正常CT解剖.ppt

Computed Tomography of The Chest Dong Yuchao Changhai Hospital Rsepiratory Department The Theory The C.T. scan machine takes images using x-rays. The patient lies on the C.T. table and is moved into the C.T. gantry. This part of the machine contains an x-ray tube and x-ray detectors that spin rapidly around the patient taking x-ray measurements. The measurements are fed to a specialized computer that assembles the measurement data into a series of C.T. pictures. The images are viewed as a series of standard 2D(dimension) pictures. When required, the image data can be used to construct 3D pictures of the body region that has been examined. CT number The attenuation values, or CT numbers, are expressed as Hounsfield units(HU). Window Setting (Level/center and width) Special Windows Special Windows Special Windows Partial Volume Artifact The CT number calculated for a layer is an average attenuation for all the contents. When the object of interest dose not completely fill a given layer, the CT number will partly reflect the attenuation of whatever extraneous matreial fills the rest volume. The change in CT number is known as a partial volume artifact. Normal Anatomy Mediastinum Anterior: thymus, lymph nodes, mammary vessels Middle: pericardium, heart, great vessels, trachea, main bronchi, fat, nerves, lymph nodes Posterior: esophagus, descending aorta, nerves, azygos and hemiazygos veins, lymph nodes Carotid Arteries Level RCC: right common carotid LCC: left common carotid RSA: right subclavian artery LSA: left subclavian artery RBV: right brachiocephalic vein LBV: left brachiocephalic vein Brachiocephalic Artery Level (Sterno-clavicular Joint Level) BA: brachiocephalic artery SCJ: Sterno-clavicular Joint LCC: left common carotid LSA: left subclavian artery RBV: right brachiocephalic vein LBV: left brachiocephalic vein Aortic Arch Level SVC: superior vena cava IMV: internal mammary vessels ＊: pretracheal-retrocaval space