General Spine

Hoang, M, Trang, D.O.
Walter, S, Bartynski, M.D., Non ASSR Member
William, E, Rothfus, M.D., Non ASSR Member
Jawad, Tsay, M.D., Non ASSR Member
Marion, Hughes, M.D., Non ASSR Member
Bryon, Nastasi, M.D., Non ASSR Member

Paper/Mentor

Purpose

Peripheral annular fissures (annular high intensity zones [HIZ]) identified on T2 weighted MR imaging are known to correlate with diskogenic low back pain as demonstrated at provocation lumbar diskography. (1) Studies have also demonstrated that enhancement may be common in peripheral annular fissures and T2 conspicuity may decrease with time. (2)
The purpose of this study was to correlate the provocation diskogram response and diskogram imaging appearance of lumbar disks with peripheral annular fissures as demonstrated on pre-procedure combined unenhanced and enhanced MR imaging.

Methods & Materials

Over the course of 5 years, 43 patients were identified who had combined unenhanced and enhanced lumbar MR imaging available as their pre-procedure study prior to provocation lumbar diskography. Peripheral posterior annular fissure was identified as focal enhancement of the annulus on post-contrast imaging at 28 un-operated disk levels in 19 of these patients (10 female, 9 male; age range 19-62 years, average 41 years) and form the focus of this study.

Signal abnormality of the posterior annulus was graded on the sagittal T2 weighted MR sequence utilizing a 4 point scale by consensus of three experienced neuroradiologists: grade 1: negative/barely visible; grade 2: slight posterior annular signal; grade 3: obvious bright posterior annular signal; grade 4: posterior annular signal comparable to CSF. Grade 1-2 was considered no annular fissure, grade 3-4 was considered likely or definite annular fissure.

Features identified at diskography were tabulated for each disk with annular fissure including: pain response (concordant, discordant, negative), anesthetic response, diskogram and post-diskogram imaging appearance (radial defect/tear, degenerative change, diskographic contrast leakage).

Results

Pain was provoked at diskography in 24 of 28 (85.7%) disk levels with an annular fissure identified on post-contrast MR imaging (concordant: 18 (64.3%), discordant: 6 (21.4%)) with 4 disk levels normal. Traditional HIZ (annular fissure) was judged to be present on sagittal T2 weighted sequence in only 15 of 28 disks (grade 3-4) and was judged not to be present in 13 of 28 disks (grade 1-2).
Diskographic contrast leakage was identified in 12 disks, with 16 disks being contained. Provoked pain response to intradiskal lidocaine injection included: total/substantial pain relief: 6 disks (leak: 6); partial improvement: 6 disks (leak: 2, contained: 4); no improvement 10 disks (leak: 2; contained: 8) with no lidocaine injected at 6 levels (normal: 4; volume restriction: 2).

Conclusion

Annular fissure as identified on post-contrast MR imaging shows high correlation with diskogenic low back pain identified at provocation lumbar diskography. Annular fissures may be missed on sagittal T2 weighted imaging due to lack of sufficient signal intensity. Routine application of post-contrast MR imaging in lumbar spine evaluation may markedly improve prediction of diskogenic low back pain. Discordant pain might represent disks that have undergone partial healing.

References/Financial Disclosures

1. Schellhas KP, Pollei SR, Gundry CR, et al. Lumbar disc high-intensity zone. Correlation of magnetic resonance imaging and discography. Spine 1996;21:79-86

2. Munter FM, Wasserman BA, Wu HM, et al. Serial MR Imaging of Annular Tears in Lumbar Intervertebral Disks. AJNR Am J Neuroradiol 2002;23:1105-1109

Nothing to disclose.