Fig 3.

T2-weighted images illustrating 4 Pfirrmann disk grades. Midsagittal images show a grade II disk (A) with high signal intensity in the central region and lower signal intensity in the peripheral region, clearly distinguishing the nucleus pulposus region from the annulus fibrosus; a grade III disk (B) with lower signal intensity in the central region and less clear distinction between the nucleus pulposus region and annulus; a grade IV disk (C) with homogeneously low signal intensity and with no distinction of the nucleus pulposus region and annulus; and a grade V disk (D), which is collapsed.