Imaging of blunt bowel and mesenteric injuries: Current status

RSNA 2023 Abdominal Trauma AI Challenge: Review and Outcomes

Purpose To evaluate the performance of the winning machine learning models from the 2023 RSNA Abdominal Trauma Detection AI Challenge. Materials and Methods The competition was hosted on Kaggle and took place between July 26 and October 15, 2023. The multicenter competition dataset consisted of 4274 abdominal trauma CT scans, in which solid organs (liver, spleen, and kidneys) were annotated as healthy, low-grade, or high-grade injury. Studies were labeled as positive or negative for the presence of bowel and mesenteric injury and active extravasation. In this study, performances of the eight award-winning models were retrospectively assessed and compared using various metrics, including the area under the receiver operating characteristic curve (AUC), for each injury category. The reported mean values of these metrics were calculated by averaging the performance across all models for each specified injury type. Results The models exhibited strong performance in detecting solid organ injuries, particularly high-grade injuries. For binary detection of injuries, the models demonstrated mean AUC values of 0.92 (range, 0.90-0.94) for liver, 0.91 (range, 0.87-0.93) for splenic, and 0.94 (range, 0.93-0.95) for kidney injuries. The models achieved mean AUC values of 0.98 (range, 0.96-0.98) for high-grade liver, 0.98 (range, 0.97-0.99) for high-grade splenic, and 0.98 (range, 0.97-0.98) for high-grade kidney injuries. For the detection of bowel and mesenteric injuries and active extravasation, the models demonstrated mean AUC values of 0.85 (range, 0.74-0.93) and 0.85 (range, 0.79-0.89), respectively. Conclusion The award-winning models from the artificial intelligence challenge demonstrated strong performance in the detection of traumatic abdominal injuries on CT scans, particularly high-grade injuries. These models may serve as a performance baseline for future investigations and algorithms. Keywords: Abdominal Trauma, CT, American Association for the Surgery of Trauma, Machine Learning, Artificial Intelligence Supplemental material is available for this article. © RSNA, 2024.

Index CT-Based Scoring Systems in Operative Blunt Bowel and Mesenteric Injury Identification

INTRODUCTION

Determining the need for surgical management of blunt bowel and mesenteric injury (BBMI) remains a clinical challenge. The Faget score and Bowel Injury Prediction Score (BIPS) have been suggested to address this issue. Their efficacy in determining the need for surgery was examined.

METHODS

A retrospective review of all adult blunt trauma patients hospitalized at a level 1 trauma center between January 2009 and August 2019 who had small bowel, colon, and/or mesenteric injury was conducted. We further analyzed those who underwent preoperative computed tomography (CT) scanning at our institution. Final index CT reports were retrospectively reviewed to calculate the Faget and BIPS CT scores. All images were also independently reviewed by an attending radiologist to determine the BIPS CT score.

RESULTS

During the study period, 14,897 blunt trauma patients were hospitalized, of which 91 had BBMI. Of these, 62 met inclusion criteria. Among patients previously identified as having BBMI in the registry, the retrospectively applied Faget score had a sensitivity of 39.1%, specificity of 81.2%, positive predictive value (PPV) of 85.7%, and negative predictive value (NPV) of 31.7% in identifying patients with operative BBMI. The retrospectively applied BIPS score had a sensitivity of 47.8%, specificity of 87.5%, PPV of 91.7%, and NPV of 36.8% in this cohort. When CT images were reviewed by an attending radiologist using the BIPS criteria, sensitivity was 56.5%, specificity 93.7%, PPV 96.3%, and NPV 42.8%.

CONCLUSIONS

Existing BBMI scoring systems had limited sensitivity but excellent PPV in predicting the need for operative intervention for BBMI. Attending radiologist review of CT images using the BIPS scoring system demonstrated improved accuracy as opposed to retrospective application of the BIPS score to radiology reports.

Anastomotic leak rates after repair of mesenteric bucket-handle injuries: A multi-center retrospective cohort study

BACKGROUND

Primary aim was to assess the relative risk (RR) of anastomotic leak (AL) in intestinal bucket-handle (BH) compared to non-BH injury.

METHODS

Multi-center study comparing AL in BH from blunt trauma 2010-2021 compared to non-BH intestinal injuries. RR was calculated for small bowel and colonic injury using R.

RESULTS

AL occurred in 20/385 (5.2%) of BH vs. 4/225 (1.8%) of non-BH small intestine injury. AL was diagnosed 11.6 ± 5.6 days from index operation in small intestine BH and 9.7 ± 4.3 days in colonic BH. Adjusted RR for AL was 2.32 [0.77-6.95] for small intestinal and 4.83 [1.47-15.89] for colonic injuries. AL increased infections, ventilator days, ICU & total length of stay, reoperation, and readmission rates, although mortality was unchanged.

CONCLUSION

BH carries a significantly higher risk of AL, particularly in the colon, than other blunt intestinal injuries.

Rates and risk factors for anastomotic leak following blunt trauma-associated bucket handle intestinal injuries: a multicenter study

Objectives

The risk factors for anastomotic leak (AL) after resection and primary anastomosis for traumatic bucket handle injury (BHI) have not been previously defined. This multicenter study was conducted to address this knowledge gap.

Methods

This is a multicenter retrospective study on small intestine and colonic BHIs from blunt trauma between 2010 and 2021. Baseline patient characteristics, risk factors, presence of shock and transfusion, operative details, and clinical outcomes were compared using R.

Results

Data on 395 subjects were submitted by 12 trauma centers, of whom 33 (8.1%) patients developed AL. Baseline details were similar, except for a higher proportion of patients in the AL group who had medical comorbidities such as diabetes, hypertension, and obesity (60.6% vs. 37.3%, p=0.015). AL had higher rates of surgical site infections (13.4% vs. 5.3%, p=0.004) and organ space infections (65.2% vs. 11.7%, p<0.001), along with higher readmission and reoperation rates (48.4% vs. 9.1%, p<0.001, and 39.4% vs. 11.6%, p<0.001, respectively). There was no difference in intensive care unit length of stay or mortality (p>0.05). More patients with AL were discharged with an ostomy (69.7% vs. 7.3%, p<0.001), and the mean duration until ostomy reversal was 5.85±3 months (range 2-12.4 months). The risk of AL significantly increased when the initial operation was a damage control procedure, after adjusting for age, sex, injury severity, presence of one or more comorbidities, shock, transfusion of >6 units of packed red blood cells, and site of injury (adjusted RR=2.32 (1.13, 5.17)), none of which were independent risk factors in themselves.

Conclusion

Damage control surgery performed as the initial operation appears to double the risk of AL after intestinal BHI, even after controlling for other markers of injury severity.

Level of evidence

III.

Multidetector CT Imaging Biomarkers as Predictors of Prognosis in Shock: Updates and Future Directions

A severe mismatch between the supply and demand of oxygen is the common sequela of all types of shock, which present a mortality of up to 80%. Various organs play a protective role in shock and contribute to whole-body homeostasis. The ever-increasing number of multidetector CT examinations in severely ill and sometimes unstable patients leads to more frequently encountered findings leading to imminent death, together called "hypovolemic shock complex". Features on CT include dense opacification of the right heart and major systemic veins, venous layering of contrast material and blood, densely opacified parenchyma in the right hepatic lobe, decreased enhancement of the abdominal organ, a dense pulmonary artery, contrast pooling in dependent lungs, and contrast stasis in pulmonary veins. These findings are biomarkers and prognostic indicators of paramount importance which stratify risk and improve patient outcomes. In this review, we illustrate the various CT patterns in shock and review the spectrum and prognostic significance of thoraco-abdominal vascular and visceral alarming signs of impending death with the intention of increasing awareness among radiologists and radiographers to prepare for immediate resuscitation when required.

Iliac ecchymosis, a valuable sign for hollow viscus injuries in blunt pelvic trauma patients

PURPOSE

Pelvic fractures are characterized by high energy injuries and often accompanied with abdominal and pelvic organ injury. CT has been applied for several decades to evaluate blunt pelvic trauma patients. However, it has a certain rate of inaccurate diagnosis of abdominal hollow viscus injury (HVI), especially in the early stage after injury. The delayed diagnosis of HVI could result in a high morbidity and mortality. The bowel injury prediction score (BIPS) applied 3 clinical variables to determine whether an early surgical intervention for blunt HVI was necessary. We recently found another clinical variable (iliac ecchymosis, IE) which appeared at the early stage of injury, could be predicted for HVI. The main objective of this study was to explore the novel combination of IE and BIPS to enhance the early diagnosis rate of HVI, and thus reduce complications and mortalities.

METHODS

We conducted a retrospective analysis from January 2008 to December 2018 and recorded blunt pelvic trauma patients in our hospital. The inclusion criteria were patients who were verified with pelvic fractures using abdomen and pelvis CT scan in the emergency department before any surgical intervention. The exclusion criteria were abdominal CT insufficiency before operation, abdominal surgery before CT scan, and CT mesenteric injury grade being 5. The MBIPS was defined as BIPS plus IE, which was calculated according to 4 variables: white blood cell counts of 17.0 or greater, abdominal tenderness, CT scan grade for mesenteric injury of 4 or higher, and the location of IE. Each clinical variable counted 1 score, totally 4 scores. The location and severity of IE was also noted.

RESULTS

In total, 635 cases were hospitalized and 62 patients were enrolled in this study. Of these included patients, 77.4% (40 males and 8 females) were operated by exploratory laparotomy and 22.6% (8 males and 6 females) were treated conservatively. In the 48 patients underwent surgical intervention, 46 were confirmed with HVI (45 with IE and 1 without IE). In 46 patients confirmed without HVI, only 3 patients had IE and the rest had no IE. The sensitivity and specificity of IE in predicting HVI was calculated as 97.8% (45/46) and 81.3% (13/16), respectively. The median MBIPS score for surgery group was 2, while 0 for the conservative treatment group. The incidence of HVI in patients with MBIPS score ≥ 2 was significantly higher than that in patients with MBIPS score less than ≤ 2 (OR = 17.3, p < 0.001).

CONCLUSION

IE can be recognized as an indirect sign of HVI because of the high sensitivity and specificity, which is a valuable sign for HVI in blunt pelvic trauma patients. MBIPS can be used to predict HVI in blunt pelvic trauma patients. When the MBIPS score is ≥ 2, HVI is strongly suggested.

Use of Enteric Contrast Material for Abdominopelvic CT in Penetrating Traumatic Injury in Adults: Comparison of Diagnostic Accuracy Systematic Review and Meta-Analysis

BACKGROUND. Scarce evidence exists on the diagnostic benefit of enteric contrast administration for abdominopelvic CT performed in the setting of penetrating trauma. OBJECTIVE. The purpose of this systematic review and meta-analysis is to compare the diagnostic accuracy of CT using enteric contrast material with that of CT not using enteric contrast material in penetrating traumatic abdominopelvic injury in adults. EVIDENCE ACQUISITION. A protocol was registered a priori (PROSPERO CRD42019139613). MEDLINE and EMBASE databases were searched until June 25, 2019. Studies were included that evaluated the diagnostic accuracy of abdominopelvic CT either with or without enteric (oral and/or rectal) contrast material in patients presenting with penetrating traumatic injury. Relevant study data metrics and risk of bias were assessed. Bivariate random-effects meta-analyses and meta-regression modeling were performed to assess and compare diagnostic accuracies. EVIDENCE SYNTHESIS. From an initial sample of 829 studies, 12 studies were included that reported on 1287 patients with penetrating injury (389 with confirmed bowel, mesenteric, or other abdominopelvic organ injury). The enteric contrast material group (seven studies; 506 patients; 124 patients with confirmed penetrating injury) showed a sensitivity of 83.8% (95% CI, 73.7-90.5%) and specificity of 93.8% (95% CI, 83.6-97.8%). The group without enteric contrast administration (six studies; 781 patients; 265 patients with confirmed penetrating injury) showed a sensitivity of 93.0% (95% CI, 86.8-96.4%) and a specificity of 90.3% (95% CI, 81.4-95.2%). No statistically significant difference was identified for sensitivity (p = .07) or specificity (p = .37) between the groups with and without enteric contrast material according to meta-regression. Nine of 12 studies showed risk of bias in at least one QUADAS-2 domain (most frequently limited reporting of blinding of radiologists or lack of blinding of radiologists, insufficient clinical follow-up for the reference standard, and limited reporting of sampling methods). CONCLUSION. The use of enteric contrast material for CT does not provide a significant diagnostic benefit for penetrating traumatic injury. CLINICAL IMPACT. Eliminating enteric contrast administration for CT in penetrating traumatic injury can prevent delays in imaging and surgery and reduce cost.