The intranuclear cleft of the intervertebral disk: magnetic resonance imaging.

Abstract

Three cadaver spines, 40 patients who were symptomatic for lumbar disc disease and 10 healthy subjects were examined by MR. T2 weighted spin echo images were used to evaluate the character of an intranuclear cleft. This cleft appears identical to annular tissue both on T2 weighted images and histologically. A 120 ms TE, 3 s TR image was used to delimit the normal nucleus pulposus from the annulus. The incidence and age distribution of the cleft were calculated. An intranuclear cleft was present in all normal discs in both control and symptomatic subjects who were 30 yr of age and older. If present in 1 disk, it was also present in 94% of the other discs in the same subject. This cleft represents a normal anatomic structure and appears to be a constant feature in subjects 30 yr of age or older. Its absence, in the presence of an increased signal intensity within the disc, suggests a pathological process with a long T2 value, such as inflammation.