Age-related Distribution of Red and Yellow Bone Marrow in Lumbar Spine of Normal Chinese Adults: MR Study

Backgound: Lumbar spine is one of the most common sites for metastases or other bone marrow infiltration diseases. A retrospective study was undertaken using magnetic resonance (MR) images of normal lumbar spine in Chinese adults to document the red and yellow bone marrow distribution in various age-related groups. Hopefully this can provide a useful guide for differentiating normal from abnormal bone marrow of the lumbar spine. Materials and Methods: We reviewed MR examinations of lumbar spine of 67 patients without bone marrow disease or primary neoplasms, including 29 males and 38 females, from 21 to 80 year-old (mean age: 53.7 years). Sagittal Ti-weighted spin-echo images (TR/TE=400/li) were evaluated and classified as four distinct patterns. Pattern I shows that the vertebral body has a uniformly low signal except for linear areas of high intensity along the basivertebral vein. Pattern Ⅱ reveals bandlike or triangular areas of high signals in the periphery of the vertebral body. Pattern Ⅲ shows diffusely distributed areas of high signals in the vertebral body; the pattern is further subclassified as Ⅲ a or Ⅲ b depending on the areas of bright signals less than, or larger than, 5 mm, respectively. Results: Four of 5 patients (80%) with pattern I bone marrow were younger than 40 years of age. All pattern Ⅱ(16/16), 76.8% of pattern Ⅲa, and 87.5% pattern Ⅲb patients were older than 40 years old. Conclusion: Our MR study revealed the normal red-to-yellow marrow conversion pattern in the lumbar spine of Chinese adults. Familiar with this bone marrow pattern of the population here will aid in differentiating abnormal from normal bone marrow.