Volume 38, Issue 1

Accelerating the data acquisition of dynamic magnetic resonance imaging leads to a challenging ill-posed inverse problem, which has received great interest from both the signal processing and machine learning communities over the last decades. The key ingredient to the problem is how to exploit the temporal correlations of the MR sequence to resolve aliasing artifacts. Traditionally, such observation led to a formulation of an optimization problem, which was solved using iterative algorithms. Recently, however, deep learning-based approaches have gained significant popularity due to their ability to solve general inverse problems. In this paper, we propose a unique, novel convolutional recurrent neural network architecture which reconstructs high quality cardiac MR images from highly undersampled k-space data by jointly exploiting the dependencies of the temporal sequences as well as the iterative nature of the traditional optimization algorithms. In particular, the proposed architecture embeds the structure of the traditional iterative algorithms, efficiently modeling the recurrence of the iterative reconstruction stages by using recurrent hidden connections over such iterations. In addition, spatio–temporal dependencies are simultaneously learnt by exploiting bidirectional recurrent hidden connections across time sequences. The proposed method is able to learn both the temporal dependence and the iterative reconstruction process effectively with only a very small number of parameters, while outperforming current MR reconstruction methods in terms of reconstruction accuracy and speed.

加速动态磁共振成像的数据采集导致了一个具有挑战性的病态逆问题，这在过去几十年中引起了信号处理和机器学习社区的极大兴趣。该问题的关键是如何利用MR序列的时间相关性来消除混叠伪影。传统上，这种观察导致了优化问题的公式化，并通过迭代算法求解。然而，近年来，基于深度学习的方法因其解决一般逆问题的能力而获得了显著的普及。在本文中，我们提出了一种独特的、新颖的卷积递归神经网络架构，该架构通过联合利用时间序列的依赖性和传统优化算法的迭代性质，从高度欠采样的k空间数据中重建高质量的心脏MR图像。特别地，所提出的架构嵌入了传统迭代算法的结构，通过在这些迭代中使用递归隐藏连接有效地模拟了迭代重建阶段的循环性。此外，通过利用跨时间序列的双向递归隐藏连接同时学习时空依赖性。所提出的方法能够以非常少的参数有效学习时间依赖性和迭代重建过程，同时在重建精度和速度方面优于当前的MR重建方法。

Undersampled magnetic resonance image (MRI) reconstruction is typically an ill-posed linear inverse task. The time and resource intensive computations require tradeoffs between accuracy and speed. In addition, state-of-the-art compressed sensing (CS) analytics are not cognizant of the image diagnostic quality. To address these challenges, we propose a novel CS framework that uses generative advers...

欠采样磁共振图像重建通常是一个不适定的线性逆问题。时间和资源密集型的计算需要在准确性和速度之间进行权衡。此外，最先进的压缩感知分析并不考虑图像的诊断质量。为了解决这些挑战，我们提出了一种新颖的压缩感知框架，该框架使用生成对抗...

Volumetric lung tumor segmentation and accurate longitudinal tracking of tumor volume changes from computed tomography images are essential for monitoring tumor response to therapy. Hence, we developed two multiple resolution residually connected network (MRRN) formulations called incremental-MRRN and dense-MRRN. Our networks simultaneously combine features across multiple image resolution and fea...

从CT图像中分割体积肺肿瘤并准确跟踪肿瘤体积变化对于监测肿瘤治疗反应至关重要。因此，我们开发了两种多分辨率残差连接网络（MRRN）公式，称为增量MRRN和密集MRRN。我们的网络同时结合了多个图像分辨率和特征...

Automated whole breast ultrasound (ABUS) has been widely used as a screening modality for examination of breast abnormalities. Reviewing hundreds of slices produced by ABUS, however, is time consuming. Therefore, in this paper, a fast and effective computer-aided detection system based on 3-D convolutional neural networks (CNNs) and prioritized candidate aggregation is proposed to accelerate this ...

自动全乳超声（ABUS）已被广泛用作检查乳腺异常的筛查方式。然而，回顾ABUS产生的数百张切片非常耗时。因此，本文提出一种基于3D卷积神经网络（CNN）和优先候选聚合的快速有效的计算机辅助检测系统，以加速这一过程...

Contemporary endoscopic simultaneous localization and mapping (SLAM) methods accurately compute endoscope poses; however, they only provide a sparse 3-D reconstruction that poorly describes the surgical scene. We propose a novel dense SLAM method whose qualities are: 1) monocular, requiring only RGB images of a handheld monocular endoscope; 2) fast, providing endoscope positional tracking and 3-D ...

当代内窥镜同步定位与地图构建（SLAM）方法能够精确计算内窥镜姿态，然而它们仅提供稀疏的三维重建，无法充分描述手术场景。我们提出了一种新颖的密集SLAM方法，其特点包括：1）单目，仅需手持单目内窥镜的RGB图像；2）快速，提供内窥镜位置追踪和三维...

Retinopathy of Prematurity (ROP) is a retinal vasproliferative disorder disease principally observed in infants born prematurely with low birth weight. ROP is an important cause of childhood blindness. Although automatic or semi-automatic diagnosis of ROP has been conducted, most previous studies have focused on “plus” disease, which is indicated by abnormalities of retinal vasculature. Few studie...

早产儿视网膜病变（ROP）是一种主要发生在早产低出生体重婴儿中的视网膜血管增生性疾病。ROP是儿童失明的重要原因。尽管已经进行了ROP的自动或半自动诊断，但大多数先前的研究集中在“plus”病上，该病由视网膜血管异常指示。少数研究...

Volumetric ultrasound is rapidly emerging as a viable imaging modality for routine prenatal examinations. Biometrics obtained from the volumetric segmentation shed light on the reformation of precise maternal and fetal health monitoring. However, the poor image quality, low contrast, boundary ambiguity, and complex anatomy shapes conspire toward a great lack of efficient tools for the segmentation...

容积超声正迅速成为常规产前检查的一种可行成像方式。从容积分割中获得的生物特征为精确的母胎健康监测提供了新的视角。然而，图像质量差、对比度低、边界模糊以及复杂的解剖形状导致严重缺乏高效的切割工具……

We focus on the practical challenge of segmenting new retinal fundus images that are dissimilar to existing well-annotated data sets. It is addressed in this paper by a supervised learning pipeline, with its core being the construction of a synthetic fundus image data set using the proposed R-sGAN technique. The resulting synthetic images are realistic-looking in terms of the query images while ma...

我们聚焦于分割与现有标注数据集不相似的新视网膜眼底图像的实际挑战。本文通过一个监督学习流程来解决这一问题，其核心是使用提出的R-sGAN技术构建合成眼底图像数据集。生成的合成图像在查询图像方面看起来逼真，同时...

Pulmonary fissure detection in computed tomography (CT) is a critical component for automatic lobar segmentation. The majority of fissure detection methods use feature descriptors that are hand-crafted, low-level, and have local spatial extent. The design of such feature detectors is typically targeted toward normal fissure anatomy, yielding low sensitivity to weak, and abnormal fissures that are ...

计算机断层扫描（CT）中的肺裂检测是自动肺叶分割的关键组成部分。大多数肺裂检测方法使用手工制作的低级特征描述符，且空间范围局限。这些特征检测器的设计通常针对正常肺裂解剖结构，导致对微弱和异常肺裂的灵敏度较低，这些肺裂...

Many medical image segmentation methods are based on the supervised classification of voxels. Such methods generally perform well when provided with a training set that is representative of the test images to the segment. However, problems may arise when training and test data follow different distributions, for example, due to differences in scanners, scanning protocols, or patient groups. Under ...

许多医学图像分割方法基于体素的监督分类。当提供代表待分割测试图像的训练集时，此类方法通常表现良好。然而，当训练数据和测试数据遵循不同分布时，例如由于扫描仪、扫描协议或患者群体的差异，可能会出现问题。在...

In this paper, we present the first proof of concept confirming the possibility to record magnetoencephalographic (MEG) signals with optically pumped magnetometers (OPMs) based on the parametric resonance of 4He atoms. The main advantage of this kind of OPM is the possibility to provide a tri-axis vector measurement of the magnetic field at room-temperature (the 4He vapor is neither cooled nor hea...

本文提出了首个概念验证，证实了基于4He原子参数共振的光泵磁力计（OPM）记录脑磁图（MEG）信号的可能性。此类OPM的主要优点是在室温下提供磁场的三轴矢量测量（4He蒸气既不冷却也不加热...）

This paper presents a novel difference imaging approach based on the recently developed parametric level set (PLS) method for estimating the change in a target conductivity from electrical impedance tomography measurements. As in conventional difference imaging, the reconstruction of conductivity change is based on data sets measured from the surface of a body before and after the change. The key ...

本文提出了一种基于最近发展的参数水平集（PLS）方法的差分成像新方法，用于从电阻抗断层成像测量中估计目标电导率的变化。与传统的差分成像一样，电导率变化的重建基于变化前后从物体表面测量的数据集。关键...

Acoustic-resolution photoacoustic microscopy (AR-PAM) is a promising technology for vascular or tumor-targeted molecular imaging. Unique advantages of AR-PM are its non-invasive, non-ionizing real-time, and deeper imaging depth. AR-PAM typically uses an ultrasound transducer with a high acoustic numerical aperture (NA) to enable deeper imaging depth. While high NA achieves good lateral resolution ...

声分辨率光声显微成像（AR-PAM）是一种用于血管或肿瘤靶向分子成像的有前景的技术。AR-PAM的独特优势在于其无创、无电离、实时以及更深的成像深度。AR-PAM通常使用具有高声学数值孔径（NA）的超声换能器以实现更深的成像深度。虽然高NA可以实现良好的横向分辨率……

Many new clinical investigations of microwave breast imaging have been published in recent years. Trials with over one hundred participants have indicated the potential of microwave imaging to detect breast cancer, with particularly encouraging sensitivity results reported from women with dense breasts. The next phase of clinical trials will involve larger and more diverse populations, including w...

近年来，许多新的微波乳腺成像临床研究已发表。涉及超过一百名参与者的试验表明，微波成像检测乳腺癌的潜力，特别是在致密乳腺女性中报告的灵敏度结果令人鼓舞。下一阶段的临床试验将涉及更大、更多样化的人群，包括...

The success of minimally invasive interventions and the remarkable technological and medical progress have made endoscopic image enhancement a very active research field. Due to the intrinsic endoscopic domain characteristics and the surgical exercise, stereo endoscopic images may suffer from different degradations which affect its quality. Therefore, in order to provide the surgeons with a better...

微创介入的成功以及显著的技术和医学进步使内窥镜图像增强成为一个非常活跃的研究领域。由于内窥镜领域的固有特性和手术操作，立体内窥镜图像可能会遭受不同的退化，影响其质量。因此，为了给外科医生提供更好的...

Functional magnetic resonance imaging is a non-invasive tomographic imaging modality that has provided insights into system-level brain function. New analysis methods are emerging to study the dynamic behavior of brain activity. The innovation-driven co-activation pattern (iCAP) approach is one such approach that relies on the detection of timepoints with a significant transient activity to subseq...

功能磁共振成像是一种非侵入性断层成像模态，为系统级脑功能提供了洞见。新的分析方法正在涌现，以研究大脑活动的动态行为。创新驱动的共激活模式方法是其中一种方法，它依赖于检测具有显著瞬态活动的时间点，以随后...

Minimum Variance (MV) beamforming is known to improve the lateral resolution of ultrasound images and enhance the separation of isolated point scatterers. This paper aims to evaluate the adaptive beamformer's performance with flowing microbubbles (MBs) which are relevant to super-resolution ultrasound imaging. Simulations using point scatterer data from single emissions were complemented by an exp...

最小方差波束成形已知能提高超声图像的横向分辨率，并增强孤立点散射体的分离。本文旨在评估该自适应波束成形器在流动微泡（MBs）上的性能，这关系到超分辨率超声成像。利用单次发射的点散射体数据进行仿真，并辅以实验...

We compare different possible scanning geometries for prostate photoacoustic tomography (PAT) while considering a realistic reconstruction scenario in which the limited view of the prostate and the directivity effect of the transducer are considered. Simulations and experiments confirm that an intra-operative configuration in which the photoacoustic signal is received by a pickup transducer from t...

我们比较了前列腺光声断层成像（PAT）的不同可能扫描几何形状，同时考虑了一个实际的重建场景，其中考虑了前列腺的有限视野和换能器的方向性效应。仿真和实验证实了一种术中配置，在该配置中，光声信号由一个拾取换能器从...接收。

The conventional calibration-based parallel imaging method assumes a linear relationship between the acquired multi-channel k-space data and the unacquired missing data, where the linear coefficients are estimated using some auto-calibration data. In this paper, we first analyze the model errors in the conventional calibration-based methods and demonstrate the nonlinear relationship. Then, a much ...

传统的基于校准的并行成像方法假设采集的多通道k空间数据与未采集的缺失数据之间存在线性关系，其中线性系数通过某些自动校准数据进行估计。本文首先分析了传统基于校准方法中的模型误差，并展示了非线性关系。然后，一个更...

The attenuation coefficient is a relevant biomarker for many diagnostic medical applications. Recently, the Depth-Resolved Confocal (DRC) technique was developed to automatically estimate the attenuation coefficients from Optical Coherence Tomography (OCT) data with pixel-level resolution. However, DRC requires that the confocal function parameters (i.e., focal plane location and apparent Rayleigh...

衰减系数是许多诊断医学应用中的相关生物标志物。最近，开发了深度分辨共焦（DRC）技术，用于从光学相干断层扫描（OCT）数据中以像素级分辨率自动估计衰减系数。然而，DRC需要共焦函数参数（即焦平面位置和表观瑞利...

Atlas-based segmentation is used in radiotherapy planning to accelerate the delineation of organs at risk (OARs). Atlas selection has been proposed to improve the performance of segmentation, assuming that the more similar the atlas is to the patient, the better the result. It follows that the larger the database of atlases from which to select, the better the results should be. This paper seeks t...

基于图谱的分割用于放射治疗计划中，以加速危险器官（OAR）的勾画。已提出图谱选择以改善分割性能，假设图谱与患者越相似，结果越好。因此，可供选择的图谱数据库越大，结果应越好。本文旨在...

The use of whole-slide images (WSIs) in pathology entails stringent storage and transmission requirements because of their huge dimensions. Therefore, image compression is an essential tool to enable efficient access to these data. In particular, color transforms are needed to exploit the very high degree of inter-component correlation and obtain competitive compression performance. Even though th...

在病理学中使用全切片图像由于尺寸巨大而需要严格的存储和传输需求。因此，图像压缩是有效访问这些数据的重要工具。特别是，需要色彩变换来利用极高的分量间相关性并获得有竞争力的压缩性能。尽管...

A vectorial representation of the vascular network that embodies quantitative features—location, direction, scale, and bifurcations—has many potential cardio- and neuro-vascular applications. We present VTrails, an end-to-end approach to extract geodesic vascular minimum spanning trees from angiographic data by solving a connectivity-optimized anisotropic level-set over a voxel-wise tensor field r...

血管网络的向量表示蕴含定量特征——位置、方向、尺度和分叉——具有许多潜在的心脑血管应用。我们提出了VTrails，一种端到端方法，通过求解体素张量场上的连通性优化各向异性水平集，从血管造影数据中提取测地血管最小生成树...

A major goal of contemporary neuroscience research is to map the structural connectivity of mammalian brain using microscopy imaging data. In this context, the reconstruction of densely labeled axons from two-photon microscopy images is a challenging and important task. The visually overlapping, crossing, and often strongly distorted images of the axons allow many ambiguous interpretations to be m...

当代神经科学研究的一个主要目标是利用显微成像数据绘制哺乳动物大脑的结构连接。在此背景下，从双光子显微镜图像中重建密集标记的轴突是一项具有挑战性且重要的任务。视觉上重叠、交叉且经常严重扭曲的轴突图像允许许多模糊的解释...

In this paper, a novel nonlinear thermoacoustic imaging (NTAI) system is developed based on the temperature-dependent thermoelastic response under microwave irradiation. Specifically, we consider the high-pulse repetition frequency (HPRF) microwave regime, where the tissue temperature increases after microwave irradiation. In this circumstance, the temperature-dependent thermodynamic parameters of...

本文基于微波照射下温度依赖的热弹性响应，开发了一种新型非线性热声成像（NTAI）系统。具体而言，我们考虑了高脉冲重复频率（HPRF）微波模式，在该模式下，微波照射后组织温度升高。在这种情况下，温度依赖的热力学参数...