Low-velocity, civilian firearm extremity injuries-review and update for radiologists

Firearm injuries are a preventable epidemic in the USA. Extremities are commonly affected in gunshot injuries. Such injuries may be complex with concomitant osseous, soft tissue, and neurovascular components. The maximum wounding potential of a projectile is determined by its kinetic energy and the proportion of the kinetic energy that is transmitted to the target. Accurate assessment of ballistic injuries is dependent on utilizing the principles of wound ballistics, accurate bullet count, and ballistic trajectory analysis. The goals of this article are to review wound ballistics and the imaging evaluation of extremity civilian firearm injuries in the adult population, with emphasis on ballistic trajectory analysis, specific ballistic fracture patterns, and diffuse, secondary soft tissue ballistic injuries.

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.

Trauma de recto penetrante: revisión de tema

Introducción. En la actualidad, el trauma de recto continúa siendo una situación clínica compleja y temida por ser potencialmente mortal. Su detección y manejo temprano es la piedra angular para impactar tanto en la mortalidad como en la morbilidad de los pacientes. Hoy en día, aun existe debate sobre la aproximación quirúrgica ideal en el trauma de recto y las decisiones de manejo intraoperatorias se ven enormemente afectadas por la experiencia y preferencias del cirujano. Métodos. Se realizó una búsqueda de la literatura en las bases de datos de PubMed, Clinical Key, Google Scholar y SciELO utilizando las palabras claves descritas y se seleccionaron los artículos mas relevantes publicados en los últimos 20 años; se tuvieron en cuenta los artículos escritos en ingles y español. Discusión. El recto es el órgano menos frecuentemente lesionado en trauma, sin embargo, las implicaciones clínicas que conlleva pasar por alto este tipo de lesiones pueden ser devastadoras para el paciente. Las opciones para el diagnóstico incluyen el tacto rectal, la tomografía computarizada y la rectosigmoidoscopia. El manejo quirúrgico va a depender de la localización, el grado de la lesión y las lesiones asociadas. Conclusión. El conocimiento de la anatomía, el mecanismo de trauma y las lesiones asociadas permitirán al cirujano realizar una aproximación clínico-quirúrgica adecuada que lleve a desenlaces clínicos óptimos de los pacientes que se presentan con trauma de recto.

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.

A Multiscale Deep Learning Method for Quantitative Visualization of Traumatic Hemoperitoneum at CT: Assessment of Feasibility and Comparison with Subjective Categorical Estimation

PURPOSE

To evaluate the feasibility of a multiscale deep learning algorithm for quantitative visualization and measurement of traumatic hemoperitoneum and to compare diagnostic performance for relevant outcomes with categorical estimation.

MATERIALS AND METHODS

This retrospective, single-institution study included 130 patients (mean age, 38 years; interquartile range, 25-50 years; 79 men) with traumatic hemoperitoneum who underwent CT of the abdomen and pelvis at trauma admission between January 2016 and April 2019. Labeled cases were separated into five combinations of training (80%) and test (20%) sets, and fivefold cross-validation was performed. Dice similarity coefficients (DSCs) were compared with those from a three-dimensional (3D) U-Net and a coarse-to-fine deep learning method. Areas under the receiver operating characteristic curve (AUCs) for a composite outcome, including hemostatic intervention, transfusion, and in-hospital mortality, were compared with consensus categorical assessment by two radiologists. An optimal cutoff was derived by using a radial basis function-based support vector machine.

RESULTS

Mean DSC for the multiscale algorithm was 0.61 ± 0.15 (standard deviation) compared with 0.32 ± 0.16 for the 3D U-Net method and 0.52 ± 0.17 for the coarse-to-fine method (P < .0001). Correlation and agreement between automated and manual volumes were excellent (Pearson r = 0.97, intraclass correlation coefficient = 0.93). The algorithm produced intuitive and explainable visual results. AUCs for automated volume measurement and categorical estimation were 0.86 and 0.77, respectively (P = .004). An optimal cutoff of 278.9 mL yielded accuracy of 84%, sensitivity of 82%, specificity of 93%, positive predictive value of 86%, and negative predictive value of 83%.

CONCLUSION

A multiscale deep learning method for traumatic hemoperitoneum quantitative visualization had improved diagnostic performance for predicting hemorrhage-control interventions and mortality compared with subjective volume estimation. Supplemental material is available for this article. © RSNA, 2020.

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.

Emergent Comprehensive Imaging of the Major Trauma Patient: A New Paradigm for Improved Clinical Decision-Making

Modern advances in the medical imaging layered onto sophisticated trauma resuscitation strategies in highly organized regionalized trauma systems have created a paradigm shift in the management of severely injured patients. Although immediate exploratory surgery to identify and control life-threatening injuries still has its place, accelerated image acquisition and interpretation procedures now make it rare for trauma surgeons in major centers to venture into damage control surgery unaided by computed tomography (CT) or other imaging, particularly in cases of blunt trauma. Indeed, because of the high incidence of clinically occult injuries associated with major mechanism trauma, and even lower energy trauma in frail or elderly patients, CT imaging has become as invaluable as physical examination, if not more so, in critical decision-making in support of optimal outcomes. In particular, whole-body computed tomography (WBCT) completed promptly after initial assessment of a major trauma provides a quick, comprehensive survey of injuries that enables better surgical planning, obviates the need for multiple subsequent studies, and permits specialized reconstructions when needed. For those at risk for problematic occult injury after modest trauma, WBCT facilitates safer discharge planning and simplified follow-up. Through standardized guidelines, streamlined protocols, synoptic reporting, accessible web-based platforms, and active collaboration with clinicians, radiologists dedicated to trauma and emergency imaging enable clearer understanding of complex injuries in high-risk patients which leads to superior clinical decision-making. Whereas dated dogma has long warned that the CT scanner is the last place to take a challenging trauma patient, modern practice suggests that, more often than not, early comprehensive imaging can be done safely and efficiently and is in the patient's best interest. This article outlines how the role of diagnostic imaging for major trauma has evolved considerably in recent years.

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.

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.

Multimodality Imaging Review of Anorectal and Perirectal Diseases with Clinical, Histologic, Endoscopic, and Operative Correlation, Part II: Infectious, Inflammatory, Congenital, and Vascular Conditions

A broad spectrum of pathology affects the rectum, anus, and perineum, and multiple imaging modalities are complementary to physical examination for assessment and treatment planning. In this pictorial essay, correlative imaging, endoscopic, pathologic, and operative images are presented for a range of rectal, perirectal, and perineal disease processes, including infectious/inflammatory, traumatic, congenital/developmental, vascular, and miscellaneous conditions. Key anatomic and surgical concepts are discussed, including radiological information pertinent for surgical planning, and current operative approaches of these anatomic spaces to assist radiologists in comprehensive reporting for gastroenterologists and surgeons.