64 MDCT in multiple trauma patients: imaging manifestations and clinical implications of active extravasation

Does delayed phase imaging in CT angiography provide additional information in patients with suspected active bleeding?

PURPOSE

We hypothesize that delayed phase imaging does not provide additional diagnostic information in patients who undergo multi-phasic CTA for suspected active bleeding.

METHODS

Data on patients who underwent multiphasic CTA (pre-contrast, arterial, porto-venous, and delayed phases) for suspected acute bleed were retrospectively collected between January 2019 and November 2021. CTA images were reviewed by a general radiologist, an interventional radiologist, and a body imaging radiologist independently. Each reader evaluated if delayed phase images provided additional information that would change the final impression of the CTA report. Additional information regarding bleeding location, time needed for delayed image acquisition, and radiation exposure were also obtained.

RESULTS

A total of 104 patients with CTAs were analyzed with an average age of 58 years ± 22. Studies rated with absent additional findings on delayed images were 102 (98.1%) by the interventional radiologist, 101 (97.1%) by the body imaging radiologist, and 100 (96.1%) by the general radiologist with percent agreement of 96.15% (kappa 0.54, p < 0.001). All the findings were characterized as unlikely to be clinically significant. Mean time added to complete a delayed phase images was 3.61 ± 3.4 min. The average CT dose length product (DLP) for the total exam was 3621.78 ± 2129.57 mGy.cm with delayed acquisition adding a mean DLP of 847.75 ± 508.8 mGy.cm.

CONCLUSION

Delayed phase imaging does not provide significant additional diagnostic information in evaluating patients with suspected active bleeding but is associated with increased examination time and radiation exposure.

Expanding Role of Dual-Energy CT for Genitourinary Tract Assessment in the Emergency Department, From the AJR Special Series on Emergency Radiology

Among explored applications of dual-energy CT (DECT) in the abdomen and pelvis, the genitourinary (GU) tract represents an area where accumulated evidence has established the role of DECT to provide useful information that may change management. This review discusses established applications of DECT for GU tract assessment in the emergency department (ED) setting, including characterization of renal stones, evaluation of traumatic injuries and hemorrhage, and characterization of incidental renal and adrenal findings. Use of DECT for such applications can reduce the need for additional multiphase CT or MRI examinations and reduce follow-up imaging recommendations. Emerging applications are also highlighted, including use of low-energy virtual monoenergetic images (VMIs) to improve image quality and potentially reduce contrast media doses and use of high-energy VMIs to mitigate renal mass pseudoenhancement. Finally, implementation of DECT into busy ED radiology practices is presented, weighing the trade-off of additional image acquisition, processing time, and interpretation time against potential additional useful clinical information. Automatic generation of DECT-derived images with direct PACS transfer can facilitate radiologists' adoption of DECT in busy ED environments and minimize impact on interpretation times. Using the described approaches, radiologists can apply DECT technology to improve the quality and efficiency of care in the ED.

CT of acute abdominopelvic hemorrhage: protocols, pearls, and pitfalls

Abdominal and pelvic hemorrhage may be secondary to a number of causes and is often a medical emergency. Patient presentation ranges from obvious trauma with evidence of hemodynamic instability to vague symptoms. CT has become the imaging modality of choice for identifying abdominopelvic hemorrhage. Recognizing acute hemorrhage as well as identifying its location and severity are key to expediting management. In the Emergency Department, ultrasound often used in the initial evaluation of trauma patients, but is not sensitive for subtle bleeds or injuries. CT is the best first-line imaging tool to identify abdominal hemorrhage and, compared with angiography, has been shown to be superior in detecting intra-abdominal bleeding, especially when the bleeding rate is low. Depending on location and etiology, abdominopelvic hemorrhage may have a characteristic appearance, such as the "sentinel clot" sign associated with blunt trauma to the solid organs or the "triangle sign" of a mesenteric bleed. The following pictorial essay reviews CT technique, study interpretation, and interpretative pearls and pitfalls in the recognition of acute abdominopelvic hemorrhage.

Multidetector CT in Vascular Injuries Resulting from Pelvic Fractures: A Primer for Diagnostic Radiologists

Pelvic vascular injuries are typically caused by high-energy trauma. The majority of these injuries are caused by motor vehicle collisions, and the rest are caused by falls and industrial or crush injuries. Pelvic vascular injuries are frequently associated with pelvic ring disruption and have a high mortality rate due to shock as a result of pelvic bleeding. Morbidity and mortality resulting from pelvic vascular injury are due to pelvic hemorrhage and resultant exsanguination, which is potentially treatable and reversible if it is diagnosed early with multidetector CT and treated promptly. The pelvic bleeding source can be arterial, venous, or osseous, and differentiating an arterial (high-pressure) bleed from a venous-osseous (low-pressure) bleed is of paramount importance in stratification for treatment. Low-pressure venous and osseous bleeds are initially treated with a pelvic binder or external fixation, while high-pressure arterial bleeds require angioembolization or surgical pelvic packing. Definitive treatment of the pelvic ring disruption includes open or closed reduction and internal fixation. Multidetector CT is important in the trauma setting to assess and characterize pelvic vascular injuries with multiphasic acquisition in the arterial and venous phases, which allows differentiation of the common vascular injury patterns. This article reviews the anatomy of the pelvic vessels and the pelvic vascular territory; discusses the multidetector CT protocols used in diagnosis and characterization of pelvic vascular injury; and describes the spectrum of pelvic vascular injuries, the differentiation of common injury patterns, mimics, and imaging pitfalls. Online supplemental material is available for this article. ^©RSNA, 2019 See discussion on this article by Dreizin.

CT findings of severe burn injuries after a motor vehicle collision: a case report

Severe burn injuries can complicate management of polytrauma. While CT is the primary imaging modality for evaluation of trauma injuries, CT findings of severe burn are rarely reported. A 31-year-old female was brought to the emergency department after motor vehicle collision in which she sustained a burn injury from contact with the vehicle muffler. Her initial trauma workup was notable for full-thickness burns to her left abdominal wall among other injuries. CT scan showed skin thickening and extensive stranding involving the whole layer of subcutaneous soft tissue. The deep fascia and underlying muscle layer were free from burn injuries. Identification of this finding on the CT scan helps establish appropriate care.

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.

CT Prediction Model for Major Arterial Injury after Blunt Pelvic Ring Disruption

Purpose To develop and test a computed tomography (CT)-based predictive model for major arterial injury after blunt pelvic ring disruptions that incorporates semiautomated pelvic hematoma volume quantification. Materials and Methods A multivariable logistic regression model was developed in patients with blunt pelvic ring disruptions who underwent arterial phase abdominopelvic CT before angiography from 2008 to 2013. Arterial injury at angiography requiring transarterial embolization (TAE) served as the outcome. Areas under the receiver operating characteristic (ROC) curve (AUCs) for the model and for two trauma radiologists were compared in a validation cohort of 36 patients from 2013 to 2015 by using the Hanley-McNeil method. Hematoma volume cutoffs for predicting the need for TAE and probability cutoffs for the secondary outcome of mortality not resulting from closed head injuries were determined by using ROC analysis. Correlation between hematoma volume and transfusion was assessed by using the Pearson coefficient. Results Independent predictor variables included hematoma volume, intravenous contrast material extravasation, atherosclerosis, rotational instability, and obturator ring fracture. In the validation cohort, the model (AUC, 0.78) had similar performance to reviewers (AUC, 0.69-0.72; P = .40-.80). A hematoma volume cutoff of 433 mL had a positive predictive value of 87%-100% for predicting major arterial injury requiring TAE. Hematoma volumes correlated with units of packed red blood cells transfused (r = 0.34-0.57; P = .0002-.0003). Predicted probabilities of 0.64 or less had a negative predictive value of 100% for excluding mortality not resulting from closed head injuries. Conclusion A logistic regression model incorporating semiautomated hematoma volume segmentation produced objective probability estimates of major arterial injury. Hematoma volumes correlated with 48-hour transfusion requirement, and low predicted probabilities excluded mortality from causes other than closed head injury. ^© RSNA, 2018 Online supplemental material is available for this article.

Errors in imaging of traumatic injuries

The advent of multi-detector computed tomography (MDCT) has drastically improved the outcomes of patients with multiple traumatic injuries. However, there are still diagnostic challenges to be considered. A missed or the delay of a diagnosis in trauma patients can sometimes be related to perception or other non-visual cues, while other errors are due to poor technique or poor image quality. In order to avoid any serious complications, it is important for the practicing radiologist to be cognizant of some of the most common types of errors. The objective of this article is to review the various types of errors in the evaluation of patients with multiple trauma injuries or polytrauma with MDCT.

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.

CT-detected traumatic small artery extremity injuries: surgery, embolize, or watch? A 10-year experience

Advances in computed tomography (CT) angiography have increased the sensitivity and specificity of detecting small branch arterial injuries in the extremities of trauma patients. However, it is unclear whether these patients should undergo surgery, angioembolization, or conservative watchful waiting. We hypothesized that uncomplicated small arterial branch injuries can be managed successfully with watchful waiting. A 10-year retrospective review of extremity CT angiograms with search findings of arterial "active extravasation" or "pseudoaneurysm" was performed at a level 1 county trauma center. Subgroup analysis was performed on those with isolated extremity injury and those with concurrent injuries. A total of 31 patients had CT-detected active extravasation (84 %) or pseudoaneurysm (16 %), 71 % of which were isolated vascular injuries. Of the patients evaluated, 71 % (n = 22) were managed with watchful waiting, 19 % (n = 6) with angioembolization, and 10 % (n = 3) with surgery. Watchful waiting complications included progression to alternative treatment (n = 1) and blood transfusions (n = 2). Complications of surgery included the inability to find active bleeding (n = 1) and postoperative psychosis (n = 1). Complications of angioembolization were limited to a postprocedure blood transfusion (n = 1). Patients with isolated vascular injuries had an average length of stay of 2.9 days, with management averages of the following: 2.7 days with watchful waiting (n = 16), 3.3 days with angioembolization (n = 3), and 3.7 days with surgery (n = 3). CT angiography has greatly increased the reported incidence of traumatic arterial injury in the extremity. We propose that small branch arterial injuries in the extremities can be managed successfully with watchful waiting and do not often require immediate embolization.

Readjustment of abdominal computed tomography protocols in a university hospital: impact on radiation dose

Objective

To assess the reduction of estimated radiation dose in abdominal computed tomography following the implementation of new scan protocols on the basis of clinical suspicion and of adjusted images acquisition parameters.

Materials and Methods

Retrospective and prospective review of reports on radiation dose from abdominal CT scans performed three months before (group A – 551 studies) and three months after (group B – 788 studies) implementation of new scan protocols proposed as a function of clinical indications. Also, the images acquisition parameters were adjusted to reduce the radiation dose at each scan phase. The groups were compared for mean number of acquisition phases, mean CTDI_vol per phase, mean DLP per phase, and mean DLP per scan.

Results

A significant reduction was observed for group B as regards all the analyzed aspects, as follows: 33.9%, 25.0%, 27.0% and 52.5%, respectively for number of acquisition phases, CTDI_vol per phase, DLP per phase and DLP per scan (p < 0.001).

Conclusion

The rational use of abdominal computed tomography scan phases based on the clinical suspicion in conjunction with the adjusted images acquisition parameters allows for a 50% reduction in the radiation dose from abdominal computed tomography scans.

[Endovascular interventions for multiple trauma]

CLINICAL ISSUE

In recent years interventional radiology has significantly changed the management of injured patients with multiple trauma. Currently nearly all vessels can be reached within a reasonably short time with the help of specially preshaped catheters and guide wires to achieve bleeding control of arterial und venous bleeding.

STANDARD TREATMENT/TREATMENT INNOVATIONS

Whereas bleeding control formerly required extensive open surgery, current interventional methods allow temporary vessel occlusion (occlusion balloons), permanent embolization and stenting.

DIAGNOSTIC WORK-UP

In injured patients with multiple trauma preinterventional procedural planning is performed with the help of multidetector computed tomography whenever possible.

PERFORMANCE

Interventional radiology not only allows minimization of therapeutic trauma but also a considerably shorter treatment time.

ACHIEVEMENTS

Interventional bleeding control has developed into a standard method in the management of vascular trauma of the chest and abdomen as well as in vascular injuries of the upper and lower extremities when open surgical access is associated with increased risk. Additionally, pelvic trauma, vascular trauma of the superior thoracic aperture and parenchymal arterial lacerations of organs that can be at least partially preserved are primarily managed by interventional methods.

PRACTICAL RECOMMENDATIONS

In an interdisciplinary setting interventional radiology provides a safe and efficient means of rapid bleeding control in nearly all vascular territories in addition to open surgical access.

Improving Outcomes in the Patient with Polytrauma: A Review of the Role of Whole-Body Computed Tomography

Whole-body computed tomography (WBCT) is used for the workup of the patient with blunt polytrauma. WBCT is associated with improved patient survival and reduces the emergency department length of stay. However, randomized studies are needed to determine whether early WBCT improves survival, to clarify which patients benefit the most, and to model the costs of this technique compared with traditional workup. Advancements in modern multidetector computed tomography technology and an improved understanding of optimal protocols have enabled one to scan the entire body and achieve adequate image quality for a comprehensive trauma assessment in a short period.

Postoperative abdominal bleeding

Postoperative bleeding following abdominal surgery is relatively rare and mainly depends on the type of surgery. Although bleeding is usually controlled by simple local treatment of symptoms, specific treatment including surgery or interventional radiology is sometimes necessary. This article reviews the clinical features that must be recognized depending on the type of surgery and especially focuses on the role of the radiologist in the management of this complication.

Emergency computed tomography for acute pelvic trauma: where is the bleeder?

Contrast medium extravasation at computed tomography (CT) is an accurate indicator of active haemorrhage in pelvic trauma. When this is present, potentially lifesaving surgical or endovascular treatment should be considered. Identification of the site or territory of haemorrhage is helpful for the interventional radiologist as it allows for focused angiographic evaluation and expedites haemostatic angio-embolisation. Even with thin-section arterial phase CT, tracing the bleeding vessel is not always possible and is often time consuming. We introduce a technique for predicting the bleeding vessel based on knowledge of the cross-sectional anatomical territory of the vessel as an alternative to tracing the vessel's course. Several case examples with digital subtraction angiography (DSA) correlation will be provided.

Utility of additional CT examinations driven by completion of a standard trauma imaging protocol in patients transferred for minor trauma

Many clinicians order focused computed tomography (CT) examinations for trauma patients based on history and physical examinations. Trauma patients transferred to our level I trauma center undergo an extensive, nonfocused standard trauma CT protocol. We hypothesize that the use of the standard trauma CT protocol does not contribute significant clinical information for patient care when compared with CT examinations based on history and physical examination. We aim to quantify the utility of the additional CT examinations required by our institution's trauma protocol compared with emergent CT examinations dictated by the patient's history and physical examination findings. In this IRB-approved study, we retrospectively evaluated 132 trauma patients transferred to our center who underwent additional CT examinations as determined by fulfillment of our institution's standard trauma CT protocol. The emergency radiologist evaluated the CT examinations acquired after the patient's transfer to determine if there were any additional acute findings that were identified on these additional examinations compared with the initial assessment undertaken at the outside institution. A total of 101 patients transferred to our trauma center met inclusion criteria. The majority of these patients sustained minor trauma. The standard trauma protocol generated 474 negative CT examinations in 101 patients. In seven patients, there were unexpected acute findings. However, these unexpected acute findings did not change clinical management in any of the patients. After initial evaluation, the acquisition of additional nonfocused CT examinations based on the standard trauma CT protocol provides little useful clinical information in patients who are transferred for minor trauma. Rather, CT utilization should be based on clinical findings. Replacement of standard trauma CT protocol with focused CT examinations in trauma patients is a way to curtail overutilization, thereby decreasing health care cost and the amount of patient radiation exposure.

Errors in imaging assessment of polytrauma patients

Although the use of multidetector computed tomography (MDCT) has increased the diagnostic quality by reducing the number of missed diagnoses in polytraumatized patients, errors remain a common phenomenon in emergency room setting. MDCT errors, contributing more commonly to missed or delayed diagnoses in polytrauma patients, are diagnostic errors commonly related to perceptual errors or to nonvisual errors. However, in some cases, misdiagnoses can be attributed to technical and methodological errors leading to incomplete or poor-quality imaging. Knowledge of common patterns of error is the most effective way to avoid future errors. The purpose of this article is to highlight the most frequent types of diagnostic errors in evaluating with MDCT of polytrauma patients.

Blunt polytrauma: evaluation with 64-section whole-body CT angiography

Blunt polytrauma remains a leading cause of death and disability worldwide. With the major advances in computed tomography (CT) technology over the past decade, whole-body CT is increasingly recognized as the emerging standard for providing rapid and accurate diagnoses within the narrow therapeutic window afforded to trauma victims with multiple severe injuries. With a single continuous acquisition, whole-body CT angiography is able to demonstrate all potentially injured organs, as well as vascular and bone structures, from the circle of Willis to the symphysis pubis. As its use becomes more widespread, the large volume of information inherent to whole-body CT poses new challenges to radiologists in providing efficient and timely interpretation. An awareness of trauma scoring systems and injury mechanisms is essential to maintain an appropriate level of suspicion in the search for multiple injuries, and the use of multiplanar reformation and three-dimensional postprocessing techniques is important to maximize efficiency in the search. Knowledge of the key injuries that require urgent surgical or percutaneous intervention, including major vascular injuries and active hemorrhage, diaphragmatic rupture, unstable spinal fractures, pancreatic injuries with ductal involvement, and injuries to the mesentery and hollow viscera, is also necessary.

Characterization of mandibular fractures using 64-slice multidetector CT

OBJECTIVE

The aim of this study was to characterize mandibular fracture locations using 64-slice multidetector CT (MDCT).

METHODS

CT scans of 138 patients with mandibular fractures who underwent 64-slice MDCT were studied. Mandibular fractures were classified into five types: median, paramedian, angle, condylar and coronoid process. Statistical analysis for the relationship between multiple fractures and type of mandibular fractures was performed using χ(2) test with Fisher's exact test.

RESULTS

The percentage of multiple mandibular fractures was 80.9% median type, 74.3% paramedian type, 52.9% angle type and 60.9% condylar type. The resultant data showed a significant relationship between multiple fractures and the median type (p = 0.000), paramedian type (p = 0.002) and condylar type (p = 0.003).

CONCLUSION

The results suggest that multiple fractures are related to the type of mandibular fractures.

The diagnostic accuracy of 64-slice computed tomography in detecting clinically significant arterial bleeding after pelvic fractures

The purpose of this study was to determine the diagnostic accuracy of the 64-slice multidetector computed tomography (MDCT) in detecting active pelvic arterial bleeding associated with blunt pelvic fractures. We hypothesized that this modality yields high accuracy. We conducted a retrospective review of all MDCT detected pelvic fractures over an 18-month period admitted to LAC+ USC Medical Center, a Level 1 trauma center. The main outcome was the presence of contrast extravasation (CE) on admission MDCT, consistent with clinically significant arterial bleeding requiring a subsequent embolization or intraoperative ligation of pelvic arteries. Overall, 127 patients met study criteria and 12 per cent (n = 15) had CE on admission MDCT of which four were managed conservatively. Eighty-two per cent (n = 9) of the remaining 11 patients who went on to have invasive procedure had active arterial bleeding that required embolization or surgical ligation. Two of the 112 (1.8%) patients without CE on their admission MDCT were subjected to embolization after further investigation with angiography as a result of the severity of their pelvic fracture and continuous transfusion requirements. The calculated sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the 64-slice MDCT to identify clinically relevant arterial bleeding were 82, 95, 60, 98, and 94 per cent, respectively. The modern 64-slice MDCT provides relatively high diagnostic accuracy in detecting a clinically relevant arterial hemorrhage after blunt pelvic fracture. Nevertheless, in patients with clinical signs of ongoing hemorrhage, timely angiography or operative intervention is warranted, even in the absence of MDCT contrast extravasation.

Contrast-enhanced ultrasound imaging of active bleeding associated with hepatic and splenic trauma

PURPOSE

The aim of this study was to evaluate contrast-enhanced ultrasound (CEUS) imaging of active bleeding from hepatic and splenic trauma.

MATERIALS AND METHODS

Three hundred and ninety-two patients with liver or/and spleen trauma (179 liver and 217 spleen injuries), who underwent CEUS examinations following contrast-enhanced computed tomography (CT), were enrolled in this retrospective study over a period of >4 years. CEUS detected contrast medium extravasation or pooling in 16% (63/396) of liver or spleen lesions in 61 patients, which was confirmed by contrast-enhanced CT. Special attention was paid to observing the presence, location, and characteristics of the extravasated or pooled contrast medium.

RESULTS

The CEUS detection rate for active bleeding was not different from that of contrast-enhanced CT (p=0.333). Information from surgery, minimally invasive treatment and conservative treatment was used as reference standard, and the sensitivities of the two techniques were not different (p=0.122). Of 63 lesions in 61 patients, CEUS showed that 74.6% (47/63) (21 liver lesions and 26 spleen lesions) presented contrast medium extravasation or pooling, both in the organ and out the capsule, in 14.3% (9/63) and only outside the capsule in 11.1% (7/63). CEUS imaging of active bleeding from hepatic and splenic trauma presented various characteristics, and the sizes and shapes of the active bleeding due to contrast medium extravasation or pooling were variable.

CONCLUSIONS

CEUS can show the active bleeding associated with hepatic and splenic trauma with various imaging characteristics, thus making it possible to diagnose active bleeding using CEUS.

Angiography and embolisation for solid abdominal organ injury in adults - a current perspective

Over the past twenty years there has been a shift towards non-operative management (NOM) for haemodynamically stable patients with abdominal trauma. Embolisation can achieve haemostasis and salvage organs without the morbidity of surgery, and the development and refinement of embolisation techniques has widened the indications for NOM in the management of solid organ injury. Advances in computed tomography (CT) technology allow faster scanning times with improved image quality. These improvements mean that whilst surgery is still usually recommended for patients with penetrating injuries, multiple bleeding sites or haemodynamic instability, the indications for NOM are expanding.

We present a current perspective on angiography and embolisation in adults with blunt and penetrating abdominal trauma with illustrative examples from our practice including technical advice.