Baastrup's disease prevalence across various age groups and its association with degenerative changes: insights from STIR sequence in MRI.

PURPOSE:Baastrup's disease is characterized by abnormal contact between adjacent spinous processes. Our study is the first to systematically incorporate the STIR sequence, recognized for its heightened sensitivity to fluid and edema, into the MRI protocol for diagnosing Baastrup's disease in symptomatic individuals. The objective is to determine its prevalence and association with lumbar spinal degenerative changes. MATERIALS AND METHODS:Lumbar spinal MRI examinations of 375 patients performed between January 2021 and 2022 were retrospectively reviewed by two radiologists. Baastrup's disease was diagnosed based on meeting any of the following criteria: lumbar interspinous bursitis, hyperintense signal changes in adjacent spinous processes, and ligaments on the STIR sequence. The study also investigated the presence of degenerative changes and interreader agreement among radiologists. RESULTS:Baastrup's disease was found in 141 of 375 individuals (37.8%). It correlated significantly with degenerative lumbar changes such as bulging (P = 0.0012), herniation (P = 0.0033), disc degeneration (P = 0.0013), Modic changes (P = 0.034), facet osteoarthritis (P = 0.0041), spinal stenosis (P = 0.005), and anterolisthesis (P = 0.0049). No significant associations were observed with gender (P = 0.468) or retrolisthesis (P = 0.167). Its occurrence increased gradually, peaking at 87.5% in individuals aged 80 and above. Radiologists showed complete agreement with Baastrup's diagnoses. CONCLUSION:Baastrup's disease is more commonly observed than being considered rare, displaying an incremental occurrence with increasing age in symptomatic individuals notably discernible on the STIR sequence. Using the STIR sequence seems to promote a consensus among radiologists, irrespective of their experience levels.