High intensity zone in lumbar spine and its correlation with disc degeneration

Purpose ; To investigate the prevalence, clinical significance of high intensity zone (HIZ), and associated disc degeneration. Materials and methods ; We undertook retrospective analysis of 228 patients, aged from 15 to 55 years, who had undergone magnetic resonance (MR) imaging of lumbar spine in outpatient clinic from 2013 to 2014. HIZ was defined as a presence of high intensity signal in the annulus on T2-weighted images. All HIZ positive discs were classified according to Pfirrmann grading system for presence of disc degeneration. Results ; Forty-three patients (18.8%) with 53 intervertebral discs demonstrated HIZ. There was no significant predominance about age and gender for the presence of HIZ. HIZ occurred mainly at L4-5 (43.3%) and L5-S1 (30.2%) levels, infrequently at L3-4 (17%) and rarely at upper levels. The prevalence of disc degenerations with Pfirrmann grade 3, 4, and 5 were significantly higher in HIZ positive patients than in randomly selected 35 HIZ negative patients (64% vs. 46%, respectively). Conclusion ; In this study we identified that the presence of HIZ was directly proportional to increased incidence of disc degeneration in remaining lumbar discs. The prevalence of significant degeneration was significantly higher in HIZ positive patient at lower three lumbar levels.