A C.A.T. scan stands for Computerized Axial Tomogram. This is a computer version of specialized xray which allows views of internal anatomy not visualized by conventional plain xray. Cross-sections and reconstructions of the images in different planes (including 3-D) allows different perspectives on the anatomy. This test is often used for visualization of the internal bone anatomy of the spine and the spinal canal. The C.A.T. scan is frequently performed for a specific anatomic region of the spine (cervical, thoracic, lumbar). A special C.A.T. scan may be helpful in determining if a spine fusion is solid (completed union of bone between two bone structures).