An experimental study on the ability of newly developed CT equipment for temporal bone to display fine bony anatomy / 中华放射学杂志

ABSTRACT

Objective:To verify the ability of the newly developed ultra-high resolution CT (U-HRCT) for displaying the fine bony anatomy of temporal bone.Methods:The cone-beam CT architecture was used on U-HRCT. The focus size of X-ray generator was 0.27 mm × 0.29 mm, the rated tube voltage was 60-100 kV, and the unit size of flat panel detector was 0.074 8 mm×0.074 8 mm. From October to December 2019, 16 adult head specimens (32 temporal bones, provided by Huanghe University of Science and Technology) were imaged using U-HRCT. The scanning mode was small-field-of-view and high-resolution scanning for unilateral temporal bone. The scanning parameters were voltage 100 kV, current 3.5 mA, rotation time 40 s, reconstructed field of view 65 mm×65 mm, voxel size 0.1 mm×0.1 mm×0.1 mm, layer number 370, slice thickness 0.1 mm, and slice interval 0.1 mm. The ultimate spatial resolution of the system was detected using a phantom with line pair card, after the scanning with the same parameters. Through multi-planar reconstruction and minimum intensity projection method, a total of 6 anatomical positions of 4 structures (stapes footplate, cochlear axis bottom, vestibular aqueduct internal orifice and isthmus, cochlear aqueduct internal orifice and auditory sac segment) were scored with 1-3 points. The Wilcoxon test was used to compare the difference of bilateral scores of each structure.Results:The phantom test results showed that the ultimate spatial resolution of the system was ≥4.0 lp/mm. The scores of stapes footplate, cochlear axis bottom and vestibular aqueduct internal orifice were ≥2 points, with a display rate of 100%. The display rates of vestibular aqueduct isthmus, cochlear aqueduct internal orifice and auditory sac segment were 87.5% (28/32), 71.9% (23/32) and 53.1% (17/32), respectively. There were no significant differences in left and right scores of all anatomical structures ( P>0.05). Conclusion:The newly developed U-HRCT has good display ability for fine bony anatomy of temporal bone and has great clinical application potential.