Fig. 2
Measuring methods used to analyze the two-dimensional tomogram images. This figure shows the measuring methods utilized to analyze the two-dimensional tomogram images using image analysis software, showing a slice of the two-dimensional tomogram images as an example. Red area: high-density area with a density equal to or greater than that of vertebral bone trabeculae in an area equal to or greater than 0.1 mm2. Yellow area: the soft tissue behind vertebrae as the PLL. The boundary between the PLL and the annular fibrosus of the intervertebral disc were defined as the line connecting the top of the rim of the upper and lower vertebrae