Prevalence of lumbar high-intensity zone: assessment using a screening tool independent of spinal symptoms.

High-intensity zone is an area of high-intensity signal within the posterior annulus fibrosus observed in magnetic resonance imaging; initially described in painful discs, recent studies have described similar prevalence in symptomatic and asymptomatic subjects. Since its' prevalence in the general population has not been established, we used a screening tool independent of spinal symptoms to determine high-intensity zone prevalence. We studied 217 patients evaluated with abdominal-pelvic magnetic resonance imaging; we looked for high-intensity zone, disc degeneration, spondylolysis, spondylolisthesis, Modic changes and scoliosis. We determined if these variables, age and sex affected the presence of high-intensity zone; through a logistic regression analysis we evaluated their independent effect. Patients' mean age was 56.3±17.4 years; 66.8% were females. Prevalence of high-intensity zone (11.06%) was larger in males (18.06%) than females (7.59%), p = 0.02. Patients with and without high-intensity zone did not differ in age or presence of scoliosis. High-intensity zone was more frequent in degenerated discs, but not in levels with spondylolisis, spondylolisthesis or Modic changes. Male sex (OR = 2.3, 1.04-5.38) and disc degeneration (OR = 6.76, 1.77-25.81) independently influenced the presence of high-intensity zone. The prevalence of high-intensity zone in this sample of the general population, including 217 subjects, was 11.06%. Similarly, a recent meta-analysis mentioned a 9.5% prevalence in asymptomatic subjects; on the other hand it stressed a 10.4% prevalence in symptomatic subjects. All these data do not plead for a strict correlation between high-intensity zone and low back pain complaints.