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. The injection of iodine based contrast into the spinal fluid filled sac surrounding the nerves and/or spinal cord promotes better definition of those structures than the images obtained on the regular C.A.T. scan. Cross-sections and reconstructions of the images in different planes (including 3-D) allows different perspectives on the anatomy. This test is often used to visualize the spinal cord and nerves in relation to the surrounding spine structures (bone, joint, disc, etc) The C.A.T. scan with contrast is frequently performed for a specific anatomic region of the spine (cervical, thoracic, lumbar).