A method and system for nodule feature extract using background contextual information in chest x-ray images is disclosed. In order to detect false positives in nodule candidates for a chest x-ray image, background contextual information, such as contextual vessel tree information, is defined in the chest x-ray image. Features are extracted for each nodule candidate based on the background contextual information, and the extracted features are used to detect whether each nodule candidate is a false positive or a genuine nodule.