Modeling, segmentation, and caliber estimation of bronchi in high resolution computerized tomography

Accurate estimation of bronchial caliber in high resolution computerized tomography (HRCT) is essential for physicians in the management and following of patients with airway disease. Although there are at present different methods of bronchi analysis, none of them can provide an absolute diagnosis of bronchial caliber. The present paper addresses a new approach of bronchi segmentation in HRCT in order to estimate the bronchial caliber. The method developed is based on mathematical morphology theory, and relies on morphological filtering, marking techniques derived from the concept of connection cost, and conditional watershed-based segmentation. In order to evaluate the robustness of the segmentation and the accuracy of the caliber estimates, a realistic bronchi modeling based on physiological characteristics has been developed. It is shown that, according to the size of the bronchi, the estimation accuracy is up to 90%.