Age-related apparent diffusion coefficients of lumbar vertebrae in healthy children at 1.5 T

Background Diffusion-weighted magnetic resonance imaging with apparent diffusion coefficient (ADC) calculation is important for detecting bone marrow pathologies. Objective To investigate age-related differences of lumbar vertebral body ADC to establish normal values for healthy children. Materials and methods Forty-nine healthy children without any history of oncological or hematological diseases (10.2±4.7 years, range: 0–20 years) were included in this retrospective study. All magnetic resonance imaging (MRI) examinations were performed at 1.5 T and with similar scan parameters. The diffusion-weighted sequences were performed with b values of 50, 400 and 800 s/mm 2 . ADC values were measured by placing regions of interest at three different levels within each lumbar vertebral body (L1 to L5). ADC values were analyzed for different age groups (0–2 years, 3–6 years, 7–11 years, 12–14 years, 15–20 years), for each vertebral and intravertebral level. Results The mean ADC of the whole study group was 0.60±0.09 × 10 −3 mm 2 /s. Children between the ages of 12 and 14 years had significantly higher ADC compared to the other age groups ( P ≤0.0003). ADC values were significantly higher in the 1st lumbar vertebral body compared to the other levels of the lumbar spine ( P <0.005) with the exception of L5, and in the upper third of the vertebral bodies compared to the middle or lower thirds ( P ≤0.003). Conclusion The age-, vertebral- and intravertebral level-dependent differences in ADC suggest a varying composition and cellularity in different age groups and in different locations.