Subscribe to RSS
DOI: 10.1055/s-0029-1241443
Computer-aided classification of colorectal polyps based on vascular patterns
Background and study aims: The aim of the present study was to develop and evaluate a computer-based method for automated classification of colorectal polyps on the basis of vascularization features.
Patients and methods: In a prospective study with 128 patients who underwent a zoom NBI colonoscopy, 209 detected polyps were imaged and subsequently removed for histological analysis. The proposed computer-based method consists of several steps: preprocessing, vessel segmentation, feature extraction and classification. The results of the automatic classification were compared to those of human observers, who were blinded to the histological gold standard.
Results: The consensus decision between the human observers resulted in a sensitivity of 93.8% and a specificity of 85.7%. Making a safe decision in case of a discrepancy yielded a sensitivity of 96.9% and a specificity of 71.4%. The overall correct classification rates were 91.9% and 90.9% for the consensus and safe decision, respectively. With suitable parameterization for the computer-based approach a sensitivity of approximately 90% and a specificity of approximately 70% was achieved. In this case the overall correct classification rate was 85.3%. To establish a direct comparison of the human and automatic results, we selected computer-based results with sensitivities identical to the results of consensus (93.8%) and safe decision (96.9%). The computer-based classification resulted in a specificity of 61.2% for a sensitivity of 93.8%, respectively 53.1% for a sensitivity of 96.9%.
Conclusions: The study has shown that automatic classification of colon polyps based on NBI vascularization features is feasible. Further research needs to improve the promising performance of the automated classification system.