Clinical outcomes in the intervention and standard CT protocolsa
| Outcome | Intervention CT Protocol (n = 73) | Standard CT Protocol (n = 73) | P Value |
|---|---|---|---|
| Primary end points | |||
| Image noise, lower neckb | |||
| Thyroid gland | 12.3 ± 5.1 | 17.2 ± 5.5 | <.001 |
| Internal jugular vein | 10.7 ± 4.4 | 14.3 ± 5.1 | <.001 |
| DLP (mGy × cm) | 397.6 ± 52.8 | 413.9 ± 56.3 | <.001 |
| Secondary end points | |||
| Streak artifactsc | 1.6 ± 0.5 | 1.9 ± 0.4 | <.001 |
| 1 | 26 (35.6%) | 11 (15.1%) | |
| 2 | 46 (63.0%) | 59 (80.8%) | |
| 3 | 1 (1.4%) | 3 (4.1%) | |
| Image noise, midneckb | |||
| Internal jugular vein | 7.1 ± 3.7 | 9.1 ± 5.8 | .009 |
| SCM muscle | 5.6 ± 2.4 | 7.3 ± 4.0 | <.001 |
| CTDIvol (mGy) | 13.4 ± 0.9 | 13.9 ± 0.9 | <.001 |
| Effective diameter (cm)d | 16.2 ± 4.4 | 19.6 ± 4.9 | <.001 |
| C7-biacromial line distance (cm)e | −2.4 ± 1.1 | −0.3 ± 1.1 | <.001 |
Note:—SCM indicates sternocleidomastoid.
↵a Data are expressed as mean ± SD.
↵b Based on the evaluation of image noise, by measurement of the SD of the CT values in Hounsfield units.
↵c Streak artifacts at the supraclavicular fossa (1, none or minimal; 2, mild; and 3, severe).
↵d Effective diameter of the neck at the level of the lower margin of the cricoid cartilage.
↵e The C7-biacromial line distance was defined as the distance from the intersection of a line connecting the acromion processes to the upper endplate of C7. Negative values indicate that the biacromial line was located caudal to the upper margin of C7, and positive values, that it was located cranial of the upper margin of C7.