Cross S S, McDonagh A J, Stephenson T J, Cotton D W, Underwood J C
Department of Pathology, University of Sheffield Medical School, England.
Am J Dermatopathol. 1995 Aug;17(4):374-8. doi: 10.1097/00000372-199508000-00012.
Accurate in vivo diagnosis of pigmented skin lesions is required to identify and excise malignant melanomas but to avoid unnecessary excision of benign lesions; the published rates of clinical diagnostic accuracy are about 65%. This study investigates whether fractal geometric analysis of pigmented skin lesions can improve the rate of diagnostic accuracy. Forty-two pigmented skin lesions (15 malignant melanomas, 21 melanocytic naevi, and 6 basal cell papillomas) on patients attending a dermatology clinic were photographed, excised, and sent for histopathological examination. The fractal dimension of the boundary of the lesions was measured using a box-counting method implemented on a microcomputer-based image analysis system. Euclidean geometric parameters were also measured. The fractal dimension of all the lesions was greater than the topological dimension (one), indicating that there is a fractal element to their structure. Using all measured parameters together, multivariate linear discriminant analysis produced a confusion matrix in which 45% of the lesions were assigned to the correct diagnostic group with a kappa statistic of 0.33. There was no significant difference between the fractal dimension of melanocytic naevi and that of malignant melanomas (p = 0.18). Although pigmented skin lesions have a fractal element to their structure, the fractal dimension of their boundaries is not a useful morphometric discriminant between the diagnostic groups of malignant melanomas and benign melanocytic naevi.
要识别并切除恶性黑色素瘤，同时避免对良性病变进行不必要的切除，就需要对色素沉着性皮肤病变进行准确的体内诊断；已公布的临床诊断准确率约为65%。本研究调查色素沉着性皮肤病变的分形几何分析是否能提高诊断准确率。对一家皮肤科诊所就诊患者的42处色素沉着性皮肤病变（15例恶性黑色素瘤、21例黑素细胞痣和6例基底细胞乳头状瘤）进行拍照、切除，并送去做组织病理学检查。使用基于微型计算机的图像分析系统上实现的盒计数法测量病变边界的分形维数。还测量了欧几里得几何参数。所有病变的分形维数均大于拓扑维数（一），表明其结构存在分形元素。综合使用所有测量参数，多变量线性判别分析生成了一个混淆矩阵，其中45%的病变被归入正确的诊断组，kappa统计量为0.33。黑素细胞痣和恶性黑色素瘤的分形维数之间无显著差异（p = 0.18）。尽管色素沉着性皮肤病变的结构存在分形元素，但其边界的分形维数并非区分恶性黑色素瘤和良性黑素细胞痣诊断组的有用形态学判别指标。
