An image-based modeling framework for patient-specific computational hemodynamics

We present a modeling framework designed for patient-specific computational hemodynamics to be performed in the context of large-scale studies. The framework takes advantage of the integration of image processing, geometric analysis and mesh generation techniques, with an accent on full automation and high-level interaction. Image segmentation is performed using implicit deformable models taking advantage of a novel approach for selective initialization of vascular branches, as well as of a strategy for the segmentation of small vessels. A robust definition of centerlines provides objective geometric criteria for the automation of surface editing and mesh generation. The framework is available as part of an open-source effort, the Vascular Modeling Toolkit, a first step towards the sharing of tools and data which will be necessary for computational hemodynamics to play a role in evidence-based medicine.     

A spectral framework for sperm shape characterization

A novel methodology for characterization of animal sperm shape involving the use of a spectral approach to multiscale curvature estimation is proposed. By using the derivative property of the Fourier transform, allied to Gaussian smoothing, accurate estimates of the curvature along the sperm contour can be obtained in such a way that the curvature peaks corresponding to the sperm head vertices can be effectively identified. The measurements derived from such a processing, namely the width of the basal region of the head, the centralization of tail implantation, and the multiscale bending energy, provide valuable resources for fertility and phylogenetic studies.     

基于三维图像的大脑病灶显示和分析

针对头部各组织在灰度分布上存在复杂的粘连和交错叠加现象,提出在管状加强滤波算法中增加体素亮度调和参数并与管状控制的其他参数一起共同控制管状响应值的产生,该管状加强滤波算法和其他相关切割算法通过采用GPU编程方式实现,并对脑部肿瘤的提取和显示技术进行了探讨。实验结果表明,本文方法对于脑部组织和相关病灶的分割提供可视的实时显示,对脑部疾病的微创手术和介入治疗提供图像导视。     

应用彩色血流像素定量技术分析子宫肌瘤介入治疗后的血流灌注变化

目的提出一种新的基于计算机彩色目标分割技术的声像图彩色血流像素定量技术。方法应用笔者开发的计算机彩色血流像素定量软件 ,分析经阴道超声引导下穿刺注射无水酒精治疗子宫肌瘤前后的血流灌注状态变化 ,对照组应用半定量计数法分析血管条数增减评介血流灌注变化。结果应用计算机彩色血流像素定量软件统计肿块血流像素/肿块像素的比值 ,介入前肿块血流像素/肿块像素比值是(15.65±9.61) % ,介入治疗后第4～6个月减少为(5.91±3.35) % ,半定量血管计数结果分别为(4.8±2.34)条和(1.23±0.59)条 ,后者结果的准确性低于应用计算机彩色血流像素定量技术自动检测的结果。结论通过临床应用分析 ,使用计算机彩色血流像素定量技术 ,对兴趣区血流灌注状态进行定量分析的方法 ,比传统半定量方法的定量概念、精确度和可操作性都有了进一步的改进和提高。     

A Numerical Measurement Method for Dynamic Granular Materials Based on Computer Vision

Granular materials are widespread in nature and human production, and their macro-mechanical behavior is significantly affected by granule movement. The development of computer vision has brought some new ideas for measuring the numerical information (including the amount of translation, the rotation angle, velocity, acceleration, etc.) of dynamic granular materials. In this paper, we propose a numerical measurement method for dynamic granular materials based on computer vision. Firstly, an improved video instance segmentation (VIS) network is introduced to perform end-to-end multi-task learning, and its temporal feature fusion module and tracking head with long-sequence external memory can improve the problems of poor video data quality and high similarity in appearance of granular materials, respectively. Secondly, the numerical information can be extracted through a series of post-processing steps. Finally, the effectiveness of the measurement method is verified by comparing the numerical measurement results with the real values. The experimental results indicate that our improved VIS obtains an average precision (AP) of 76.6, the relative errors and standard deviations are maintained at a low level, and this method can effectively be used to measure the numerical information of dynamic granular materials. This study provides an intelligent proposal for the task of measuring numerical information of dynamic granular materials, which is of great significance for studying the spatial distribution, motion mode and macro-mechanical behavior of granular materials.     

食管癌110例三维适形放射治疗的疗效观察

目的:观察三维适形放射治疗食管癌的疗效.方法:采用放射治疗食管癌110例,200cGy/次,1次/天,总量为6000～7000cGy/32～35次.三维适形治疗60例,常规治疗50例.结果:三维适形放射治疗与常规放疗治疗食管癌的1、2、3年局部控制率分别为78.3％、66.7％、56.6％和54％、46％、30％,差异有统计学意义(x2=7.05,P＜0.05).1、2、3年生存率分别为78.3％、66.7％、45％和51％、41％,27％,差异有统计学意义(x2=6.34,P＜0.05).结论:三维适形放射治疗食管癌近期疗效较常规放疗疗效好.     

基于密集特征匹配的胸片肺野自动分割

目的X线胸片中肺野的准确分割是胸片图像自动分析的必要步骤。本文采用局部特征的密集匹配和标号融合进行胸片
肺野的自动分割。方法对于输入的待分割胸片,基于每个像素点提取密集SIFT描述子和图像块作为局部特征,采用密集匹配
直接在整个参考图像特征集合中快速搜索近邻;密集匹配分为受限的随机初始化、近邻场传播和受限的随机搜索三步,并数次
迭代后两步。利用匹配得到的近邻场,提取标号图像块并进行加权,权重为匹配的相似度,最后重组为肺野的概率图,经阈值化
处理即可得到肺野的分割。结果在公开的JSRT胸片图像数据集上进行测试,本文方法的Jaccard指标可达95.5%。结论利用
局部特征的密集匹配和标号融合能取得准确性高且稳定的胸片肺野分割效果,并且优于当前最好的胸片肺野分割方法。
     

一种视网膜血管的分割方法

目的探讨一种自动的视网膜血管分割方法。方法在2个尺度下增强血管图像,由基于直方图的加权模糊C均值聚类算法和形态学细化算子提取血管的近似中心线;通过多尺度形态学重构得到主要血管,再由较小尺度的匹配滤波增强中小血管;合并上述两部分得到最终的血管分割结果。结果对DRIVE数据库测试图像分割的灵敏性为0.7017,特异性为0．9816,准确率为0．9457。结论较同类无监督的血管分割算法具有更高的准确率,但对于小血管的灵敏性不高。     

数字摄影有效照射野控制与影像切割

目的:应用DR图像切割技术,探讨降低患者吸收剂量、节省存储空间、提高影像质量的途径。方法:选用不同大小的FPD照射野进行曝光,对诊断区外的影像切割后进行存储,在患者剂量、存储空间、影像质量等方面比较其与最大射野时的差异。结果:FPD受照面积分别为8×10英寸、10×12英寸、14×17英寸时,对应的与射野等大的存储文件大小分别为3.96MB、8.58MB、15MB,切割后存储文件最小分别可达2.1MB、5.2MB、7.5MB;与板等大照射野吸收剂量分别是2.16 dGy、10.61 dGy、2.78 dGy,与诊断区等大照射野吸收剂量分别为1.64 dGy、6.71 dGy、1.61 dGy。结论:在应用DR进行摄影时,缩小照射野至诊断区大小,并对图像进行切割,可以降低患者吸收剂量,节省存储空间,并提高影像质量。     

Micro-CT中椎弓根螺钉伪影对其周围骨计量学检测结果的影响及其校正

目的:减少椎弓根螺钉伪影对其周围骨计量学结果的影响.方法:通过在绵羊腰椎内植入椎弓根螺钉后,行去钉扫描和带钉扫描后,以去钉扫描组为对照组,带钉扫描组为实验组,分别采用不同的分割阈值对实验组螺钉周围骨质进行图像重建分析,结果与对照组钉道周围骨质情况进行比较,观察不同分割阈值对于减少螺钉伪影的影响及真实反映螺钉周围骨质情况的能力.结果:与对照组分割阈值为1 000时比较,当实验组分割阈值为1000时,实验组螺钉周围骨量明显优于对照组钉道周围骨量(P＜0.05);当实验组分割阈值为1 500时,2组之间无显著差异(P＞05);当实验组分割阈值为2000时,对照组钉道周围骨量明显优于实验组螺钉周围骨量(P＜0.05).结论:通过一定程度的提高分割阈值,有效地减少了螺钉伪影的影响,有利于准确了解螺钉周围骨质的情况.