting all trabeculae carneae and papillary muscles in SM had a significant adverse effect on the global systolic function(P<0.01).Discussion and conclusions Most patient-specific LV studies in the literature have used smoothed ventricular geometries.We used high resolution MRI to capture the endocardial details of the LV.Though reproducing very fine trabeculae carneae was restricted by the MRI resolution,our results demonstrated the importance of considering endocardial structures,i.e.papillary muscles and trabeculae carneae,in the assessment of LV global function in patient-specific computational LV models.The present work is consistent with the observation that diastolic performance improved after severing trabeculae carneae due to a reduction in LV stiffness[2].Furthermore,our results also suggest that severing trabeculae carneae(without affecting papillary muscle)may improve LV systolic function.Our model results are consistent with experimental measurements using ex vivo rabbit heart perfusion[5].This improvement would be greater in hypertrophic hearts because trabeculae carneae are also hypertrophic and more fibrotic.Left ventricular hypertrophy is often associated with heart failure with preserved ejection fraction(HFpEF).There is no effective treatment for HFpEF,which is characterized by impaired diastolic relaxation due to increased LV stiffness.Our results indicate that trabecular cutting could be an effective treatment for HFpEF.展开更多
We present a computational framework for the study of cardiac motion.The bio-mechanical model captures the passive and active properties of the cardiac tissue as well as the fiber architecture.We focus on the analysis...We present a computational framework for the study of cardiac motion.The bio-mechanical model captures the passive and active properties of the cardiac tissue as well as the fiber architecture.We focus on the analysis of deformations of a beating left ventricle(LV),comparing numerical simulations with real data acquired by echocardiography.The goal is to determine the clinical relevance of the LV strains pattern and to investigate the relationships between that pattern and the arrangement of myocardial fibers.The proposed framework could in principle be used for a wide range of clinical applications.展开更多
Cardiovascular computational fluid dynamics(CFD)based on patient-specific modeling is increasingly used to predict changes in hemodynamic parameters before or after surgery/interventional treatment for aortic dissecti...Cardiovascular computational fluid dynamics(CFD)based on patient-specific modeling is increasingly used to predict changes in hemodynamic parameters before or after surgery/interventional treatment for aortic dissection(AD).This study investigated the effects of flow boundary conditions(BCs)on patient-specific aortic hemodynamics.We compared the changes in hemodynamic parameters in a type A dissection model and normal aortic model under different BCs:inflow from the auxiliary and truncated structures at aortic valve,pressure control and Windkessel model outflow conditions,and steady and unsteady inflow conditions.The auxiliary entrance remarkably enhanced the physiological authenticity of numerical simulations of flow in the ascending aortic cavity.Thus,the auxiliary entrance can well reproduce the injection flow fromthe aortic valve.In addition,simulations of the aortic model reconstructed with an auxiliary inflow structure and pressure control and the Windkessel model outflow conditions exhibited highly similar flow patterns and wall shear stress distribution in the ascending aorta under steady and unsteady inflow conditions.Therefore,the inflow structure at the valve plays a crucial role in the hemodynamics of the aorta.Under limited time and calculation cost,the steady-state study with an auxiliary inflow valve can reasonably reflect the blood flow state in the ascending aorta and aortic arch.With reasonable BC settings,cardiovascular CFD based on patient-specific ADmodels can aid physicians in noninvasive and rapid diagnosis.展开更多
Bicuspid aortic valve(BAV)is a common congenital malformation of the aortic valve with various structural characteristics.Different types of BAV can cause secondary aortic diseases,including calcific aortic valve sten...Bicuspid aortic valve(BAV)is a common congenital malformation of the aortic valve with various structural characteristics.Different types of BAV can cause secondary aortic diseases,including calcific aortic valve stenosis and aortic dilation,although their pathogenesis remains unclear.In this study,we first established patient-specific BAV simulation models and silicone models(Type 0 A-P,Type 1 R-N,and Type 1 L-R)based on clinical computed tomography angiography(CTA)and pressure data.Next,we applied a research method combining fluid-structure interaction(FSI)simulation and digital particle image velocimetry(DPIV)experiment to quantitatively analyze the hemodynamic,structural mechanical,and flow field characteristics of patients with different BAV types.Simulation-based hemodynamic parameters and experimental results were consistent with clinical data,affirming the accuracy of the model.The location of the maximum principal strain in the patientspecific model was associated with the calcification site,which characterized the mechanism of secondary aortic valve stenosis.The maximum wall shear stress(WSS)of the patient-specific model(>67.1 Pa)exceeded 37.9 Pa and could cause endothelial surface injury as well as remodeling under long-term exposure,thus increasing the risk of aortic dilation.The distribution of WSS was mainly caused by BAV type,resulting in different degrees of dilation in different parts guided by the type.The patient-specific model revealed a maximum viscous shear stress(VSS)value of 5.23 Pa,which was smaller than the threshold for shear-induced hemolysis of red blood cells(150 Pa)and platelet activation(10 Pa),but close to the threshold for platelet sensitization(6 Pa).The results of flow field characteristics revealed a low risk of hemolysis but a relative high risk of thrombus formation in the patient-specific model.This study not only provides a basis for future comprehensive research on BAV diseases,but also generates relevant insights for theoretical guidance for calcific aortic valve stenosis and aortic dilation caused by different types of BAV,as well as biomechanical evidence for the potential risk of hemolysis and thrombus formation in BAV,which is of great value for clinical diagnosis and treatment of BAV.展开更多
The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients wi...The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients with malignant pelvic tumors who were admitted to our hospital between March 2014 and December 2020 were retrospectively enrolled.Patients underwent hemi-pelvic resection and reconstruction by 3D-printed individualized prostheses.The registration between the designed model and the postoperative segmented model of the prosthesis was used to obtain the intraoperative osteotomy plane and reduce metal artifacts in postoperative computed tomography(CT)images.The distance and angle between the planned and actual osteotomy planes were then used to assess the accuracy of the intraoperative osteotomy.Eight patients with 13 osteotomy planes were enrolled,including four males and four females.The median age at the time of imaging examination was 44 years(range,33–54 years).All intraoperative osteotomy planes were assessed successfully.The mean distance between the planned and true intraoperative osteotomy planes was−0.69 cm(−7.5–7.35 cm),and the mean angle was 6.57°±3.36°(1.05°–11.88°).This new assessment method of registering the designed model and the postoperative CT segmented model of the prosthesis may be used to assess the accuracy of intraoperative osteotomy for pelvic tumors,using 3D printed patient-specific templates.展开更多
文摘The recent increase in the adoption of total ankle arthroplasty(TAA)reflects the improvements in implant designs and surgical techniques,including the use of preoperative navigation system and patient-specific instrumentation(PSI),such as custom-made cutting guides.Cutting guides are customized with respect to each patient's anatomy based on preoperative ankle computed tomography scans,and they drive the saw intra-operatively to improve the accuracy of bone resection and implant positioning.Despite some promising results,the main queries in the literature are whether PSI improves the reliability of achieving neutral ankle alignment and more accurate implant sizing,whether it is actually superior over standard techniques,and whether it is cost effective.Moreover,the advantages of PSI in clinical outcomes are still theoretical because the current literature does not allow to confirm its superiority.The purpose of this review article is therefore to assess the current literature on PSI in TAA with regard to current implants with PSI,templating and preoperative planning strategies,alignment and sizing,clinical outcomes,cost analysis,and comparison with standard techniques.
基金Young Teacher Project of Basic Scientific Research in Beijing University of Chinese Medicine(No.2019-JYB-JS-178)。
文摘Objective:To observe the clinical efficacy and advantages of 3D printed patient-specific instrumentation(PSI)assisted distal tibial tuberosity-high tibial osteotomy in the treatment of medial compartment knee osteoarthritis.Methods:75 patients with medial compartment knee osteoarthritis were included in the study performed DTT-HTO in our hospital from August 2017 to August 2019.The patients were divided into the PSI group(n=39)and conventional group(n=36)According to whether PSI was used in surgery.The differences of lateral cortical fracture rate,time of intraoperative X-ray exposure,intraoperative blood loss,operative time,weight bearing line(WBL),Posterior tibial slope(PTS)and Caton-Deschamps index(CDI)were compared between the two groups.Visual analogue scale(VAS)scores and Hospital for Special Surgery(HSS)scores were recorded to evaluate knee pain and function before surgery and after surgery at 3 months and 12 months.Results:All 75 patients were followed up for more than 12 months,the ranged from 12-26(18.74±6.21)months.Three lateral cortical fractures in the conventional group and no fracture in PSI group.The lateral cortical fracture rate,time of intraoperative X-ray exposure,intraoperative blood loss,operative time in PSI group were lower than those in conventional group(p敿0.05).WBL in two groups were significantly improved after surgery(p敿0.05),and PTS,CDI were no statistically improved after surgery(p>0.05).While there was no statistically significant difference with WBL,PTS and CDI between two groups(p>0.05).At 1 months,3 months and 12 months after surgery;VAS and HSS scores in both groups were significantly improved compared with that before surgery(p0.05),and were no statistically significant difference between two groups.Conclusion:3D printed patient-specific instrumentation assisted DTT-HTO has significant clinical efficacy,and effectively standardized surgical procedures,meanwhile reduced the time of intraoperative X-ray exposure,intraoperative blood loss and risk of lateral cortical fracture.
文摘AIM: To summarise and compare currently available evidence regarding accuracy of pre-operative imaging, which is one of the key choices for surgeons contemplating patient-specific instrumentation(PSI) surgery.METHODS: The MEDLINE and EMBASE medical literature databases were searched, from January 1990 to December 2013, to identify relevant studies. The data from several clinical studies was assimilated to allow appreciation and comparison of the accuracy of each modality. The overall accuracy of each modality was calculated as proportion of outliers > 3% in the coronal plane of both computerised tomography(CT) or magnetic resonance imaging(MRI). RESULTS: Seven clinical studies matched our inclusion criteria for comparison and were included in our study for statistical analysis. Three of these reported series using MRI and four with CT. Overall percentage of outliers > 3% in patients with CT-based PSI systems was 12.5% vs 16.9% for MRI-based systems. These results were not statistically significant. CONCLUSION: Although many studies have been undertaken to determine the ideal pre-operative imaging modality, conclusions remain speculative in the absence of long term data. Ultimately, information regarding accuracy of CT and MRI will be the main determining factor. Increased accuracy of pre-operative imaging could result in longer-term savings, and reduced accumulated dose of radiation by eliminating the need for post-operative imaging and revision surgery.
文摘Serous Purpose: There is limited information in the literature surrounding the use of patient-specific instrumentation (PSI) by a large number of surgeons. This prospective observational study was therefore designed to evaluate the logistics of using PSI for total knee arthroplasty (TKA) in a multi-surgeon environment, as well as its accuracy in positioning components. Methods: Of 73 patients enrolled in this study, 3 were excluded after the surgeon decided intraoperatively to switch to conventional instrumentation. Results: Mean operative time was 77.6 minutes. The component size had to be changed in 19 patients and bone cuts corrected in 12. In 65 of the 70 cases (92.9%), mechanical alignment was within the optimal range from 3° varus to 3° valgus, with the remaining 5 cases considered outliers (7.1%). Mean overall mechanical alignment was 0.3° varus (standard deviation, ±2°). There was a distinct variance with regard to the position of the tibial component in the sagittal plane. Conclusions: PSI can be effectively incorporated in larger, multisurgeon practices. Although high accuracy was observed for overall mechanical alignment and component positioning in the frontal and sagittal planes, further attention must be paid to the tibial slope. We highly recommend the use of the extramedullary alignment rod to the proper position of the tibial block, as well as double-checking the slope before performing bone cuts.
文摘Background： Restoring good alignment after total knee replacement （TKR） is still a challenge globally, and the clinical efficiency of patient-specific instruments （PSIs） remains controversial. In this study, we aimed to explore the value and significance of three-dimensional printing PSls based on knee joint computed tomography （CT） and full-length lower extremity radiography in TKR. Methods： Between June 2013 and October 2014, 31 TKRs were performed using PSIs based on knee joint CT and full-length lower extremity radiography in 31 patients （5 males and 26 females; mean age： 67.6 ± 7.9 years, body mass index [BMI]： 27.4 ±3.5 kg/m2）. Thirty-one matched patients （4 males and 27 females; mean age： 67.4± 7.2 years; mean BM 1：28.1 ± 4.6 kg/m2） who underwent TKR using conventional instruments in the same period served as the control group. The mean follow-up period was 38 months （31-47 months）. Knee Society Score （KSS）, surgical time, and postoperative drainage volume were recorded. Coronal alignment was measured on full-length radiography. Results： Twenty-three （74.2%） and 20 （64.5%） patients showed good postoperative alignment in the PSI and control groups, respectively, without significant difference between the two groups （χ2 = 0.68, P = 0.409）. The mean surgical time was 81.48± 16.40 rain and 72.90 ± 18.10 min for the PSl and control groups, respectively, without significant difference between the two groups （t = 0.41, P = 0.055）. The postoperative drainage volume was 250.9 ± 148.8 ml in the PSI group, which was significantly less than that in the control group （602. 1± 230.6 ml, t = 6.83, P 〈 0.001）. No significant difference in the KSS at the final follow-up was found between the PSI and control groups （91.06 ± 3.26 vs. 90.19±3.84, t= 0.95, P=0.870）. Conclusions： The use of PSls based on knee joint CT and standing full-length lower extremity radiography in TKR resulted in acceptable alignment compared with the use of conventional instruments, although the marginal advantage was not statistically different. Surgical time and clinical results were also similar between the two groups, However, the PSI group had less postoperative drainage.
基金funded by the TaipeiMedical University-National Taiwan University of Science and Technology joint research program under Grant No.TMU-NTUST-109-09.
文摘Reconstruction of a traumatic distal femur defect remains a therapeutic challenge.Bone defect implants have been proposed to substitute the bone defect,and their biomechanical performances can be analyzed via a numerical approach.However,the material assumptions for past computational human femur simulations were mainly homogeneous.Thus,this study aimed to design and analyze scaffolds for reconstructing the distal femur defect using a patient-specific finite element modeling technique.A three-dimensional finite element model of the human femur with accurate geometry and material distribution was developed using the finite element method and material mapping technique.An intact femur and a distal femur defect model treated with nine microstructure scaffolds and two solid scaffolds were investigated and compared under a single-leg stance loading.The results showed that the metal solid scaffold design could provide the most stable fixation for reconstructing the distal femur defect.However,the fixation stability was affected by various microstructure designs and pillar diameters.A microstructure scaffold can be designed to satisfy all the biomechanical indexes,opening up future possibilities for more stable reconstructions.A three-dimensional finite element model of the femur with real bone geometry and bone material distribution can be developed,and this patient-specific femur model can be used for studying other femoral fractures or injuries,paving the way for more comprehensive research in the field.Besides,this patient-specific finite element modeling technique can also be applied to developing other human or animal bone models,expanding the scope of biomechanical research.
基金supported by the Central Government Guidance Funds for Local Science and Technology Development Program(grant no.ZYYD2025ZY21)the Science and Technology Plan Project of the Xinjiang Production and Construction Corps(2023AB036)+1 种基金the Xinjiang Meteorological Bureau High-Level Key Talent Programthe Natural Science Foundation of the Xinjiang Uygur Autonomous Region(2023D01A17 and 2025D01A109).
文摘Low-visibility phenomena strongly impact the environment,as well as transportation,aviation and other fields that are closely related to people's livelihoods;thus,they represent important ecological issues of social concern.Based on observation data concerning low-visibility phenomena derived from 105 national meteorological stations in Xinjiang,China over the past 20 years,we systematically analyzed the differences between manual and instrument observations for six types of low-visibility phenomena,with a focus on exploring their spatiotemporal distribution characteristics using instrument data.The results revealed that low-visibility phenomena were dominated by fog-and haze-related events(mist,fog,and haze)in northern Xinjiang and dust-related events(dust storms,blowing sand,and floating dust)in southern Xinjiang,with transitional characteristics observed in eastern Xinjiang.Compared with manual observations,the instrument measurements significantly improved the fine-scale low-visibility phenomenon identification process.On the basis of the instrument observation data,spatial-dimension analysis results indicated that low-visibility phenomena in Xinjiang were significantly influenced by terrain factors.Constrained by the Tianshan Mountains,haze-like phenomena formed a core agglomeration area in northern Xinjiang,whereas dust-and sand-related phenomena radiated outward,with the Taklimakan Desert at the center.Moreover,the gripping effect of the terrain promoted dust transmission along low-altitude channels.Temporally,fog-and haze-related phenomena occurred mainly during autumn and winter,and the proportion of these events decreased from 76.7%to 55.1%.The fog-and haze-related phenomena demonstrated a U-shaped rebound trend,while the proportion of mist phenomena decreased by 34.2%.Dust storms occurred during spring,accounting for 23.3%to 44.9%of all storms.Instrument measurement technology has the advantages of high spatial and temporal resolutions and multiparameter coordination but provides a limited dust-haze mixed-pollution identification capacity.This study provides crucial reference data for enhancing the understanding of low-visibility events in Xinjiang and the potential responses while improving the accuracy of pollution source tracking and meteorological process diagnosis tasks.
基金Management Research Project on the Transformation of Scientific and Technological Achievements at Peking University Health Science Center(Grant No.KT202501)Peking University Health Science Center 2025 Party Building Research Project(General Category,No.2)。
文摘Scientific instruments serve as foundational pillars for both scientific progress and industrial innovation,enabling deep exploration and driving technological breakthroughs.Their independent controllability and continuous innovation are indispensable for sustaining a competitive advantage in technological development,thereby securing national scientific capacity and long-term strategic growth.At present,however,China faces substantial risks of technological"stranglehold"in the high-end scientific instrument domain.The underlying causes are multifaceted,arising not only from insufficient accumulation of core technologies but also from entrenched systemic and ecosystem-level barriers that impede the application,scaling,and promotion of domestic instruments.This paper provides a systematic analysis of the challenges hindering the widespread adoption of domestically developed scientific instruments and proposes practical pathways to build a new,integrated"R&D-application-promotion"ecosystem.This ecosystem is anchored in trust,driven by user demand,and shaped through collaborative innovation.Key initiatives include organizing user visits to instrument manufacturers,convening seminars on domestic alternatives to imported equipment,establishing demonstration centers for application and promotion,and involving end-users directly in the R&D and iterative upgrading of domestic instruments.Together,these efforts aim to close the final critical gap,advancing domestic instruments from merely"functional"to genuinely"user-friendly",and ultimately to"widely implemented".By doing so,this framework offers both theoretical grounding and practical guidance for achieving high-level scientific and technological self-reliance and sustained innovation capacity.
文摘Chinese video game Black Myth:Wukong has been a h it among gaming enthusiasts worldwide since its release in 2024, its breakout success demonstrating the potential global appeal of traditional Chinese culture. Based on the 16th-century classic novel Journey to the West, the game not only introduces international audiences to Chinese literature but has also become a far-reaching platform for traditional Chinese music.
基金the National Key Research and Development Program of China(No.2017YFB1104104)the Clinical Research Program of Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine(No.JYLJ025)+6 种基金the Project of the Shanghai Collaborative Innovation Center for Translational Medicine(No.TM201814)the Technology and Innovation Fund(Chuang Ke)of the Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine(No.CK2018011)the 3D Snowball Project of Shanghai Jiao Tong University School of Medicine(No.GXQ202007)the National Natural Science Foundation of China(No.81772425)the Science and Technology Commission of Shanghai Municipality(No.16441908700)Shanghai Jiao Tong University(No.YG2016MS11)the Science and Technology Project of Guangdong Province(No.201707010089)。
文摘Patient-specific instrumentation(PSI)enables a more accurate alignment of the lower limbs in a high tibial osteotomy(HTO)than in traditional surgery;however,the current design of commercial PSIs is not perfect.Therefore,we designed a new patient-specific surgical guide to improve the accuracy of the osteotomy and verified its reliability through a clinical operation.Here,we describe a patient with isolated medial-compartment bilateral knee osteoarthritis,accompanied by a varus deformity of the proximal tibia.The patient was treated with HTO using a patient-specific 3D-printed surgical guide.We concluded that the patient-specific 3D-printed surgical guide improved the accuracy of the osteotomy and the alignment of the lower limb.
基金Supported by the National Natural Science Foundation of China(61571063)Key Scientific Research Projects of Colleges and Universities in Henan Province(20A510014)Key Scientific and Technological Projects in Henan Province。
文摘The automatic detection of cardiac arrhythmias through remote monitoring is still a challenging task since electrocardiograms(ECGs)are easily contaminated by physiological artifacts and external noises,and these morphological characteristics show significant variations for different patients.A fast patient-specific arrhythmia diagnosis classifier scheme is proposed,in which a wavelet adaptive threshold denoising is combined with quantum genetic algorithm(QAG)based on least squares twin support vector machine(LSTSVM).The wavelet adaptive threshold denoising is employed for noise reduction,and then morphological features combined with the timing interval features are extracted to evaluate the classifier.For each patient,an individual and fast classifier will be trained by common and patient-specific training data.Following the recommendations of the Association for the Advancements of Medical Instrumentation(AAMI),experimental results over the MIT-BIH arrhythmia benchmark database demonstrated that our proposed method achieved the average detection accuracy of 98.22%,99.65%and 99.41%for the abnormal,ventricular ectopic beats(VEBs)and supra-VEBs(SVEBs),respectively.Besides the detection accuracy,sensitivity and specificity,our proposed method consumes the less CPU running time compared with the other representative state of the art methods.It can be ported to Android based embedded system,henceforth suitable for a wearable device.
文摘The complex meniscus tissue plays a critical role in the knee. The high susceptibility to injury has led to an intense pursuit for better tissue engineering regenerative strategies, where scaffolds play a major role. In this study, indirect printed hierarchical multilayered sca ffolds composed by a silk fibroin (SF) upper layer and an 80/20 (w/w) ratio of SF/ionic-doped β-tricalcium phosphate (TCP) bottom layer were developed. Furthermore, a comparative analysis between two types of sca ffolds pro- duced using di fferent SF concentrations, i.e., 8% (w/v) (Hi8) and 16% (w/v) (Hi16) was performed. In terms of architecture and morphology, the produced sca ffolds presented homogeneous porosity in both layers and no di fferences were observed when comparing both sca ffolds. A decrease in terms of mechanical performance of the sca ffolds was observed when SF concentration decreased from 16 to 8% (w/v). Hi16 revealed a static compressive modulus of 0.66 ± 0.05 MPa and dynamical mechanical properties ranging from 2.17 ± 0.25 to 3.19 ± 0.38 MPa. By its turn, Hi8 presented a compressive modulus of 0.27 ± 0.08 MPa and dynamical mechanical properties ranging from 1.03 ± 0.08 MPa to 1.56 ± 0.13 MPa. In vitro bioactivity studies showed formation of apatite crystals onto the surface of Hi8 and Hi16 bottom layers. Human meniscus cells (hMCs) and human primary osteoblasts were cultured separately onto the top layer (SF8 and SF16) and bottom layer (SF8/TCP and SF16/TCP) of the hierarchical sca ffolds Hi8 and Hi16, respectively. Both cell types showed good adhesion and proliferation as denoted by the live/dead staining, Alamar Blue assay and DNA quanti fication analysis. Subcutaneous implantation in mice revealed weak in flammation and sca ffold’s integrity. The hierarchical indirect printed SF sca ffolds can be promising candidate for meniscus TE sca ffolding applications due their suitable mechanical properties, good biological performance and possibility of being applied in a patient-speci fic approach.
基金The study was partially supported by the Innovative Scientific Team Research Fund(2018IT100212)Science and Technology Bureau,Fo Shan,Guangdong,China.It was also partially supported by the Health and Medical Research Fund(05161626)Food and Health Bureau,Hong Kong,China.
文摘Craniomaxillofacial reconstruction implants,which are extensively used in head and neck surgery,are conventionally made in standardized forms.During surgery,the implant must be bended manually to match the anatomy of the individual bones.The bending process is time-consuming,especially for inexperienced surgeons.Moreover,repetitive bending may induce undesirable internal stress concentration,resulting in fatigue under masticatory loading in v iv o and causing various complications such as implant fracture,screw loosening,and bone resorption.There have been reports on the use of patient-specific 3D-printed implants for craniomaxillofacial reconstruction,although few reports have considered implant quality.In this paper,we present a systematic approach for making 3D-printed patientspecific surgical implants for craniomaxillofacial reconstruction.The approach consists of three parts:First,an easy-to-use design module is developed using Solidworks®software,which helps surgeons to design the implants and the axillary fixtures for surgery.Design engineers can then carry out the detailed design and use finite-element modeling(FEM)to optimize the design.Second,the fabrication process is carried out in three steps:0 testing the quality of the powder;(2)setting up the appropriate process parameters and running the 3D printing process;and (3)conducting post-processing treatments(i.e.,heat and surface treatments)to ensure the quality and performance of the implant.Third,the operation begins after the final checking of the implant and sterilization.After the surgery,postoperative rehabilitation follow-up can be carried out using our patient tracking software.Following this systematic approach,we have successfully conducted a total of 41 surgical cases.3D-printed patient-specific implants have a number of advantages;in particular,their use reduces surgery time and shortens patient recovery time.Moreover,the presented approach helps to ensure implant quality.
基金This work was kindly supported by National Natural Science Foundation of China(11602053,51576033)Education Department of Liaoning Province general project(L2015113).
文摘To improve aneurysm treatment,this study examined the influence of clip locations on hemodynamic factors in patient-specific anterior communicating artery(ACoA)aneurysms with different aneurysmal angle.We proposed a simplified classification of ACoA aneurysms using aneurysmal angle,defined by the angle of pivot of the aneurysmal dome and the virtual two-dimensional plane created by both proximal A2 segments of anterior cerebral artery(ACA).ACoA aneurysms with three different aneurysmal angles,which are 15°,80°and 120°,were analyzed in our study.In this work,we obtained hemodynamics before and after clipping surgery with three clip locations based on clinical clipping strategies in three ACoA aneurysms with different aneurysm angles.Results showed that local high pressure occurs at impingement region of the ACoA aneurysm before clipping and new impingement region close to the clipping location after clipping treatment.For clipping the aneurysm with aneurysmal angle 15°and a wide neck,wall shear stress(WSS)distribution is more uniform when the clipping angle of two clips close to 180°comparing with other two angles.In addition,for clipping the aneurysm with aneurysmal angle 80°and 120°,local high pressure appears on new impingement region and high WSS distributes around the clipping location when the clip plane is normal to the direction of inflow of aneurysm from the dominance of A1 segment of ACA.Hence,we should avoid the impingement of inflow from the A1 segment and choose a favorable clipping location for the fastness of clip.The results of our study could preoperatively give a useful information to the decision of surgical plan.
文摘Radiochromic film for spot-scanning QA provides high spatial resolution and efficiency gains from one-shot irradiation for multiple depths. However, calibration can be a tedious procedure which may limit widespread use. Moreover, since there may be an energy dependence, which manifests as a depth dependence, this may require additional measurements for each patient. We present a one-scan protocol to simplify the procedure. A calibration using an EBT3 film, exposed by a 6-level step-wedge plan on a Proteus®PLUS proton system (IBA, Belgium), was performed at depths of 18, 20, 24 cm using Plastic Water®(CIRS, Norfolk, VA). The calibration doses ranged from 65 - 250 cGy (RBE) (relative biological effectiveness) for proton energies of 170 - 200 MeV. A clinical prostate + nodes plan was used for validation. The planar doses at selected depths were measured with EBT3 films and analyzed using one-scan protocol (one-scan digitization of QA film and at least one film exposed to a known dose). The gamma passing rates, dose-difference maps, and profiles of 2D planar doses measured with EBT3 film and IBA MatriXX-PT, versus the RayStation TPS calculations were analyzed and compared. The EBT3 film measurement results matched well with the TPS calculation data with an average passing rate of ~95% for 2%/2 mm and slightly lower passing rates were obtained from an ion chamber array detector. We were able to demonstrate that the use of a proton step-wedge provided clinically acceptable results and minimized variations between film-scanner orientation, inter-scan, and scanning conditions. Furthermore, for relative dosimetry (calibration is not done at the time of experiment), it could be derived from no more than two films exposed to known doses (one could be zero) for rescaling the master calibration curve at each depth. The sensitivity of the calibration to depth variations has been explored. One-scan protocol results appear to be comparable to that of the ion chamber array detector. The use of a proton step-wedge for calibration of EBT3 film potentially increases efficiency in patient-specific QA of proton beams.
基金supported by a National Innovation Award(15IRG23320009)from the American Heart Association
文摘Introduction Trabeculae carneae are irregular structures that cover the endocardial surfaces of both ventricles of human heart and account for a significant portion of the ventricular mass.However,the role of trabeculae carneae in left ventricular(LV)function is not well understood.Previous reports suggested that trabeculae help squeeze blood from the apical region during systole[1].Our recent study suggests that trabeculae carneae hypertrophy and fibrosis contribute to increased LV stiffness in patients with diastolic heart failure,and severing free-running trabeculae carneae may improve diastolic compliance of the LV[2].Objective To understand the role of trabeculae carneae in the left ventricular diastolic and systolic functions using anatomically detailed patient-specific finite element models of the human LV.Methods(1)Image acquisition An explanted human heart was collected from a 63 year old female donor with a history of stroke and congestive heart failure within 24 hours postmortem from South Texas Blood and Tissue Center(San Antonio,TX).The heart was de-identified in accordance with Institutional Review Board(IRB)requirements and informed consent for research was obtained from the donor’s family.Three-dimensional MRI scanning was conducted on a 3T(128 MHz)MRI system(TIM Trio,Siemens Medical Solutions),comprised of a superconducting magnet with a 60 cm diameter accessible bore,when the heart was submerged in a saline filled plastic container.(2)Finite element analysis Three distinct LV models were derived from the MR images.The first model was the intact trabeculated model(TM)which contained all trabeculae carneae and papillary muscles.This high-resolution anatomically detailed 3D model of the LV was segmented from 2D MR images in DICOM format using Mimics(Materialise NV,Leuven,Belgium).The second model was the papillary model(PM),in which the papillary muscles remain intact but most of the trabeculae carneae were excluded in the smoothing process.The third model was the smooth model(SM)in which the trabeculae carneae and papillary muscles were excluded during image segmentation.Finite element(FE)models of the TM,PM and SM were created by meshing 3D reconstructions of the acquired MR images using tetrahedral elements(ICEM,Ansys Inc.,Canonsburg,PA).The mesh size was selected after a pilot study on mesh sensitivity.The passive cardiac muscle was characterized as a hyperelastic,incompressible,transversely isotropic material with a Fung exponential strain energy function.The material constants were determined by matching the end-diastolic pressure-volume relationship with the empirical Klotz relation[3].A rule-based myocardial fiber algorithm was adopted to generate the myofiber directions[4].The active contraction(i.e.,systolic contraction)was modeled by the time varying'Elastance'active contraction model.The contractile parameter Tmax was determined and calibrated so that the FE predicted ejection fraction(EF)of TM matched the EF of a normal human heart at the specified end-systolic pressure[3].The analysis of the TM,PM,and SM models were implemented using the open-source finite element package FEBio(www.febio.org).In all models,the rigid body motion was suppressed by constraining the base from moving in all directions.The end-diastolic and end-systolic pressure-volume relationships(EDPVR and ESPVR)were obtained and characterized by an exponential function and the slope,respectively.Results Our simulation results showed that independent of the material model,the EDPVR curve shifts to the right in PM and SM compared to TM.However,the ESPVR curve may shift to the right or left in PM compared to TM,while shifting tothe right in SM for all material models.EDPVR was steeper in TM compared to PM and SM;however,ESPVR was found to be steeper in PM than in TM and SM.The predicted parameters of EDPVR and ESPVR showed lower average exponential term in PM and SM compared to TM,indicating a significant improvement in the compliance and global diastolic function of less trabeculated LV models(P<0.01).Similarly,the higher average elastance EEs and lower volume intersect in PM compared to TM,suggests that mild cutting of trabeculae carneae slightly improves the global systolic function of the LV(P=0.89).However,cutting all trabeculae carneae and papillary muscles in SM had a significant adverse effect on the global systolic function(P<0.01).Discussion and conclusions Most patient-specific LV studies in the literature have used smoothed ventricular geometries.We used high resolution MRI to capture the endocardial details of the LV.Though reproducing very fine trabeculae carneae was restricted by the MRI resolution,our results demonstrated the importance of considering endocardial structures,i.e.papillary muscles and trabeculae carneae,in the assessment of LV global function in patient-specific computational LV models.The present work is consistent with the observation that diastolic performance improved after severing trabeculae carneae due to a reduction in LV stiffness[2].Furthermore,our results also suggest that severing trabeculae carneae(without affecting papillary muscle)may improve LV systolic function.Our model results are consistent with experimental measurements using ex vivo rabbit heart perfusion[5].This improvement would be greater in hypertrophic hearts because trabeculae carneae are also hypertrophic and more fibrotic.Left ventricular hypertrophy is often associated with heart failure with preserved ejection fraction(HFpEF).There is no effective treatment for HFpEF,which is characterized by impaired diastolic relaxation due to increased LV stiffness.Our results indicate that trabecular cutting could be an effective treatment for HFpEF.
基金the Italian Minister for Education,Research,and University(Grant No.2017KL4EF3)“Sapienza”Universiti di Roma(Grant No.RM120172A77FB346)。
文摘We present a computational framework for the study of cardiac motion.The bio-mechanical model captures the passive and active properties of the cardiac tissue as well as the fiber architecture.We focus on the analysis of deformations of a beating left ventricle(LV),comparing numerical simulations with real data acquired by echocardiography.The goal is to determine the clinical relevance of the LV strains pattern and to investigate the relationships between that pattern and the arrangement of myocardial fibers.The proposed framework could in principle be used for a wide range of clinical applications.
基金This work was partially supported by the National Natural Science Foundation of China[No.51976026]the Fundamental Research Funds for the Central Universities[DUT21JC25,DUT20GJ203].
文摘Cardiovascular computational fluid dynamics(CFD)based on patient-specific modeling is increasingly used to predict changes in hemodynamic parameters before or after surgery/interventional treatment for aortic dissection(AD).This study investigated the effects of flow boundary conditions(BCs)on patient-specific aortic hemodynamics.We compared the changes in hemodynamic parameters in a type A dissection model and normal aortic model under different BCs:inflow from the auxiliary and truncated structures at aortic valve,pressure control and Windkessel model outflow conditions,and steady and unsteady inflow conditions.The auxiliary entrance remarkably enhanced the physiological authenticity of numerical simulations of flow in the ascending aortic cavity.Thus,the auxiliary entrance can well reproduce the injection flow fromthe aortic valve.In addition,simulations of the aortic model reconstructed with an auxiliary inflow structure and pressure control and the Windkessel model outflow conditions exhibited highly similar flow patterns and wall shear stress distribution in the ascending aorta under steady and unsteady inflow conditions.Therefore,the inflow structure at the valve plays a crucial role in the hemodynamics of the aorta.Under limited time and calculation cost,the steady-state study with an auxiliary inflow valve can reasonably reflect the blood flow state in the ascending aorta and aortic arch.With reasonable BC settings,cardiovascular CFD based on patient-specific ADmodels can aid physicians in noninvasive and rapid diagnosis.
基金supported by Zhuhai Fudan Innovation Institute and Science and Technology Project of Shanghai Administration for Market Regulation(Grant No.2022-71).
文摘Bicuspid aortic valve(BAV)is a common congenital malformation of the aortic valve with various structural characteristics.Different types of BAV can cause secondary aortic diseases,including calcific aortic valve stenosis and aortic dilation,although their pathogenesis remains unclear.In this study,we first established patient-specific BAV simulation models and silicone models(Type 0 A-P,Type 1 R-N,and Type 1 L-R)based on clinical computed tomography angiography(CTA)and pressure data.Next,we applied a research method combining fluid-structure interaction(FSI)simulation and digital particle image velocimetry(DPIV)experiment to quantitatively analyze the hemodynamic,structural mechanical,and flow field characteristics of patients with different BAV types.Simulation-based hemodynamic parameters and experimental results were consistent with clinical data,affirming the accuracy of the model.The location of the maximum principal strain in the patientspecific model was associated with the calcification site,which characterized the mechanism of secondary aortic valve stenosis.The maximum wall shear stress(WSS)of the patient-specific model(>67.1 Pa)exceeded 37.9 Pa and could cause endothelial surface injury as well as remodeling under long-term exposure,thus increasing the risk of aortic dilation.The distribution of WSS was mainly caused by BAV type,resulting in different degrees of dilation in different parts guided by the type.The patient-specific model revealed a maximum viscous shear stress(VSS)value of 5.23 Pa,which was smaller than the threshold for shear-induced hemolysis of red blood cells(150 Pa)and platelet activation(10 Pa),but close to the threshold for platelet sensitization(6 Pa).The results of flow field characteristics revealed a low risk of hemolysis but a relative high risk of thrombus formation in the patient-specific model.This study not only provides a basis for future comprehensive research on BAV diseases,but also generates relevant insights for theoretical guidance for calcific aortic valve stenosis and aortic dilation caused by different types of BAV,as well as biomechanical evidence for the potential risk of hemolysis and thrombus formation in BAV,which is of great value for clinical diagnosis and treatment of BAV.
基金the Technology Project of Shanghai Science and Technology Commission(Nos.19441902700 and 18441903100)the Clinical Research Plan of SHDC(No.SHDC2020CR3083B)the Shanghai Municipal Education Commission(No.20152221)。
文摘The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients with malignant pelvic tumors who were admitted to our hospital between March 2014 and December 2020 were retrospectively enrolled.Patients underwent hemi-pelvic resection and reconstruction by 3D-printed individualized prostheses.The registration between the designed model and the postoperative segmented model of the prosthesis was used to obtain the intraoperative osteotomy plane and reduce metal artifacts in postoperative computed tomography(CT)images.The distance and angle between the planned and actual osteotomy planes were then used to assess the accuracy of the intraoperative osteotomy.Eight patients with 13 osteotomy planes were enrolled,including four males and four females.The median age at the time of imaging examination was 44 years(range,33–54 years).All intraoperative osteotomy planes were assessed successfully.The mean distance between the planned and true intraoperative osteotomy planes was−0.69 cm(−7.5–7.35 cm),and the mean angle was 6.57°±3.36°(1.05°–11.88°).This new assessment method of registering the designed model and the postoperative CT segmented model of the prosthesis may be used to assess the accuracy of intraoperative osteotomy for pelvic tumors,using 3D printed patient-specific templates.
