医学影像学英语名词解释.doc

Accessory lobe: additional pleura extending into the pulmonary segments, forming additional pulmonary lobe. The most commonly seen are azygos lobe in the inner zone superior to the right hilum, and inferior accessory lobe in the inner zone of inferior lobe. Air bronchogram sign : Because the air in the alveoli is replaced by exudates, while the air in the bronchus is not displaced and remain patent. This produces contrast between the air in the bronchial tree and the surrounding airless parenchyma. Ankylosis of joint: bony or fibrous tissues connect the articular surface. In plain film, it is characterized by a narrowed articular space. Whether the trabeculae pass through the articular space distinguishes bony or fibrous ankylosis. Artificial contrast:Those organs or spaces lack of natural contrast，can be renderde to be visible by means of contrast agents to create an artificial contrast. Bone destruction: localized absence of normal bone tissue and replaced by pathological tissues. Both the cortical and spongy bone are destructed because of either the absorption of bone tissues or the activation of osteoclasts by the pathological tissue. In plain film, it appears to be a decrease in bone density locally, absence of normal bone tissue, and probably worm-eaten or sievelike cortical bone. Cavity: formed as a result of the expulsion of necrotic tissues through bronchus. It can be devided into worm-eaten, thin-walled, and thick-walled cavities. often seen in TB, pulmonary abscess, and lung cancer. Codman’ triangle: Codman’ triangle is due to direct erosion of the already formed periosteal new bone by fast growing tumor. Colles’ fracture : The fracture line is within 2-3cm from the articular end of the radius, the distal fragment is displaced dorsally and radially and is often associated with fracture of the styloid process of the ulna and separation of the radioulnar joint. CTR: the ratio between maximal transverse diameter of the heart: summation of maximal diame