Alessandro A. Lemos MD, Presenter: Nothing to Disclose

Maria Cristina Firetto MD, Abstract Co-Author: Nothing to Disclose

Roberto Brambilla PhD, Abstract Co-Author: Nothing to Disclose

Matilde De Simone MD, Abstract Co-Author: Nothing to Disclose

Marco Garavaglia MD, Abstract Co-Author: Nothing to Disclose

Pietro R. Biondetti MD, Abstract Co-Author: Nothing to Disclose

Patiens who have sustained multiple trauma are often young and the radiation doses in this range confer a lifetime cancer risk of up to 1/500. It is therefore clear that these scans have to be fully justified either in terms of imaging findings or in potential change in management. Thus, the purpose of our study was to evaluate whether in a selected group of patients, targeted region specific CT (focused CT) can replace Whole-Body CT (WBCT) by using the Injury Severity Score(ISS).

A continuous series of 170 patients (mean age 35.2 years ) were included. All patients underwent WBCT ( head to symphysis), with a 64-slice scanner ( Somaton Definition, Siemens, Germany), equipped  with an automatic tube current modulation system (Care Dose 4D)  In order to evaluate any discrepancy in terms of  clinical indications for WBCT, the ISS of each patient was retrospectevely evaluated and compared to the discharge diagnosis. We used an ISS of 15 as a cut-off point because we were interested in evaluating whether below this point a more focussed scan, aimed at specific areas of clinical concern would have been more appropriate.Radiation dose was calculated using a mathematical phantom ( ImPACT CT Patient Dosimetry Calculator, version 0,99x 01/02/2006).  

The Effective dose associated with WBCT is in the region of 16-42 mSv,  depending upon how many phases are incorporated. This can be even higher if additional images are required to confirm the diagnosis. The Effective dose for focused CT is in the region of 5-14 mSv, depending upon how extended is the FOV.  Forty per cent of the WBCT scans had an ISS  <=15 , and revealed no trauma-related pathology.Analysis of our data confirms that many of these negatives scans were clinically indicated , but in a proportion,  a more focussed scan , aimed at specific areas of clinical concerns, would have been more appropriate.

The associated radiation dose with WBCT is high and patients should be carefully selected by using the ISS. When the ISS is <= 15, a more targeted region specific CT is recommended.

According to our results, we have introduced a specific Trauma CT referral request to ensure that all scans are fully justified and meet the National radiation protection guidelines,Istisan 07/26.

Lemos, A, Firetto, M, Brambilla, R, De Simone, M, Garavaglia, M, Biondetti, P, Whole-Body CT for Trauma: Strategies to Justify Radiation Dose by Using the Injury Severity Score.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11001535.html