MRI ANALYSIS OF LUMBAR INTERVERTEBRAL DISC HEIGHT IN YOUNG AND OLDER POPULATIONS

Measurements of length and section area on MR images are made conventi onally by the manipulation of a tracker ball to move a cursor to defin e end points or delineate boundaries, This operator-dependent method l acks the objectivity that computer-based image analysis techniques, su ch as edge-detection algorithms, can give, me describe an image analys is routine, based on earlier work by Vincent and Soille using algorith ms of mathematical morphology, for automatically extracting the bounda ry of lumbar intervertebral discs on MR images, This is applied to the automatic measurement of the maximum disc space height and section ar ea of non-degenerate intervertebral discs on MR images obtained for he althy male subjects of two distinct age ranges, i.e. twenty 20- to 30- year-olds and twenty 50- to 60-year-olds. Throughout the levels L1 to L4, intervertebral disc height is found to be significantly greater (P = .0003 to .0161) in the older than in the younger age group. The dat a support a model of the spine in which the disc adopts a more concave form as a result of microfracturing of the end plates during adult li fe.