Automated classification of cells in sub-epithelial connective tissue of oral sub-mucous fibrosis—An SVM based approach M. Muthu Rama Krishnan a , Mousumi Pal b , Suneel K Bomminayuni c , Chandan Chakraborty a,Ã , Ranjan Rashmi Paul b , Jyotirmoy Chatterjee a , Ajoy K. Ray a,c a School of Medical Science & Technology, I.I.T, Kharagpur, India b Department of Oral and Maxillofacial Pathology, Guru Nanak Institute of Dental Science and Research, Panihati, Kolkata, India c Department of Electronics & Electrical Communication Engineering, I.I.T, Kharagpur, India article info Article history: Received 1 September 2008 Accepted 18 September 2009 Keywords: Sub-epithelial connective tissue (SECT) Oral sub-mucous fibrosis (OSF) Multi-level thresholding Support vector machine (SVM) abstract Quantitative evaluation of histopathological features is not only vital for precise characterization of any precancerous condition but also crucial in developing automated computer aided diagnostic system. In this study segmentation and classification of sub-epithelial connective tissue (SECT) cells except endothelial cells in oral mucosa of normal and OSF conditions has been reported. Segmentation has been carried out using multi-level thresholding and subsequently the cell population has been classified using support vector machine (SVM) based classifier. Moreover, the geometric features used here have been observed to be statistically significant, which enhance the statistical learning potential and classification accuracy of the classifier. Automated classification of SECT cells characterizes this precancerous condition very precisely in a quantitative manner and unveils the opportunity to understand OSF related changes in cell population having definite geometric properties. The paper presents an automated classification method for understanding the deviation of normal structural profile of oral mucosa during precancerous changes. & 2009 Elsevier Ltd. All rights reserved. 1. Introduction There has been an increase in the cancers of the oral cavity in recent years and each year more than 0.3 million new cases [1] of oral cancer are reported. A high incidence of oral cancer [2] is mainly due to late diagnosis of potential precancerous lesions and conditions. Oral submucous fibrosis (OSF), a precancerous condi- tion was first described in the early 1950s, as a potentially malignant disease. It is predominantly found among the people of Asian descent and the disorder is chronic, progressive and its clinical presentation depends on the stage of the disease at detection. Patients with this disease are found to have varying degrees of limitations in opening their mouth and the movement of their tongue [3]. Increase in the number of OSF cases in the Indian subcontinent has predominantly been due to the use of smokeless tobacco in various forms, which is very popular in this region. This habit has been blamed for the generalized fibrosis of oral soft tissues, as Arecoline, an active alkaloid found in betel nuts has been reported to stimulate fibroblasts with 150% increase [4–6] in collagen production. This precancerous lesion converts to squamous cell carcinoma and the malignant transformation rate [7] is in the order of 7.6%. This disease is now a public health issue in many parts of the world including the UK [8], South Africa [4], and many Southeast Asian countries [9,10]. The most intriguing part of OSF is that, the cause or origin of the disease is yet to be ascertained. However, studies have shown that, apart from usage of tobacco products, other factors such as intake of excess of chillies, deficiency in trace metals and vitamins, allergic reactions to certain dietary constituents as well as genetic and immunological reasons [11–13] are attributed as causes of this disease. Currently, the diagnosis of OSF and their grading with respect to the progression and malignant potenti- ality is mainly qualitative. Interpretation based on histopatholo- gical techniques varies from one expert to another depending upon their acumen. No specific quantitative evaluation procedure is available till date to assess and analyze the vital histopatholo- gical changes [1] to explain these pathological conditions precisely. Histopathologically OSF is characterized by concomitant pre- sence of less vacularized collagenous connective tissue with overlying atrophic epithelium in oral mucosa [14], which may be associated with variable degrees of dysplastic changes also. Atrophy of the muscle fibers and varied degree of chronic inflammatory infiltrate are also recorded in this pathosis. Here it is interesting to note that in OSF, though malignancy develops only in the epithelium, significant pathological changes are ARTICLE IN PRESS Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/cbm Computers in Biology and Medicine 0010-4825/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.compbiomed.2009.09.004 Ã Corresponding author. Tel.: +913222 28880; fax: +913222 28881. E-mail address: chandanc@smst.iitkgp.ernet.in (C. Chakraborty). Computers in Biology and Medicine 39 (2009) 1096–1104