European Radiology

, Volume 24, Issue 5, pp 969–979

Emergency CT head and neck imaging: effects of swimmer’s position on dose and image quality

  • Fabian G. Mueck
  • Sebastian Roesch
  • Lucas Geyer
  • Michael Scherr
  • Michael Seidenbusch
  • Robert Stahl
  • Zsuzsanna Deak
  • Stefan Wirth
Computed Tomography

DOI: 10.1007/s00330-014-3105-1

Cite this article as:
Mueck, F.G., Roesch, S., Geyer, L. et al. Eur Radiol (2014) 24: 969. doi:10.1007/s00330-014-3105-1

Abstract

Objectives

To compare the effects of different arm positions on dose exposure and image quality (IQ) in cervical spine CT after trauma in different patient groups.

Methods

Patients in standard (STD = 126) and in swimmer’s position (SWIM = 254) were included. Body mass index (BMI subgroup 1 = underweight to subgroup 4 = obese), anterior–posterior diameter (AP), left–right diameter (LR), area of an ellipse (AoE) and angle between the humeral heads (optimal STD < 3°, optimal SWIM > 10°) were used as grouping criteria. Computed tomography dose index (CTDI) was documented. Two radiologists rated the IQ at three levels (CV1/2, CV4/5, CV7/T1) using a semi-quantitative scale (0 = not diagnostic, 1 = diagnostic with limitations, 2 = diagnostic without limitations). The Mann–Whitney U test correlations of grouping criteria with dose effects and intra-class correlation (ICC) were calculated.

Results

ICC was 0.87. BMI grouping showed the strongest correlation with dose effects: CTDI of optimal STD versus optimal SWIM positioning was 3.17 mGy versus 2.46 mGy (subgroup 1), 5.47 mGy versus 3.97 mGy (subgroup 2), 7.35 mGy versus 5.96 mGy (subgroup 3) and 8.71 mGy versus 8.18 mGy (subgroup 4). Mean IQ at CV7/T1 was 1.65 versus 1.23 (subgroup 1), 1.27 versus 1.46 (subgroup 2), 1.06 versus 1.46 (subgroup 3), 0.79 versus 1.5 (subgroup 4).

Conclusion

Patients with a BMI > 20 kg/m2 benefited from both potential dose reduction and improved image quality at the critical cervicothoracic junction when swimmer’s position was used.

Key Points

• BMI is a useful metric for personalized optimization in CT for the c-spine.

• Using swimmer’s position, patients can benefit from dose reduction.

• In some patients a superior image quality can be achieved with swimmer’s position.

• For swimmer’s positioning an angle of more than 10° is optimal.

Keywords

CT Trauma Spine Patient positioning Personalized medicine 

Copyright information

© European Society of Radiology 2014

Authors and Affiliations

  • Fabian G. Mueck
    • 1
  • Sebastian Roesch
    • 1
  • Lucas Geyer
    • 1
  • Michael Scherr
    • 1
  • Michael Seidenbusch
    • 1
  • Robert Stahl
    • 1
  • Zsuzsanna Deak
    • 1
  • Stefan Wirth
    • 1
  1. 1.Institut für Klinische Radiologie, LMU Klinikum der Universität München - Innenstadt, Department of Clinical RadiologyLMU Hospital of the University of Munich - Downtown CampusMunichGermany