Comparison of digital radiography and computed tomography morphometric profiles of cervical spinal canal vertebrae

The study aim was to determine the size of the normal cervical spinal canal on plain film and to correlate it with its size on computed tomography (CT) to make a diagnostic model of spinal stenosis based on plain film radiography. The study included 51 subjects who had no spinal deformities (age range, 16-60 years). We measured the sagittal and interpedicular diameters of the cervical canal by plain film and by CT. If the CT result was normal, anteroposterior and lateral x-rays of the cervical spine were taken in the neutral position at a 100-cm focal-film distance. SPSS statistical software was used to measure and analyze the sagittal diameter of the cervical canal and interpedicular diameters. The mean sagittal diameter of the cervical canal ranged from 16 mm (C4) to 18 mm (C6). The mean interpedicular diameter ranged from 25.2 mm (C3) to 26.2 mm (C6). There were significant differences in the sagittal and interpedicular diameters between sex, height, and weight groups. There was a strong correlation between the radiographic and CT sagittal canal diameters but a weak one between the interpedicular diameters. The plain film/CT sagittal canal diameter correlation coefficients were 0.73 (C3), 0.75 (C4-C6), and 0.77 (C7).