Article Figures & Data
Figures
- Fig 1.
Effect of shoulder position on image quality in the lower cervical spine. Axial CT scan obtained in a 55-year-old man before (A) and following (B) shoulder lowering, demonstrating substantial improvement in image quality. The images were acquired only a few minutes apart, as part of an interventional procedure, by using otherwise identical scan techniques (CT fluoroscopy; 120 kVp; 60 mA; 2.5-mm section thickness; 1-second rotation time; display FOV, 12 cm).
- Fig 2.
Position of the CT table strap relative to the arms in the control (A) and intervention (B) groups. Images were obtained by using an asymptomatic volunteer.
- Fig 3.
Determination of shoulder level. The level was defined on the anteroposterior scout image as the intersection of a line connecting the acromion processes with the spinal axis.
- Fig 4.
Method for grading spinal cord visibility. The level was defined as the lowest spinal level where the margins of the spinal cord were distinguishable from the adjacent CSF (arrow).
- Fig 5.
Determination of neck diameter based on the shortest transverse diameter measured on the anteroposterior scout image.
- Fig 6.
Box-and-whisker plots showing differences in DLP (A), CTDIvol (B), and SSDE (C) values in the control and intervention groups.
- Fig 7.
Box-and-whisker plots showing differences in shoulder lowering (A) and spinal cord visibility (B) in the control and intervention groups. Note that the vertical axis has been reversed to correspond with the anatomic orientation of the vertebral levels.
Tables
Control Group (n = 25) Intervention Group (n = 26) P Value Age (yr) Mean 49.2 ± 21.8 49.9 ± 20.4 Median 47 46 .87a Range 18–90 19–88 Sex Male (No.) (%) 13 (52.0) 13 (50.0) Female (No.) (%) 12 (48.0) 13 (50.0) 1.0b Scan length (cm) Mean 19.3 ± 1.1 19.1 ± 1.4 Median 20 20 .55a Range 16–20 16–22 Neck width (cm) Mean 13.2 ± 1.4 12.7 ± 1.3 Median 13.0 12.5 .28a Range 11.1–17.8 10.2–14.7 Image Noise Control Group Intervention Group P Valuea At C4 Mean 26.8 ± 6.2 25.4 ± 7.1 Median 27.9 26.5 .60 Range 14.4–37.8 5.7–34.3 At C7 Mean 30.2 ± 10.7 27.7 ± 8.3 Median 29.9 26.4 .49 Range 13.8–58.3 15.9–48.9 At T1 Mean 39.0 ± 9.8 34.7 ± 14.9 Median 37.6 32.6 .11 Range 24.1–66.4 7.3–70.1 ↵a Based on the 2-sample Wilcoxon test.
