Hounsfield units in assessing bone mineral density in ankylosing spondylitis patients with cervical fracture-dislocation

Figure 1 Hounsfield unit imaging assessments. A: A 60-year-old male cervical fracture-dislocation patient with ankylosing spondylitis. Using a three-dimensional reconstruction, the middle sagittal plane was selected. Using nine reference lines, every vertebra was equally divided into 16 regions; B: The right, middle, and left sagittal planes were selected according to three reference lines.