Whole-body CT in multiple trauma patients. Clinically adapted usage of differently weighted CT protocols

Whole-body CT (wbCT) has been established as an internationally accepted diagnostic modality in multiple trauma. Until 2011, a uniform CT scanning protocol was used for all multiple trauma patients (pat.) at our hospital (OLD protocol =OP). In 2011, 2 new differently weighted protocols were introduced: TIME protocol (TP) for hemodynamically unstable pat. and DOSE protocol (DP) for pat. with stable vital parameters. The aim of this study was to compare the original ''One-fits-all-concept'' with the new, clinically oriented approach to wbCT. This study retrospectively evaluated 3 distinct wbCT protocols, looking at automatic exposure control variation (AEC; OP/TP) and arm positioning close to the body/overhead (TP/DP). The analysis included waist circumference (WC, cm), injury severity score (ISS), examination time (ET, min), image noise (IN), and effective dose (E, mSv). Normality of distribution was assessed with the Kolmogorov- Smirnov test. Data are given as median and range. Test of significance with Kruskal-Wallis test or Mann-Whitney-U-test. Level of significance: 0.05. 308 pat. were included in the study (77 % m; age: 46 a, 18 - 90 a; WC: 93 cm, 66 - 145 cm). ISS was 14 (OP; n = 104; 0 - 75), 18 (TP; n = 102; 0 - 75) and 9 (DP; n = 102; 0 - 50). ET was 3.9 min (OP; 3.3 - 5.6 min), 4.1min (TP; 2.8 - 7.2 min) and 7.7 min (DP; 6 - 10 min). IN showed no significant differences when comparing OP/TP but was significantly reduced in DP. For a wbCT (vertex to ischium), E could be reduced from 49.7 mSv to 35.4 mSv by optimizing AEC (OP/TP). Through the overhead repositioning of the arms in DP, a further reduction to 28.2 mSv was achieved. Conclusion AEC and arm repositioning have a crucial influence on image quality and dose. The presented clinical approach is superior to the original concept.