Single-Contrast CT for Detecting Bowel Injuries in Penetrating Abdominopelvic Trauma

Concordance of CT imaging and surgical lesions in penetrating abdominal trauma

OBJECTIVE

The management of penetrating abdominal wounds has greatly benefited from the development of computed tomography (CT), particularly in stable patients. In this setting, the scanner is the reference examination. Our study aims to evaluate the performance of preoperative CT in the assessment of penetrating abdominal lesions.

MATERIAL AND METHODS

Between January 1, 2015 and January 1, 2022, 81 patients were hospitalized following penetrating abdominal trauma at the Army Training Hospitals of Sainte-Anne and Laveran. Fifty-one stable patients who had an abdominopelvic CT scan and thereafter underwent abdominal surgery (laparotomy or laparoscopy) were included. Radiological and surgical data were collected from the electronic record and compared by a descriptive analysis (calculation of the sensitivity, specificity, positive and negative predictive value of the CT for the detection of lesions of the various organs) and by a correlation of the CT findings with surgical findings using Kripendorff's alpha coefficient.

RESULTS

The cohort was largely male (n=45; 88%), with injuries by knife wound in 62.7% of cases (n=32) and gunshot in 35.3% (n=18) of cases. The median age was 36years (25-47). The median index of severity score (ISS) was 17 (10-26). Excellent agreement between predicted and actual findings was obtained for solid organs (α=0.801) with high sensitivity and specificity (81.8% and 96.6%, respectively). The largest discrepancies were observed for the hollow organs (α=26.2%, sensitivity of 53.3% and specificity of 76.2%) and the diaphragm (α=67.3%, sensitivity 75%, specificity 92.3%). Surgical exploration was non-therapeutic for five patients (9.8%). The failure rate for non-operative treatment was 10% (n=1).

CONCLUSION

CT detection of solid organ lesions in patients with penetrating abdominal wounds is excellent. However, the detection of hollow organ and diaphragmatic wounds remains a challenge with a risk of over- and underdiagnosis. Laparoscopic exploration should be able to fill in the gaps in the CT findings.

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.

Accuracy of CT Scan for Detecting Hollow Viscus Injury in Penetrating Abdominal Trauma

BACKGROUND

In penetrating abdominal trauma, computed tomography (CT) is routinely performed to evaluate stable patients for selective non-operative management (SNOM). Triple-contrast CT (oral, rectal, and IV) has traditionally been used. However, due to its disadvantages, most trauma centres, including our unit at the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH), now perform single-contrast intravenous-only CT scans. We performed a retrospective review to determine the accuracy of single-contrast CT scans for detecting hollow viscus injuries (HVI) in penetrating abdominal trauma.

METHODS

A retrospective review of all patients who presented to CMJAH with penetrating abdominal injuries was performed between 01 August 2017 and 31 August 2019 and were evaluated for SNOM with CT (IV contrast only). Patient records were reviewed to determine pertinent demographics, mechanism, and site of injury, as well as metabolic parameters. CT findings were compared to findings at laparotomy.

RESULTS

A total of 437 patients met the inclusion criteria. The majority were male (92.7%), with a mean age of 31.5 yrs (SD 8.7). Injuries were predominantly due to stab wounds (72,5%, n = 317). CT scan was negative in 342 patients, of which 314 completed SNOM successfully. A total of 93 patients proceeded to laparotomy. CT had a sensitivity of 95.1%, specificity of 44.2%, positive predictive value of 57.4%, and negative predictive value of 92%.

CONCLUSION

Single-contrast CT in penetrating abdominal trauma is a valuable investigative tool in identifying patients for SNOM. Features of HVI on single-contrast CT are not very specific and should be interpreted along with other clinical factors including wound trajectory and serial abdominal examinations. Other associated injuries such as diaphragmatic and solid organ injuries should be considered in the final management plan.

CT after emergency surgery in penetrating trauma: a seven-year experience in a level I Nordic trauma center

BACKGROUND

Patients with severe penetrating trauma may require emergency surgery on arrival, and postoperative computed tomography (CT) can reveal significant additional injuries.

PURPOSE

To determine the utility of postoperative CT performed within 48 h of emergency surgery after penetrating trauma.

MATERIAL AND METHODS

Trauma registry data were retrieved over a seven-year period at a single level 1 trauma center. All patients aged ≥17 years, admitted with penetrating injury, who underwent urgent surgery and postoperative CT imaging within 48 h, were included. Pre- and intraoperative medical records were compared to CT findings. Age, sex, Injury Severity Score (ISS), New Injury Severity Score (NISS), 30-day mortality, injury mechanism, surgical intervention, and intensive care unit length of stay were extracted.

RESULTS

Out of 1262 patients, 38 fulfilled the study criteria (36 men [94.7%], 2 women [5.3%]; mean age = 31.5 years. Stab wound (SW) was the most common injury mechanism (26/38, 68.4%) followed by gunshot wound (GSW; 10/38, 26.3%). Patients with GSWs were more severely injured than SW victims (median NISS = 34 [range = 3-75]; for GSWs = 34; for SWs = 26; P = 0.045). Out of 38 patients, 20 (52.6%) had additional findings at postoperative CT. Six patients (15.8%) had unidentified or underestimated findings at CT that were severe enough to warrant additional surgery or angiography.

CONCLUSION

Postoperative CT imaging after emergency surgery in penetrating trauma is an important tool in evaluating the injury panorama. Out of 38 patients, 6 (15.8%) had findings at postoperative CT that warranted additional surgical or angiographic intervention.

Comparison of the diagnostic accuracy of CT scan with oral and intravenous contrast versus CT scan with intravenous contrast alone in the diagnosis of blunt abdominal traumas

PURPOSE

Abdominal CT scan using oral and intravenous (IV) contrast is helpful in the diagnosis of intra-abdominal injuries. However, the use of oral and IV contrast delays the process of diagnosis and increases the risk of aspiration. It has also been shown that CT scan with IV contrast alone is as helpful as CT scan with oral and IV contrast and rectal CT scan in detecting abdominal injuries. Therefore, the present study aims to prospectively compare the diagnostic value of CT scan with oral and IV contrast versus CT scan with IV contrast alone in the diagnosis of blunt abdominal traumas (BATs).

METHODS

Altogether 123 BAT patients, 60 (48.8%) women and 63 (51.2%) men with the mean age of (40.4 ± 18.7) years who referred to the emergency department of Imam Khomeini Educational and Medical Center in Sari, Iran (a tertiary trauma center in north of Iran) from November 2014 to March 2017 and underwent abdominal CT scans + laparotomy were investigated. Those with penetrating traumas or hemodynamically unstable patients were excluded. The participants were randomly allocated to two groups: abdominal CT scan with oral and IV contrast (n = 63) and CT scan with IV contrast alone (n = 60). No statistically significant difference was found between two groups regarding the hemodynamic parameters, age, gender, injury mechanisms (all p > 0.05). The results of CT scan were compared with that of laparotomy results. The collected data were recorded in SPSS version 22.0 for Windows. Quantitative data were presented as mean and SD.

RESULTS

The sensitivity and specificity of CT scan using oral and IV contrast in the diagnosis of BATs were estimated at 96.48 (95% CI: 90.73-99.92) and 92.67 (95% CI: 89.65-94.88), respectively; while CT scan with IV contrast alone achieved a comparable sensitivity and specificity of 96.6 (95% CI: 87.45-99.42) and 92.84 (95% CI: 89.88-95.00), respectively.

CONCLUSION

CT scan with IV contrast alone can be used to assess visceral injuries in BAT patients with normal hemodynamics to avoid diagnostic delay.

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.

WSES guidelines on blunt and penetrating bowel injury: diagnosis, investigations, and treatment

The aim of this paper was to review the recent literature to create recommendations for the day-to-day diagnosis and surgical management of small bowel and colon injuries. Where knowledge gaps were identified, expert consensus was pursued during the 8th International Congress of the World Society of Emergency Surgery Annual (September 2021, Edinburgh). This process also aimed to guide future research.

Correlation of gastrointestinal perforation location and amount of free air and ascites on CT imaging

PURPOSE

To analyze the amount of free abdominal gas and ascites on computed tomography (CT) images relative to the location of a perforation.

METHODS

We retrospectively included 172 consecutive patients (93:79 = m:f) with GIT perforation, who underwent abdominal surgery (ground truth for perforation location). The volume of free air and ascites were quantified on CT images by 4 radiologists and a semiautomated software. The relation of the perforation location (upper/lower GIT) and amount of free air and ascites was analyzed by the Mann-Whitney test. Furthermore, best volume cutoff for upper and lower GIT perforation, areas under the curve (AUC), and interreader volume agreement were assessed.

RESULTS

There was significantly more abdominal ascites with upper GIT perforation (333 ml, range 5 to 2000 ml) than with lower GIT perforation (100 ml, range 5 to 2000 ml, p = 0.022). The highest volume of free air was found with perforations of the stomach, descending colon and sigmoid colon. Significantly less free air was found with perforations of the small bowel and ascending colon compared to the aforementioned. An ascites volume > 333 ml was associated with an upper GIT perforation demonstrating an AUC of 0.63 ± 0.04.

CONCLUSION

Using a two-step process based on the volumes of free air and free fluid can help localizing the site of perforation to the upper, middle or lower GI tract.

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.

Imaging Ballistic Injuries

Here in Canada, we often think of gun violence as confined to conflict zones, terrorism, and more of a problem for our southern neighbor. However, in recent years, it has also become a Canadian problem with increased gun violence related to criminal activity presenting in daily practice. Radiologists play a critical role in the evaluation of ballistic trauma and must therefore be familiar with both the common and uncommon patterns of ballistic injury. In this article, we review the mechanisms of ballistic trauma as well as their resultant injury patterns in order to guide image interpretation.

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.

Positive Oral Contrast Material for Abdominal CT: Current Clinical Indications and Areas of Controversy

OBJECTIVE. The use of positive oral contrast material for abdominal CT is a frequent protocol issue. Confusion abounds regarding its use, and practice patterns often appear arbitrary. Turning to the existing literature for answers is unrewarding, because most studies are underpowered or not designed to address key endpoints. Even worse, many decisions are now being driven by nonradiologists for throughput gains rather than patient-specific considerations. Herein, the current indications for positive oral contrast material are discussed, including areas of controversy. CONCLUSION. As radiologists, we owe it to our patients to drive the appropriate use of positive oral contrast material. At the very least, we should not allow nonradiologists to restrict its use solely on the basis of throughput concerns; rather, we should allow considerations of image quality and diagnostic confidence to enter into the decision process. Based on differences in prior training and practice patterns, some radiologists will prefer to limit the use of positive oral contrast material more than others. However, for those who believe (as I do) that it can genuinely increase diagnostic confidence and can sometimes (rather unpredictably) make a major impact on diagnosis, it behooves us to keep fighting for its use.

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

PURPOSE

There is controversy regarding the administration of oral and rectal contrast for CT performed to detect bowel injury in the context of penetrating torso trauma. Given the lack of published societal guidelines, our goal was to survey radiologists from the American Society of Emergency Radiology membership database to determine consensus on CT protocols for penetrating trauma.

METHODS

With ethics board approval, an anonymous ten-question online survey was distributed via email to 589 radiologists in the American Society of Emergency Radiology (ASER) member database. The survey was open for a 4-week period in February 2018. A commercially available website that allows subscribers to create and analyze survey results was used for analysis.

RESULTS

We received 124 responses (21% response rate) with a majority from U.S. institutions (82%). Seventy-four percent of respondents indicated they do not routinely administer oral contrast in penetrating trauma, 68% do not administer rectal contrast, and 90% do not use commercially available software to assess penetrating injury trajectory. Results from U.S. and non-U.S. practices were comparable. The decision to administer intraluminal contrast is made by the referring physician at 52% of institutions. There is in-house attending level radiology coverage at 54% of institutions and when asked if trauma scans are reviewed before removing the patient from the table, 41% of respondents answered "No."

CONCLUSION

Enteric contrast is used in a minority of respondents' centers for penetrating trauma cases, which is likely driven by a perceived lack of added benefit and delays in patient care.