Marchevsky A M, Truong H, Tolmachoff T
Department of Pathology and Laboratory Medicine, Cedars Sinai Medical Center, Los Angeles, California 90048, USA.
Cytometry. 1997 Feb 15;30(1):39-46. doi: 10.1002/(sici)1097-0320(19970215)30:1<39::aid-cyto6>3.0.co;2-a.
DNA "ploidy" histogram interpretation is one of the most important sources of variation in DNA image cytometry and is influenced by multiple technical factors such as scaling, selection of peaks, and variable classification criteria. A rule-based expert system was developed to automate and eliminate subjectivity from this interpretative process. Ninety-eight Feulgen stained histologic sections from patients with breast, colon, and lung cancer were measured with the CAS 200 image analysis system (Becton Dickinson, Santa Clara, CA); they included diploid (n = 42), aneuploid (n = 46), tetraploid (n = 7), and multiploid (n = 3) examples. The data was converted from listmode format into ASCII with the aid of CELLSHEET software (JVC Imaging, Elmhurst, IL). Individual microphotometric nuclear measurements were sorted to one of 64 bins based on DNA index. The 64 bins were then divided into 5 semi-arbitrarily defined ranges: hypodiploid, diploid, aneuploid, tetraploid, and hypertetraploid. The nuclear percentages in each range were calculated with EXCEL 4.0 (Microsoft, Redmond, WA). The histograms were divided into 2 equal sets: training and testing. The data from the training set were used to develop 16 IF-THEN rules to classify the histograms into diploid, aneuploid, or tetraploid. A macro was programmed in EXCEL to automate all these operations. The rule-based expert system classified correctly 45/50 histograms of the training set. Two tetraploid histograms were classified as aneuploid. Three multiploid histograms were classified as tetraploid. All histograms in the testing set were correctly classified by the expert system. The potential role of rule-based expert system technology for the objective classification of DNA "ploidy" histograms measured by image cytometry is discussed.
DNA“倍体”直方图解释是DNA图像细胞术变异的最重要来源之一，并且受到多种技术因素的影响，如缩放、峰的选择和可变的分类标准。开发了一个基于规则的专家系统，以使这个解释过程自动化并消除主观性。使用CAS 200图像分析系统（贝克顿·迪金森公司，加利福尼亚州圣克拉拉）对98例来自乳腺癌、结肠癌和肺癌患者的福尔根染色组织切片进行测量；其中包括二倍体（n = 42）、非整倍体（n = 46）、四倍体（n = 7）和多倍体（n = 3）样本。借助CELLSHEET软件（JVC影像公司，伊利诺伊州埃尔姆赫斯特）将数据从列表模式格式转换为ASCII格式。根据DNA指数将各个显微光度核测量值分类到64个箱中的一个。然后将这64个箱分为5个半任意定义的范围：亚二倍体、二倍体、非整倍体、四倍体和超四倍体。使用EXCEL 4.0（微软公司，华盛顿州雷德蒙德）计算每个范围内的核百分比。将直方图分为两个相等的集合：训练集和测试集。使用训练集的数据制定16条“如果……那么……”规则，以将直方图分类为二倍体、非整倍体或四倍体。在EXCEL中编写了一个宏，以使所有这些操作自动化。基于规则的专家系统正确分类了训练集中45/50的直方图。两个四倍体直方图被分类为非整倍体。三个多倍体直方图被分类为四倍体。测试集中的所有直方图都被专家系统正确分类。讨论了基于规则的专家系统技术在通过图像细胞术测量的DNA“倍体”直方图客观分类中的潜在作用。
