MR imaging of thoracic annular fissures.

Objective: Annular fissures are common findings on MR studies of the lumbar spine but have not been specifically examined in the thoracic spine. We sought to review the prevalence and stability of MRI imaging features of thoracic annular fissures and the association of thoracic AFs with intervertebral degenerative disk changes.

Materials And Methods: We surveyed 10 years of MRI studies in which patients had one or more repeated examinations of the thoracic spine. For every annular fissure, we recorded its imaging features on all pulse sequences and the evolution of those imaging findings across all time periods.

Results: We reviewed 210 patients and discovered that 66 (31.4%) had at least one thoracic annular fissure. The presence of annular fissures was positively correlated with older age and male gender. The initial annular fissure was always hyperintense on T2WI and annular fissures remained hyperintense on T2WI over time in all cases but showed less hyperintensity in 23.9% (n = 39/163) and more hyperintensity in 4.9% (n = 8/163). The rate of concomitant disk bulges was 85.8% (n = 140/163). Of the 71 annular fissures in which gadolinium-enhanced studies were performed, 20 (28.1%) showed enhancement and 14/20 (70%) annular fissures showed persistent enhancement over time (mean follow-up = 39.6 ± 44.1 months).

Conclusion: Thoracic annular fissures rarely resolve, remain hyperintense on T2WI, and, if they enhance, that enhancement generally persists.