QDA, Quadratic discriminant analysis

  • 文章类型: Journal Article
    未经证实:目前还没有确定的生物标志物用于抗VEGF治疗新生血管性年龄相关性黄斑变性(nAMD)的疗效和持久性。这项研究评估了基于放射学的定量OCT生物标志物,这些生物标志物可以预测抗VEGF治疗的反应和持久性。
    UNASSIGNED:使用机器学习(ML)分类器评估基线生物标志物以预测抗VEGF治疗的耐受性。
    未经评估:来自OSPREY研究的81名接受治疗的nAMD参与者,包括15名超级应答者(达到并维持视网膜液分辨率的患者)和66名非超级应答者(未达到或维持视网膜液分辨率的患者)。
    UNASSIGNED:从流体中提取了总共962个基于纹理的放射学特征,视网膜下高反射材料(SHRM),和OCT扫描的不同视网膜组织区室。前8个特点,通过最小冗余最大相关性特征选择方法选择,在交叉验证的方法中使用4个ML分类器进行评估,以区分2个患者组。还进行了基线和第3个月之间不同基于纹理的放射学描述符(δ-纹理特征)变化的纵向评估,以评估它们与治疗反应的关联。此外,8基线临床参数和基线OCT的组合,三角洲纹理特征,并通过交叉验证的方法评估了临床参数与治疗反应的相关性.
    UNASSIGNED:受试者工作特征曲线(AUC)下的交叉验证面积,准确度,灵敏度,并计算特异性以验证分类器的性能。
    UNASSIGNED:使用基于纹理的基线OCT特征,二次判别分析分类器的交叉验证AUC为0.75±0.09。基线和第3个月之间不同OCT区室内的δ-纹理特征产生0.78±0.08的AUC。基线临床参数视网膜下色素上皮体积和视网膜内液体积产生0.62±0.07的AUC。当所有的基线,delta,和临床特征相结合,分类器性能的统计显着提高(AUC,获得0.81±0.07)。
    UNASSIGNED:基于放射组学的OCT图像定量评估显示可区分nAMD中抗VEGF治疗的超应答者和非超应答者。发现基线流体和SHRM三角洲纹理特征在各组之间最具区别。
    UNASSIGNED: No established biomarkers currently exist for therapeutic efficacy and durability of anti-VEGF therapy in neovascular age-related macular degeneration (nAMD). This study evaluated radiomic-based quantitative OCT biomarkers that may be predictive of anti-VEGF treatment response and durability.
    UNASSIGNED: Assessment of baseline biomarkers using machine learning (ML) classifiers to predict tolerance to anti-VEGF therapy.
    UNASSIGNED: Eighty-one participants with treatment-naïve nAMD from the OSPREY study, including 15 super responders (patients who achieved and maintained retinal fluid resolution) and 66 non-super responders (patients who did not achieve or maintain retinal fluid resolution).
    UNASSIGNED: A total of 962 texture-based radiomic features were extracted from fluid, subretinal hyperreflective material (SHRM), and different retinal tissue compartments of OCT scans. The top 8 features, chosen by the minimum redundancy maximum relevance feature selection method, were evaluated using 4 ML classifiers in a cross-validated approach to distinguish between the 2 patient groups. Longitudinal assessment of changes in different texture-based radiomic descriptors (delta-texture features) between baseline and month 3 also was performed to evaluate their association with treatment response. Additionally, 8 baseline clinical parameters and a combination of baseline OCT, delta-texture features, and the clinical parameters were evaluated in a cross-validated approach in terms of association with therapeutic response.
    UNASSIGNED: The cross-validated area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity were calculated to validate the classifier performance.
    UNASSIGNED: The cross-validated AUC by the quadratic discriminant analysis classifier was 0.75 ± 0.09 using texture-based baseline OCT features. The delta-texture features within different OCT compartments between baseline and month 3 yielded an AUC of 0.78 ± 0.08. The baseline clinical parameters sub-retinal pigment epithelium volume and intraretinal fluid volume yielded an AUC of 0.62 ± 0.07. When all the baseline, delta, and clinical features were combined, a statistically significant improvement in the classifier performance (AUC, 0.81 ± 0.07) was obtained.
    UNASSIGNED: Radiomic-based quantitative assessment of OCT images was shown to distinguish between super responders and non-super responders to anti-VEGF therapy in nAMD. The baseline fluid and SHRM delta-texture features were found to be most discriminating across groups.
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  • 文章类型: Journal Article
    未经授权:放疗计划和定量成像生物标志物目的都需要肿瘤勾画。这是一个手册,时间和劳动密集型的过程容易出现观察者之间和观察者之间的变化。半自动或全自动分割可以提供更好的效率和一致性。本研究旨在研究包含和结合功能与解剖磁共振成像(MRI)序列对自动分割质量的影响。
    未经评估:T2加权(T2w),扩散加权,多回波T2*加权,分析中使用了81例直肠癌患者的动态多回声(DME)MR图像。四种经典的机器学习算法;自适应增强(ADA),线性和二次判别分析和支持向量机,使用MR图像的不同组合作为输入来训练肿瘤和正常组织的自动分割,其次是半自动形态学后处理。两位专家的人工描述是事实。Sørensen-Dice相似性系数(DICE)和平均对称表面距离(MSD)用作留一交叉验证中的性能指标。
    未经评估:单独使用T2w图像,ADA优于其他算法,每位患者的平均DICE为0.67,MSD为3.6毫米。当添加功能图像时,性能得到改善,对于基于T2w和DME图像(DICE:0.72,MSD:2.7mm)或所有四个MRI序列(DICE:0.72,MSD:2.5mm)的模型,性能最高。
    未经评估:使用功能性MRI的机器学习模型,特别是DME,相对于单独使用T2wMRI的模型,有可能改善直肠癌的自动分割。
    UNASSIGNED: Tumor delineation is required both for radiotherapy planning and quantitative imaging biomarker purposes. It is a manual, time- and labor-intensive process prone to inter- and intraobserver variations. Semi or fully automatic segmentation could provide better efficiency and consistency. This study aimed to investigate the influence of including and combining functional with anatomical magnetic resonance imaging (MRI) sequences on the quality of automatic segmentations.
    UNASSIGNED: T2-weighted (T2w), diffusion weighted, multi-echo T2*-weighted, and contrast enhanced dynamic multi-echo (DME) MR images of eighty-one patients with rectal cancer were used in the analysis. Four classical machine learning algorithms; adaptive boosting (ADA), linear and quadratic discriminant analysis and support vector machines, were trained for automatic segmentation of tumor and normal tissue using different combinations of the MR images as input, followed by semi-automatic morphological post-processing. Manual delineations from two experts served as ground truth. The Sørensen-Dice similarity coefficient (DICE) and mean symmetric surface distance (MSD) were used as performance metric in leave-one-out cross validation.
    UNASSIGNED: Using T2w images alone, ADA outperformed the other algorithms, yielding a median per patient DICE of 0.67 and MSD of 3.6 mm. The performance improved when functional images were added and was highest for models based on either T2w and DME images (DICE: 0.72, MSD: 2.7 mm) or all four MRI sequences (DICE: 0.72, MSD: 2.5 mm).
    UNASSIGNED: Machine learning models using functional MRI, in particular DME, have the potential to improve automatic segmentation of rectal cancer relative to models using T2w MRI alone.
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  • 文章类型: Journal Article
    开发识别早产的计算方法对于及时诊断和治疗早产很重要。这项研究的主要目的是评估在不同孕周记录的心电图(EHG)信号,以使用随机森林(RF)识别早产。根据记录的时间将300名孕妇的EHG信号分为两组:i)早产和足月分娩,在妊娠第26周之前记录EHG(以PE和TE组表示),和ii)在妊娠第26周期间或之后记录EHG的早产和足月分娩(用PL和TL组表示)。从每个EHG信号中得出31个线性特征和非线性特征,然后在PE和TE组内进行综合比较,PL和TL组。在采用自适应合成抽样方法和六重交叉验证后,精度(ACC),灵敏度,应用特异性和曲线下面积(AUC)评估RF分类.对于PL和TL组,RF的ACC为0.93,灵敏度为0.89,特异性为0.97,AUC为0.80。同样,PE和TE组的相应值分别为0.92、0.88、0.96和0.88,表明RF可用于有效识别早产,并在妊娠26周之前记录EHG信号。
    Developing a computational method for recognizing preterm delivery is important for timely diagnosis and treatment of preterm delivery. The main aim of this study was to evaluate electrohysterogram (EHG) signals recorded at different gestational weeks for recognizing the preterm delivery using random forest (RF). EHG signals from 300 pregnant women were divided into two groups depending on when the signals were recorded: i) preterm and term delivery with EHG recorded before the 26th week of gestation (denoted by PE and TE group), and ii) preterm and term delivery with EHG recorded during or after the 26th week of gestation (denoted by PL and TL group). 31 linear features and nonlinear features were derived from each EHG signal, and then compared comprehensively within PE and TE group, and PL and TL group. After employing the adaptive synthetic sampling approach and six-fold cross-validation, the accuracy (ACC), sensitivity, specificity and area under the curve (AUC) were applied to evaluate RF classification. For PL and TL group, RF achieved the ACC of 0.93, sensitivity of 0.89, specificity of 0.97, and AUC of 0.80. Similarly, their corresponding values were 0.92, 0.88, 0.96 and 0.88 for PE and TE group, indicating that RF could be used to recognize preterm delivery effectively with EHG signals recorded before the 26th week of gestation.
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