Fig 1.
Flowchart of the inclusion and exclusion criteria.
Table 1.
Patient demographics and acquisition parameters.
Fig 2.
Example for scan range adaptation using the interactive dose-simulator tool in a 35 year-old patient with a peritonsillar abscess.
Fig 3.
Example of automatic attenuation-based tube current modulation and the resulting slice selective changes of the effective dose as calculated by the dose-simulator tool.
The white line indicates the scan range of CTred (reduction of scan length 26%). The DLP could be reduced by 23%, which is approximately similar to the scan range reduction, due to the proportional mathematical relationship. This also applies for the DLP derived effective dose estimation (dose reduction of 23% with an effective dose of 0.7 mSv for CTred and 0.9 mSv for CTstd.). The dose management platform calculations however revealed an effective dose reduction of only 14% (1.3 mSv for CTred and 1.5 mSv for CTstd) and the absolute effective dose values are approximately 45% higher than for the DLP derived approach. This can be explained by the fact, that the dose management platform algorithm selectively considers radiosensitive organs in the irradiated area and their individual contribution to the effective dose whereas the DLP derived approach only allows for a rough dose estimation that underestimates the actual effective dose and at the same time overestimates the relative dose reduction associated with the scan range reduction due to the underlying mathematical principles.
Fig 4.
Scout image and the most cranial as well as most caudal slices of CTred and CTstd of a 33 year-old patient with a parapharyngeal abscess.
The white lines in the scout image indicate the cranial (CTstd—solid line; CTred—dashed line) and caudal (solid line for both, CTstd and CTred) margin of the scan range. Effective dose could be reduced by approximately 10% (2.2 mSv for CTstd and 2.0 mSv for CTred).
Fig 5.
Axial and coronal images of a 31 year-old patient with a peritonsillar abscess (circle).
The dashed line indicates the cranial margin of the CTred reconstruction clearly demonstrating that the abscess would have also been covered in its full extent with a reduced scan length without affecting the diagnostic performance. In this case effective dose could be reduced by approximately 14% (4.2 mSv for CTstd and 3.6 mSv for CTred).
Table 2.
Descriptive statistics and results of pairwise comparison for effective dose and organ doses after Bonferroni correction.
Table 3.
Dose values.