[The "time" factor. Its impact in pathophysiology and therapy of multiple trauma]

Comparison of thick- and thin-slice images in thoracoabdominal trauma CT: a retrospective analysis

PURPOSE

To compare thick (5 mm) and thin slice images (1.5 mm) of lung, soft tissue, and bone window in thoracoabdominal trauma computed tomography.

MATERIALS AND METHODS

167 Patients that underwent thoracoabdominal trauma CT between November 2014 and December 2015 were included in the study. CT data were reconstructed in a transverse direction with 5 mm and 1.5 mm slice images of lung, soft tissue, and bone window. Two blinded raters (radiologists) evaluated the collected data by detecting predefined injuries in different organ areas. Reconstruction and evaluation times as well as detected injuries were noted and compared.

RESULTS

Reconstruction and evaluation times were significantly higher with 1.5 mm thin-slice images, and the effect strength according to Rosenthal displayed a strong effect of 0.61 (< 0.1 small effect, 0.3 middle effect, and > 0.5 strong effect). Average evaluation time differences were 62.7 s (33.9 s-91.5 s) in bone window between 1.5 mm and 3 mm for rater 1 (p < 0.001) and 71.4 s (43.1 s-99.7 s) for rater 2 (p < 0.001). Average time differences between 1.5 mm and 5 mm were 68,7 s (43.9 s-93.5 s) for rater 1 and 75.3 s (44.7 s-105.9 s) for rater 2 in lung window (p < 0.001) and 66.6 s (28.8 s-104.4 s) for rater 1 and 114 s (74.4 s-153.6 s) for rater 2 in soft-tissue window (p < 0.001). There was no significant difference regarding soft-tissue and lung injuries, except non-significant improvement in the detection of bone fractures.

CONCLUSION

Thin-slice images do not bring any significant benefit in thoracoabdominal trauma CT of soft-tissue and lung injuries, but they can be helpful for the diagnosis of bone fractures and incidental findings.

64-MDCT in mass casualty incidents: volume image reading boosts radiological workflow

OBJECTIVE

The purpose of this study was to evaluate the impact of the use of 64-MDCT and volume image reading on the radiologic workflow during a mass casualty incident simulation.

MATERIALS AND METHODS

For this simulation, casualties were taken to our level I trauma center, and triage was done with whole-body 64-MDCT. The complete raw dataset of thin-section images was sent to a dedicated 3D workstation for further interpretation and simultaneous reformations. This new reading method is called volume image reading. Several time frames were documented to evaluate the workflow: examination time, time needed for image processing, and mean image transfer rates. The results were compared with those of a previous study using a 4-MDCT with axial images only and transfer of data to a PACS.

RESULTS

The time for complete image processing (acquisition, reconstruction, and transfer) for 64-MDCT was 4.1 minutes (range, 3.9-4.3 minutes) compared with 9.0 minutes (range, 6.4-10.2 minutes) for 4-MDCT (p ≤ 0.001). The image processing capacity was 14.8 examinations/h for 64-MDCT compared with 6.7 examinations/h for 4-MDCT. The mean number of images was 953 for 64-MDCT compared with 202 for 4-MDCT (p ≤ 0.001). There were no significant differences between 64- and 4-MDCT for the time needed to prepare patients.

CONCLUSION

The use of 64-MDCT with volume image reading led to evident advantages in the radiologic trauma workflow compared with 4-MDCT. Reading of the full image set including reformations can be initiated earlier with volume image reading.

[Different case fatality rates at German trauma centres : Critical analysis]

OBJECTIVE

The level of trauma care in Germany belongs to one of the best worldwide. Nevertheless, previous studies have shown significant differences in the case fatality rates of multiple trauma patients in German trauma centres. The objective of this study was to indentify the reasons for the different outcomes based on data of the trauma registry of the German Society of Orthopaedic Surgery and Traumatology.

METHODS

Due to the inadequacy of comparing only the case fataltiy rates in the different trauma centres, the data recorded in the trauma registry were analyzed in a retrospective, multicentre study to calculate the probability of survival, revised injury severity classification (RISC) and, additionally, the standardized mortality ratio (SMR) for ranking of the participating trauma centres. As a criterion for inclusion in the study, a minimum of 100 trauma patients admitted directly from the scene within a 4 year period was set. The ranking was carried out using the SMR (observed mortality divided by probability of survival). With the help of data from the trauma registry an attempt was made to find the differences in trauma management between the top 10 centres (lowest SMR), the 10 middle and the last 10 centres (highest SMR) in the ranking.

RESULTS

The data of 6,522 patients were included in the study. There were significant differences in the pre-hospital time, the time spent in the emergency room (ER) and time until a CT scan had been performed. Pre-hospital time was longer in patients admitted to the top centres, whereas time in the ER was longer in the last centres of the ranking. Comparing the sum of pre-hospital time and time in the ER, there were no differences between the top and the last centres. At the scene of accident overall intubation rate and intubation rate in patients with traumatic brain injury were higher in patients admitted to the top centres. Regarding the transport modality, significantly more patients were transported by helicopter in the group of the top centres. In top centres CT scans, in particular whole-body CTs, were initiated sooner and used much more frequently so that the rate of missed injuries was much lower. The amount of fluid given at the scene of accident did not differ between the centres but the amount of fluid given in ER and the operating room until admission to the intensive care unit was significantly higher in the top centres.

CONCLUSION

There are significant differences in the pre-hospital and clinical care of patients admitted to German trauma centres. Under clinical conditions a tight time management, an immediate and complete diagnostic approach, particularly by means of whole-body CT and a liberal fluid resuscitation seem to be favorable factors.