Disc desiccation is an extremely common degenerative change of intervertebral discs. The incidence climbs with age, and to a large degree a gradual desiccation is a 'normal' part of disc aging. It results from replacement of the hydrophilic glycosaminoglycans within the nucleus polposus with fibrocartilage.
Although commonly thought result in reduced disc height due to reduction in nucleus polposus volume, this has been shown not to be the case. Rather disc height loss is as a result of annular bulging and vertebral endplate bowing.
On imaging, the disc loses its high T2 signal, and the horizontal midline low signal cleft is no longer apparent.