Christoph Alexander Karlo MD, Presenter: Nothing to Disclose

Ralph Gnannt, Abstract Co-Author: Nothing to Disclose

Thomas Frauenfelder MD, Abstract Co-Author: Nothing to Disclose

Sebastian Leschka MD, Abstract Co-Author: Nothing to Disclose

Guido Wanner, Abstract Co-Author: Nothing to Disclose

Hatem Alkadhi MD, Abstract Co-Author: Nothing to Disclose

To assess the influence of different arm positioning techniques on thoracic and abdominal image quality and radiation dose of whole-body trauma CT (wbCT).

150 polytrauma patients (104 male, mean age 47±20years) underwent wbCT with arms elevated above the head (group A, n=50), alongside the abdomen (group B, n=50), and on a pillow ventrally to the chest with both arms flexed (group C, n=50). Two blinded, independent observers measured image noise and rated image quality (scores 1-3) of the liver, aorta, spleen, spine, and lower lungs. Radiation dose parameters were noted, and the abdomens’ anterior-posterior diameter, and scan lengths were measured.

Interreader agreements for image noise (r=0.86;p<0.001) and subjective image quality (k=0.71-0.84) was good. Noise was lower (p<0.05), image quality of the liver, aorta, spleen, and spine was higher, and radiation dose lower in group A than in groups B and C (p<0.001, each). Image quality of the spleen, liver, and aorta were higher in group C than in group B (p<0.05, each). No significant differences in scan length (p=0.61) were found among groups. Abdominal anterior-posterior diameter correlated significantly with noise (r=0.82;p<0.01) and dose (r=0.47;p<0.001). Estimated effective radiation doses significantly (p<0.001) higher in groups B (21.2mSv) and C (21.9mSv) as compared to A (16.1mSv).

In wbCT for polytrauma patients, positioning of the arms above the head results in better image quality and lower radiation dose. Placing the flexed arms on a large pillow ventrally to the chest significantly improves image quality as compared to positioning alongside the abdomen.

Arm positioning highly influences radiation dose and thoraco-abdominal image quality of whole-body trauma CT.

Karlo, C, Gnannt, R, Frauenfelder, T, Leschka, S, Wanner, G, Alkadhi, H, Whole-Body CT in Polytrauma Patients: Effect of Arm Positioning on Thoracic and Abdominal Image Quality.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11002052.html