Volume 30, Issue 6

Automatic retinal image analysis is emerging as an important screening tool for early detection of eye diseases. Glaucoma is one of the most common causes of blindness. The manual examination of optic disk (OD) is a standard procedure used for detecting glaucoma. In this paper, we present an automatic OD parameterization technique based on segmented OD and cup regions obtained from monocular retinal images. A novel OD segmentation method is proposed which integrates the local image information around each point of interest in multidimensional feature space to provide robustness against variations found in and around the OD region. We also propose a novel cup segmentation method which is based on anatomical evidence such as vessel bends at the cup boundary, considered relevant by glaucoma experts. Bends in a vessel are robustly detected using a region of support concept, which automatically selects the right scale for analysis. A multi-stage strategy is employed to derive a reliable subset of vessel bends called r-bends followed by a local spline fitting to derive the desired cup boundary. The method has been evaluated on 138 images comprising 33 normal and 105 glaucomatous images against three glaucoma experts. The obtained segmentation results show consistency in handling various geometric and photometric variations found across the dataset. The estimation error of the method for vertical cup-to-disk diameter ratio is 0.09/0.08 (mean/standard deviation) while for cup-to-disk area ratio it is 0.12/0.10. Overall, the obtained qualitative and quantitative results show effectiveness in both segmentation and subsequent OD parameterization for glaucoma assessment.

自动视网膜图像分析正成为早期检测眼病的重要筛查工具。青光眼是导致失明的最常见原因之一。视盘的手动检查是用于检测青光眼的标准程序。本文提出了一种基于从单目视网膜图像中分割出的视盘和视杯区域的自动视盘参数化技术。提出了一种新颖的视盘分割方法，该方法在多维特征空间中整合每个兴趣点周围的局部图像信息，以增强对视盘区域及其周围变化的鲁棒性。我们还提出了一种新颖的视杯分割方法，该方法基于解剖学证据，如视杯边界处的血管弯曲，这些弯曲被青光眼专家认为是相关的。使用支持区域概念稳健地检测血管弯曲，该概念自动选择正确的分析尺度。采用多阶段策略来获取称为r-bends的可靠血管弯曲子集，然后进行局部样条拟合以得出所需的视杯边界。该方法在138张图像（包括33张正常和105张青光眼图像）上进行了评估，并与三位青光眼专家进行了比较。获得的分割结果显示，该方法在处理数据集中发现的各种几何和光度变化方面具有一致性。该方法对垂直杯盘直径比的估计误差为0.09/0.08（均值/标准差），对杯盘面积比的估计误差为0.12/0.10。总体而言，获得的定性和定量结果表明，该方法在分割和后续的青光眼评估中的视盘参数化方面均有效。

The magnetic particle imaging method allows for the quantitative determination of spatial distributions of superparamagnetic nanoparticles in vivo. Recently, it was shown that the 1-D magnetic particle imaging process can be formulated as a convolution. Analyzing the width of the convolution kernel allows for predicting the spatial resolution of the method. However, this measure does not take into...

磁粒子成像方法能够对体内超顺磁性纳米粒子的空间分布进行定量测定。最近，研究表明一维磁粒子成像过程可以表述为卷积形式。通过分析卷积核的宽度，可以预测该方法的空间分辨率。然而，这种度量没有考虑...

This paper proposes an algorithm to measure the width of retinal vessels in fundus photographs using graph-based algorithm to segment both vessel edges simultaneously. First, the simultaneous two-boundary segmentation problem is modeled as a two-slice, 3-D surface segmentation problem, which is further converted into the problem of computing a minimum closed set in a node-weighted graph. An initia...

本文提出一种算法，利用基于图的方法同时分割血管边缘，以测量眼底照片中视网膜血管的宽度。首先，将同时分割两个边界的问题建模为两切片三维表面分割问题，进一步转化为在节点加权图中计算最小闭合集的问题。初步...

The high sensitivity of fluorescence imaging enables the detection of molecular processes in living organisms. However, diffuse light propagation in tissue prevents accurate recovery of tomographic information on fluorophore distribution for structures embedded deeper than 0.5 mm. Combining optical with magnetic resonance imaging (MRI) provides an accurate anatomical reference for fluorescence ima...

荧光成像的高灵敏度使得能够检测活体生物中的分子过程。然而，组织中光的漫射传播阻碍了对嵌入深度超过0.5毫米的结构中荧光团分布的断层成像信息的准确恢复。将光学成像与磁共振成像（MRI）相结合，为荧光成像提供了准确的解剖参考...

The alignment and normalization of individual brain structures is a prerequisite for group-level analyses of structural and functional neuroimaging data. The techniques currently available are either based on volume and/or surface attributes, with limited insight regarding the consistent alignment of anatomical landmarks across individuals. This article details a global, geometric approach that pe...

个体脑结构的对齐和标准化是进行结构和功能神经影像数据组级分析的前提。当前可用的技术要么基于体积和/或表面属性，对跨个体解剖标志的一致对齐了解有限。本文详细介绍了一种全局几何方法，该方法...

The accurate and reliable estimation of fiber orientation distributions, based on diffusion-sensitized magnetic resonance images is a major prerequisite for tractography algorithms or any other derived statistical analysis. In this work, we formulate the principle of fiber continuity (FC), which is based on the simple observation that the imaging of fibrous tissue implies certain expectations for ...

基于扩散敏感磁共振图像的纤维方向分布的准确可靠估计是纤维束成像算法或任何其他衍生统计分析的主要前提。在这项工作中，我们提出了纤维连续性（FC）原理，该原理基于一个简单的观察：纤维组织的成像对方向分布函数（ODF）的估计产生了某些期望……

Reflectance diffuse optical tomography (rDOT) of brain function is limited by its high sensitivity to the superficial tissues (i.e., the scalp and skull) and by its severe decrease in measurement sensitivity with increased depth. Significant interference in rDOT results from spontaneous fluctuations that are embedded in both the superficial tissues and brain, such as arterial pulsation and vasomot...

脑功能的反射漫射光学断层扫描(rDOT)因其对浅表组织(即头皮和颅骨)的高敏感性以及随着深度增加测量灵敏度严重下降而受到限制。rDOT中的显著干扰来自嵌入浅表组织和大脑的自发波动，例如动脉搏动和血管运动...

Being able to segment the esophagus without user interaction from 3-D CT data is of high value to radiologists during oncological examinations of the mediastinum. The segmentation can serve as a guideline and prevent confusion with pathological tissue. However, limited contrast to surrounding structures and versatile shape and appearance make segmentation a challenging problem. This paper presents...

能够在三维CT数据中无需用户交互即可分割食管，对放射科医生在纵隔肿瘤学检查中具有很高价值。分割可作为指南，防止与病理组织混淆。然而，与周围结构的对比度有限以及多变的形状和外观使分割成为一个具有挑战性的问题。本文提出...

Optical coherence tomography (OCT) is widely used in the assessment of retinal nerve fibre layer thickness (RNFLT) in glaucoma. Images are typically acquired with a circular scan around the optic nerve head. Accurate registration of OCT scans is essential for measurement reproducibility and longitudinal examination. This study developed and evaluated a special image registration algorithm to align...

光学相干断层扫描（OCT）广泛用于青光眼视网膜神经纤维层厚度（RNFLT）的评估。图像通常通过视盘周围的环形扫描采集。OCT扫描的精确配准对于测量重复性和纵向检查至关重要。本研究开发并评估了一种特殊的图像配准算法，用于对齐...

Three-dimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as effective scatterer diameter (ESD), can be estimated. Additionally, the 3DZM can be exploited to visualize and i...

三维阻抗图（3DZMs）是从组织学构建的声阻抗值虚拟体积，用于声学上表示组织微观结构。通过3DZM，可以预测超声背散射功率谱，并估计基于模型的散射体属性，如有效散射体直径（ESD）。此外，3DZM可用于可视化和...

In simultaneous dual-isotope myocardial perfusion SPECT (MPS) imaging, data are simultaneously acquired to determine the distributions of two radioactive isotopes. The goal of this work was to develop penalized maximum likelihood (PML) algorithms for a novel cross-tracer prior that exploits the fact that the two images reconstructed from simultaneous dual-isotope MPS projection data are perfectly ...

在同时双同位素心肌灌注SPECT（MPS）成像中，同时采集数据以确定两种放射性同位素的分布。本工作的目标是开发一种针对新型交叉示踪先验的惩罚最大似然（PML）算法，该先验利用了从同时双同位素MPS投影数据重建的两幅图像完美...

Much current research in functional magnetic resonance imaging (fMRI) employs multivariate machine learning approaches (e.g., support vector machines) to detect distributed spatial patterns from the temporal fluctuations of the neural signal. The aim of many studies is not classification, however, but investigation of multivariate spatial patterns, which pattern classifiers detect only indirectly....

目前功能性磁共振成像（fMRI）的许多研究采用多元机器学习方法（例如支持向量机）从神经信号的时间波动中检测分布式空间模式。然而，许多研究的目标并非分类，而是调查多元空间模式，分类器只能间接检测这些模式。

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