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Diffusion-weighted imaging of the liver:Current applications 被引量:8
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作者 Kazuhiro Saito Yu Tajima Taiyo L Harada 《World Journal of Radiology》 CAS 2016年第11期857-867,共11页
Diffusion-weighted imaging(DWI) of the liver can be performed using most commercially available machines and is currently accepted in routine sequence. This sequence has some potential as an imaging biomarker for fibr... Diffusion-weighted imaging(DWI) of the liver can be performed using most commercially available machines and is currently accepted in routine sequence. This sequence has some potential as an imaging biomarker for fibrosis, tumor detection/characterization, and following/predicting therapy. To improve reliability including accuracy and reproducibility, researchers have validated this new technique in terms of image acquisition, data sampling, and analysis. The added value of DWI in contrastenhanced magnetic resonance imaging was established in the detection of malignant liver lesions. However, some limitations remain in terms of lesion characterization and fibrosis detection. Furthermore, the methodologies of image acquisition and data analysis have been inconsistent. Therefore, researchers should make every effort to not only improve accuracy and reproducibility but also standardize imaging parameters. 展开更多
关键词 Diffusion weighted imaging LIVER FIBROSIS lesion characterization
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Colonic lesion characterization in inflammatory bowel disease:A systematic review and meta-analysis 被引量:3
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作者 Richard Lord Nicholas E Burr +1 位作者 Noor Mohammed Venkataraman Subramanian 《World Journal of Gastroenterology》 SCIE CAS 2018年第10期1167-1180,共14页
AIM To perform a systematic review and meta-analysis for the diagnostic accuracy of in vivo lesion characterization in colonic inflammatory bowel disease(IBD), using optical imaging techniques, including virtual chrom... AIM To perform a systematic review and meta-analysis for the diagnostic accuracy of in vivo lesion characterization in colonic inflammatory bowel disease(IBD), using optical imaging techniques, including virtual chromoendoscopy(VCE), dye-based chromoendoscopy(DBC), magnification endoscopy and confocal laser endomicroscopy(CLE). METHODS We searched Medline, Embase and the Cochrane library. We performed a bivariate meta-analysis to calculate the pooled estimate sensitivities, specificities, positive and negative likelihood ratios(+LHR,-LHR), diagnostic odds ratios(DOR), and area under the SROC curve(AUSROC) for each technology group. A subgroup analysis was performed to investigate differences in real-time nonmagnified Kudo pit patterns(with VCE and DBC) and real-time CLE.RESULTS We included 22 studies [1491 patients; 4674 polyps, of which 539(11.5%) were neoplastic]. Real-time CLE had a pooled sensitivity of 91%(95%CI: 66%-98%), specificity of 97%(95%CI: 94%-98%), and an AUSROC of 0.98(95%CI: 0.97-0.99). Magnification endoscopy had a pooled sensitivity of 90%(95%CI: 77%-96%)and specificity of 87%(95%CI: 81%-91%). VCE had a pooled sensitivity of 86%(95%CI: 62%-95%) and specificity of 87%(95%CI: 72%-95%). DBC had a pooled sensitivity of 67%(95%CI: 44%-84%) and specificity of 86%(95%CI: 72%-94%). CONCLUSION Real-time CLE is a highly accurate technology for differentiating neoplastic from non-neoplastic lesions in patients with colonic IBD. However, most CLE studies were performed by single expert users within tertiary centres, potentially confounding these results. 展开更多
关键词 Inflammatory bowel disease DYSPLASIA lesion characterization Confocal laser ENDOMICROSCOPY Narrow band imaging I-scan Fujinon intelligence CHROMOENDOSCOPY
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The role of apparent diffusion coefficient values in characterization of solid focal liver lesions:a prospective and comparative clinical study 被引量:3
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作者 Dawei Yang 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第1期16-22,共7页
We evaluated and compared the diagnostic accuracy(DA) of apparent diffusion coefficient(ADC) values with that of lesion-to-liver ADC ratios in the characterization of solid focal liver lesions(FLLs).This prospective s... We evaluated and compared the diagnostic accuracy(DA) of apparent diffusion coefficient(ADC) values with that of lesion-to-liver ADC ratios in the characterization of solid focal liver lesions(FLLs).This prospective study was approved by the Institutional Human Ethics Board,after waiving written informed consent.Diffusion-weighted imaging and other routine magnetic resonance imaging were performed on 142 consecutive patients with suspected liver disease.The mean ADC values and lesion-to-liver ADC ratios were compared between benign and malignant solid FLLs.Receiver operating characteristic analysis was performed.The study participants included 46 patients(28 men,18 women;mean age,52.5 years) with 57 solid FLLs(32 malignant and 25 benign FLLs).The mean ADC values and ADC ratios of benign solid FLLs were significantly higher than those of malignant lesions(P<0.01).The difference between the area under the receiver operating characteristic curve of the ADC values(0.699) and ADC ratios(0.752) was not significant.Our study suggests that the DA of the ADC ratio is not significantly higher than that of ADC in characterizing solid FLLs. 展开更多
关键词 magnetic resonance diffusion-weighted imaging lesion characterization liver sensitivity SPECIFICITY
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基于非参数分类k最邻近节点算法的多维放射诊断数据评价(英文)
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作者 Matthias Dietzel Andreas Dietzel +4 位作者 Ramy Zoubi Hartmut P. Burmeister Martin Bogdan Werner A. Kaiser Pascal A.T. Baltzer 《磁共振成像》 CAS 2012年第6期401-409,共9页
目的 k最近邻节点算法(k-nearest neighbor algorithm,kNN)可以将复杂的医疗信息集合成临床诊断信息(比如确定良性或恶性病变)。该研究旨在分析kNN算法应用于大量临床数据集时的AUC(ROC曲线下面积)。材料与方法该研究经IRB批准,且实验... 目的 k最近邻节点算法(k-nearest neighbor algorithm,kNN)可以将复杂的医疗信息集合成临床诊断信息(比如确定良性或恶性病变)。该研究旨在分析kNN算法应用于大量临床数据集时的AUC(ROC曲线下面积)。材料与方法该研究经IRB批准,且实验选取了543例经病理证实为乳腺病灶的MR图像进行分析,所有的病灶由两名经验丰富的放射科医师用现有的描述方法进行前瞻性评估。kNN算法应用于诊断恶性与良性病变的步骤如下:首先,用递归特征消除来确定单个特征描述的重要性,将其按照重要性排列。然后,采取多类别描述方法的策略,将对照组分为4组:top-3、top-7、top-12和top-18组,相应的特征描述作为kNN算法的输入向量。最后,用kNN算法对四组数据处理,对结果进行量化,比较各组数据的AUC(为了尽量消除数据模型和测试数据的偏差,运用了4倍交叉验证)。病理组织学显示,实验数据组共有196个良性病变和347个恶性病变。结果测得最高的AUC为0.940(用top-18描述)。如果用top-12来描述,AUC降为0.928(P=0.23)。减少特征描述输入向量的维数会显著降低(P<0.05)kNN算法的AUC("top-7":AUC=0.895;"top-3":AUC=0.816)。结论 kNN对预测恶性肿瘤的精确度较高(AUC为0.940),由于这种描述方法对n≥12是有效的,说明kNN算法对多维数据的评估更加有效。 展开更多
关键词 k最邻近节点算法 磁共振成像 早期肿瘤 影像诊断 计算机辅助诊断 病变特征
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四种短体线虫的形态和分子生物学鉴定 被引量:8
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作者 杜宇 邓宗汉 +4 位作者 丁元明 刘冰洋 李旻 雷屈文 林萌 《植物病理学报》 CAS CSCD 北大核心 2020年第1期28-39,共12页
采用形态学和分子生物学方法对来自荷兰的藏橐吾和铃兰、泰国的高山榕、缅甸的香蕉等种苗(球)分别鉴定出玻利维亚短体线虫Pratylenchus bolivianus、铃兰短体线虫P.convallariae、咖啡短体线虫P.coffeae和斯佩奇短体线虫P.speijeri。对... 采用形态学和分子生物学方法对来自荷兰的藏橐吾和铃兰、泰国的高山榕、缅甸的香蕉等种苗(球)分别鉴定出玻利维亚短体线虫Pratylenchus bolivianus、铃兰短体线虫P.convallariae、咖啡短体线虫P.coffeae和斯佩奇短体线虫P.speijeri。对这4种线虫的形态特征进行较为详细的描述后,认为头环、口针、侧区、生殖系统和尾形等形态特征是种类鉴定的重要依据;进一步利用引物28S-D2A/28S-D3Br扩增测序得到上述4种线虫的28S rRNA基因D2/D3区序列,序列分析发现玻利维亚短体线虫从欧洲到美洲的不同种群之间的遗传距离变异较小,仅为0~0.007;铃兰短体线虫同一种群不同个体之间的遗传变异较大,为0.006~0.029;咖啡短体线虫不同种群之间的平均遗传距离为0.013;斯佩奇短体线虫不同种群之间的平均遗传距离为0.010;咖啡短体线虫P.coffeae和斯佩奇短体线虫P.speijeri亲缘关系很近,二者种间平均遗传距离仅为0.026。本研究再次证明线虫28S rRNA基因D2/D3区基因序列可作为短体线虫种间鉴定的依据。 展开更多
关键词 短体线虫 形态特征 28S rRNA 系统进化树 鉴定
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肺孤立性占位中CT形态特征和PET代谢特征的比较研究 被引量:6
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作者 刘建军 陈虞梅 +4 位作者 黄钢 华佳 宋少莉 孙晓光 万良荣 《中国医学计算机成像杂志》 CSCD 2008年第4期355-360,共6页
目的:比较分析肺孤立性占位^(18)F-FDG PET/CT图像中CT形态特征对PET代谢特征的影响。材料和方法:回顾性收集211例完成全身^(18)F-FDG PET/CT显像的肺孤立性占位患者,所有患者均经病理证实或影像学随访一年以上。在CT图像中分析每个病... 目的:比较分析肺孤立性占位^(18)F-FDG PET/CT图像中CT形态特征对PET代谢特征的影响。材料和方法:回顾性收集211例完成全身^(18)F-FDG PET/CT显像的肺孤立性占位患者,所有患者均经病理证实或影像学随访一年以上。在CT图像中分析每个病灶的大小、分叶征、毛刺征和胸膜牵拉征等形态特征,在PET图像中获取每个病灶的平均标准摄取值(SUVave)等代谢特征。所有特征均与病理和临床随访结果相比较。结果:211例肺孤立性占位患者中恶性占位163例,良性占位48例。以SUVave=2.5作为良恶性鉴别的定量依据,^(18)F-FDG PET对肺孤立性占位的诊断灵敏度、特异性及准确性分别为86.5%,52.1%和78.7%。163例恶性占位中,57例>3cm的恶性占位,其SUVave明显高于106例≤3cm的病灶(6.84±2.06比4.13±2.42,P<0.01);116例具有分叶特征的恶性病灶SUVave明显高于47例无分叶特征的恶性病灶(5.45±2.40比4.25±2.86,P<0.01)。106例≤3cm的恶性占位(肺孤立性结节),具有分叶、毛刺征的SUVave明显高于无毛刺征的恶性占位(4.70±2.41比3.30±2.20;4.55±2.20比3.58±2.59,P均<0.01)。胸膜牵拉征对SUVave的影响没有差异。结论:^(18)F-FDG PET显像可以较好的鉴别诊断肺内孤立性占位。肿瘤大小、分叶对恶性肿瘤代谢特征均有明显影响;毛刺征对恶性肿瘤代谢特征的影响主要体现在肺孤立性结节中,胸膜牵拉征对代谢特征影响不明显。 展开更多
关键词 肺孤立性占位 ^18F—FDG PET/CT 形态特征 代谢特征
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