Volume 32, Issue 6

Glaucoma is a chronic eye disease that leads to vision loss. As it cannot be cured, detecting the disease in time is important. Current tests using intraocular pressure (IOP) are not sensitive enough for population based glaucoma screening. Optic nerve head assessment in retinal fundus images is both more promising and superior. This paper proposes optic disc and optic cup segmentation using superpixel classification for glaucoma screening. In optic disc segmentation, histograms, and center surround statistics are used to classify each superpixel as disc or non-disc. A self-assessment reliability score is computed to evaluate the quality of the automated optic disc segmentation. For optic cup segmentation, in addition to the histograms and center surround statistics, the location information is also included into the feature space to boost the performance. The proposed segmentation methods have been evaluated in a database of 650 images with optic disc and optic cup boundaries manually marked by trained professionals. Experimental results show an average overlapping error of 9.5% and 24.1% in optic disc and optic cup segmentation, respectively. The results also show an increase in overlapping error as the reliability score is reduced, which justifies the effectiveness of the self-assessment. The segmented optic disc and optic cup are then used to compute the cup to disc ratio for glaucoma screening. Our proposed method achieves areas under curve of 0.800 and 0.822 in two data sets, which is higher than other methods. The methods can be used for segmentation and glaucoma screening. The self-assessment will be used as an indicator of cases with large errors and enhance the clinical deployment of the automatic segmentation and screening.

青光眼是一种导致视力丧失的慢性眼病。由于无法治愈，及时检测该疾病至关重要。目前使用眼压（IOP）的测试对于基于人群的青光眼筛查不够敏感。视网膜眼底图像中的视神经头评估更有前景且更优越。本文提出使用超像素分类进行视盘和视杯分割，用于青光眼筛查。在视盘分割中，使用直方图和中心环绕统计将每个超像素分类为盘或非盘。计算自我评估可靠性分数以评估自动视盘分割的质量。对于视杯分割，除了直方图和中心环绕统计外，还将位置信息纳入特征空间以提高性能。所提出的分割方法在650张图像的数据集上进行了评估，这些图像的视盘和视杯边界由训练有素的专业人员手动标记。实验结果显示，视盘和视杯分割的平均重叠误差分别为9.5%和24.1%。结果还显示，随着可靠性分数的降低，重叠误差增加，这证明了自我评估的有效性。分割后的视盘和视杯随后用于计算杯盘比，以进行青光眼筛查。我们提出的方法在两个数据集中实现了0.800和0.822的曲线下面积，高于其他方法。这些方法可用于分割和青光眼筛查。自我评估将作为大误差病例的指标，并增强自动分割和筛查的临床部署。

Existing approaches to image reconstruction in photoacoustic computed tomography (PACT) with acoustically heterogeneous media are limited to weakly varying media, are computationally burdensome, and/or cannot effectively mitigate the effects of measurement data incompleteness and noise. In this work, we develop and investigate a discrete imaging model for PACT that is based on the exact photoacous...

现有的针对声学非均匀介质的光声计算层析成像（PACT）图像重建方法仅限于弱变化介质，计算负担大，并且/或者不能有效减轻测量数据不完整和噪声的影响。在这项工作中，我们开发并研究了一种基于精确光声模型的PACT离散成像模型。

We propose a novel blind compressive sensing (BCS) frame work to recover dynamic magnetic resonance images from undersampled measurements. This scheme models the dynamic signal as a sparse linear combination of temporal basis functions, chosen from a large dictionary. In contrast to classical compressed sensing, the BCS scheme simultaneously estimates the dictionary and the sparse coefficients fro...

我们提出了一种新颖的盲压缩感知（BCS）框架，用于从欠采样测量中恢复动态磁共振图像。该方案将动态信号建模为从大型字典中选择的时间基函数的稀疏线性组合。与经典压缩感知不同，BCS方案同时估计字典和稀疏系数...

We present a fast and robust approach to tracking the evolving shape of whole fluorescent cells in time-lapse series. The proposed tracking scheme involves two steps. First, coherence-enhancing diffusion filtering is applied on each frame to reduce the amount of noise and enhance flow-like structures. Second, the cell boundaries are detected by minimizing the Chan–Vese model in the fast level set-...

我们提出了一种快速且稳健的方法，用于追踪延时序列中完整荧光细胞的演化形状。所提出的追踪方案包括两个步骤。首先，对每一帧应用相干增强扩散滤波以减少噪声并增强流状结构。其次，通过快速水平集方法最小化Chan–Vese模型来检测细胞边界...

Cancer diagnosis is based on visual examination under a microscope of tissue sections from biopsies. But whereas pathologists rely on tissue stains to identify morphological features, automated tissue recognition using color is fraught with problems that stem from image intensity variations due to variations in tissue preparation, variations in spectral signatures of the stained tissue, spectral o...

癌症诊断基于对活检组织切片在显微镜下的视觉检查。但是，虽然病理学家依赖组织染色来识别形态特征，但利用颜色进行自动组织识别却存在许多问题，这些问题源于由于组织制备变化、染色组织光谱特征变化、光谱等导致的图像强度变化。

Elevated specific absorption rate (SAR) associated with increased main magnetic field strength remains a major safety concern in ultra-high-field (UHF) magnetic resonance imaging (MRI) applications. The calculation of local SAR requires the knowledge of the electric field induced by radio-frequency (RF) excitation, and the local electrical properties of tissues. Since electric field distribution c...

随着主磁场强度增加而升高的特定吸收率（SAR）仍然是超高场（UHF）磁共振成像（MRI）应用中的一个主要安全问题。局部SAR的计算需要了解射频（RF）激励感应的电场以及组织的局部电性质。由于电场分布...

Radiation therapy is used to treat cancer patients around the world. High quality treatment plans maximally radiate the targets while minimally radiating healthy organs at risk. In order to judge plan quality and safety, segmentations of the targets and organs at risk are created, and the amount of radiation that will be delivered to each structure is estimated prior to treatment. If the targets o...

放射治疗用于治疗全球癌症患者。高质量的治疗计划在最大限度地照射靶区的同时，最小限度地照射危及器官。为了判断计划的质量和安全性，需要创建靶区和危及器官的分割，并在治疗前估计每个结构将受到的辐射剂量。如果靶区...

More rapid and accurate high-throughput screening in molecular cellular biology research has become possible with the development of automated microscopy imaging, for which cell nucleus segmentation commonly constitutes the core step. Although several promising methods exist for segmenting the nuclei of monolayer isolated and less-confluent cells, it still remains an open problem to segment the nu...

随着自动显微镜成像技术的发展，分子细胞生物学研究中更快速、准确的高通量筛选成为可能，其中细胞核分割通常是核心步骤。尽管有几种有前景的方法可以分割单层分离和低融合细胞的细胞核，但分割...仍是一个未解决的问题。

In this paper a psychophysical experiment and a multidimensional scaling (MDS) analysis are undergone to determine the physical characteristics that physicians employ to diagnose a burn depth. Subsequently, these characteristics are translated into mathematical features, correlated with these physical characteristics analysis. Finally, a study to verify the ability of these mathematical features t...

本文通过心理物理实验和多维尺度分析（MDS）来确定医生用于诊断烧伤深度的物理特征。随后，将这些特征转化为数学特征，并与这些物理特征分析相关联。最后，进行了一项研究以验证这些数学特征的能力...

We investigate whether it is possible to use the bidomain model and body surface potential maps (BSPMs) to compute the size and position of ischemic regions in the human heart. This leads to a severely ill posed inverse problem for a potential equation. We do not use the classical inverse problems of electrocardiography, in which the unknown sources are the epicardial potential distribution or the...

我们研究是否可以使用双域模型和体表电位图（BSPM）来计算人类心脏中缺血区域的大小和位置。这导致了一个严重不适定的势方程逆问题。我们不使用经典的心电图逆问题，其中未知源是心外膜电位分布或...

The trade-off between signal-to-noise ratio (SNR) and spatial specificity governs the choice of spatial resolution in magnetic resonance imaging (MRI); diffusion-weighted (DW) MRI is no exception. Images of lower resolution have higher signal to noise ratio, but also more partial volume artifacts. We present a data-fusion approach for tackling this trade-off by combining DW MRI data acquired both ...

信号噪声比（SNR）与空间特异性之间的权衡决定了磁共振成像（MRI）中空间分辨率的选择；扩散加权（DW）MRI也不例外。较低分辨率的图像具有更高的信噪比，但也会产生更多的部分容积伪影。我们提出了一种数据融合方法，通过结合不同空间分辨率的DW MRI数据来解决这一权衡问题。

In optical coherence tomography (OCT) and ultrasound, unbiased Doppler frequency estimators with low variance are desirable for blood velocity estimation. Hardware improvements in OCT mean that ever higher acquisition rates are possible, which should also, in principle, improve estimation performance. Paradoxically, however, the widely used Kasai autocorrelation estimator's performance worsens wit...

在光学相干断层扫描(OCT)和超声中，低方差的无偏多普勒频率估计器对于血流速度估计是理想的。OCT硬件的改进意味着可实现更高的采集速率，原则上这也应能提高估计性能。然而，矛盾的是，广泛使用的Kasai自相关估计器的性能却随采集速率的提高而恶化...

Schistosomiasis is a parasitic disease with a global health impact second only to malaria. The World Health Organization has classified schistosomiasis as an illness for which new therapies are urgently needed. However, the causative parasite is refractory to current high-throughput drug screening due to the diversity and complexity of shape, appearance and movement-based phenotypes exhibited in r...

血吸虫病是一种寄生虫病，其全球健康影响仅次于疟疾。世界卫生组织已将其列为亟需新疗法的疾病。然而，由于病原体在形状、外观和运动表型上表现出多样性和复杂性，目前的通量药物筛选方法难以有效处理该寄生虫。

A coil design termed as broadside-coupled loop (BCL) coil and based on the broadside-coupled split ring resonator (BC-SRR) is proposed as an alternative to a conventional loop design at 7T. The BCL coil has an inherent uniform current which assures the rotational symmetry of the radio-frequency field around the coil axis. A comparative analysis of the signal-to-noise ratio provided by BCL coils an...

提出了一种称为边耦合环（BCL）线圈的线圈设计，它基于边耦合分裂环谐振器（BC-SRR），作为7T传统环设计的一种替代方案。BCL线圈具有固有的均匀电流，确保了射频场围绕线圈轴的旋转对称性。对BCL线圈提供的信噪比进行了比较分析...

Registration of histopathology to in vivo magnetic resonance imaging (MRI) of the prostate is an important task that can be used to optimize in vivo imaging for cancer detection. Such registration is challenging due to the change in volume and deformation of the prostate during excision and fixation. One approach towards this problem involves the use of an ex vivo MRI of the excised prostate speci...

组织病理学到前列腺在体磁共振成像（MRI）的配准是一项重要任务，可用于优化癌症检测的在体成像。由于切除和固定过程中前列腺体积和形状的变化，这种配准具有挑战性。解决该问题的一种方法涉及使用切除的前列腺标本的离体MRI...

Phantom measurements with glass inserts in a hot background are still used frequently for calibration and performance assessment of volume delineation algorithms in positron emission tomography (PET). Taking as an example the recent paper “Comparative study with new accuracy metrics for target volume contouring in PET image guided radiation therapy” (Shepherd, 2012), we demonstrate that this is no...

在正电子发射断层扫描（PET）中，使用热背景中的玻璃插件进行体模测量仍然常用于体积勾画算法的校准和性能评估。以近期论文《PET图像引导放射治疗中目标体积勾画新精度指标的对比研究》（Shepherd, 2012）为例，我们证明这不再...

This communication is submitted in response to the letter of van den Hoff and Hofheinz (2013). Based on findings in their earlier study (Hofheinz , 2010) the letter criticizes the use of a physical positron emission tomography (PET) phantom with “cold wall” volumes of interest, in part of the evaluation of PET segmentation tools in our experiment reported in this issue (Shepherd , 2012). In additi...

本通讯是对van den Hoff和Hofheinz（2013）来信的回复。该来信基于其早期研究（Hofheinz，2010）的结果，批评了在本期报道的实验中（Shepherd，2012），在评估PET分割工具的部分使用了带“冷壁”感兴趣区域的物理正电子发射断层扫描（PET）体模。此外...

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