Medical image processing

医学图像处理
  • 文章类型: Journal Article
    乳腺密度的评估,乳腺癌风险的关键指标,传统上由放射科医生通过乳房X线照相术图像的视觉检查来执行,利用乳腺成像报告和数据系统(BI-RADS)乳腺密度类别。然而,这种方法在观察者之间存在很大的可变性,导致密度评估和后续风险估计的不一致和潜在的不准确。为了解决这个问题,我们提出了一种基于深度学习的自动检测算法(DLAD),旨在自动评估乳腺密度。我们的多中心,多读者研究利用了来自三个机构的122个全视野数字乳房X线摄影研究的不同数据集(CC和MLO投影中的488张图像)。我们邀请了两位经验丰富的放射科医师进行回顾性分析,为72项乳房X线照相术研究(BI-RADSA类:18,BI-RADSB类:43,BI-RADSC类:7,BI-RADSD类:4)。然后将DLAD的功效与具有不同经验水平的五名独立放射科医师的表现进行比较。DLAD显示出强大的性能,达到0.819的准确度(95%CI:0.736-0.903),F1得分为0.798(0.594-0.905),精度为0.806(0.596-0.896),召回0.830(0.650-0.946),科恩的卡帕(κ)为0.708(0.562-0.841)。该算法实现了匹配的稳健性能,并且在四种情况下超过了单个放射科医生的稳健性能。统计分析并没有发现DLAD和放射科医师之间的准确性存在显着差异。强调该模型与专业放射科医生评估的竞争性诊断一致性。这些结果表明,基于深度学习的自动检测算法可以提高乳腺密度评估的准确性和一致性,为改善乳腺癌筛查结果提供了可靠的工具。
    The evaluation of mammographic breast density, a critical indicator of breast cancer risk, is traditionally performed by radiologists via visual inspection of mammography images, utilizing the Breast Imaging-Reporting and Data System (BI-RADS) breast density categories. However, this method is subject to substantial interobserver variability, leading to inconsistencies and potential inaccuracies in density assessment and subsequent risk estimations. To address this, we present a deep learning-based automatic detection algorithm (DLAD) designed for the automated evaluation of breast density. Our multicentric, multi-reader study leverages a diverse dataset of 122 full-field digital mammography studies (488 images in CC and MLO projections) sourced from three institutions. We invited two experienced radiologists to conduct a retrospective analysis, establishing a ground truth for 72 mammography studies (BI-RADS class A: 18, BI-RADS class B: 43, BI-RADS class C: 7, BI-RADS class D: 4). The efficacy of the DLAD was then compared to the performance of five independent radiologists with varying levels of experience. The DLAD showed robust performance, achieving an accuracy of 0.819 (95% CI: 0.736-0.903), along with an F1 score of 0.798 (0.594-0.905), precision of 0.806 (0.596-0.896), recall of 0.830 (0.650-0.946), and a Cohen\'s Kappa (κ) of 0.708 (0.562-0.841). The algorithm achieved robust performance that matches and in four cases exceeds that of individual radiologists. The statistical analysis did not reveal a significant difference in accuracy between DLAD and the radiologists, underscoring the model\'s competitive diagnostic alignment with professional radiologist assessments. These results demonstrate that the deep learning-based automatic detection algorithm can enhance the accuracy and consistency of breast density assessments, offering a reliable tool for improving breast cancer screening outcomes.
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  • 文章类型: Review
    背景:近年来,在观察性研究中使用脑磁共振成像(MRI)呈指数增长,提供研究样本的细节至关重要,图像处理,并提取成像标记以验证和复制研究结果。本文回顾了现已完成的BiDirect队列研究的脑MRI数据集,作为前两个审查时间点后发布的可行性报告的更新和扩展。
    方法:我们报告了参与者的样本和流程,这些参与者跨越四个研究阶段和12年。此外,我们提供有关获取协议的详细信息;处理管道,包括标准化和质量控制方法;以及使用的分析工具和可用的标记。
    结果:所有数据均从2010年至2021年在明斯特的单个站点收集,德国,从3个不同队列中的2,257名基线参与者开始:基于人群的队列(n=911基线,672与MRI数据),诊断为抑郁症的患者(n=999,736,MRI数据),和明显心血管疾病的患者(n=347,MRI数据为52)。在学习期间,共进行了4,315次MRI检查,超过535名参与者在所有4个时间点接受了MRI检查.
    结论:将图像转换为大脑成像数据结构(组织和描述神经成像数据的标准),并使用常用工具进行分析,例如CAT12,FSL,Freesurfer,和BIANCA提取成像生物标志物。BiDirect研究包括具有结构和功能MRI数据的彻底表型研究群体。
    结论:BiDirect研究包括一个基于人群的样本和两个基于患者的样本,其MRI数据可以帮助回答许多神经精神病学和心血管研究问题。
    结论:•BiDirect研究包括具有MRI数据的以患者和人群为基础的队列。•将数据标准化至脑成像数据结构,并用常用软件处理。•MRI数据和标记可根据要求提供。
    BACKGROUND: The use of cerebral magnetic resonance imaging (MRI) in observational studies has increased exponentially in recent years, making it critical to provide details about the study sample, image processing, and extracted imaging markers to validate and replicate study results. This article reviews the cerebral MRI dataset from the now-completed BiDirect cohort study, as an update and extension of the feasibility report published after the first two examination time points.
    METHODS: We report the sample and flow of participants spanning four study sessions and twelve years. In addition, we provide details on the acquisition protocol; the processing pipelines, including standardization and quality control methods; and the analytical tools used and markers available.
    RESULTS: All data were collected from 2010 to 2021 at a single site in Münster, Germany, starting with a population of 2,257 participants at baseline in 3 different cohorts: a population-based cohort (n = 911 at baseline, 672 with MRI data), patients diagnosed with depression (n = 999, 736 with MRI data), and patients with manifest cardiovascular disease (n = 347, 52 with MRI data). During the study period, a total of 4,315 MRI sessions were performed, and over 535 participants underwent MRI at all 4 time points.
    CONCLUSIONS: Images were converted to Brain Imaging Data Structure (a standard for organizing and describing neuroimaging data) and analyzed using common tools, such as CAT12, FSL, Freesurfer, and BIANCA to extract imaging biomarkers. The BiDirect study comprises a thoroughly phenotyped study population with structural and functional MRI data.
    CONCLUSIONS: The BiDirect Study includes a population-based sample and two patient-based samples whose MRI data can help answer numerous neuropsychiatric and cardiovascular research questions.
    CONCLUSIONS: • The BiDirect study included characterized patient- and population-based cohorts with MRI data. • Data were standardized to Brain Imaging Data Structure and processed with commonly available software. • MRI data and markers are available upon request.
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  • 文章类型: Journal Article
    背景:上肢关节镜手术是一种高度依赖技术的手术,需要外科医生评估困难的软骨状况,并控制狭窄关节腔内关节囊附近神经和血管的医源性损伤风险,并且需要一种可以安全地协助此过程的设备。
    方法:在本研究中,我们开发了一种用于上肢关节手术的小型关节内超声(AUS)探头,使用水下声场测量评估其安全性,并用嵌入神经和血管的幻影测试了它的可视化。
    结果:声场测量实验证实了AUS探头输出的生物安全性,同时确认作为超声测量探头获得了足够的输出功率级性能。此外,使用琼脂体模的A模式成像有区别地重建血管和神经的图像。
    结论:本研究提供了AUS探针在上肢手术中的概念验证。需要进一步的研究才能获得批准用于未来的医疗设备。
    BACKGROUND: Upper extremity arthroscopic surgery is a highly technique-dependent procedure that requires the surgeon to assess difficult cartilage conditions and manage the risk of iatrogenic damage to nerves and vessels adjacent to the joint capsule in a confined joint space, and a device that can safely assist in this procedure has been in demand.
    METHODS: In this study, we developed a small intra-articular ultrasound (AUS) probe for upper extremity joint surgery, evaluated its safety using underwater sound field measurement, and tested its visualization with a phantom in which nerves and blood vessels were embedded.
    RESULTS: Sound field measurement experiments confirmed the biological safety of the AUS probe\'s output, while confirming that sufficient output power level performance was obtained as an ultrasound measurement probe. In addition, images of blood vessels and nerves were reconstructed discriminatively using A-mode imaging of the agar phantom.
    CONCLUSIONS: This study provides proof-of-concept of the AUS probe in upper extremity surgery. Further studies are needed to obtain approval for use in future medical devices.
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  • 文章类型: Journal Article
    在临床常规中,伤口记录是治疗急性或慢性伤口患者的最重要因素之一。伤口记录过程目前非常耗时,通常依赖审查员,因此不精确。这项研究旨在验证一种基于软件的方法,用于使用MaskR-CNN(基于区域的卷积神经网络)自动分割和测量摄影图像上的伤口。在验证期间,5名医学专家在两个不同的时间点手动分割了一个独立的数据集,其中包含35张伤口照片,间隔为1个月。同时,使用MaskR-CNN自动分割数据集。之后,比较了分割结果,以及进行的评估者内和评估者间分析。在统计评估中,进行方差分析(ANOVA)并计算骰子系数.ANOVA在第一轮分割(F=1.424和p>0.228)和第二轮分割(F=0.9969和p>0.411)中显示所有评估者和网络中没有统计学上的显着差异。重复测量分析表明,随着时间的推移,医学专家的分割质量没有统计学上的显着差异(F=6.05和p>0.09)。然而,某个评分者内部的差异是明显的,而MaskR-CNN始终提供相同的分割,而不管时间点。使用基于软件的方法对照片上的伤口进行分割和测量,可以加快记录过程,并在保持质量和精度的同时提高测量值的一致性。
    In clinical routine, wound documentation is one of the most important contributing factors to treating patients with acute or chronic wounds. The wound documentation process is currently very time-consuming, often examiner-dependent, and therefore imprecise. This study aimed to validate a software-based method for automated segmentation and measurement of wounds on photographic images using the Mask R-CNN (Region-based Convolutional Neural Network). During the validation, five medical experts manually segmented an independent dataset with 35 wound photographs at two different points in time with an interval of 1 month. Simultaneously, the dataset was automatically segmented using the Mask R-CNN. Afterwards, the segmentation results were compared, and intra- and inter-rater analyses performed. In the statistical evaluation, an analysis of variance (ANOVA) was carried out and dice coefficients were calculated. The ANOVA showed no statistically significant differences throughout all raters and the network in the first segmentation round (F = 1.424 and p > 0.228) and the second segmentation round (F = 0.9969 and p > 0.411). The repeated measure analysis demonstrated no statistically significant differences in the segmentation quality of the medical experts over time (F = 6.05 and p > 0.09). However, a certain intra-rater variability was apparent, whereas the Mask R-CNN consistently provided identical segmentations regardless of the point in time. Using the software-based method for segmentation and measurement of wounds on photographs can accelerate the documentation process and improve the consistency of measured values while maintaining quality and precision.
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    文章类型: Journal Article
    Nowadays, it is obvious that there is a relationship between changes in the retinal vessel structure and diseases such as diabetic, hypertension, stroke, and the other cardiovascular diseases in adults as well as retinopathy of prematurity in infants. Retinal fundus images provide non-invasive visualization of the retinal vessel structure. Applying image processing techniques in the study of digital color fundus photographs and analyzing their vasculature is a reliable approach for early diagnosis of the aforementioned diseases. Reduction in the arteriolar-venular ratio of retina is one of the primary signs of hypertension, diabetic, and cardiovascular diseases which can be calculated by analyzing the fundus images. To achieve a precise measuring of this parameter and meaningful diagnostic results, accurate classification of arteries and veins is necessary. Classification of vessels in fundus images faces with some challenges that make it difficult. In this paper, a comprehensive study of the proposed methods for classification of arteries and veins in fundus images is presented. Considering that these methods are evaluated on different datasets and use different evaluation criteria, it is not possible to conduct a fair comparison of their performance. Therefore, we evaluate the classification methods from modeling perspective. This analysis reveals that most of the proposed approaches have focused on statistics, and geometric models in spatial domain and transform domain models have received less attention. This could suggest the possibility of using transform models, especially data adaptive ones, for modeling of the fundus images in future classification approaches.
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  • 文章类型: Journal Article
    OBJECTIVE: The twinkling artifact is an undesired phenomenon within color Doppler sonograms that usually appears at the site of internal calcifications. Since the appearance of the twinkling artifact is correlated with the roughness of the calculi, noninvasive roughness estimation of the internal stones may be considered as a potential twinkling artifact application. This article proposes a novel quantitative approach for measurement and analysis of twinkling artifact data for roughness estimation.
    METHODS: A phantom was developed with 7 quantified levels of roughness. The Doppler system was initially calibrated by the proposed procedure to facilitate the analysis. A total of 1050 twinkling artifact images were acquired from the phantom, and 32 novel numerical measures were introduced and computed for each image. The measures were then ranked on the basis of roughness quantification ability using different methods. The performance of the proposed twinkling artifact-based surface roughness quantification method was finally investigated for different combinations of features and classifiers.
    RESULTS: Eleven features were shown to be the most efficient numerical twinkling artifact measures in roughness characterization. The linear classifier outperformed other methods for twinkling artifact classification. The pixel count measures produced better results among the other categories. The sequential selection method showed higher accuracy than other individual rankings. The best roughness recognition average accuracy of 98.33% was obtained by the first 5 principle components and the linear classifier.
    CONCLUSIONS: The proposed twinkling artifact analysis method could recognize the phantom surface roughness with average accuracy of 98.33%. This method may also be applicable for noninvasive calculi characterization in treatment management.
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