경부 CT검사시 선속경화현상 감소를 위한 환자 자세 및 영상 평가

Evaluation of Image Quality With a Change of Patient Position to Reduce Beam Hardening Effect in Neck CT Scanning

Purpose The goals of this study was to examine the changes of beam hardening effect in shoulder and to evaluate the change of image quality which follows in positional change in patients with neck diseases. Materials and methods 30 patients with neck diseases were included in this study and 16-slice MDCT (Sensation 16, Siemens, Erlangen, Germany) was undergone. Positions of patients had changed with time such as neutral position with(group N), position with raising left arm (group S), and position with getting off everted both arms maximally(group P). ROI (1cm in area) located at supraclavicular fatty tissue for measuring CT noise was measured(3 times) and an average was recorded. For analysis of radiation exposure, parameters were fixed and scanned topograms of changed positions were compared with CTDIvol values measured at same position. Two investigators assessed image qualities, which were graded to unacceptable, suboptimal, adequate, good, excellent diagnostic quality. Results In CT noise, group S and group P showed 23% and 19% decrement rather than those of group N respectively. In radiation exposure, group S and group P showed 12% and 11% decrement rather than those of group N respectively. In 30 patients, image qualities of group N, group S, and group P were analyzed to unacceptable(n=0, 0, 0), suboptimal (n=0, 28, 2), adequate (n=24, 26, 3), good (N=28, 6, 22), and excellent diagnostic quality (n=8, 0, 33). Conclusion Appropriate positional change in neck CT scanning is useful method for obtaining images of improved quality and reducing beam hardening effect by shoulder.