CT evaluation of the lumbar discs

1-The discs are soft tissue structures, so they should be evaluated in soft tissue window.

2-The section suitable to judge the disc is the section just passing in the center of that disc, this could be judged by comparing the density of the disc by the density of para vertebral muscles which should be the same.

3-The angle of the section on the scanogram should be parallel to the angle of the disc to achieve that.

4-Normally the posterior border of the disc should be concave(minor or major concavity should be considered normal).

5-If the posterior border of the disc becomes straight or convex, this means that this disc is abnormal.

6-At the level of L5-S1 and because this disc is subjected to the whole weight of the body, so you can allow its posterior margin normally convex, look to the next section, if the disc margin is still convex you can consider it abnormal, but if it is not convex, you can consider it normal.