Diagnosis of fractures of the hand and/or forearm was more often delayed in cases without clinical symptoms and if the affected area was not included in the scan field of the WBCT.
Regarding the factors that contribute to delayed diagnoses (table 1), we included only intubated patients with a GCS of 3, thus standardising the factors “altered state of consciousness” and “reduced GCS”. Even in reduced GCS, patients might give clues about painful areas which is difficult to categorise.
As delayed diagnoses can be attributed to “life threatening injury” and “injury severity”, as well as “reduced attention in high ISS”, we determined the ISS. While our study sample showed a higher ISS in patients with fractures of the hand and/or forearm compared to those without, the ISS of patients with delayed diagnoses was not higher than that of patients with early diagnoses. This differs to previous studies were hand fractures were associated with reduced injury severity or there was no association found [22, 23].
We searched the admission files for documentation on clinical symptoms, but we could not verify the quality of the examination. In both included centres, symptoms may not have been recorded in writing but still communicated to the radiologist as the trauma team leader will discuss the findings during the WBCT and shortly after. Equally, it is possible that signs of fracture were documented in the admission report but weren’t apparent to the radiologist. Also, we did not examine if injuries were visible in the WBCT. We only differentiated if they were included at all in the scan field.
Full inclusion of the hand and forearm was most often observed when the respective hand was placed on the trunk. Almost 60 % of fractures without clinical symptoms were identified if the area was included in the CT scan field. The optimised patient positioning with flexed arms on the chest is not standard in the two analysed centres [24, 25]. Nevertheless, our findings support that this positioning can be recommended for fracture detection.
On the other hand, placement of the hands next to or on the body is not recommended from a radiologist’s point of view because of artefacts and higher radiation dose [21, 24, 25]. Elevation of the arms showed a dose reduction of 3.5 mSv, corresponding to 16-22 % [26]. However, this difference was also noted between a 16- and 64- slice CT with a dose reduction of 25 % [26].
A study on the clinical impact of arm positioning and image quality showed significantly degraded image quality when arms were placed next to the patient [21]. The authors recommend placement of the arms on the upper abdomen if elevation is not possible. As this study was done on a 16-slice CT, this problem might be addressed by a 64-slice device combined with iterative reconstruction which was shown to reduce beam hardening artefacts [27, 28].
In the diagnostic work-up of trauma patients, time is an important factor to take into consideration. In single-pass WBCTs, arms are not elevated in the sense of a time adapted protocol [29]. In these cases, using the WBCT images for hand and forearm diagnostics creates no further adverse effects. On the contrary it adds gain as we could show, that even without particular attention on hand and forearm diagnosis, 74 % of fractures were diagnosed through WBCT. One aspect that still has to be assessed is the visibility of fractures of hand and/or forearm in the whole-body CT.
As we analysed a subpopulation of all polytrauma patients, the results cannot be directly compared with available publications that included all traumatised patients [18, 19].
Our findings resulted in an increased awareness for injuries of the hand and/or forearm that might be visible in the initial WBCT. While on duty, the senior author discovered fractures of the forearm in the WBCT of two patients shortly after admission that were not reported during the preparation of this manuscript. Elevation of the arms for WBCT is still being discussed in the participating centres.