Volume 36, Issue 9

Automatic skin lesion segmentation in dermoscopic images is a challenging task due to the low contrast between lesion and the surrounding skin, the irregular and fuzzy lesion borders, the existence of various artifacts, and various imaging acquisition conditions. In this paper, we present a fully automatic method for skin lesion segmentation by leveraging 19-layer deep convolutional neural networks that is trained end-to-end and does not rely on prior knowledge of the data. We propose a set of strategies to ensure effective and efficient learning with limited training data. Furthermore, we design a novel loss function based on Jaccard distance to eliminate the need of sample re-weighting, a typical procedure when using cross entropy as the loss function for image segmentation due to the strong imbalance between the number of foreground and background pixels. We evaluated the effectiveness, efficiency, as well as the generalization capability of the proposed framework on two publicly available databases. One is from ISBI 2016 skin lesion analysis towards melanoma detection challenge, and the other is the PH2 database. Experimental results showed that the proposed method outperformed other state-of-the-art algorithms on these two databases. Our method is general enough and only needs minimum pre- and post-processing, which allows its adoption in a variety of medical image segmentation tasks.

在皮肤镜图像中自动分割皮肤病变是一项具有挑战性的任务，因为病变与周围皮肤之间的对比度低，病变边界不规则且模糊，存在各种伪影以及不同的成像采集条件。本文提出了一种全自动的皮肤病变分割方法，利用19层深度卷积神经网络进行端到端训练，无需依赖数据的先验知识。我们提出了一系列策略，以确保在有限的训练数据下实现有效且高效的学习。此外，我们设计了一种基于Jaccard距离的新型损失函数，以消除样本重新加权的需要——在使用交叉熵作为图像分割损失函数时，由于前景和背景像素数量严重不平衡，通常需要进行样本重新加权。我们在两个公开数据库上评估了所提框架的有效性、效率以及泛化能力。一个来自ISBI 2016皮肤病变分析挑战赛（针对黑色素瘤检测），另一个是PH2数据库。实验结果表明，所提方法在这两个数据库上优于其他最先进的算法。我们的方法足够通用，只需要最少的预处理和后处理，因此可以应用于各种医学图像分割任务。

Angle-closure glaucoma is a major cause of irreversible visual impairment and can be identified by measuring the anterior chamber angle (ACA) of the eye. The ACA can be viewed clearly through anterior segment optical coherence tomography (AS-OCT), but the imaging characteristics and the shapes and locations of major ocular structures can vary significantly among different AS-OCT modalities, thus c...

闭角型青光眼是导致不可逆视力损伤的主要原因之一，可通过测量眼睛的前房角（ACA）进行识别。前段光学相干断层扫描（AS-OCT）可以清晰显示ACA，但不同AS-OCT模态的成像特征以及主要眼部结构的形状和位置可能存在显著差异，因此...

Recent advances in hyperspectral imaging have made it a promising solution for intra-operative tissue characterization, with the advantages of being non-contact, non-ionizing, and non-invasive. Working with hyperspectral images in vivo, however, is not straightforward as the high dimensionality of the data makes real-time processing challenging. In this paper, a novel dimensionality reduction sche...

高光谱成像的最新进展使其成为术中组织特征描述的一种有前景的解决方案，具有非接触、非电离和非侵入性的优点。然而，在体内使用高光谱图像并不简单，因为数据的高维度使得实时处理具有挑战性。在本文中，一种新颖的降维方案...

Optimal optoacoustic tomographic sampling is often hindered by the frequency-dependent directivity of ultrasound sensors, which can only be accounted for with an accurate 3-D model. Herein, we introduce a 3-D model-based reconstruction method applicable to optoacoustic imaging systems employing detection elements with arbitrary size and shape. The computational complexity and memory requirements a...

最佳的光声断层扫描采样常常受到超声传感器频率相关指向性的阻碍，而只有精确的三维模型才能考虑这一点。本文提出了一种适用于采用任意大小和形状检测元件的光声成像系统的三维模型重建方法。计算复杂度和内存需求...

Imaging that fuses multiple modes has become a useful tool for diagnosis and therapeutic monitoring. As a next step, real-time fusion imaging has attracted interest as for a tool to guide surgery. One widespread fusion imaging technique in surgery combines real-time ultrasound (US) imaging and pre-acquired magnetic resonance (MR) imaging. However, US imaging visualizes only structural information ...

融合多种模态的成像已成为诊断和治疗监测的有用工具。作为下一步，实时融合成像作为引导手术的工具引起了兴趣。手术中一种广泛应用的融合成像技术结合了实时超声（US）成像和预先获取的磁共振（MR）成像。然而，超声成像仅能显示结构信息……

The proposed spectral CT method solves the constrained one-step spectral CT reconstruction (cOSSCIR) optimization problem to estimate basis material maps while modeling the nonlinear X-ray detection process and enforcing convex constraints on the basis map images. In order to apply the optimization-based reconstruction approach to experimental data, the presented method empirically estimates the e...

所提出的光谱CT方法解决了约束一步光谱CT重建（cOSSCIR）优化问题，在建模非线性X射线检测过程并对基图图像施加凸约束的同时，估计基材料图。为了将基于优化的重建方法应用于实验数据，所提出的方法经验性地估计了电子...

Wireless capsule endoscopy has opened a new era by enabling remote diagnostic assessment of the gastrointestinaltract in a painless procedure. Video capsule endoscopy is currently commercially available worldwide. However, it is limited to visualization of superficial tissue. Ultrasound (US) imaging is a complementary solution as it is capable of acquiring transmural information from the tissue wa...

无线胶囊内窥镜通过无痛过程实现对胃肠道的远程诊断评估，开启了新时代。视频胶囊内窥镜目前已在全球范围内商业化。然而，它仅限于浅表组织的可视化。超声（US）成像是一种互补的解决方案，因为它能够获取组织的跨壁信息……

Sequential dictionary learning algorithms have been successfully applied to functional magnetic resonance imaging (fMRI) data analysis. fMRI data sets are, however, structured data matrices with the notions of temporal smoothness in the column direction. This prior information, which can be converted into a constraint of smoothness on the learned dictionary atoms, has seldomly been included in cla...

序贯字典学习算法已成功应用于功能磁共振成像（fMRI）数据分析。然而，fMRI数据集是结构化数据矩阵，具有列方向上的时间平滑性概念。这种先验信息可以转化为对学习到的字典原子的平滑性约束，但很少被包含在经典...

Conventional Doppler ultrasound is useful for visualizing fast blood flow in large resolvable vessels. However, frame rate and tissue clutter caused by movement of the patient or sonographer make visualizing slow flow with ultrasound difficult. Patient and sonographer motion causes spectral broadening of the clutter signal, which limits ultrasound's sensitivity to velocities greater than 5-10 mm/s...

传统的多普勒超声有助于可视化大血管中快速的血流。然而，由于患者或超声医师运动引起的帧率和组织杂波，使得用超声可视化缓慢的血流变得困难。患者和超声医师的运动会导致杂波信号的频谱展宽，从而限制了超声对速度大于5-10毫米/秒的血流的灵敏度...

In image-guided interventional procedures, live 2-D X-ray images can be augmented with preoperative 3-D computed tomography or MRI images to provide planning landmarks and enhanced spatial perception. An accurate alignment between the 3-D and 2-D images is a prerequisite for fusion applications. This paper presents a dynamic rigid 2-D/3-D registration framework, which measures the local 3-D-to-2-D...

在图像引导介入手术中，实时二维X射线图像可以与术前三维计算机断层扫描或MRI图像相结合，以提供规划标志和增强的空间感知。三维与二维图像之间的精确对准是融合应用的先决条件。本文提出了一种动态刚性2-D/3-D配准框架，该框架测量局部3-D到2-D...

Prediction of treatment responses from available data is key to optimizing personalized treatment. Retinal diseases are treated over long periods and patients’ response patterns differ substantially, ranging from a complete response to a recurrence of the disease and need for re-treatment at different intervals. Linking observable variables in high-dimensional observations to outcome is challengin...

从可用数据预测治疗反应是个性化治疗优化的关键。视网膜疾病的治疗周期长，患者的反应模式差异很大，从完全反应到疾病复发并在不同间隔需要再次治疗。将高维观测数据中的可观测变量与结果联系起来具有挑战性……

A real-time implementation of Calderón's method for the reconstruction of a 2-D conductivity from electrical impedance tomography data is presented, in which domain-specific modeling is taken into account. This is the first implementation of Calderón's method that accounts for correct modeling of non-symmetric domain boundaries in image reconstruction. The domain-specific Calderón's method is deri...

本文提出了卡尔德隆方法的一种实时实现，用于从电阻抗断层成像数据重建二维电导率，其中考虑了特定域建模。这是第一次在图像重建中考虑非对称域边界正确建模的卡尔德隆方法实现。域特定卡尔德隆方法推导...

To obtain a patient-specific cardiac electro-physiological (EP) model, it is important to estimate the 3-D distributed tissue properties of the myocardium. Ideally, the tissue property should be estimated at the resolution of the cardiac mesh. However, such high-dimensional estimation faces major challenges in identifiability and computation. Most existing works reduce this dimension by partitioni...

为了获得患者特异性心脏电生理模型，估计心肌的三维分布组织特性非常重要。理想情况下，组织特性应以心脏网格的分辨率进行估计。然而，这种高维估计在可识别性和计算方面面临重大挑战。大多数现有工作通过分区来降低这一维度...

While plane-wave imaging can improve the performance of power Doppler by enabling much longer ensembles than systems using focused beams, the long-ensemble averaging of the zero-lag autocorrelation R(0) estimates does not directly decrease the mean noise level, but only decreases its variance. Spatial variation of the noise due to the time-gain compensation and the received beamforming aperture ul...

虽然平面波成像可以通过使用比聚焦波束系统更长的序列来提高功率多普勒的性能，但零延迟自相关R(0)估计的长序列平均并不能直接降低平均噪声水平，而只能降低其方差。由于时间增益补偿和接收波束形成孔径导致的空间噪声变化...

Contrast-enhanced digital mammography (CEDM) is an alternative to conventional X-ray mammography for imaging dense breasts. However, conventional approaches to CEDM require a double exposure of the patient, implying higher dose, and risk of incorrect image registration due to motion artifacts. A novel approach is presented, based on hyperspectral imaging, where a detector combining positional and ...

对比增强数字乳腺摄影（CEDM）是传统X射线乳腺摄影用于致密乳腺成像的替代方法。然而，传统的CEDM方法需要患者进行两次曝光，这意味着更高的剂量，以及由于运动伪影导致的图像配准错误风险。提出了一种基于高光谱成像的新方法，其中结合位置和...

Measurement and analysis of bone morphometry in 3D micro-computed tomography volumes using automated image processing and analysis improve the accuracy, consistency, reproducibility, and speed of preclinical osteological research studies. Automating segmentation and separation of individual bones in 3D microcomputed tomography volumes of murine models presents significant challenges considering pa...

使用自动图像处理和分析在三维显微计算机断层扫描体积中测量和分析骨骼形态测量，提高了临床前骨学研究的准确性、一致性、可重复性和速度。自动分割和分离小鼠模型三维显微计算机断层扫描体积中的个体骨骼面临着重大挑战，考虑到...

The objective of electrical impedance tomographic reconstruction is to identify the distribution of tissue conductivity from electrical boundary conditions. This is an ill-posed inverse problem usually solved under the finite-element method framework. In previous studies, standard sparse regularization was used for difference electrical impedance tomography to achieve a sparse solution. However, r...

电阻抗断层重建的目标是从电边界条件识别组织电导率的分布。这是一个不适定逆问题，通常在有限元方法框架下求解。在以往的研究中，标准稀疏正则化用于差分电阻抗断层扫描以获得稀疏解。然而，...

It is essential for physicians to obtain the accurate venous tree from abdominal CT angiography (CTA) series in order to carry out the preoperative planning and intraoperative navigation for hepatic surgery. In this process, one of the important tasks is to separate the given liver venous mask into its hepatic and portal parts. In this paper, we present a novel method for liver venous tree separat...

为了进行肝脏手术的术前规划和术中导航，医生需要从腹部CT血管造影（CTA）序列中获取准确的静脉树。在此过程中，一项重要任务是将给定的肝脏静脉掩膜分离为肝静脉和门静脉部分。本文提出了一种新颖的肝脏静脉树分离方法……

High-resolution, low-noise X-ray detectors based on CMOS active pixel sensor (APS) technology have demonstrated superior imaging performance for digital breast tomosynthesis (DBT). This paper presents a task-based model for a high-resolution medical imaging system to evaluate its ability to detect simulated microcalcifications and masses as lesions for breast cancer. A 3-D cascaded system analysis...

基于CMOS有源像素传感器（APS）技术的高分辨率、低噪声X射线探测器已在数字乳腺断层合成（DBT）中展现出卓越的成像性能。本文提出了一个用于高分辨率医学成像系统的任务驱动模型，以评估其检测乳腺癌模拟微钙化和肿块作为病变的能力。采用了3D级联系统分析...

In the above-title paper [ibid., vol. 36, no. 6, pp. 1221-1230, Jun. 2017], the first footnote should have indicated the following information: A. H. Abdi and C. Luong are joint first authors.

在上述标题的论文[同上，第36卷，第6期，第1221-1230页，2017年6月]中，第一个脚注应注明以下信息：A. H. Abdi和C. Luong为共同第一作者。

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