Spiral CT scan is a conventional computerized axial tomography scan. It is an x-ray procedure which combines many x-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body. This scan is used to define normal and abnormal structures in the body and/or assist in procedures by helping to accurately guide the placement of instruments or treatments. Spiral CT scanning can permit greater visualization of blood vessels and internal tissues, such as those within the chest cavity. This form of scanner may be particularly helpful in the rapid evaluation of severe trauma injuries, such as those sustained in automobile accidents.