MR imaging determination of the normal level of conus medullaris.

The location of conus medullaris according to age and sex was retrospectively evaluated with a 0.5-T magnetic resonance (MR) imaging system. A total of 639 subjects without any conspicuous spinal canal pathology on the lumbar MR imaging examination were selected. The level of conus medullaris was most commonly located at the T(12)-L(1) intervertebral disc level in the whole population. Our results do not correlate with the previous studies. No significant difference in the conus level was found with increasing age.