1. An "inflammatory" type characterized by a defect in one or two neighbouring vertebral bodies surrounded by reactive sclerosis and associated with varying degrees of disc space narrowing.
2. A "non-inflammatory" type showing predominantly osteolytic destruction with little disc space narrowing and sclerosis.
The MRI characteristics of the disc also help to distinguish the Anderson lesion from infection spondylitis. In most cases the major part of the disc shows decreased signal intensity on T2 weighted images (due to fibrous replacement of the disc), while generalized increased signal intensity due to inflammatory oedema and granulation tissue would be expected in established acute infective spondylitis
Erosions on the antero-lateral margins of the vertebrae with sclerosis associated with enthesitis are known as Romanus sign or Shiny corner sign.
Focal areas of increased signal intensity in disc correspond to active inflammatory granulation tissue.
Bone marrow fat deposits can be seen as hyperintense areas in vertebrae on both T1 and T2 sagittal images.
In severe cases, ankylosis followed by kyphosis noted.
Paravertebral soft tissue masses are uncommon as seen in infective diskitis.
No comments:
Post a Comment