Fig. 1.

Axial and mid-sagittal T2-mappings of L4/5 intervertebral discs. a) Healthy disc (grade 1) with clear demarcation of NP/inner/outer annulus; the annulus shows a uniform thickness. b) Moderately degenerated disc (grade 2); demarcation becomes unclear, loss of orientation of annulus fibres, uniform thinning of the AF. c) Moderately degenerated disc (grade 2) with unilateral, posterior thinning of the AF and relatively healthy contralateral AF (Watanabe et al., 2007).