Volume 33, Issue 2

Tuberculosis is a major health threat in many regions of the world. Opportunistic infections in immunocompromised HIV/AIDS patients and multi-drug-resistant bacterial strains have exacerbated the problem, while diagnosing tuberculosis still remains a challenge. When left undiagnosed and thus untreated, mortality rates of patients with tuberculosis are high. Standard diagnostics still rely on methods developed in the last century. They are slow and often unreliable. In an effort to reduce the burden of the disease, this paper presents our automated approach for detecting tuberculosis in conventional posteroanterior chest radiographs. We first extract the lung region using a graph cut segmentation method. For this lung region, we compute a set of texture and shape features, which enable the X-rays to be classified as normal or abnormal using a binary classifier. We measure the performance of our system on two datasets: a set collected by the tuberculosis control program of our local county's health department in the United States, and a set collected by Shenzhen Hospital, China. The proposed computer-aided diagnostic system for TB screening, which is ready for field deployment, achieves a performance that approaches the performance of human experts. We achieve an area under the ROC curve (AUC) of 87% (78.3% accuracy) for the first set, and an AUC of 90% (84% accuracy) for the second set. For the first set, we compare our system performance with the performance of radiologists. When trying not to miss any positive cases, radiologists achieve an accuracy of about 82% on this set, and their false positive rate is about half of our system's rate.

结核病在全球许多地区构成重大健康威胁。免疫功能低下的HIV/AIDS患者中的机会性感染以及耐多药菌株加剧了这一问题，而结核病的诊断仍然具有挑战性。一旦未确诊因而未治疗，结核病患者的死亡率很高。标准诊断仍依赖于上世纪开发的方法，这些方法缓慢且常常不可靠。为减轻疾病负担，本文提出了一种在常规后前位胸部X光片中自动检测结核病的方法。我们首先使用图割分割方法提取肺部区域。针对该肺部区域，我们计算一组纹理和形状特征，从而使用二元分类器将X光片分为正常或异常。我们在两个数据集上测量系统的性能：一组由美国本地县卫生部门的结核病控制项目收集，另一组由中国深圳医院收集。所提出的用于结核病筛查的计算机辅助诊断系统已准备好进行现场部署，其性能接近人类专家的水平。我们在第一个数据集上实现了ROC曲线下面积（AUC）87%（准确率78.3%），在第二个数据集上实现了AUC 90%（准确率84%）。对于第一个数据集，我们将系统性能与放射科医生的性能进行了比较。在不遗漏任何阳性病例的情况下，放射科医生在该数据集上的准确率约为82%，其假阳性率约为我们系统的一半。

The National Library of Medicine (NLM) is developing a digital chest X-ray (CXR) screening system for deployment in resource constrained communities and developing countries worldwide with a focus on early detection of tuberculosis. A critical component in the computer-aided diagnosis of digital CXRs is the automatic detection of the lung regions. In this paper, we present a nonrigid registration-driven robust lung segmentation method using image retrieval-based patient specific adaptive lung models that detects lung boundaries, surpassing state-of-the-art performance. The method consists of three main stages: 1) a content-based image retrieval approach for identifying training images (with masks) most similar to the patient CXR using a partial Radon transform and Bhattacharyya shape similarity measure, 2) creating the initial patient-specific anatomical model of lung shape using SIFT-flow for deformable registration of training masks to the patient CXR, and 3) extracting refined lung boundaries using a graph cuts optimization approach with a customized energy function. Our average accuracy of 95.4% on the public JSRT database is the highest among published results. A similar degree of accuracy of 94.1% and 91.7% on two new CXR datasets from Montgomery County, MD, USA, and India, respectively, demonstrates the robustness of our lung segmentation approach.

美国国家医学图书馆（NLM）正在开发一种数字胸部X光（CXR）筛查系统，用于资源受限的社区和发展中国家，重点关注结核病的早期检测。在数字CXR的计算机辅助诊断中，自动检测肺部区域是一个关键组成部分。本文提出了一种非刚性配准方法...

Validation is arguably the bottleneck in the diffusion magnetic resonance imaging (MRI) community. This paper evaluates and compares 20 algorithms for recovering the local intra-voxel fiber structure from diffusion MRI data and is based on the results of the “HARDI reconstruction challenge” organized in the context of the “ISBI 2012” conference. Evaluated methods encompass a mixture of classical t...

验证可以说是扩散磁共振成像（MRI）领域的瓶颈。本文评估并比较了20种从扩散MRI数据中恢复局部体素内纤维结构的算法，基于在“ISBI 2012”会议背景下组织的“HARDI重建挑战”的结果。评估的方法涵盖了经典混合...

Multifrequency electrical impedance tomography (MFEIT) exploits the dependence of tissue impedance on frequency to recover an image of conductivity. MFEIT could provide emergency diagnosis of pathologies such as acute stroke, brain injury and breast cancer. We present a method for performing MFEIT using spectral constraints. Boundary voltage data is employed directly to reconstruct the volume frac...

多频电阻抗断层成像利用组织阻抗随频率变化的特性来重建电导率图像。该方法可应用于急性中风、脑损伤和乳腺癌等疾病的紧急诊断。我们提出了一种使用频谱约束进行多频电阻抗断层成像的方法。边界电压数据直接用于重建体积分数...

Most 3-D magnetic particle imaging (MPI) scanners currently use permanent magnets to create the strong gradient field required for high resolution MPI. However, using permanent magnets limits the field of view (FOV) due to the large amount of energy required to move the field free point (FFP) from the center of the scanner. To address this issue, an alternative approach called “Traveling Wave MPI”...

大多数三维磁粒子成像（MPI）扫描仪目前使用永磁体来产生高分辨率MPI所需的强梯度场。然而，使用永磁体限制了视场（FOV），因为将场自由点（FFP）从扫描仪中心移动需要大量能量。为了解决这个问题，一种称为“行波MPI”的替代方法...

This paper presents an approach to 3-D diffusion tensor image (DTI) reconstruction from multi-slice diffusion weighted (DW) magnetic resonance imaging acquisitions of the moving fetal brain. Motion scatters the slice measurements in the spatial and spherical diffusion domain with respect to the underlying anatomy. Previous image registration techniques have been described to estimate the between s...

本文提出了一种方法，用于从移动胎儿脑部的多层扩散加权磁共振成像采集中进行三维扩散张量图像重建。运动使切片测量在空间和球面扩散域中相对于底层解剖结构发生散射。先前已描述了图像配准技术来估计帧间...

13C steady state free precession (SSFP) magnetic resonance imaging and effective spin-spin relaxation time (T2) mapping were performed using hyperpolarized [13C] urea and [13 C,15N2] urea injected intravenously in rats. 15N labeling gave large T2 increases both in solution and in vivo due to the elimination of a strong scalar relaxation pathway. The T2 increase was pronounced in the kidney, with [...

利用超极化[13C]尿素和[13C,15N2]尿素对大鼠进行静脉注射，进行了13C稳态自由进动（SSFP）磁共振成像和有效自旋-自旋弛豫时间（T2）映射。由于消除了强标量弛豫途径，15N标记在溶液和体内均导致T2显著增加。在肾脏中T2增加尤为明显，[...]

Automating the detection and localization of segmental (regional) left ventricle (LV) abnormalities in magnetic resonance imaging (MRI) has recently sparked an impressive research effort, with promising performances and a breadth of techniques. However, despite such an effort, the problem is still acknowledged to be challenging, with much room for improvements in regard to accuracy. Furthermore, m...

近来，利用磁共振成像自动检测和定位左心室节段性（区域性）异常引起了显著的研究努力，展示了有前景的性能和广泛的技术。然而，尽管付出了这样的努力，该问题仍被认为具有挑战性，在准确性方面仍有很大的改进空间。此外，...

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of the breast has become an invaluable tool in the clinical work-up of patients suspected of having breast carcinoma. The purpose of this study is to introduce novel features extracted from the kinetics of contrast agent uptake imaged by a short (100 s) view-sharing MRI protocol, and to investigate how these features measure up to comm...

乳腺的动态对比增强磁共振成像（DCE-MRI）已成为临床评估疑似乳腺癌患者的重要工具。本研究的目的是引入从短时间（100秒）视图共享MRI协议成像的对比剂摄取动力学中提取的新特征，并研究这些特征如何与常规...

This paper describes a novel 3-D segmentation technique posed within the Random Forests (RF) classification framework. Two improvements over the traditional RF framework are considered. Motivated by the high redundancy of feature selection in the traditional RF framework, the first contribution develops methods to improve voxel classification by selecting relatively “strong” features and neglectin...

本文提出了一种基于随机森林分类框架的新颖3D分割技术。考虑了传统随机森林框架的两个改进。鉴于传统随机森林中特征选择的高度冗余性，第一个贡献是开发了通过选择相对“强”特征来改进体素分类的方法，并忽略了...

Population analysis of brain morphology from magnetic resonance images contributes to the study and understanding of neurological diseases. Such analysis typically involves segmentation of a large set of images and comparisons of these segmentations between relevant subgroups of images (e.g., “normal” versus “diseased”). The images of each subgroup are usually selected in advance in a supervised w...

从磁共振图像进行脑形态学的人群分析有助于研究和理解神经系统疾病。这种分析通常涉及大量图像的分割以及这些分割在相关图像亚组（例如“正常”与“患病”）之间的比较。每个亚组的图像通常以监督方式预先选择。

SPIRiT (iterative self-consistent parallel imaging reconstruction), and its sparsity-regularized variant ${\rm L}_{1}$-SPIRiT, are compatible with both Cartesian and non-Cartesian magnetic resonance imaging sampling trajectories. However, the non-Cartesian framework is more expensive computationally, involving a nonuniform Fourier transform with a nontrivial Gram matrix. We propose a novel impleme...

SPIRiT（迭代自一致并行成像重建）及其稀疏正则化变体 L1-SPIRiT 与笛卡尔和非笛卡尔磁共振成像采样轨迹兼容。然而，非笛卡尔框架计算成本更高，涉及具有非平凡 Gram 矩阵的非均匀傅里叶变换。我们提出了一种新的实现...

Most lung nodules that are missed by radiologists as well as computer-aided detection (CADe) schemes overlap with ribs or clavicles in chest radiographs (CXRs). The purpose of this study was to separate bony structures such as ribs and clavicles from soft tissue in CXRs. To achieve this, we developed anatomically specific multiple massive-training artificial neural networks (MTANNs) combined with ...

大多数被放射科医生以及计算机辅助检测（CADe）方案遗漏的肺结节在胸部X光片（CXR）中与肋骨或锁骨重叠。本研究的目的是从CXR的软组织中分离出诸如肋骨和锁骨等骨性结构。为了实现这一点，我们开发了解剖特异性多大规模训练人工神经网络（MTANN），并结合了...

In oncological chemotherapy monitoring, the change of a tumor's size is an important criterion for assessing cancer therapeutics. Measuring the volume of a tumor requires its delineation in 3-D. This is called segmentation, which is an intensively studied problem in medical image processing. However, simply counting the voxels within a binary segmentation result can lead to significant differences...

在肿瘤化疗监测中，肿瘤大小的变化是评估癌症治疗效果的重要指标。测量肿瘤体积需要对其进行三维勾画，这称为分割，是医学图像处理中一个被广泛研究的问题。然而，仅计算二值分割结果中的体素可能导致显著差异...

Optoacoustic (photoacoustic) imaging uniquely visualizes optical contrast in high resolution and comes with very attractive characteristics for clinical imaging applications. In this paper, we showcase the performance of a scanner based on a 24 MHz center-frequency 128 element array, developed for applications in dermatology. We perform system characterization to examine the imaging performance ac...

光声（光声）成像独特地以高分辨率可视化光学对比度，并具有非常吸引人的临床成像应用特性。本文展示了一种基于24 MHz中心频率128元阵列的扫描仪的性能，该扫描仪专为皮肤科应用而开发。我们进行系统表征以检查成像性能。

As a minimally invasive surgery to treat atrial fibrillation (AF), catheter based ablation uses high radio-frequency energy to eliminate potential sources of abnormal electrical events, especially around the ostia of pulmonary veins (PV). Fusing a patient-specific left atrium (LA) model (including LA chamber, appendage, and PVs) with electro-anatomical maps or overlaying the model onto 2-D real-ti...

作为治疗房颤（AF）的微创手术，导管消融使用高频射频能量消除异常电活动潜在来源，尤其是肺静脉（PV）开口周围。将患者特异性左心房（LA）模型（包括LA腔、心耳和PV）与电解剖图融合，或将模型叠加到二维实时...

Image quality in 3-D optoacoustic (photoacoustic) tomography is greatly influenced by both the measurement system, in particular the number and spatial arrangement of ultrasound sensors, and the ability to account for the spatio-temporal response of the sensor element(s) in the reconstruction algorithm. Herein we present a reconstruction procedure based on the inversion of a time-domain forward mo...

三维光声（光声）断层扫描的图像质量受到测量系统（特别是超声传感器的数量和空间排列）以及重建算法中考虑传感器元件时空响应的能力的显著影响。本文提出了一种基于时域前向模型反演的重建程序...

We address the problem of segmenting high angular resolution diffusion imaging (HARDI) data into multiple regions (or fiber tracts) with distinct diffusion properties. We use the orientation distribution function (ODF) to model diffusion and cast the ODF segmentation problem as a clustering problem in the space of ODFs. Our approach integrates tools from sparse representation theory and Riemannian...

我们解决了将高角分辨率扩散成像（HARDI）数据分割成具有不同扩散特性的多个区域（或纤维束）的问题。我们使用方向分布函数（ODF）来建模扩散，并将ODF分割问题转化为ODF空间中的聚类问题。我们的方法结合了稀疏表示理论和黎曼几何的工具...

Diffusion tensor imaging (DTI) is unable to represent the diffusion signal arising from multiple crossing fascicles and freely diffusing water molecules. Generative models of the diffusion signal, such as multi-fascicle models, overcome this limitation by providing a parametric representation for the signal contribution of each population of water molecules. These models are of great interest in p...

弥散张量成像（DTI）无法表示来自多个交叉纤维束和自由扩散水分子的扩散信号。扩散信号的生成模型，如多束模型，通过为每个水分子群体的信号贡献提供参数化表示，克服了这一局限性。这些模型在群体研究中对脑微结构的分析具有重要价值……

This work presents the results of a new tool for 3-D segmentation, quantification and visualization of cardiac left atrium fibrosis, based on late gadolinium enhancement magnetic resonance imaging (LGE-MRI), for stratifying patients with atrial fibrillation (AF) that are candidates for radio-frequency catheter ablation. In this study 10 consecutive patients suffering AF with different grades of at...

本研究展示了一种基于晚期钆增强磁共振成像（LGE-MRI）的新型工具，用于三维分割、量化和可视化心脏左心房纤维化，以对接受射频导管消融治疗的房颤（AF）患者进行分层。本研究包括10名连续患有不同级别房颤的患者...

We present a lesion detection and characterization method for 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) images of the thorax in the evaluation of patients with primary nonsmall cell lung cancer (NSCLC) with regional nodal disease. Lesion detection can be difficult due to low contrast between lesions and normal anatomical structures. Lesion characterizatio...

我们提出了一种用于原发性非小细胞肺癌（NSCLC）伴区域淋巴结病变患者评估的胸腔18F-氟脱氧葡萄糖正电子发射断层扫描-计算机断层扫描（FDG PET-CT）图像的病变检测与表征方法。由于病变与正常解剖结构之间的低对比度，病变检测可能很困难。病变表征...

We present a novel method of hierarchical manifold learning which aims to automatically discover regional properties of image datasets. While traditional manifold learning methods have become widely used for dimensionality reduction in medical imaging, they suffer from only being able to consider whole images as single data points. We extend conventional techniques by additionally examining local ...

我们提出了一种新颖的分层流形学习方法，旨在自动发现图像数据集的区域特性。虽然传统的流形学习方法已广泛应用于医学影像的降维，但它们只能将整幅图像视为单个数据点。我们通过额外考察局部...来扩展传统技术。

The aim of this work is the evaluation of the design for a nonconventional PET scanner, the voxel imaging PET (VIP), based on pixelated room-temperature CdTe detectors yielding a true 3-D impact point with a density of 450 ${\hbox {channels}}/{\hbox {cm}}^{3}$ , for a total 6 336 000 channels in a seamless ring shaped volume. The system is simulated and evaluated following the prescriptions of the...

本工作的目的是评估一种非常规PET扫描仪——体素成像PET（VIP）的设计，该扫描仪基于像素化的室温CdTe探测器，能够以450通道/cm³的密度提供真正的三维撞击点，在无缝环形体积内共有6,336,000个通道。系统按照...的规定进行模拟和评估。

Image-guided radiotherapy (IGRT) requires fast and accurate localization of the prostate in 3-D treatment-guided radiotherapy, which is challenging due to low tissue contrast and large anatomical variation across patients. On the other hand, the IGRT workflow involves collecting a series of computed tomography (CT) images from the same patient under treatment. These images contain valuable patient...

图像引导放疗需要快速准确地在三维治疗引导放疗中定位前列腺，由于组织对比度低和患者间解剖变异大，这具有挑战性。另一方面，IGRT工作流程包括收集同一患者治疗过程中的一系列计算机断层扫描(CT)图像。这些图像包含有价值的患者...

We compare the theoretical limits of iodine quantification for the photon counting multibin and dual energy technologies. Dual energy systems by necessity have to make prior assumptions in order to quantify iodine. We explicitly allow the multibin system to make the same assumptions and also allow them to be wrong. We isolate the effect of technology from imperfections and implementation issues by...

我们比较了光子计数多能谱和双能技术用于碘定量的理论极限。双能系统必须做出先验假设才能定量碘。我们明确允许多能谱系统做出相同的假设，并且允许这些假设是错误的。我们通过将技术效应与不完美和实施问题隔离开来...