Accurate Determination of Lung Boundary from Lung Apex to Costophrenic Angle in Chest Radiographs

Determination of the lung boundary from lung apex to costophrenic angle is important for image registration in temporal subtraction and contralateral subtraction which are CAD schemes to detect lung nodules in chest radiographs. In this paper we propose a rule-based algorithm for determination of the lung boundary from lung apex to costophrenic angle in chest radiographs. We made experiments using all 247 images of JSRT database which is a public database. As the result, for 246 images, the proposed algorithm could accurately determine the lung boundary from lung apex to costophrenic angle for each of right and left lungs.