Influence of age and sex on lumbar vertebral morphometry determined using sagittal magnetic resonance imaging.

We evaluated age-related changes in the morphometric features of lumbar vertebrae in both sexes using magnetic resonance imaging (MRI). Midsagittal MRI scans of 366 individuals (156 males, 210 females; 25-82 years old) were evaluated retrospectively. The anterior height (H(a)), central height (H(c)), posterior height (H(p)), and anteroposterior diameter (D) of the body of each lumbar vertebra were measured. These measurements were used to calculate three indices, namely, the anterior wedge index (H(a)/H(p)), the biconcavity index (H(c)/H(p)), and the compression index (H(p)/D). The values of each of the three indices for the upper lumbar vertebrae of females were higher than those of the same vertebrae in males. The values of the compression index for all lumbar vertebrae decreased with age in females, whereas in males the compression index of the L1-L4 vertebrae decreased with age. No significant changes were observed in the value of the anterior wedge index in either sex. The biconcavity indices of the L1 and L5 vertebrae decreased with age in males. These results may be useful for evaluating age-related morphological changes that occur in the lumbar vertebrae.