This policy addresses whole-body computed tomography (CT) scanning or whole-body CT screening as a potential preventive measure for individuals who have no signs or symptoms of disease. CT scan is synonymous with computed axial tomography (CAT) scan.
Whole body CT scans, encompassing the body from the neck to the pelvis, have been proposed as a general screening or scanning test for preventive, proactive or early detection methods or measures for healthy individuals who do not have any signs, symptoms or suspicion of disease, including but not limited to the following examples:
- aneurysms, or
- cysts in any location, or
- emphysema, or
- enlarged lymph nodes, or
- gallstones, or
- hiatal hernia, or
- kidney stones, or
- liver disease, or
- osteoporosis, or
- suspicious masses in other organs.
Often the CT screening test is marketed directly to the patient and is offered at a radiology center or through mobile CT scanners that travel from community to community. The whole body CT is performed without intravenous contrast and can be completed within ten minutes.
Types of CT systems that are promoted for screening may include, and are not limited to:
- Full-body ultrafast (electron-beam) computed tomography (EBCT),Cine computed x-ray tomography, Dynamic contrast enhanced CT, Dynamic spatial reconstructor,
- Spiral CT,Helical CT, Multidetector row CT, or Multislice CT.
Frequently, the type of CT scanner used for whole body imaging is the EBCT, which utilizes advanced high-speed digital technology with rapid scan times to freeze moving structures (stop-action pictures) and to reduce or eliminate distortion and/or blurring usually created by motion. The scan needs only one-tenth of a second to make an x-ray image of the body area. This rapid scanning is made possible by an electron beam rather than the mechanical movement of an x-ray tube as required by conventional CT scanners.
Helical or spiral CT uses different technology than EBCT. In recent years, helical CT has gained widespread clinical acceptance over older axial CT scanning technologies and EBCT. Helical CT may be performed on scanners with either single-detector or more advanced multi-detector CT or multi-slice CT imaging capabilities.
All of the technologies referred to above represent types of CT scans. Both EBCT and spiral or helical CT have demonstrated benefit over older generation scanners, due to their rapid acquisition times which reduce potential image degradation from motion (e.g., body movement as well as cardiac motion, respiration and bowel peristalsis, depending on the anatomic region under investigation).
The importance of CT is well established in numerous clinical scenarios, a few of which include diagnostic assessment for abnormal symptoms, physical exam and laboratory findings, trauma evaluation, and therapy planning. The intent of CT imaging under these circumstances is considered distinctly different from whole body CT as a screening test.
NOTE: This policy addresses whole-body CT scan for screening. Different applications of rapid CT scanning as a screening or diagnostic test have been addressed in individual policies. Refer to the specific policies for those applications, e.g., cardiac or coronary artery, colonoscopy, lung, etc.