CT imaging signs of surgically proven bowel trauma

The objective of this study was to determine the incidence and interobserver agreement of individual CT findings as well as the bowel injury prediction score (BIPS) in surgically proven bowel injury after blunt abdominal trauma. This HIPAA-compliant retrospective study was IRB approved and consent was waived. All patients 14 years or older who sustained surgically proven bowel injury after blunt abdominal trauma between 1/1/2004 and 6/30/2015 were included. Admission trauma MDCT scans were independently interpreted by two abdominal fellowship-trained radiologists who recorded the following CT findings: intraperitoneal fluid, mesenteric hematoma/fat stranding, bowel wall thickening/hematoma, active intravenous contrast extravasation, free intraperitoneal air, bowel wall discontinuity, and focal bowel hypoenhancement. Subsequently, the electronic medical records of the included patients, admission abdominal physical exam results, admission white blood cell count, and findings at exploratory laparotomy of the included patients were recorded. Thirty-three patients met the inclusion criteria. The incidence and interobserver agreement of the CT findings were as follows: intraperitoneal fluid 93.9 %, kappa = 0.784 (good); mesenteric hematoma/fat stranding 84.8 %, kappa = 0.718 (good); bowel wall thickening/hematoma 42.4 %, kappa = 0.491 (moderate); active IV contrast extravasation 36.3 %, kappa = 1.00 (perfect); free intraperitoneal air 21.2 %, kappa = 0.904 (very good), bowel wall discontinuity 6.1 %, kappa = 1.00 (perfect); and focal bowel hypoenhancement 6.1 %, kappa = 0.468 (moderate). An absence of the specified CT findings was encountered in 9.1 % with surgically proven bowel injuries (kappa = 1.00, perfect). In our study, 9/16 patients or 56.3 % had a bowel injury prediction score (BIPS) of 2 or more as defined by McNutt et al. (J Trauma Acute Care Surg 78(1):105-111, 2014). The presence of intraperitoneal fluid and mesenteric hematoma/fat stranding are the most common CT findings in bowel injuries proven at laparotomy. A small percentage of patients have no abnormal CT findings. This grading system did not prove to be useful in our study likely due to our inherently small patient population; however, the use of BIPS deserves further investigation as it may help in identifying blunt bowel and mesenteric injury patients with often subtle or nonspecific CT findings.