An international survey to assess use of oral and rectal contrast in CT protocols for penetrating torso trauma

ACR Appropriateness Criteria® Penetrating Torso Trauma

This document assesses the appropriateness of various imaging studies for acute penetrating trauma to the torso. Penetrating trauma most commonly occurs from gunshots and stabbings, although any object can impale the patient. Anatomic location, type of penetrating trauma, and hemodynamic status are among the many important factors when deciding upon if, what, and when imaging is needed to further evaluate the patient. Imaging plays a critical role in the management of these patients. CT, in particular, aids in identifying and predicting internal injuries based upon trajectory of the object. Clinical variants are distinguished by ballistic versus nonballistic injuries, hemodynamic status, and compartment of the body injured. Ballistic trauma trajectory is less predictable, and imaging recommendations are adjusted for this unpredictability. Excluded from this document are penetrating traumatic injuries to pediatric patients and specific recommendations when the genitourinary system is clinically suspected to be injured, the latter of which is more specifically discussed in other Appropriateness Criteria documents. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are documented annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer documented journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer documented literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Intravenous Versus Rectal Contrast in CT Imaging for Abdominal Gunshot Wounds

CT imaging with rectal contrast historically has been a useful tool to help identify potential colon/rectal injuries; however, recent trends have shown less utilization of rectal contrast, in favor of IV contrast CT imaging alone. A retrospective review of patients with abdominal gunshot wounds was carried out to compare the two CT imaging techniques. An analysis of patients with colorectal injuries was conducted. Patients with IV contrast had a sensitivity of 84% and specificity of 96.8%. The PPV was 87.5% and NPV was 95.8%. In the IV and rectal contrast group, the sensitivity was 88.9% and specificity was 90.5%. The PPV was 80% and NPV was 95%. The proportion of missed injuries between the two was not statistically significant, p=0.18. The study suggests that while CT imaging with rectal contrast confidently identifies colon/rectal injuries, there are often secondary findings that will correctly prompt surgical exploration.

Rectal Contrast CT Scans of Limited Utility in Diagnosing Colonic Injuries in Penetrating Trauma: A Meta-Analysis

OBJECTIVES

Using rectal contrast computed tomography (CT) to identify traumatic colorectal injuries has become commonplace; however, these injuries remain relatively infrequent findings on CTs obtained for penetrating back and flank trauma. We conducted a meta-analysis to ascertain the efficacy of rectal contrast CT in identifying such injuries in victims penetrating injuries.

METHODS

PubMed and Embase were queried for relevant articles between 1974 and 2022. Review articles, case studies, and non-English manuscripts were excluded. Studies without descriptive CT and operative findings were excluded. Positive scans refer to rectal contrast extravasation. Sensitivity and specificity of rectal contrast CT scans were calculated with aggregated CT findings that were cross-referenced with laparotomy findings.

RESULTS

Only 8 manuscripts representing 506 patients quantified colorectal injuries and specified patients with rectal contrast extravasation. Seven patients with true colorectal injuries had no contrast extravasation on CT. There was one true positive scan. Another scan identified contrast extravasation, but laparotomy revealed no colorectal injury. Rectal contrast had sensitivity of 12.5%, specificity 99.8%, positive predictive value (PPV) 50%, negative predictive value (NPV) 99%, and a false negative rate of 88% in identifying colonic injuries.

DISCUSSION

The summation of 8 manuscripts suggest that the addition of rectal contrast in identifying colonic and rectal injuries may be of limited utility given its poor sensitivity and may be unnecessary. In its absence, subtle clues such as hematomas, extraluminal air, IV-dye extravasation, and trajectory may be additional indicators of injury. Further investigations are required to demonstrate a true benefit for the addition of rectal contrast.

Diagnostic performance of triple-contrast versus single-contrast multi-detector computed tomography for the evaluation of penetrating bowel injury

PURPOSE

Selecting groups of low-risk penetrating trauma patients to forego laparotomy can be challenging. The presence of bowel injury may prevent non-operative management. Optimal CT technique to detect bowel injury related to penetrating injury is controversial. Our goal is to compare the diagnostic performance of triple-contrast (oral, rectal, and IV) against IV contrast-only CT, for the detection of bowel injury from penetrating abdominopelvic trauma, using surgical diagnosis as the reference standard.

METHODS

Nine hundred ninety-seven patients who underwent CT for penetrating torso trauma at a single institution between 2009 and 2016 in our HIPPA-compliant and institutional review board-approved retrospective cohort study. A total of 143 patients, including 15 females and 123 males underwent a pre-operative CT, followed by exploratory laparotomy. Of these, 56 patients received triple-contrast CT. CT examinations were independently reviewed by two radiologists, blinded to surgical outcome and clinical presentation. Results were stratified by contrast type and injury mechanism and were compared based upon diagnostic performance indicators of sensitivity, specificity, negative predictive value, and positive predictive value. Area under the receiving operating characteristics curves were analyzed for determination of diagnostic accuracy.

RESULTS

Bowel injury was present in 45 out of 143 patients (10 on triple-contrast group and 35 on IV contrast-only group). Specificity and accuracy were higher with triple-contrast CT (98% specific, 97-99% accurate) compared to IV contrast-only CT (66% specific, 78-79% accurate). Sensitivity was highest with IV contrast-only CT (91% sensitive) compared with triple-contrast CT (75% sensitive), although this difference was not statistically significant. Triple-contrast technique increased diagnostic accuracy for both radiologists regardless of mechanism of injury.

CONCLUSION

In our retrospective single-institution cohort study, triple-contrast MDCT had greater accuracy, specificity, and positive predictive values when compared to IV contrast-only CT in evaluating for bowel injury from penetrating wounds.

CT of Penetrating Abdominopelvic Trauma

Penetrating abdominopelvic trauma usually results from abdominal cavity violation from a firearm injury or a stab wound and is a leading cause of morbidity and mortality from traumatic injuries. Penetrating trauma can have subtle or complex imaging findings, posing a diagnostic challenge for radiologists. Contrast-enhanced CT is the modality of choice for evaluating penetrating injuries, with good sensitivity and specificity for solid-organ and hollow viscus injuries. Familiarity with the projectile kinetics of penetrating injuries is an important skill set for radiologists and aids in the diagnosis of both overt and subtle injuries. CT trajectography is a useful tool in CT interpretation that allows the identification of subtle injuries from the transfer of kinetic injury from the projectile to surrounding tissue. In CT trajectography, after the entry and exit wounds are delineated, the two points can be connected by placing cross-cursors and swiveling the cut planes obliquely in orthogonal planes to obtain a double-oblique orientation to visualize the wound track in profile. The path of the projectile and its ensuing damage is not always straight, and the imaging characteristics of free fluid of different attenuation in the abdomen (including hemoperitoneum) can support the diagnosis of visceral and vascular injuries. In addition, CT is increasingly used for evaluation of patients after damage control surgery and helps guide the management of injuries that were overlooked at surgery. An invited commentary by Paes and Munera is available online. Online supplemental material is available for this article. ©RSNA, 2021.

Utility of enteric contrast material in abdominal penetrating trauma: A narrative review

Penetrating trauma is an important cause of morbidity and mortality. With the possibility of conservative management for hemodynamically stable trauma patient, computed tomography (CT) has become an important tool in diagnosis and management of penetrating trauma. There have been multiple studies examining the utility and lack of perceived benefit of using enteric contrast material in the initial CT evaluation. We provide a narrative review of the surgical and radiological literature, offer our own protocol for how to approach the imaging of patients with suspected bowel injury following penetrating traumatic injury and discuss the potential of using enteric contrast material.

Diagnostic performance of CT and the use of GI contrast material for detection of hollow viscus injury after penetrating abdominal trauma. Experience from a level 1 Nordic trauma center

BACKGROUND

Use of gastrointestinal (GI) contrast material for computed tomography (CT) diagnosis of hollow viscus injury (HVI) after penetrating abdominal trauma is still controversial.

PURPOSE

To assess the sensitivity of CT and GI contrast material use in detecting HVI after penetrating abdominal trauma.

MATERIAL AND METHODS

Retrospective analysis (2013-2016) of patients with penetrating abdominal trauma. Data from the local trauma registry, medical records, and imaging from PACS were reviewed. CT and surgical findings were compared.

RESULTS

Of 636 patients with penetrating trauma, 177 (163 men, 14 women) had abdominal trauma (mean age 34 years, age range 16-88 years): 155/177 (85%) were imaged with CT on arrival; 128/155 (83%) were stab wounds and 21/155 (14%) were gunshot wounds; 47/155 (30%) had emergent surgery after CT. Two patients were imaged using oral, rectal and i.v. contrast; 23 with rectal and i.v. contrast; and 22 with i.v. contrast only. Surgery revealed HVI in 26 patients. CT had an overall sensitivity 69.2%, specificity 90.5%, PPV 90.0%, and NPV 70.4%. CT with oral and/or rectal contrast (n = 25) had sensitivity 66.7%, specificity 71.4%, PPV 85.7%, and NPV 45.5%. CT with i.v. contrast only (n = 22) had 75% sensitivity, 100% specificity, PPV 100%, and NPV 87.5%. No statistically significant difference was found between sensitivity of CT with GI contrast material and i.v. contrast only (P = 1).

CONCLUSION

Stab wounds were the most common cause of penetrating abdominal trauma. CT had 69.2% sensitivity and 90.5% specificity in detecting HVI. CT with GI contrast had similar sensitivity as CT with i.v. contrast only.

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.

Accuracy of Preoperative MDCT in Patients With Penetrating Abdominal and Pelvic Trauma

Purpose:

This study aims to evaluate the overall diagnostic accuracy of preoperative multidetector computed tomography (MDCT) in penetrating abdominal and pelvic injuries (PAPI).

Method and Materials:

We used our hospitals’ trauma registry to retrospectively identify patients with PAPI from January 1, 2006, to December 31, 2016. Only patients who had a 64-MDCT scan at presentation and subsequently underwent laparotomy or laparoscopy were included in our study cohort. Each finding noted on MDCT was rated using a 5-point scale to indicate certainty of injury, with a score of 0 being definitive. Using surgical findings as the gold standard, the accuracy of radiology reports was analyzed in 2 ways. A κ statistic was calculated to evaluate each pair of values for absolute agreement, and ratings for all organ systems were analyzed using a repeated measures analysis of variance (ANOVA) to determine whether radiology and surgical findings were similar enough to be clinically meaningful. Qualitative review of the radiology and surgical reports focused on the gastrointestinal (GI) tract was conducted.

Results:

Our cohort consisted of 38 males and 4 females with a median age of 29 years and a median injury severity score of 15.6. For this study, 12 different organ groups were categorized and analyzed. Of those organ groups, absolute agreement between MDCT and surgical findings was found only for liver and spleen (κ values ranging from 0.2 to 0.5). Additionally, the ANOVA revealed an interaction between finding type and organ system ( F 1, 33 = 7.4, P < .001). The most clinically significant discrepancies between MDCT and surgical findings were for gallbladder, bowel, mesenteric, and diaphragmatic injuries. Qualitative review of the GI tract revealed that radiologists can detect significant findings such as presence of injury, however, localization and extent of injury pose a challenge.

Conclusion:

The detection of clinically significant injuries to solid organs in trauma patients with PAPI on 64-MDCT is adequate. However, detection of injury to the remaining organ groups on MDCT, especially bowel, mesentery, and diaphragm, remains a challenge.