We carried out MRI studies of 74 patients with end-plate and vertebral bone-marrow changes associated with degenerative lumbar disc disease. Abnormalities were classified into type A, with decreased signal intensities, and type B, with increased signal intensities on T1-weighted spin-echo images. Twenty-seven (73%) of the 37 patients with type-A changes had low back pain, in contrast to only four (11%) of the 37 patients with type-B changes. Lateral flexion-extension radiographs showed hypermobility in 26 patients (70%) with type-A changes, and in only six (16%) with type-B changes. Type-A changes correlated with segmental hypermobility and low back pain, while type-B changes were more common in patients with stable degenerative disc disease.

Our results suggest that the XbaI site polymorphism is associated with curve severity. DNA analysis may predict curve progression.

Bone marrow edema was not present on initial MR imaging of osteonecrosis. Bone marrow edema should be considered a marker for potential progression to advanced osteonecrosis, and careful examinations for osteonecrosis are necessary when bone marrow edema is seen.

In asymptomatic hips, abnormal findings regarding the shape and signal intensity of the acetabular labrum can be detected by means of MR imaging. The fact that the findings vary according to age and labral portion should be considered in interpreting MR images in patients suspected of having a labral lesion.

Foramen magnum decompression for neural axis malformations could prevent permanent neurologic complications during scoliosis surgery. There is little risk of neurologic complications in patients with "idiopathic" scoliosis whose neurologic status is normal, even if these patients have a neural axis malformation on MRI.