Optical Microsphere Nano-Imaging:Progress and Challenges

The optical diffraction effect imposes a radical obstacle preventing conventional optical microscopes from achieving an imaging resolution beyond the Abbe diffraction limit and thereby restricting their usage in a multitude of nanoscale applications.Over the past decade,the optical microsphere nanoimaging technique has been demonstrated to be a cost-effective solution for overcoming the diffraction limit and has achieved an imaging resolution of up to about k6k8 in a real-time and label-free manner,making it highly competitive among numerous super-resolution imaging technologies.In this review,we summarize the underlying nano-imaging mechanisms of the microsphere nanoscope and key advancements aimed at imaging performance enhancement:first,to change the working environment or modify the peripheral hardware of a single microsphere nanoscope at the system level;second,to compose the microsphere compound lens;and third,to engineer the geometry or ingredients of microspheres.We also analyze challenges yet to be overcome in optical microsphere nano-imaging,followed by an outlook of this technique.

Epileptic brain network mechanisms and neuroimaging techniques for the brain network

Epilepsy can be defined as a dysfunction of the brain network,and each type of epilepsy involves different brain-network changes that are implicated diffe rently in the control and propagation of interictal or ictal discharges.Gaining more detailed information on brain network alterations can help us to further understand the mechanisms of epilepsy and pave the way for brain network-based precise therapeutic approaches in clinical practice.An increasing number of advanced neuroimaging techniques and electrophysiological techniques such as diffusion tensor imaging-based fiber tra ctography,diffusion kurtosis imaging-based fiber tractography,fiber ball imagingbased tra ctography,electroencephalography,functional magnetic resonance imaging,magnetoencephalography,positron emission tomography,molecular imaging,and functional ultrasound imaging have been extensively used to delineate epileptic networks.In this review,we summarize the relevant neuroimaging and neuroelectrophysiological techniques for assessing structural and functional brain networks in patients with epilepsy,and extensively analyze the imaging mechanisms,advantages,limitations,and clinical application ranges of each technique.A greater focus on emerging advanced technologies,new data analysis software,a combination of multiple techniques,and the construction of personalized virtual epilepsy models can provide a theoretical basis to better understand the brain network mechanisms of epilepsy and make surgical decisions.

Application Research of Medical Imaging Practical Teaching Based on Virtual Simulation Teaching Platform

Objective:To explore the application effect of virtual simulation teaching platform in the practical teaching of medical imaging.Methods:A total of 97 students majoring in medical imaging technology of class 2022 were selected and divided into two groups according to the random number method:control group(n=48)and observation group(n=49).The observation group was under the practical teaching mode based on the virtual simulation teaching platform,while the control group was under the traditional multimedia teaching mode.Questionnaire survey and teaching assessment were carried out after the teaching period,and the application effects of the two teaching modes were compared.Results:The reading and theoretical scores of the students in the observation group were significantly higher than those of the students in the control group(P<0.01);there were statistically significant differences in the results of the questionnaire survey(improved learning interest,improved language expression,improved ability to comprehensively analyze problems,and improved teamwork awareness)between the two groups of students(P<0.05);the students in the observation group were markedly more satisfied with the teaching content,teaching methods,and teaching quality than the students in the control group(P<0.05).Conclusion:The medical imaging practical teaching mode based on virtual simulation platform not only helps improve students’theoretical understanding and practical ability in medical imaging technology,but also improves students’learning interest,language expression ability,ability to comprehensively analyze problems,communication skills,teamwork awareness,and satisfaction with the teaching content,teaching methods,and teaching quality.Therefore,it has wide application value in medical specialty education.

Experiment Combined with Picture Archiving and Communication System in the Practical Teaching of Medical Imaging

Objective:To explore the application effect of virtual simulation experiment combined with picture archiving and communication system(PACS)in medical imaging practical teaching.Methods:97 students from the medical imaging class of 2022 were divided into two groups;the control group(n=48)was taught by the traditional teaching method,whereas the research group was taught by virtual simulation experiment combined with PACS(n=49).The teaching achievements and teaching effects of the two groups were compared to define the advantages of the two teaching modes.Results:Initially,there were no significant differences in the basic theory,image analysis,report writing,and differential diagnosis scores between the two groups of students(P>0.05);however,after 16 weeks of teaching,the scores of the research group were better than those of the control group(P<0.05);the pass rate of students in the study group(93.88%)was higher than that in the control group(81.25%);the scores of students in the research group in terms of clinical inquiry skills,X-ray/computed tomography/magnetic resonance imaging(X-ray/CT/MRI)operation skills,and doctor-patient communication skills were significantly higher than those in the control group(P<0.05).Conclusion:In medical imaging practical teaching,the application of virtual simulation experiment combined with PACS can effectively address several problems in the traditional teaching mode,including the single teaching method,the single teaching content,and the lack of innovation,and,at the same time,improve students’basic theoretical knowledge,X-ray/CT/MRI operation skills,consultation skills,and doctor-patient communication skills,thereby effectively improving the teaching quality and learning effect.

Adaptive Virtual Source Imaging Using the Sequence Intensity Factor:Simulation and Experimental Study

Virtual source(VS)imaging has been proposed to improve image resolution in medical ultrasound imaging.However,VS obtains a limited contrast due to the non-adaptive delay-and-sum(DAS)beamforming.To improve the image contrast and provide an enhanced resolution,adaptive weighting algorithms were applied in VS imaging.In this paper,we proposed an adjustable generalized coherence factor(aGCF)for the synthetic aperture sequential beamforming(SASB)ofVS imaging to improve image quality.The value of aGCF is adjusted by a sequence intensity factor(SIF)that is defined as the ratio between the effective low resolution scan lines(LRLs)intensity and total LRLs strength.The aGCF-weighted VS(aGCF-VS)images were compared with standard VS images and GCF-weighted VS(GCF-VS)images.Simulation and experimental results demonstrated that the contrast ratio(CR)and contrastto-noise ratio(CNR)of aGCF-VS are greatly improved,compared with standard VS imaging.And in comparison with GCF-VS,aGCF-VS can obtain better CNR and speckle signal-to-noise ratio(sSNR)whilemaintaining similar CR.Therefore,aGCF is suitable for VS imaging to improve contrast and preserve speckle pattern.

Hybrid ultrasound imaging techniques(fusion imaging)

Visualization of tumor angiogenesis can facilitate noninvasive evaluation of tumor vascular characteristics to supplement the conventional diagnostic imaging goals of depicting tumor location,size,and morphology.Hybrid imaging techniques combine anatomic [ultrasound,computed tomography(CT),and/or magnetic resonance imaging(MRI)] and molecular(single photon emission CT and positron emission tomography) imaging modalities.One example is real-time virtual sonography,which combines ultrasound(grayscale,colour Doppler,or dynamic contrast harmonic imaging) with contrast-enhanced CT/MRI.The benefits of fusion imaging include an increased diagnostic confidence,direct comparison of the lesions using different imaging modalities,more precise monitoring of interventional procedures,and reduced radiation exposure.

Characterization for elastic constants of fused deposition modelling-fabricated materials based on the virtual fields method and digital image correlation

Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?.

Preliminary results of acoustic radiation force impulses (ARFI) ultrasound imaging of solid suspicious breast lesions

Objective： The aim of our study was to make the qualitative and quantitative analysis to breast lesions using acoustic radiation force impulses （ARFI）, and assess the diagnostic value of ARFI for differentiation between benign and malignant solid breast masses, meanwhile evaluate the influences of ARFI with breast imaging reporting and data system （BI-RADS） of suspicious masses. Methods： Seventy-five women with 86 breast lesions underwent conventional breast ultra- sound examination. Then B-mode BI-RADS features and assessments were recorded and standard breast US supplemented by ARFI elastographic examination were repeated. The data were recorded and analyzed as following： area ratio of breast lesion, the shear-wave velocity, the ratio of the shear-wave velocity between lesions and surrounding normal tissues, and according to the elastographic data reconsidered the BI-RADS category, all the results have been correlated with pathological results and make statistical evaluations of ARFI for differentiation between benign and malignant solid breast masses. Meantime our study has correlated the adjusted BI-RADS category of suspicious breast lesions with the pathological results and made assessment. Results： Thirty-eight patients were malignant breast carcinoma （31 invasive ductal carcinoma, 5 intraductal carcinoma in situ, 2 medullary carcinoma, 2 invasive Iobular carcinoma）, 48 patients were benign breast lesions （23 fibroadenoma, 12 benign nodular hyperplasia, 5 phyllodes tumor, 6 adenosis, 2 intraductal papilloma）. Underwent conventional breast ultrasound exam, 42 cases were BI-RADS category 3, 23 cases were BI-RADS category 4. When adding elastographic data, 46 cases were BI-RADS category 3 and 20 cases were BI-RADS category 4. Compared with pathological results showed for both the specificity of BIRADS features and the area under ROC curve has risen. Virtual touch tissue imaging （VTI） and virtual touch tissue quantification （VTQ） data showed the area ratio （AR） between elastographic lesions area and B-mode lesions area, SWV （maximal shear-wave velocity of lesions）, R-SWV （shear-wave velocity ratio between lesions and surrounding normal tissues） in benign breast lesions were lower than those in malignant lesions which has statistical significance and the cut-off point were 1.1,4.65 m/s, 5.18 respectively. Conclusion： The ARFI elastography can provide the reliable qualitative and quantitative analysis about hardness of breast lesions, supply the new BI-RADS category features to suspicious breast masses and serve as an effective diagnostic tool for differentiation between benign and malignant solid masses.

Significance of an Advanced Image-Based Virtual Monoenergetic Reconstruction of Dual Source Dual-Energy CT Data at Low keV Increases Image Quality for Portal Vein System of Pancreatic Cancer Patients

Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving image quality for portal vein system of pancreatic cancer patients. Materials and methods: 47 patients with clinically suspected pancreatic cancer (all confirmed by pathology) were collected. Routine plain scan was performed with Siemens Force dual-source dual-energy CT followed by 3 scans respectively carried out in arterial phase, portal phase and delayed phase. Traditional virtual monoenergetic reconstructions (Mono_E) and new generation of virtual monoenergetic reconstructions (Mono+) were respectively performed on portal vein images to obtain virtual single energy images including Mono_ E70 keV, Mono_E 55 keV and Mono+ 70 keV and Mono+ 55 keV. The signal-to-noise ratio (SNR) and noise of portal vein, normal pancreatic tissues and pancreatic lesions of 100 kV, Mono_E and Mono+ images were compared. In addition, the contrast noise ratio of portal vein and lesions as well as pancreatic tissues and lesions (CNR PV, CNRtumor) were also compared. At the same time, two imaging physicians with rich clinical experiences read the films and scored the images of each group by using the 5-point scoring method. Results: Mono+ 55 keV images including SNRpv, SNRpanc, SNRtumor, Noise, CNRpv, CNRtumor were statistically different from 100 KV images and Mono_E images (P < 0.05). As for the subjective score, Mono+ 55 keV image score also had the highest score, which had statistical significance (P < 0.05). The results showed that Mono+ 55 keV images had the best quality. Conclusion: The new generation of virtual Mono+ post-treatment can reduce image noise. Low energy Mono+ images can improve the contrast between pancreatic cancer lesions and portal of pancreatic cancer patients.

A modeling method for virtual scene based on multi-view image sequence

Through the analysis and comparison of shortcomings and advantages of existing technologies on object modeling in 3D applications,we propose a new modeling method for virtual scene based on multi-view image sequence to model irregular objects efficiently in 3D application.In 3D scene,this method can get better visual effect by tracking the viewer's real-time perspective position and projecting the photos from different perspectives dynamically.The philosophy of design,the steps of development and some other relevant topics are discussed in details,and the validity of the algorithm is analyzed.The results demonstrate that this method represents more superiority on simulating irregular objects by applying it to the modeling of virtual museum.

Semi-reference image quality metric for virtual view images in free-viewpoint television

A semi-reference image quality assessment metric based on similarity measurement for synthesized virtual viewpoint image （VVI） in free-viewpoint television system （FFV） is proposed in this paper. The key point of the proposed metric is taking resemblant information between VVI and its neighbor view images for quality assessment to make our metric to be extended to multi-semi-reference image quality assessment easily. The proposed metric first extracts impact factors from image features, then combines an image synthesis technique and similarity functions, in which, disparity information are taken into account for registering the resemblant regions. Experiments are divided into three phases. Phase I is to verify the validation of the proposed metric by taking impaired images and original reference into account. The experimental results show the agreement between evaluation scores and bio-characteristic of human visual system. Phase II shows the accordance with Phase I by taking neighbor view as reference. The proposed metric can be taken as a full reference one to evaluate the image quality even though the original reference is absent. Phase III is then performed to evaluate the quality of WI. Evaluation scores in the experimental results are able to evaluate the quality of VVI.

Can preoperative planning using IRIS™three-dimensional anatomical virtual models predict operative findings during robot-assisted partial nephrectomy?

Objective To evaluate the predictive validity of IRIS™(Intuitive Surgical®,Sunnyvale,CA,USA)as a planning tool for robot-assisted partial nephrectomy(RAPN)by assessing the degree of overlap with intraoperative execution.Methods Thirty-one patients scheduled for RAPN by four experienced urologists were enrolled in a prospective study.Prior to surgery,urologists reviewed the IRIS™three-dimensional model on an iphone Operating System(iOS)app and completed a questionnaire outlining their surgical plan including surgical approach,and ischemia technique as well as confidence in executing this plan.Postoperatively,questionnaires assessing the procedural approach,clinical utility,efficiency,and effectiveness of IRIS™were completed.The degree of overlap between the preoperative and intraoperative questionnaires and between the planned approach and actual execution of the procedure was analyzed.Questionnaires were answered on a 5-point Likert scale and scores of 4 or greater were considered positive.Results Mean age was 65.1 years with a mean tumor size of 27.7 mm(interquartile range 17.5-44.0 mm).Hilar tumors consisted of 32.3%;48.4%of patients had R.E.N.A.L.nephrometry scores of 7-9.On preoperative questionnaires,the surgeons reported that in 67.7%cases they were confident that they can perform the procedure successfully,and on intraoperative questionnaires,the surgeons reported that in 96.8%cases IRIS™helped achieve good spatial sensation of the anatomy.There was a high degree of overlap between preoperative and intraoperative questionnaires for the surgical approach,interpreting anatomical details and clinical utility.When comparing plans for selective or off-clamp,the preoperative plan was executed in 90.0%of cases intraoperatively.Conclusion A high degree of overlap between the preoperative surgical approach and intraoperative RAPN execution was found using IRIS™.This is the first study to evaluate the predictive accuracy of IRIS™during RAPN by comparing preoperative plan and intraoperative execution.

双能量CT非线性融合和噪声优化的虚拟单能量图像技术在喉鳞状细胞癌中的应用

目的:探讨双能量CT线性融合图像(linear blending imaging,LBI)、非线性融合图像(nonlinear blending image,NBI)和噪声优化的虚拟单能量图像(noise-optimized virtual monoenergetic image,VMI+)技术在喉鳞状细胞癌中的应用价值。方法:回顾性分析2019年6月至2022年3月61例经病理证实为喉鳞状细胞癌患者的双能量CT资料。双能量图像采用LBI[融合系数为1(80 kV)和0.6(M0.6)]、NBI和VMI+(40 keV、55 keV)技术重建。比较5组图像的客观图像质量[对比噪声比(contrast-tonoise ratio,CNR)、肿瘤CT值、噪声]和主观图像质量(肿瘤边界评分和整体图像质量评分)。结果:40 keV的CNR、肿瘤CT值和肿瘤边界评分均明显高于80 kV、M0.6、NBI和55 keV,差异均有统计学意义(均P<0.05)。NBI的整体图像质量评分明显高于80 kV、M0.6、40 keV和55 keV,差异均有统计学意义(均P<0.05)。NBI的噪声明显低于80 kV、40 keV和55 keV,差异均有统计学意义(均P<0.05)。结论:在喉鳞状细胞癌的双能量CT中,采用VMI+技术(40 keV)能提供更好的CNR、肿瘤CT值和肿瘤边界,采用NBI技术能提供更低的噪声和更好的整体图像质量。

数字图像处理及应用虚拟仿真实验平台设计

针对数字图像处理及应用实验教学的需要,结合当下图像处理技术的热点应用,利用虚拟仿真技术、交互操作等信息化手段进行实验教学,设计并开发了数字图像处理及应用虚拟仿真实验教学平台。实验教学平台包含交通标志数字图像处理、图像分类、图像识别、视频处理、自动驾驶应用等5个虚拟仿真实验教学资源,共13个交互实验步骤。该平台特色显著、虚实结合,达到了良好的教学效果,为“新工科”背景下的虚拟仿真实验教学提供有益的参考。

基于虚拟现实的大视差图像网格优化拼接算法

图像亮度、局部区域信息强度影响图像清晰度,导致图像拼接效果不佳,为提升图像拼接效果,提出一种基于虚拟现实的大视差图像网格优化拼接算法。基于虚拟现实技术建立一个虚拟现实拼接环境,在此环境下开展图像拼接处理,对待拼接图像实施灰度化处理,增强图像局部区域信息强度;基于投影算法建立低密度的网格,并根据待拼接图像的匹配点分布结果建立网格矩阵,结合全局最佳相似变换矩阵实施矩阵加权叠加,对图像重叠区域展开失真校正;使用内容感知算法对图像重叠区域展开感知识别,找出其中的积累最小像素线,实施图像融合处理,通过融合结果完成大视差图像网格优化拼接。实验结果表明,使用该方法开展图像拼接时,图像拼接时间较短,均方根误差较低,拼接效果较好。

双低剂量技术在双能量头颈部CT血管成像中的应用

目的 探讨双低剂量扫描技术在双能量头颈部CTA扫描中的可行性。方法 前瞻性收集2021年1月~2021年5月间本院102名因头颈部血管疾病行头颈部CTA的患者纳入研究,随机分为CD、DLD两组,CD组行常规剂量扫描,DLD组行双低剂量扫描;分别对两组图像行MIP、VR、 MPR、 CPR、双能量去骨去钙化等后处理,用5分法对两组图像质量进行主观评价,选取颈总动脉起始部、颈内动脉起始部和大脑中动脉M1段测量血管的噪声、SNR、CNR,记录2组患者的x线剂量参数,包括CTDIvol(mGy)和DLP(mGy·cm),计算其有效剂量ED(mSv),亦计算2组患者的碘摄入量I(mg),对结果进行统计学分析。结果 CD组与DLD组的主观图像质量评分均≥3分,均能满足诊断的要求。2名医师对2组图像质量评价的一致性好(Kappa值分别为0.817、0.82 5)。2名医师对2组图像的主观质量评分的差异无统计学意义(Z=-0.572、-0.2 83,均P>0.05)。CD组与DLD组图像各层面血管CT值的差异均无统计学意义(t=-0.05、0.689、0.906,均P<0.05);颈内动脉起始部、大脑中动脉M1段层面血管噪声、SNR、CNR的差异均无统计学意义(t=-0.830~1.842,均P>0.05);颈总动脉起始部层面CD组噪声大于DLD组(t=2.855,P<0.05),SNR、CNR小于DLD组(t=-4.959、-5.041,均P<0.05)。DLD组患者C TDIvol、DLP及ED较CD组分别降低36.9%、35.3%、35.2%(t=186.138、37.753、37.753,均P<0.05)。DLD组患者碘摄入量较CD组降低57.1%(10.5g VS.245g)。结论 双低剂量双能量头颈部CTA扫描技术在不影响图像质量的前提下,降低了患者接受的辐射剂量和对比剂碘摄入量。

基于空程和方向的船体装配线划线路径优化

为解决复杂船体装配线划线路径优化时精度低和收敛速度慢的问题,进而提高数控划线枪的作业效率,提出了基于空程和方向的船体装配线划线路径的调参免疫优化。首先以装配线的划线顺序和划线方向建立目标函数;然后借鉴凸透镜虚实成像原理设计了新免疫优化算法,基于进化代数和种群浓度自适应调节交叉和变异概率,并引入疫苗操作实现了船体装配线划线路径求解;最后基于马尔科夫链理论证明了免疫优化算法的收敛性。六组高维函数测试结果表明,与遗传算法、免疫遗传算法和自适应改进遗传算法相比,所提算法实现了100%寻优,且最小收敛代数、平均收敛代数、迭代代数标准差分别平均减少了29.63%、28.96%和18.33%。四种船体结构的装配线划线路径优化测试结果表明,相比起其他三种算法,所提算法的路径规划性能最佳,其最小值和平均值分别平均减少了1.38%和2.39%,平均收敛代数和迭代代数标准差分别平均减少了17.19%和13.08%,从而进一步验证了船体装配线划线路径调参免疫优化的有效性和优越性。

虚实坐标智能匹配与自适应三维轨迹规划

针对数字孪生增材修复任务中,物件仿真与真实坐标对应困难、三维轨迹误差较大的问题,提出虚实坐标智能匹配与自适应三维轨迹规划方法。采用图像分割方法获取实际场景下物件的分割图像,通过最小外接矩形预估物件真实坐标,仿真端据此执行旋转与平移操作,调整仿真物件的模型位置,实现坐标智能匹配;为最小化虚实坐标误差,设计基于Attention的多尺度残差UNet图像分割模型,利用多尺度残差模块获取物件多尺度特征,通过Attention策略增强网络对位置信息的描述。三维轨迹规划部分,设计融合特征高度的自适应分层算法,减少分层高度偏移,缩减阶梯误差;根据分层结果进行轮廓提取、填充,生成三维轨迹。结果表明,坐标匹配误差小于1mm,三维修复轨迹规划质量较高。

虚拟仿真平台+Mini-CEX评估法在医学影像学中的应用

目的:探讨虚拟仿真平台+Mini-CEX评估法在医学影像实践课中的应用价值。方法:将186名学生随机分组并分别应用虚拟仿真平台和传统教学法实习教学。通过考试和Mini-CEX评估法评价教学效果及满意度。结果:试验组在主观成绩、总成绩、学习主动性和综合学习能力方面评价结果优于对照组,具有较高满意度(P<0.05)。结论:虚拟仿真平台+Mini-CEX评估法能满足医学影像学实践教学和评估需要,有利于提高学习成绩、加强影像诊断思维能力培养。

多传感约束下三维运动图像连带动作高质量仿真

因非刚体三维运动图像在成像过程中,传感器区域的随机性对动作限制大、操作复杂,导致动作虚拟精度较低、图像质量差。为此,提出了多传感约束下三维运动图像连带动作高质量仿真。根据多传感器受重力加速度以及地磁场的作用,求解传感器从原始状态到运动当前状态的角度变化。根据变化数值对图像进行去噪,提取连带动作特征。在Vicon系统中计算连带动作空间位置,捕捉连带动作变换轨迹,将运动轨迹结果输入PAR系统,完成连带动作虚拟成像。仿真结果表明:该方法图像去噪效果较好,传感器响应时间始终低于0.52 s,传感器响应速度较快,连带动作轨迹误差始终低于0.045,动作虚拟仿真精度较高,能够有效提高三维运动图像质量。