Application of cervical anterior flexion in CT examination of neck for preschool children with Dose Right technique

Objective To analyze the influence on radiation dose and image quality of children neck CT with anterior flexion of cervical spine using self-made sponge pad with DoseRight technique. Methods A total of 125 children aged 1-5 years who underwent neck CT examination were consecutively collected prospectively. The patients were divided into control group and test group with computer random number method . The control group was supine on the scanning bed and fixed in the CT skull stent. The test group was supine on the scanning bed with a self-made sponge cushion under the neck to extend the head and droop the shoulder. The data was acquired with Philips Brilliance iCT and CTDIVOL was obtained from the dose report. SSDEED and SSDEWD were calculated seperately.The image quality by measuring the noise value and signal-to-noise ratio of the paravertebral muscle area at the middle level of the third cervical vertebra and thyroid area. Subjective evaluation of image quality by 5-point scoring systemwas performed. Results The noise values of paravertebral muscles and thyroid regions in the test group were lower than those in the control group(t=-6.93, -7.41, P<0.05), and the signal-to-noise ratios were higher than those in the control group (t=5.74, 6.14, P<0.05). The subjective score of the test group (4.32±0.70) was better than that of the control group (3.70±0.66), and the difference was statistically significant (Z=-4.27, P<0.05). The jaw-pharynx angle and the number of vertebra displayed of the test group were higher than those of the control group (t=4.94, 5.09, P<0.05). CTDIVOL, and in the control group were 22.1%, 26.0% and 27.1% higher than those in the test group (t=6.17, 5.11, 4.35, P<0.01). Conclusions is more accurate to indicate the CT radiation dose of children. The self-made sponge pad keeping the cervical spine in anterior flexion can reduce radiation dose and improve image quality. Key words: Neck; Preschool children; Radiation dose; Size-specific dose estimate