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. 2022 Nov 2;12(11):2661.
doi: 10.3390/diagnostics12112661.

Changing the Patient's Position: Pitfalls and Benefits for Radiation Dose and Image Quality of Computed Tomography in Polytrauma

Jessica Graef  1 , Keno K Bressem  1   2 , Patrick Asbach  1 , Bernd Hamm  1 , Stefan M Niehues  1
Affiliations

Changing the Patient's Position: Pitfalls and Benefits for Radiation Dose and Image Quality of Computed Tomography in Polytrauma

Jessica Graef et al. Diagnostics (Basel). .

Abstract

For computed tomography (CT), representing the diagnostic standard for trauma patients, image quality is essential. The positioning of the patient’s arms next to the abdomen causes artifacts and is also considered to increase radiation exposure. The aim of this study was to evaluate the effect of various positionings during different CT examination steps on the extent of artifacts as well as radiation dose using iterative reconstruction (IR). 354 trauma-CTs were analyzed retrospectively. All datasets were reconstructed using IR and three different examination protocols were applied. Arm elevation led to a significant improvement of the image quality across all examination protocols (p < 0.001). Variation in arm positioning during image acquisition did not lead to a reduction of radiation dose (p = 0.123). Only elevation during scout acquisition resulted in the reduction of radiation exposure (p < 0.001). To receive high-quality CT images, patients should be placed with elevated arms for the trunk scan, as artifacts remain even with the IR. Arm repositioning during the examination itself had no effect on the applied radiation dose because its modulation refers to the initial scout obtained. In order to achieve a dose effect by different positioning, a two-scout protocol (dual scout) should be used.

Keywords: computed tomography; image quality; iterative reconstruction; patient’s positioning; polytrauma; radiation exposure.

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Conflict of interest statement

Jessica Graef, Keno Bressem and Patrick Asbach declare no conflict of interest. Stefan Niehues declares a relationship (honorary speaker) with the following company: Canon Medical Systems. Bernd Hamm declares relationships (institutional support) with the following companies: Abbott, Actelion Pharmaceuticals, Bayer Schering Pharma, Bayer Vital, BRACCO Group, Bristol Myers Squibb, Charité Research Organisation GmbH, Deutsche Krebshilfe, Dt. Stiftung für Herz- forschung, Essex Pharma, EU Programmes (Past President of ESR), Fibrex Medical Inc., Focused Ultrasound Surgery Foundation, Fraunhofer Gesellschaft, Guerbet, INC Research, InSightec Ltd., IPSEN Pharma, Kendle/MorphoSys AG, Lilly GmbH, Lundbeck GmbH, MeVis Medical Solutions AG, Nexus Oncology, Novartis, Parexel CRO Service, Perceptive, Pfizer GmbH, Phillips, sanofi-aventis S.A., Siemens, Spectranetics GmbH, Terumo Medical Corporation, TNS Healthcare GmbH, Toshiba, UCB Pharma, Wyeth Pharma, Zukunftsfonds Berlin (TSB).

Figures

Figure 1
Figure 1
Example for the different positions of the patient during the scout varying between the evaluated computed tomography protocols. Image (A) shows the scout obtained for protocol A and B, whereas image (B) displays the scout of protocol C.
Figure 2
Figure 2
Axial contrast-enhanced CT images of the upper abdomen representing examples of the evaluation of the subjective image quality: (A) no artifacts resulting from the arms (score = 1), (B) artifacts without impairment of the image quality (score = 2), (C) artifacts with a moderate impairment (score = 3), (D) massive artifacts (score = 4).
Figure 3
Figure 3
Rating of the image quality displayed by the different protocols (p < 0.001). When the examination is carried out in elevation in the protocols B and C, no artifacts from the upper extremities occur and all images are rated with score 1.0 (right). When the arms are placed next to the abdomen in protocol A, artifacts occur to a variable degree (left). The extent of artifacts is represented in percentages by the different colors according to the legend included in the figure.
Figure 4
Figure 4
Comparison of medians and interquartile ranges of radiation dose depending on the CT protocol applied. No difference between the radiation doses of protocol A and B could be detected (p = 0.123), but between protocols A and B compared to protocol C (p < 0.001). The circles and stars (*) refer to radiation doses outside the interquartile ranges.
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