Helical CT scan is a special type of CT scan technique that involves continuous movement of the patient through the scanner with the ability to scan faster and with higher definition of internal structures. Helical 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. A helical CT scan is also referred to as spiral CT scans.