Blunt Abdominal Trauma: Performance of CT without Oral Contrast Material

Incidence of intra-abdominal injuries in hemodynamically stable blunt trauma patients with a normal computed tomography scan admitted to the emergency department

OBJECTIVES

Blunt abdominal trauma is a common cause of emergency department admission. Computed tomography (CT) scanning is the gold standard method for identifying intra-abdominal injuries in patients experiencing blunt trauma, especially those with high-energy trauma. Although the diagnostic accuracy of this imaging technique is very high, patient admission and prolonged observation protocols are still common practices worldwide. We aimed to evaluate the incidence of intra-abdominal injury in hemodynamically stable patients with high-energy blunt trauma and a normal abdominal CT scan at a Level-1 Trauma Center in Colombia, South America, to assess the relevance of a prolonged observation period.

METHODS

We performed a retrospective study of patients admitted to the emergency department for blunt trauma between 2021 and 2022. All consecutive patients with high-energy mechanisms of trauma and a normal CT scan at admission were included. Our primary outcomes were the incidence of intra-abdominal injury identified during a 24-hour observation period or hospital stay, ICU admission, and death.

RESULTS

We included 480 patients who met the inclusion criteria. The median age was 33 (IQR 25.5, 47), and 74.2% were male. The most common mechanisms of injury were motor vehicle accidents (64.2%), falls from height (26%), and falls from bikes (3.1%). A total of 99.2% of patients had a Revised Trauma Score of 8. Only 1 patient (0.2%) (95% CI: 0.01-1.16) presented with an abdominal injury during the observation period. No ICU admissions or deaths were reported.

CONCLUSION

The incidence of intra-abdominal injury in patients with hemodynamically stable blunt trauma and a negative abdominal CT scan is extremely low, and prolonged observation may not be justified in these patients.

Bowel Emergencies in Patients With Cancer

Cancer is the second most common cause of death worldwide. Bowel emergencies in patients with cancer are becoming increasingly more prevalent due to advances in cancer therapy and longer overall patient survival. When these patients present acutely, they are often frail and may have pre-existing co-morbidities. This article discusses the imaging features of bowel emergencies commonly encountered in oncological patients in clinical practice. These include chemotherapy related colitis, neutropenia enterocolitis and typhlitis, toxic megacolon, bowel perforation, malignant bowel obstruction and gastrointestinal haemorrhage. The radiologist plays a key role in identifying these oncological emergencies and guiding further management.

CT-based diagnostic algorithm to identify bowel and/or mesenteric injury in patients with blunt abdominal trauma

OBJECTIVES

To develop a CT-based algorithm and evaluate its performance for the diagnosis of blunt bowel and/or mesenteric injury (BBMI) in patients with blunt abdominal trauma.

METHODS

This retrospective study included a training cohort of 79 patients (29 with BBMI and 50 patients with blunt abdominal trauma without BBMI) and a validation cohort of 37 patients (13 patients with BBMI and 24 patients with blunt abdominal trauma without BBMI). CT examinations were blindly analyzed by two independent radiologists. For each CT sign, the kappa value, sensitivity, specificity, and accuracy were calculated. A diagnostic algorithm was built using a recursive partitioning model on the training cohort, and its performances were assessed on the validation cohort.

RESULTS

CT signs with kappa value > 0.6 were extraluminal gas, hemoperitoneum, no or moderate bowel wall enhancement, and solid organ injury. CT signs yielding best accuracies in the training cohort were extraluminal gas (98%; 95% CI: 91-100), bowel wall defect (97%; 95% CI: 91-100), irregularity of mesenteric vessels (97%; 95% CI: 90-99), and mesenteric vessel extravasation (97%; 95% CI: 90-99). Using a recursive partitioning model, a decision tree algorithm including extraluminal gas and no/moderate bowel wall enhancement was built, achieving 86% sensitivity (95% CI: 74-99) and 96% specificity (95% CI: 91-100) in the training cohort and 92% sensitivity (95% CI: 78-97) and 88% specificity (95% CI: 74-100) in the validation cohort for the diagnosis of BBMI.

CONCLUSIONS

An effective diagnostic algorithm was built to identify BBMI in patients with blunt abdominal trauma using only extraluminal gas and no/moderate bowel wall enhancement on CT examination.

KEY POINTS

• A CT diagnostic algorithm that included extraluminal gas and no/moderate bowel wall enhancement was built for the diagnosis of surgical blunt bowel and/or mesenteric injury. • A decision tree combining only two reproducible CT signs has high diagnostic performance for the diagnosis of surgical blunt bowel and/or mesenteric injury.

Single Center Retrospective Review of Post-laparotomy CT Abdomen and Pelvis Findings and Trends

Purpose

To identify common findings visualized on CT following damage control laparotomy, including post-surgical changes and additional injuries, and to determine change in frequency of post-laparotomy CT at our institution over time.

Methods

Single institution, IRB-Exempt, retrospective review of the University of Kentucky trauma registry from 1/2006 to 2/2019 for all trauma patients undergoing exploratory laparotomy initially and subsequently undergoing CT of the abdomen and pelvis within 24 hours. Operative findings from surgical operation notes and findings reported on post-laparotomy CT were recorded, including vascular and solid organ injuries, operative changes, free intraperitoneal fluid/air, and retroperitoneal findings. Next steps in management were also recorded.

Results

In total 1,047 patients underwent exploratory laparotomy initially at our institution between 1/2006-2/2019. Of those, only 96 had a diagnostic CT of the abdomen and pelvis within 24 h after initial surgery, first occurring in 2010. Among these 96, there were 71 blunt and 25 penetrating injuries. Most common injuries recognized during exploratory laparotomy were bowel/mesentery (55), spleen (34), and liver (26). Regarding CT findings, all patients (96/96, 100%) had residual pneumoperitoneum, 84/96 (87.5%) had residual hemoperitoneum, 36/96 (37.5%) noted post-surgical changes or additional injuries to the spleen, 36/96 (37.5%) to the bowel/mesentery, and 32/96 (33.3%) to the liver, and 34/96 (35.4%) were noted to have pelvic fractures. After CT, 31/96 (32.3%) went back to the OR for relook laparotomy and additional surgical intervention and 7/96 (7.3%) went to IR for embolization. Most common procedures during relaparotomy involved the bowel (8) and solid organs (6).

Conclusions

CT examination within 24 h post damage control laparotomy was exceedingly rare at our institution prior to 2012 but has steadily increased. Frequency now averages 20.5% yearly. Damage control laparotomy is an uncommon clinical scenario; however, knowledge of frequent injuries and common post-operative changes will aid in radiologist detection of additional injuries helping shape next step management and provide adequate therapy.

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.

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.

Evaluation of Bowel and Mesentery in Abdominal Trauma

Since the advent of multidetecter computed tomography (CT), radiologist sensitivity in detection of traumatic bowel and mesenteric abnormalities has significantly improved. Although several CT signs have been described to identify intestinal injury, accurate interpretation of these findings can remain challenging. Early detection of bowel and mesenteric injury is important as it alters patient management, disposition, and follow-up. This article reviews the common imaging findings of traumatic small bowel and mesenteric injury.

Imaging of blunt bowel and mesenteric injuries: Current status

Blunt abdominal trauma often presents a diagnostic challenge. Clinical examination demonstrates low reliability in detecting abdominal injury (16 %) when there is a history of head injury or loss of consciousness. This can prove detrimental, as delays in the diagnosis of traumatic bowel injury of 8 h or less can result in increased morbidity and mortality, as well as prolonged hospitalization. Although hemodynamically unstable patients will require an urgent laparotomy following clinical assessment, MDCT is the modality of choice for comprehensive imaging of blunt abdominal trauma in hemodynamically stable patients. Despite the use of MDCT, blunt injury to the bowel and mesentery, which accounts for up to 5% of injuries in cases of trauma, may be difficult to detect. The use of a constellation of direct and indirect signs on MDCT can help make the diagnosis and guide clinical management. Direct signs on MDCT, such as bowel wall discontinuity, and extraluminal gas may assist in the diagnosis of traumatic bowel injury. However, these signs are not sensitive. Therefore, the astute radiologist may have to rely on indirect signs of injury, such as free fluid, bowel wall thickening, and abnormal bowel wall enhancement to make the diagnosis. This review will focus on MDCT imaging findings of bowel and mesenteric injuries secondary to blunt abdominal trauma.

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.

Duodeno-pancreatic and extrahepatic biliary tree trauma: WSES-AAST guidelines

Duodeno-pancreatic and extrahepatic biliary tree injuries are rare in both adult and pediatric trauma patients, and due to their anatomical location, associated injuries are very common. Mortality is primarily related to associated injuries, but morbidity remains high even in isolated injuries. Optimal management of duodeno-bilio-pancreatic injuries is dictated primarily by hemodynamic stability, clinical presentation, and grade of injury. Endoscopic and percutaneous interventions have increased the ability to non-operatively manage these injuries. Late diagnosis and treatment are both associated to increased morbidity and mortality. Sequelae of late presentations of pancreatic injury and complications of severe pancreatic trauma are also increasingly addressed endoscopically and with interventional radiology procedures. However, for moderate and severe extrahepatic biliary and severe duodeno-pancreatic injuries, immediate operative intervention is preferred as associated injuries are frequent and commonly present with hemodynamic instability or peritonitis. The aim of this paper is to present the World Society of Emergency Surgery (WSES) and American Association for the Surgery of Trauma (AAST) duodenal, pancreatic, and extrahepatic biliary tree trauma management guidelines.

No need for surgery? Patterns and outcomes of blunt abdominal trauma

Introduction

The management of a patient suffering from blunt abdominal trauma (BAT) remains a challenge for the emergency physician. Within the last few years, the standard therapy for hemodynamically stable patients with BAT has transitioned to a non-operative approach. The purpose of this study is to evaluate the outcome of patients with BAT and to determine the reasons for failure of non-operative management (NOM).

Materials and methods

Analysis of 176 consecutive patients treated for BAT was conducted in a German level 1 trauma center from 2004 to 2011. Abdominal injuries were classified according to the American Association for the Surgery of Trauma (AAST). Patients included were demonstrated to have objective abdominal trauma with either free fluid on focused assessment with sonography for trauma (FAST) or computed tomography (CT), or proven organ injury.

Results

Patients, 142 of 176 (80.7%), with BAT were initially managed non-operatively, with a success rate of 90%. The rates of NOM success were higher among those with less severe injuries; 100% with Abbreviated Injury Scale (AIS) of 1. In total, 125 patients (71.0%) were managed non-operatively, and 51 (29.0%) required surgical intervention. NOM failure occurred in 9.2% of the patients, the most common reason being initially undiagnosed intestinal perforation (46.2%). Positive correlation was identified (r = 0.512; p < 0.001) between the ISS (injury severity score) and the NACA (National Advisory Committee of Aeronautics) score. The delay in operation in NOM failure was 6 h in patients with underlying hepatic or splenic rupture and 34 h with intestinal perforation. The overall mortality of 5.1% was attributed especially to old age (p = 0.016), high severity of injury (p < 0.001), and greater need for blood transfusion (p < 0.001).

Conclusion

NOM was successful for the vast majority of blunt abdominal trauma patients, especially those with less severe injuries. NOM failure and operative delay were most commonly due to occult hollow viscus injury (HVI), the detection of which was achieved by close clinical observation and abdominal ultrasound in conjunction with monitoring for rising markers of infection and by multidetector computed tomography (MDCT) if additionally indicated. Based on this concept, the delay in operation in patients with NOM failure was short. This study underscores the feasibility and benefit of NOM in BAT.

[Imaging techniques in modern trauma diagnostics]

Modern trauma room management requires interdisciplinary teamwork and synchronous communication between a team of anaesthesists, surgeons and radiologists. As the length of stay in the trauma room influences morbidity and mortality of a severely injured person, optimizing time is one of the main targets. With the direct involvement of modern imaging techniques the injuries caused by trauma should be detected within a very short period of time in order to enable a priority-orientated treatment. Radiology influences structure and process quality, management and development of trauma room algorithms regarding the use of imaging techniques. For the individual case interventional therapy methods can be added. Based on current data and on the Frankfurt experience the current diagnostic concepts of trauma diagnostics are presented.

Multidetector Computed Tomography Imaging of Damage Control Surgery Patients

Damage control surgery is a staged surgical procedure in a patient who has suffered penetrating or blunt abdominal traumatic injury with severe metabolic derangements. Multidetector computed tomography scanning is a vital tool for patient management in the damage control patient, providing many uses, including assessing the extent of traumatic injury, evaluating areas that were not surgically explored, evaluating for injuries that were missed during the initial surgery, and assessing the stability of surgical repair. Understanding the postsurgical multidetector computed tomography appearance of these patients can aid the radiologist in protocol optimization and provide immediate accurate diagnoses.

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.

Assessment of organ dose and image quality in head and chest CT examinations: a phantom study

The purpose of this study is to assess dose for radiosensitive organs and image quality in head and chest computed tomography (CT) examinations. Our focus was in the brain, eye lens and lung organs using two protocols; one protocol with fixed mAs and filtered back projection (FBP) and another with tube current modulation (TCM) and sinogram affirmed iterative reconstruction (SAFIRE). Measurements were performed on a 128-slice CT scanner by placing thermoluminescent dosimeters (TLDs) in an anthropomorphic adult phantom. Results were compared to a CT-Expo software. Objective image quality was assessed in terms of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). SPSS software was used for data analyses. Results showed that, using TCM, doses were reduced by 22.84%-25.06% for brain, by 21.82%-23.48% for eye lens and by 54%-53.22% for lung with TLD and CT-Expo respectively. The increased SNR and CNR values achieved for scans performed with TCM combined with iterative reconstruction techniques were 38.68%-58.81% and 38.91%-43.60% respectively. We conclude that, using TCM, a significant mean organ dose reduction is achieved for brain, eye lens and lung organs. Then, combined with iterative reconstruction, image quality was well maintained in terms of SNR and CNR. Thus it is highly recommended in clinical practice optimization in head and chest CT examinations.

3D MRI Modeling of Thin and Spatially Complex Soft Tissue Structures without Shrinkage: Lamprey Myosepta as an Example

3D imaging techniques enable the nondestructive analysis and modeling of complex structures. Among these, MRI exhibits good soft tissue contrast, but is currently less commonly used for nonclinical research than X-ray CT, even though the latter requires contrast-staining that shrinks and distorts soft tissues. When the objective is the creation of a realistic and complete 3D model of soft tissue structures, MRI data are more demanding to acquire and visualize and require extensive post-processing because they comprise noncubic voxels with dimensions that represent a trade-off between tissue contrast and image resolution. Therefore, thin soft tissue structures with complex spatial configurations are not always visible in a single MRI dataset, so that standard segmentation techniques are not sufficient for their complete visualization. By using the example of the thin and spatially complex connective tissue myosepta in lampreys, we developed a workflow protocol for the selection of the appropriate parameters for the acquisition of MRI data and for the visualization and 3D modeling of soft tissue structures. This protocol includes a novel recursive segmentation technique for supplementing missing data in one dataset with data from another dataset to produce realistic and complete 3D models. Such 3D models are needed for the modeling of dynamic processes, such as the biomechanics of fish locomotion. However, our methodology is applicable to the visualization of any thin soft tissue structures with complex spatial configurations, such as fasciae, aponeuroses, and small blood vessels and nerves, for clinical research and the further exploration of tensegrity. Anat Rec, 301:1745-1763, 2018. © 2018 Wiley Periodicals, Inc.

[Imaging techniques in modern trauma diagnostics]

Modern trauma room management requires interdisciplinary teamwork and synchronous communication between a team of anaesthesists, surgeons and radiologists. As the length of stay in the trauma room influences morbidity and mortality of a severely injured person, optimizing time is one of the main targets. With the direct involvement of modern imaging techniques the injuries caused by trauma should be detected within a very short period of time in order to enable a priority-orientated treatment. Radiology influences structure and process quality, management and development of trauma room algorithms regarding the use of imaging techniques. For the individual case interventional therapy methods can be added. Based on current data and on the Frankfurt experience the current diagnostic concepts of trauma diagnostics are presented.

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

OBJECTIVE

Many centers advocate use of triple-contrast (IV, oral, and rectal) CT for assessing hemodynamically stable patients with penetrating abdominopelvic trauma. Enteric contrast material has several disadvantages, leading our practice to pursue use of single-contrast (IV) CT. We conducted a retrospective review of electronic medical records at our institution to assess the accuracy of single-contrast CT for diagnosing bowel injuries in cases of penetrating abdominopelvic trauma.

MATERIALS AND METHODS

We retrospectively reviewed patients who presented to our emergency department between January 1, 2004, and March 1, 2014, with penetrating abdominopelvic trauma, underwent an abdominopelvic CT, and had surgery performed thereafter. We reviewed pertinent emergency department records for details regarding the site of injury, the number of injuries per patient, and the type of weapon used. We correlated CT reports with operative notes for presence and sites of bowel injury.

RESULTS

A total of 274 patients (median age, 27 years old) met our inclusion criteria; 77% had sustained gunshot wounds (GSWs). CT showed bowel injury in 173 cases; surgery revealed bowel injury in 162 cases. CT had 142 true-positive, 31 false-positive, 81 true-negative, and 20 false-negative cases, resulting in sensitivity of 88%, specificity of 72%, positive predictive value of 82%, and negative predictive value of 80% for detecting bowel injuries. CT had the highest sensitivity and specificity in patients with multiple GSWs (94% and 79%, respectively) and those with injuries to the stomach and rectum.

CONCLUSION

Single-contrast CT can show bowel injuries in patients with penetrating abdominopelvic trauma with accuracy comparable with that reported for triple-contrast CT.

Utility of CT oral contrast administration in the emergency department of a quaternary oncology hospital: diagnostic implications, turnaround times, and assessment of ED physician ordering

PURPOSE

To compare studies with and without oral contrast on performance of multidetector computed tomography (CT) and the order to CT examination turnaround time in cancer patients presenting to the emergency department (ED). To the best of our knowledge, oral contrast utility has not previously been specifically assessed in cancer patients presenting to the emergency department.

MATERIALS & METHODS

Retrospective review of CT abdomen examinations performed in oncology patients presenting to the emergency department during one month. CT examinations performed with and without oral contrast were rated by two consensus readers for degree of confidence and diagnostic ability. Correlations were assessed for primary cancer type, age, sex, chief complaint/examination indication, body mass index, intravenous contrast status, repeat CT examination within 4 weeks, and disposition. Turnaround times from order to the start of the CT examination were calculated.

RESULTS

The studied group consisted of 267 patients (127 men and 140 women) with a mean age of 56 years and a mean body mass index of 27.8 kg/m². One hundred sixty CT examinations were performed without oral contrast, and 107 CT examinations were performed with oral contrast. There was no significant difference between cases with oral contrast and cases without oral contrast in the number of cases rated as "improved confidence" (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.23-1.31, P = 0.17), "improved diagnosis" (OR 0.58, 95% CI 0.20-1.64, P = 0.3), "impaired confidence" (OR 3.92, 95% CI 0.46-33.06, P = 0.21), or "impaired diagnosis" (OR 2.63, 95% CI 0.29-23.89, P = 0.39). The turnaround time in the group receiving oral contrast (mean, 141 min; standard deviation, 49.8 min) was significantly longer than that in the group not receiving oral contrast (mean, 109.2 min; standard deviation, 64.8 min) with a mean difference of 31.8 min (P < 0.0001).

CONCLUSION

On the basis of our findings and prior studies, targeted rather than default use of oral contrast shows acceptable diagnostic ability in the emergency setting for oncology patients. Benefit from oral contrast use is suggested in scenarios such as suspected fistula/bowel leak/abscess, hypoattenuating peritoneal disease, prior bowel surgery such as gastric bypass, and the absence of intravenous contrast administration. Improvement through the use of targeted oral contrast administration also supports the emergency department need for prompt diagnosis and disposition.

Educational Review of Predictive Value and Findings of Computed Tomography Scan in Diagnosing Bowel and Mesenteric Injuries after Blunt Trauma: Correlation with Trauma Surgery Findings in 163 Patients

Background and Aims

Laparotomy can detect bowel and mesenteric injuries in 1.2%–5% of patients following blunt abdominal trauma. Delayed diagnosis in such cases is strongly related to increased risk of ongoing sepsis, with subsequent higher morbidity and mortality. Computed tomography (CT) scanning is the gold standard in the evaluation of blunt abdominal trauma, being accurate in the diagnosis of bowel and mesenteric injuries in case of hemodynamically stable trauma patients. Aims of the present study are to 1) review the correlation between CT signs and intraoperative findings in case of bowel and mesenteric injuries following blunt abdominal trauma, analysing the correlation between radiological features and intraoperative findings from our experience on 25 trauma patients with small bowel and mesenteric injuries (SBMI); 2) identify the diagnostic specificity of those signs found at CT with practical considerations on the following clinical management; and 3) distinguish the bowel and mesenteric injuries requiring immediate surgical intervention from those amenable to initial nonoperative management.

Materials and Methods

Between January 1, 2008, and May 31, 2010, 163 patients required laparotomy following blunt abdominal trauma. Among them, 25 patients presented bowel or mesenteric injuries. Data were analysed retrospectively, correlating operative surgical reports with the preoperative CT findings.

Results

We are presenting a pictorial review of significant and frequent findings of bowel and mesenteric lesions at CT scan, confirmed intraoperatively at laparotomy. Moreover, the predictive value of CT scan for SBMI is assessed.

Conclusions

Multidetector CT scan is the gold standard in the assessment of intra-abdominal blunt abdominal trauma for not only parenchymal organs injuries but also detecting SBMI; in the presence of specific signs it provides an accurate assessment of hollow viscus injuries, helping the trauma surgeons to choose the correct initial clinical management.

Can multidetector CT detect the site of gastrointestinal tract injury in trauma? - A retrospective study

PURPOSE

We aimed to assess the performance of computed tomography (CT) in localizing site of traumatic gastrointestinal tract (GIT) injury and determine the diagnostic value of CT signs in site localization.

METHODS

CT scans of 97 patients with surgically proven GIT or mesenteric injuries were retrospectively reviewed by radiologists blinded to surgical findings. Diagnosis of either GIT or mesenteric injuries was made. In patients with GIT injuries, site of injury and presence of CT signs such as focal bowel wall hyperenhancement, hypoenhancement, wall discontinuity, wall thickening, extramural air, intramural air, perivisceral infiltration, and active vascular contrast leak were evaluated.

RESULTS

Out of 97 patients, 90 had GIT injuries (70 single site injuries and 20 multiple site injuries) and seven had isolated mesenteric injury. The overall concordance between CT and operative findings for exact site localization was 67.8% (61/90), partial concordance rate was 11.1% (10/90), and discordance rate was 21.1% (19/90). For single site localization, concordance rate was 77.1% (54/70), discordance rate was 21.4% (15/70), and partial concordance rate was 1.4% (1/70). In multiple site injury, concordance rate for all sites of injury was 35% (7/20), partial concordance rate was 45% (9/20), and discordance rate was 20% (4/20). For upper GIT injuries, wall discontinuity was the most accurate sign for localization. For small bowel injury, intramural air and hyperenhancement were the most specific signs for site localization, while for large bowel injury, wall discontinuity and hypoenhancement were the most specific signs.

CONCLUSION

CT performs better in diagnosing small bowel injury compared with large bowel injury. CT can well predict the presence of multiple site injury but has limited performance in exact localization of all injury sites.

Peritoneal fluid of low CT Hounsfield units as a screening criterion for traumatic bowel perforation

PURPOSE

To investigate whether peritoneal fluid of low CT Hounsfield units is an important screening criterion for traumatic bowel perforation.

MATERIALS AND METHODS

We performed a retrospective study on two cohorts of blunt trauma patients who had peritoneal fluid. Intravenous and oral contrast was used for the first cohort (61 patients) as opposed to intravenous contrast only for the second cohort (60 patients). We compared the CT Hounsfield units of peritoneal fluid with bowel perforation. The optimal cutoff value of CT Hounsfield units was determined, and its diagnostic values for bowel perforation were calculated.

RESULTS

The mean CT Hounsfield units (HU) of peritoneal fluid with bowel perforation were significantly lower (30.3 ± 9.0 versus 44.1 ± 13.6 HU, p = 0.008) in the second cohort. The optimal cutoff value was 43 HU, and its sensitivity, specificity, accuracy and positive likelihood ratio were 100.0, 69.2, 73.3% and 3.3, respectively, for bowel perforation. Comparisons of CT HUs of peritoneal fluid with bowel perforation in the first cohort that used additional oral contrast for CT did not show statistically significant differences.

CONCLUSION

Peritoneal fluid of low CT HU is a sensitive and important CT screening criterion for traumatic bowel perforation.

Are We Missing Traumatic Bowel and Mesenteric Injuries?

Purpose

Traumatic bowel and mesenteric injury (TBMI), although an uncommon entity, can be lethal if not detected and treated in a timely manner. The purpose of our study was to evaluate the diagnostic accuracy of 64-slice multidetector computed tomography (MDCT) for the detection of TBMI in patients at our level 1 trauma centre.

Methods

We used our hospital's trauma registry to identify patients with a diagnosis of TBMI from January 1, 2006, to June 30, 2013. Only patients who had a 64-slice MDCT scan at presentation and subsequently underwent laparotomy or laparoscopy were included in the study cohort. Using the surgical findings as the gold standard, the accuracy of prospective radiology reports was analyzed.

Results

Of the 4781 trauma patients who presented to our institution, 44 (0.92%) had surgically proven TBMI. Twenty-two of 44 were excluded as they did not have MDCT before surgery. The study cohort consisted of 14 males and 8 females with a median age of 41.5 years and a median injury severity score of 27. In total 17 of 22 had blunt trauma and 5 of 22 had penetrating injury. A correct preoperative imaging diagnosis of TBMI was made in 14 of 22 of patients. The overall sensitivity of the radiology reports was 63.6% (95% confidence interval [CI]: 41%-82%), specificity was 79.6% (95% CI: 67%-89%), PPV was 53.9% (95% CI: 33%-73%), and the NPV was 85.5% (95% CI: 73%-94%). Accuracy was calculated at 75.3%. However, only 59% (10 of 17) of patients with blunt injury had a correct preoperative diagnosis. Review of the findings demonstrated that majority of patients with missed blunt TBMI (5 of 7) demonstrated only indirect signs of injury.

Conclusion

The detection of TBMI in trauma patients on 64-slice MDCT can be improved, especially in patients presenting with blunt injury. Missed cases in this population occurred because the possibility of TBMI was not considered despite the presence of indirect imaging signs. The prospective diagnosis of TBMI remains challenging despite advances in CT technology and widespread use of 64-slice MDCT.

Core curriculum illustration: blunt trauma to the bowel

This is the 22nd installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .

Damage control surgery: use of diagnostic CT after life-saving laparotomy

Damage control surgery (DCS) is a limited exploratory laparotomy that is performed in unstable trauma patients who, without immediate intervention, would acutely decompensate. Patients usually present with shock physiology and metabolic derangements including acidosis, hypothermia, and coagulopathy. Delayed medical correction of these metabolic derangements leads to an irreversible state of coagulopathic hemorrhagic shock and inevitable patient demise. Therefore, once a patient meets DCS criteria, a limited exploratory laparotomy is performed to stabilize life-threatening injury and expedite initiation of medical resuscitation in the intensive care unit (ICU). The surgeon plans to return to the operating room for definitive surgical treatment once the patient is hemodynamically stabilized and the metabolic derangements have been corrected. DCS patients are frequently sent to the ICU with an open abdomen and purposefully retained surgical equipment. The lack of response to resuscitation efforts, persistent hypotension, tachycardia, and/or the development of sepsis are common indications for this patient population to undergo CT imaging. The indications and findings of multi-detector CT (MDCT) in patients post-DCS have not been thoroughly evaluated in the radiology literature. A radiologist's knowledge of the DCS protocol and pre-imaging surgical interventions helps optimize the MDCT protocol. This enhances the radiologist's ability to evaluate for failure of surgical interventions performed prior to imaging and to search for injuries in areas that were not explored or that were missed during the initial surgical exploration.

Unenhanced Computed Tomography to Visualize Hollow Viscera and/or Mesenteric Injury After Blunt Abdominal Trauma: A Single-Institution Experience

To identify and describe the major features of unenhanced computed tomography (CT) images of blunt hollow viscera and/or mesenteric injury (BHVI/MI) and to determine the value of unenhanced CT in the diagnosis of BHVI/MI. This retrospective study included 151 patients who underwent unenhanced CT before laparotomy for blunt abdominal trauma between January 2011 and December 2013. According to surgical observations, patients were classified as having BHVI/MI (n = 73) or not (n = 78). Sensitivity, specificity, P values, and likelihood ratios were calculated by comparing CT findings between the 2 groups. Six significant CT findings (P < 0.05) for BHVI/MI were identified and their sensitivity and specificity values determined, as follows: bowel wall thickening (39.7%, 96.2%), mesentery thickening (46.6%, 88.5%), mesenteric fat infiltration (12.3%, 98.7%), peritoneal fat infiltration (31.5%, 87.1%), parietal peritoneum thickening (30.1%, 85.9%), and intra- or retro-peritoneal air (34.2%, 96.2%). Unenhanced CT scan was useful as an initial assessment tool for BHVI/MI after blunt abdominal trauma. Six key features on CT were correlated with BHVI/MI.

Ketamine Sedation After Administration of Oral Contrast: A Retrospective Cohort Study

BACKGROUND

The American Academy of Pediatrics and American Society of Anesthesiologists have published consensus-based fasting guidelines intended to reduce the risk of pulmonary aspiration. The purpose of our study was to compare the rate of adverse events in patients sedated with ketamine within 2 hours of oral contrast intake to those who were nil per os (NPO).

METHODS

A retrospective cohort review of a database of children between July 2008 and May 2011. The rate of adverse events in children sedated with ketamine after intake of oral contrast for an abdominal computed tomography were compared with those sedated without taking oral contrast.

RESULTS

One hundred and four patients sedated for a computed tomography scan; 22 patients were sedated within 2 hours of taking oral contrast, and 82 were NPO. The 2 groups were comparable with regard to gender, race, and American Society of Anesthesiologists status. The mean (SD) time between the second dose of oral contrast and induction of sedation was 58 (24) minutes. Vomiting occurred in 4 of 22 patients in the oral contrast group (18%; 95% confidence interval 2%-34%) and 1 of 82 patients in the NPO group (1%; 95% confidence interval, 0%, 4%; P < .001). There was no difference in oxygen desaturation between the groups (P = .6).

CONCLUSIONS

Children who received oral contrast up to 58 minutes before ketamine sedation had a higher rate of vomiting than those who did not receive oral contrast. We did not identify cases of clinical aspiration, and the incidence of hypoxia between the 2 groups was not statistically significant.

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).

Diagnostic Performance of CT Angiography in Patients Visiting Emergency Department with Overt Gastrointestinal Bleeding

Objective

To investigate the diagnostic performance of computed tomography angiography (CTA) in identifying the cause of bleeding and to determine the clinical features associated with a positive test result of CTA in patients visiting emergency department with overt gastrointestinal (GI) bleeding.

Materials and Methods

We included 111 consecutive patients (61 men and 50 women; mean age: 63.4 years; range: 28-89 years) who visited emergency department with overt GI bleeding. They underwent CTA as a first-line diagnostic modality from July through December 2010. Two radiologists retrospectively reviewed the CTA images and determined the presence of any definite or potential bleeding focus by consensus. An independent assessor determined the cause of bleeding based on other diagnostic studies and/or clinical follow-up. The diagnostic performance of CTA and clinical characteristics associated with positive CTA results were analyzed.

Results

To identify a definite or potential bleeding focus, the diagnostic yield of CTA was 61.3% (68 of 111). The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value were 84.8% (67 of 79), 96.9% (31 of 32), 98.5% (67 of 68), and 72.1% (31 of 43), respectively. Positive CTA results were associated with the presence of massive bleeding (p = 0.001, odds ratio: 11.506).

Conclusion

Computed tomography angiography as a first-line diagnostic modality in patients presenting with overt GI bleeding showed a fairly high accuracy. It could identify definite or potential bleeding focus with a moderate diagnostic yield and a high PPV. CTA is particularly useful in patients with massive bleeding.

Blunt abdominal trauma: imaging and intervention

Interventional radiology, particularly percutaneous angioembolization, plays an important role in the management of blunt abdominal trauma involving solid organs and pelvic fractures. The traumatic injuries of the central nervous system, heart, and great vessels often lead to death at the site of trauma. Although patients with visceral organ injuries can also die at the site of trauma, these patients often reach the hospital thus giving us an opportunity to treat them with surgical or radiological intervention depending on the clinical condition of the patient. The management of these patients with trauma is now well codified-patients who remain unstable despite resuscitation should be shifted either to an operating room for laparotomy if the ultrasound (US) revealed hemoperitoneum or to a interventional room for angioembolization in cases of pelvic fractures. In all other cases, computed tomography is essential. Currently, multidetector computed tomography with contrast is the gold standard imaging modality for the diagnosis of traumatic abdominal injuries; it helps in assessing the extent of injuries, and further management can be planned.

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.

Assessment and treatment of the trauma patient in shock

High-volume crystalloid resuscitation is associated with increased length of stay, ICU and ventilator days, and organ failure and infection rates. Rapid evaluation of a hemodynamically unstable trauma patient is vital to diagnosis and treatment of the cause of shock. CT scanning should be used liberally in trauma patients to effect decreased mortality. Nonoperative management and catheter-based interventions are becoming the standard of care in appropriately selected patients with solid organ injuries.

An evaluation of the use of oral contrast media in abdominopelvic CT

OBJECTIVES

To evaluate the diagnostic efficacy of different oral contrast media (OCM) for abdominopelvic CT examinations performed for follow-up general oncological indications. The objectives were to establish anatomical image quality criteria for abdominopelvic CT; use these criteria to evaluate and compare image quality using positive OCM, neutral OCM and no OCM; and evaluate possible benefits for the medical imaging department.

METHODS

Forty-six adult patients attending a follow-up abdominopelvic CT for general oncological indications and who had a previous abdominopelvic CT with positive OCM (n = 46) were recruited and prospectively placed into either the water (n = 25) or no OCM (n = 21) group. Three radiologists performed absolute visual grading analysis (VGA) to assess image quality by grading the fulfilment of 24 anatomical image quality criteria.

RESULTS

Visual grading characteristics (VGC) analysis of the data showed comparable image quality with regards to reproduction of abdominal structures, bowel discrimination, presence of artefacts, and visualization of the amount of intra-abdominal fat for the three OCM protocols.

CONCLUSION

All three OCM protocols provided similar image quality for follow-up abdominopelvic CT for general oncological indications.

KEY POINTS

• Positive oral contrast media are routinely used for abdominopelvic multidetector computed tomography • Experimental study comparing image quality using three different oral contrast materials • Three different oral contrast materials result in comparable CT image quality • Benefits for patients and medical imaging department.