1. MRI of the axial skeletal manifestations of ankylosing spondylitis
D.S Levine, S.M Forbat, A Saifuddin 
Clinical Radiology 
Volume 59, Issue 5, Pages (May 2004)
DOI: /j.crad

2. Figure 1
Early sacroiliitis. (a) Coronal oblique STIR image and (b) axial T2W fast spin-echo images of the sacroiliac joints showing sacral bone marrow oedema parallel to the sacroiliac joints.
Clinical Radiology  , DOI: ( /j.crad )

3. Figure 2
Established sacroiliitis. Axial proton density weighted image through the sacroiliac joints demonstrating subchondral sclerosis either side of the joints.
Clinical Radiology  , DOI: ( /j.crad )

4. Figure 3
Ankylosis of the sacroiliac joints. Axial proton density weighted image through the sacroiliac joints demonstrating continuous medullary bone across the obliterated joint, more clearly demonstrated on the right side.
Clinical Radiology  , DOI: ( /j.crad )

5. Figure 4
Romanus lesion. (a) Sagittal T1W spin-echo and (b) T2W fast spin-echo sequence at the thoracolumbar junction demonstrating focal oedema at the anterior discovertebral junction (arrows).
Clinical Radiology  , DOI: ( /j.crad )

6. Figure 5
Syndesmophytes. (a) Sagittal T1W spin-echo and (b) T2W fast spin-echo sequence of the lower thoracic and lumbar spine showing lower thoracic kyphosis and ossification of the anterior annulus resulting in vertebral body fusion from T7 to T10. Discovertebral lesions and hyperintense nuclear disc calcification are also noted in the lumbar region (arrows).
Clinical Radiology  , DOI: ( /j.crad )

7. Figure 6
Type 1 discovertebral lesion. (a) Sagittal T1W spin-echo and (b) fat-suppressed T2W fast spin-echo sequence of the lower thoracic and lumbar spine showing a Schmorl's node in the inferior end-plate of T9 with marrow oedema on both sides of the disc space. (c) Pre- and (d) post-contrast axial T1W images through the inferior end-plate of T9 showing enhancement within the herniated disc and also of the marrow oedema.
Clinical Radiology  , DOI: ( /j.crad )

8. Figure 6
Type 1 discovertebral lesion. (a) Sagittal T1W spin-echo and (b) fat-suppressed T2W fast spin-echo sequence of the lower thoracic and lumbar spine showing a Schmorl's node in the inferior end-plate of T9 with marrow oedema on both sides of the disc space. (c) Pre- and (d) post-contrast axial T1W images through the inferior end-plate of T9 showing enhancement within the herniated disc and also of the marrow oedema.
Clinical Radiology  , DOI: ( /j.crad )

9. Figure 7
Type 3 discovertebral lesion. (a) Sagittal T1W spin-echo and (b) fat-suppressed T2W fast spin-echo sequence of the lower thoracic and lumbar spine showing a chronic type 3 discovertebral lesion at L1/2. The disc space is narrowed and irregular with foci of hyperintensity on T2. A combination of fatty and oedematous end-plate changes is present. An acute fracture is seen at T10/11. This is differentiated from disc calcification since the disc shows normal SI on T1W while being hyperintense on T2W due to oedema. Solid-type disc calcification is also present at several levels (arrows).
Clinical Radiology  , DOI: ( /j.crad )

10. Figure 8
Annular calcification. (a) Sagittal T1W spin-echo and (b) T2W fast spin-echo sequence of the lumbar spine showing hyperintensity on both T1W and T2W in the anterior and posterior annulus of the upper lumbar discs, consistent with calcification. Ankylosis has not yet occurred. A Romanus lesion is seen at L4/5.
Clinical Radiology  , DOI: ( /j.crad )

11. Figure 9
Disc calcification. (a) T2W fast spin-echo sequence of the lumbar spine showing hyperintensity in the L2/3, L3/4 and L5/S1 intervertebral discs due to radiographically occult disc calcification. (b) Lateral radiograph of the mid-lumbar spine shows anterior ligamentous ossification only.
Clinical Radiology  , DOI: ( /j.crad )

12. Figure 10
Costovertebral joint arthropathy. (a) Sagittal T1W spin-echo MRI and (b) sagittal CT MPR of the thoracic spine showing sclerosis in the posteroinferior margin of the vertebral body. This is manifest as low SI on T1W MRI and corresponding medullary sclerosis on CT. (c) Axial T2W MRI and (d) CT showing irregularity and subchondral sclerosis affecting the left costovertebral joint.
Clinical Radiology  , DOI: ( /j.crad )

13. Figure 10
Costovertebral joint arthropathy. (a) Sagittal T1W spin-echo MRI and (b) sagittal CT MPR of the thoracic spine showing sclerosis in the posteroinferior margin of the vertebral body. This is manifest as low SI on T1W MRI and corresponding medullary sclerosis on CT. (c) Axial T2W MRI and (d) CT showing irregularity and subchondral sclerosis affecting the left costovertebral joint.
Clinical Radiology  , DOI: ( /j.crad )

14. Figure 11
Costovertebral joint ankylosis. Axial T1W spin-echo MRI through the mid-thoracic region showing bilateral costovertebral joint ankylosis, manifest as obliteration of the joint space and continuous medullary bone across the joint.
Clinical Radiology  , DOI: ( /j.crad )

15. Figure 12
Facet joint and neurocentral joint ankylosis. (a) Parasagittal T1W spin-echo MRI through the cervical spine demonstrates multilevel ankylosis of the facet joints. (b) Parasagittal T1W spin-echo MRI through the cervical vertebral bodies demonstrates multi-level ankylosis of the neurocentral joints of Luschka (arrows).
Clinical Radiology  , DOI: ( /j.crad )

16. Figure 13
Ligamentum flavum ossification. Axial T2W MRI through the lumbar spine demonstrates bilateral ossification of the ligamentum flavum (arrows). Note also facet ankylosis.
Clinical Radiology  , DOI: ( /j.crad )

17. Figure 14
Erosion of the dens. Sagittal T1W spin-echo MRI shows chronic erosion of the odontoid peg.
Clinical Radiology  , DOI: ( /j.crad )

18. Figure 15
Atlanto-axial fusion. Sagittal T2W MRI of the cervical spine demonstrates spontaneous atlanto-axial fusion.
Clinical Radiology  , DOI: ( /j.crad )

19. Figure 16
Cervical spine fracture. (a) Sagittal CT MPR of the cervical spine demonstrates a fracture through the C5/6 disc space. (b) Sagittal T1W MRI demonstrates fracture of the ossified anterior longitudinal ligament (arrow).
Clinical Radiology  , DOI: ( /j.crad )

20. Figure 17
Thoracic fracture with cord compression. (a) Sagittal T1W spin-echo and (b) T2W fast spin-echo MRI through the lower thoracic region demonstrates a fracture through the subchondral region extending posteriorly through the ossified interspinous ligament. Compression of the cauda equina and tip of conus is evident.
Clinical Radiology  , DOI: ( /j.crad )