Diagnostic performance of 64-MDCT for blunt small bowel perforation

Contrast-enhanced CT scan (CECT) for the detection of hollow viscus and mesenteric injuries in blunt trauma - an updated systematic review of the literature and meta-analysis of diagnostic test accuracy

BACKGROUND

Despite improved awareness of blunt traumatic hollow viscus and mesenteric injuries (THVMI), the accuracy of contrast-enhanced CT (CECT) varies considerably among studies. This systematic review and meta-analysis of test accuracy aims to explore the diagnostic performance of CECT in detecting THVMI in blunt trauma.

METHODS

The study was conducted according to the Cochrane recommendations searching the PubMed, Scopus, and Cochrane Library datasets from 2000 to 8 September 2023 (PROSPERO ID: CRD42023473041). Surgical exploration, autopsy, and discharge from the hospital after monitoring were set as reference standard. To explore the diagnostic accuracy of CECT in detecting THVMI hierarchical models were developed. The risk of bias in individual studies was assessed with the QUADAS-2 tool. Sensitivity analysis was conducted to detect sources of heterogeneity.

RESULTS

Twelve studies, for a total of 4537 patients, were deemed eligible. After identification of outliers and sensitivity analysis, the pooled sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio were 0.85 (95% CI: 0.69-0.93), 0.94 (95% CI: 0.8-0.98), 14.65 (95% CI: 4.22-50.85), 0.16 (95% CI: 0.07-0.34), 92.3 (95% CI: 29.75-286.34), respectively. The Area under the HSROC curve was 0.95 (95% CI: 0.92-0.96). Meta-regression analysis identified the year of publication as a covariate significantly associated with heterogeneity. A high risk of bias was detected in the "patient selection" domains.

CONCLUSION

CECT has a fundamental role in identifying THVMI with high specificity but suboptimal sensitivity. Clinical criteria are still of paramount importance, especially in cases of ambiguous initial CECT images.

Diagnostic Accuracy of Computed Tomography for the Prediction of the Need for Laparotomy for Traumatic Hollow Viscus Injury: Systematic Review and Meta-Analysis

BACKGROUND

Traumatic hollow viscus injury (THVI) is one of the most difficult challenges in the trauma setting. Computed tomography (CT) is the most common modality used to diagnose THVI; however, various performance outcomes of CT have been reported. We conducted a systematic review and meta-analysis to analyze how precise and reliable CT is as a tool for the assessment of THVI.

METHOD

A systematic review and meta-analysis were conducted on studies on the use of CT to diagnose THVI. Publications were retrieved by performing structured searches in databases, review articles and major textbooks. For the statistical analysis, summary receiver operating characteristic (SROC) curves were constructed using hierarchical models.

RESULTS

Sixteen studies enrolling 12,514 patients were eligible for the final analysis. The summary sensitivity and specificity of CT for the diagnosis of THVI were 0.678 (95% CI: 0.501-0.809) and 0.969 (95% CI: 0.920-0.989), respectively. The summary false positive rate was 0.031 (95% CI 0.011-0.071).

CONCLUSION

In this meta-analysis, we found that CT had indeterminate sensitivity and excellent specificity for the diagnosis of THVI.

The Current Diagnostic Accuracy on Free Peritoneal Fluid in Computed Tomography to Determinate the Necessity of Surgery in Blunt Bowel and Mesenteric Trauma-Systemic Review and Meta-Analysis

Traumatic bowel mesenteric injury (TBMI) is a challenge in trauma care. The presence of free peritoneal fluid (FF) in computed tomography (CT) was considered the indication for surgical intervention. However, conservative treatment should be applied for minor injuries. We conduct a systematic review to analyze how reliable the FF is to assess the TBMI. Publications were retrieved by structured searching among databases, review articles and major textbooks. For statistical analysis, summary receiver operating characteristic curves (SROCs) were computed using hierarchical models. Fourteen studies enrolling 4336 patients were eligible for final qualitative analysis. The SROC line was created by a hierarchical summary receiver operating characteristic model. The summary sensitivity of FF to predict surgical TBMI was 0.793 (95% CI: 0.635-0.894), and the summary specificity of FF to predict surgical TBMI was 0.733 (95% CI: 0.468-0.896). The diagnostic odds ratio was 10.531 (95% CI: 5.556-19.961). This study represents the most robust evidence (level 3a) to date that FF is not the absolute but an acceptable indicator for surgically important TBMI. However, there is still a need for randomized controlled trials to confirm.

Diagnostic options for blunt abdominal trauma

PURPOSE

Physical examination, laboratory tests, ultrasound, conventional radiography, multislice computed tomography (MSCT), and diagnostic laparoscopy are used for diagnosing blunt abdominal trauma. In this article, we investigate and evaluate the usefulness and limitations of various diagnostic modalities on the basis of a comprehensive review of the literature.

METHODS

We searched commonly used databases in order to obtain information about the aforementioned diagnostic modalities. Relevant articles were included in the literature review. On the basis of the results of our comprehensive analysis of the literature and a current case, we offer a diagnostic algorithm.

RESULTS

A total of 86 studies were included in the review. Ecchymosis of the abdominal wall (seat belt sign) is a clinical sign that has a high predictive value. Laboratory values such as those for haematocrit, haemoglobin, base excess or deficit, and international normalised ratio (INR) are prognostic parameters that are useful in guiding therapy. Extended focused assessment with sonography for trauma (eFAST) has become a well established component of the trauma room algorithm but is of limited usefulness in the diagnosis of blunt abdominal trauma. Compared with all other diagnostic modalities, MSCT has the highest sensitivity and specificity. Diagnostic laparoscopy is an invasive technique that may also serve as a therapeutic tool and is particularly suited for haemodynamically stable patients with suspected hollow viscus injuries.

CONCLUSIONS

MSCT is the gold standard diagnostic modality for blunt abdominal trauma because of its high sensitivity and specificity in detecting relevant intra-abdominal injuries. In many cases, however, clinical, laboratory and imaging findings must be interpreted jointly for an adequate evaluation of a patient's injuries and for treatment planning since these data supplement and complement one another. Patients with blunt abdominal trauma should be admitted for clinical observation over a minimum period of 24 h since there is no investigation that can reliably rule out intra-abdominal injuries.

Isolated free fluid on computed tomography for blunt abdominal trauma

INTRODUCTION

The clinical significance of isolated free fluid on abdominal computed tomography (CT) in patients with blunt abdominal trauma is unclear. This audit reviews our unit's experience with isolated free fluid and attempts to refine our clinical algorithms for the assessment of patients with blunt abdominal trauma.

MATERIALS AND METHODS

All patients who sustained blunt abdominal trauma between December 2012 and December 2017 who were subjected to multidetector CT of the abdomen as part of their initial investigation were included in this study.

RESULTS

During the five-year period under review, a total of 1066 patients underwent abdominal CT following blunt poly trauma. A total of 84 (7.9%) patients died. There were 148 (14%) patients with CT finding of isolated free fluid. Of these, 128 (67%) were selected for non-operative management, which included a period of serial abdominal examinations. In this non-operative group, five patients failed their abdominal observations and underwent laparotomy. Findings in these five cases were negative (1), non-therapeutic (1), splenic injury (1), Pancreatic and splenic injury (1) and bladder injury (1). Thirteen patients (10%) died, none of whom had surgery. The causes of death were exsanguination from a major traumatic lower limb injury (1), multiple organ failure (1), traumatic brain injury (10) and spinal cord injury (1). The remaining 20 patients underwent laparotomy. The indications were failed non-operative management (5), abdominal distension (1) and suspicion of a missed hollow viscus injury (14). In this group there were 11 therapeutic and 6 non-therapeutic surgeries and three negative laparotomies. For the 15 patients selected for operative management, the findings were as follows: hollow viscus injury (3), mesenteric bleeds (2), splenic and pancreatic injury (1), liver and bladder injury (1), splenic and bladder injury (1), non-therapeutic (4), negative (3). The finding of isolated free fluid on CT is 98% sensitive and 96% specific for true isolated free fluid (chi square 331.598; P = 0.000). This finding predicts successful non-operative management with a positive predictive value of 93% and a negative predictive value of 96%.

DISCUSSION

In patients with blunt abdominal trauma, the finding of isolated free fluid on abdominal CT alone is no longer an indication for laparotomy. Other clinical factors must be taken into account when deciding on the need for laparotomy, such as haemodynamic status, clinical abdominal findings and the ability to reliably assess the abdomen. In the absence of a clinical indication for urgent laparotomy, patients with isolated free fluid may be observed.

Occult bowel injury after blunt abdominal trauma

BACKGROUND

Following blunt abdominal trauma, bowel injuries are often missed on admission computed tomography (CT) scan.

METHODS

Multicenter retrospective analysis of 176 adults with moderate-critical blunt abdominal trauma and admission CT scan who underwent operative exploration. Patients with a bowel injury missed on CT (n = 36, 20%) were compared to all other patients (n = 140, 80%).

RESULTS

The missed injury group had greater incidence free fluid without solid organ injury on CT scan (44% vs. 25%, p = 0.038) and visceral adhesions (28% vs. 6%, p = 0.001). Independent predictors of missed bowel injury included prior abdominal inflammation (OR 3.74, 95% CI 1.37-10.18), CT evidence of free fluid in the absence of solid organ injury (OR 2.31, 95% CI 1.03-5.19) and intraoperative identification of visceral adhesions (OR 4.46, 95% CI 1.52-13.13).

CONCLUSIONS

Patients with visceral adhesive disease and indirect evidence of bowel injury on CT scan were more likely to have occult bowel injury.

The Impact of Prior Laparotomy and Intra-abdominal Adhesions on Bowel and Mesenteric Injury Following Blunt Abdominal Trauma

BACKGROUND

Early recognition of bowel and mesenteric injury following blunt abdominal trauma remains difficult. We hypothesized that patients with intra-abdominal adhesions from prior laparotomy would be subjected to visceral sheering deceleration forces and increased risk for bowel and mesenteric injury following blunt abdominal trauma.

METHODS

We performed a multicenter retrospective cohort analysis of 267 consecutive adult trauma patients who underwent operative exploration following moderate-critical (abdominal injury score 2-5) blunt abdominal trauma, comparing patients with prior laparotomy (n = 31) to patients with no prior laparotomy (n = 236). Multivariable regression was performed to identify predictors of bowel or mesenteric injury.

RESULTS

There were no significant differences between groups for injury severity scores or findings on abdominal ultrasound, diagnostic peritoneal aspirate/lavage, pelvic radiography, or preoperative CT scan. The prior laparotomy cohort had greater incidence of full thickness bowel injury (26 vs. 9%, p = 0.010) and mesenteric injury (61 vs. 31%, p = 0.001). The proportion of bowel and mesenteric injuries occurring at the ligament of Treitz or ileocecal region was greater in the no prior laparotomy group (52 vs. 25%, p = 0.003). Prior laparotomy was an independent predictor of bowel or mesenteric injury (OR 5.1, 95% CI 1.6-16.8) along with prior abdominal inflammation and free fluid without solid organ injury (model AUC: 0.81, 95% CI 0.74-0.88).

CONCLUSIONS

Patients with a prior laparotomy are at increased risk for bowel and mesenteric injury following blunt abdominal trauma. The distribution of bowel and mesenteric injuries among patients with no prior laparotomy favors embryologic transition points tethering free intraperitoneal structures to the retroperitoneum.

Effectiveness of computed tomography scanning to detect blunt bowel and mesenteric injuries requiring surgical intervention: A systematic literature review

BACKGROUND

Computed tomography (CT) diagnostic accuracy for blunt bowel and mesenteric injuries (BBMI) is controversial.

DATA SOURCES

A literature review to compute aggregate CT performance and individual CT sign sensitivity, specificity, and positive predictive value (PPV) for operative BBMI.

CONCLUSIONS

Sensitivity, specificity, and PPV were: overall CT performance 85.3%, 96.1%, 51.4%; abnormal wall enhancement 30.1%, 95.7%, 64.0%; bowel wall discontinuity 22.3%, 99.0%, 87.9%; bowel wall hematoma 22.5%, 100%, 19.5%; bowel wall thickening 35.2%, 96.5%, 32.1%; free air 32.0%, 98.7%, 57.1%; free fluid 65.6%, 85.0%, 25.5%; mesenteric air 27.6%, 99.1%, 85.3%; mesenteric extravasation 22.9%, 99.6%, 73.9%; mesenteric hematoma/fluid 33.9%, 98.7%, 52.8%; mesenteric stranding/streaking 34.3%, 91.8%, 31.6%; mesenteric vessel beading 32.1%, 97.2%, 60.4%; mesenteric vessel termination 31.6%, 97.2%, 63.5%; oral contrast extravasation 10.0%, 100%, 100%; retroperitoneal air 9.4%, 94.9%, 55.6%; and retroperitoneal fluid 44.2%, 49.4%, 38.5%. Sensitivity, specificity, and PPV vary substantially among known signs. Other clinical factors are necessary for comprehensive BBMI identification.

Ability of specific and nonspecific signs of multidetector computed tomography (MDCT) in the diagnosis of blunt surgically important bowel and mesenteric injuries

PURPOSE

To determine the accuracy of MDCT in the evaluation of blunt surgically relevant bowel and/or mesenteric injuries (BMIs) using single specific CT signs together with specific pairs of nonspecific signs.

METHODS

Fifty-four patients examined with MDCT were divided into two groups: a 'surgical' group of 20 patients-which underwent surgery for blunt BMIs-and a control group of 34 'nonsurgical' trauma patients. Two radiologists with different experience performed a double-blind retrospective evaluation of the images, classifying the patients in the two groups by using only single specific signs; then, the images were reviewed in consensus with a third radiologist and sensitivity and specificity were calculated. Subsequently, the frequency of every single sign and of every possible combination of nonspecific signs in the two groups was registered, to find combinations present only in the surgical group; sensitivity and specificity were calculated by using even those specific combinations.

RESULTS

At the first consensual evaluation, sensitivity and specificity were 75 and 100%, respectively. Two combinations of nonspecific signs (focal wall thickening + extraluminal air; focal wall thickening + seat belt sign) were found only in surgical patients that did not present any single specific sign: Sensitivity calculated adding those two combinations was 95%, without a decrease in specificity.

CONCLUSIONS

MDCT is an accurate technique in the evaluation of blunt surgically relevant BMIs. The single specific CT signs were sufficient for the diagnosis in only 75% of the cases; adding the two specific combinations allowed an increase in sensitivity of 20%.

Isolated free intra-abdominal fluid on CT in blunt trauma: The continued diagnostic dilemma

PURPOSE

The clinical significance of isolated free fluid (FF) without solid organ injury on computed to- mography (CT) continues to pose significant dilemma in the management of patients with blunt abdominal trauma (BAT).

METHODS

We reviewed the incidence of FF and the clinical outcome amongst patients with blunt abdominal trauma in a metropolitan trauma service in South Africa. We performed a retrospective study of 121 consecutive CT scans over a period of 12 months to determine the incidence of isolated FF and the clinical outcome of patients managed in a large metropolitan trauma service.

RESULTS

Of the 121 CTs, FF was identified in 36 patients (30%). Seven patients (6%) had isolated FF. Of the 29 patients who had free fluid and associated organ injuries, 33 organ injuries were identified. 86% (25/ 29) of all 29 patients had a single organ injury and 14% had multiple organ injuries. There were 26 solid organ injuries and 7 hollow organ injuries. The 33 organs injured were: spleen, 12; liver, 8; kidney, 5; pancreas, 2; small bowel, 4; duodenum, 1. Six (21%) patients required operative management for small bowel perforations in 4 cases and pancreatic tail injury in 2 cases. All 7 patients with isolated FF were initially observed, and 3 (43%) were eventually subjected to operative intervention. They were found to have an intra-peritoneal bladder rupture in 1 case, a non-expanding zone 3 haematoma in 1 case, and a negative laparotomy in 1 case. Four (57%) patients were successfully managed without surgical interventions.

CONCLUSIONS

Isolated FF is uncommon and the clinical significance remains unclear. Provided that reli- able serial physical examination can be performed by experienced surgeons, an initial non-operative approach should be considered.

Imaging Patients With Alimentary Tract Perforation: Literature Review

Alimentary tract perforation is a frequent emergency condition. Imaging plays an important role to make an accurate diagnosis, defining the presence, the level, and the cause of the perforation, essential information to enable the most correct therapeutic choice. Plain radiography is generally performed as the first choice. In case of a clinically suspected bowel perforation, not detected on x-ray imaging, the contribution of computed tomography is essential. Magnetic resonance is not yet widely used in diagnostic workup of patients with acute abdominal pain, but it can be useful in the differential diagnosis of acute abdomen in specific patients (pregnancy and pediatric patients).

Bowel and mesenteric injuries from blunt abdominal trauma: a review

The bowel and the mesentery represent the third most frequently involved structures in blunt abdominal trauma after the liver and the spleen. Clinical assessment alone in patients with suspected intestinal and/or mesenteric injury from blunt abdominal trauma is associated with unacceptable diagnostic delays. Multi-detector computed tomography, thanks to its high spatial, time and contrast resolutions, allows a prompt identification and proper classification of such conditions. The radiologist, in fact, is asked not only to identify the signs of trauma but also to provide an indication of their clinical significance, suggesting the chance of conservative treatment in the cases of mild and moderate, non-complicated or self-limiting injuries and focusing on life-threatening conditions which may benefit from immediate surgical or interventional procedures. Specific and non-specific CT signs of bowel and mesenteric injuries from blunt abdominal trauma are reviewed in this paper.