Making the transition: the role of helical CT in the evaluation of potentially acute thoracic aortic injuries

Major vascular traumas to the neck, upper limbs, and chest: Clinical presentation, diagnostic approach, and management strategies

Major vascular traumas to the neck, upper limbs, and chest may arise from penetrating and/or blunt mechanisms, resulting in a range of clinical scenarios. Lesions to the carotid arteries may also lead to neurologic complications, such as stroke. The increasing use of invasive arterial access for diagnostic and/or interventional purposes has increased the rate of iatrogenic injuries, which usually occur in older and hospitalized patients. Bleeding control and restoration of perfusion represent the two main goals of treatment for vascular traumatic lesions. Open surgery still represents the gold standard for most lesions, although endovascular approaches have increasingly emerged as feasible and effective options, particularly for management of subclavian and aortic injuries. In addition to advanced imaging (including ultrasound, contrast-enhanced cross-sectional imaging, and arteriography) and life support measures, multidisciplinary care is required, particularly in the setting of concomitant injuries to the bones, soft tissues, or other vital organs. Modern vascular surgeons should be familiar with the whole armamentarium of open and endovascular techniques needed to manage major vascular traumas safely and promptly.

Artificial intelligence-based full aortic CT angiography imaging with ultra-low-dose contrast medium: a preliminary study

OBJECTIVES

To further reduce the contrast medium (CM) dose of full aortic CT angiography (ACTA) imaging using the augmented cycle-consistent adversarial framework (Au-CycleGAN) algorithm.

METHODS

We prospectively enrolled 150 consecutive patients with suspected aortic disease. All received ACTA scans of ultra-low-dose CM (ULDCM) protocol and low-dose CM (LDCM) protocol. These data were randomly assigned to the training datasets (n = 100) and the validation datasets (n = 50). The ULDCM images were reconstructed by the Au-CycleGAN algorithm. Then, the AI-based ULDCM images were compared with LDCM images in terms of image quality and diagnostic accuracy.

RESULTS

The mean image quality score of each location in the AI-based ULDCM group was higher than that in the ULDCM group but a little lower than that in the LDCM group (all p < 0.05). All AI-based ULDCM images met the diagnostic requirements (score ≥ 3). Except for the image noise, the AI-based ULDCM images had higher attenuation value than the ULDCM and LDCM images as well as higher SNR and CNR in all locations of the aorta analyzed (all p < 0.05). Similar results were also seen in obese patients (BMI > 25, all p < 0.05). Using the findings of LDCM images as the reference, the AI-based ULDCM images showed good diagnostic parameters and no significant differences in any of the analyzed aortic disease diagnoses (all K-values > 0.80, p < 0.05).

CONCLUSIONS

The required dose of CM for full ACTA imaging can be reduced to one-third of the CM dose of the LDCM protocol while maintaining image quality and diagnostic accuracy using the Au-CycleGAN algorithm.

KEY POINTS

• The required dose of contrast medium (CM) for full ACTA imaging can be reduced to one-third of the CM dose of the low-dose contrast medium (LDCM) protocol using the Au-CycleGAN algorithm. • Except for the image noise, the AI-based ultra-low-dose contrast medium (ULDCM) images had better quantitative image quality parameters than the ULDCM and LDCM images. • No significant diagnostic differences were noted between the AI-based ULDCM and LDCM images regarding all the analyzed aortic disease diagnoses.

Minimal Aortic Injury Detected on Computed Tomography Angiography during Initial Trauma Imaging: Single Academic Level 1 Trauma Center Experience

BACKGROUND

 Minimal aortic injury (MAI), a subtype of acute traumatic aortic injury, is being increasingly recognized with better imaging techniques. Given conservative management, the role of follow-up imaging albeit important yet has to be defined.

METHODS

 All trauma chest computed tomography angiographies (CTAs) at our center between January 2012 and January 2019 were retrospectively reviewed for presence of MAI. MAIs were generally reimaged at 24 to 72 hours and then at a 7- and 30-day interval. Follow-up CTAs were reviewed for stability, progression, or resolution of MAI, along with assessment of injury severity scores (ISS) and concomitant injuries, respectively.

RESULTS

 A total of 17,569 chest CTAs were performed over this period. Incidence of MAI on the initial chest CTA was 113 (0.65%), with 105 patients receiving follow-up CTAs. The first, second, third, and fourth follow-up CTAs were performed at a median of 2, 10, 28, and 261 days, respectively. Forty five (42.9%), 22 (21%), 5 (4.8%), and 1 (1%) of the MAIs were resolved by first, second, third, and fourth follow-up CTAs. Altogether, 21 patients showed stability (mean ISS of 16.6), and 11 demonstrated improvement (mean ISS 25.8) of MAIs. Eight patients had no follow-up CTA (mean ISS 21). No progression to higher-grade injury was observed. Advancing age decreased the odds of MAI resolution on follow-up. A possible trend (p-value 0.22) between increasing ISS and time to resolution of MAIs was noted.

CONCLUSION

 In our series of acute traumatic MAIs diagnosed on CTA imaging, there was no progression of injuries with conservative management, questioning the necessity of sequential follow-up imaging.

Concurrent Thoracic Endovascular Aortic Repair and Liver Transplant: Multidisciplinary Management of Multiple Posttraumatic Lesions

Association of thoracic and abdominal injuries in patients with major trauma is common. Under emergency conditions, it is often difficult to promptly perform a certain diagnosis and identify treatment priorities of life-threatening lesions. We present the case of a young man with combined thoracic and abdominal injuries after a motorcycle accident. Primary evaluation through echography and X-ray showed fluid within the hepatorenal recess and an enlarged mediastinum. Volume load, blood transfusions, and vasoactive agents were initiated to sustain circulation. Despite hemodynamic instability, we decided to perform computed tomographic angiography (CTA) scan that revealed a high-grade traumatic aortic pseudoaneurysm, multiple and severe areas of liver contusion, and a small amount of hemoperitoneum, without active bleeding spots. The patient was successfully submitted to thoracic endovascular aortic repair (TEVAR). Immediately after the end of the successful TEVAR, signs of massive abdominal bleeding revealed. Immediate explorative laparotomy was performed showing massive hepatic hemorrhage. After liver packing and Pringle's maneuver, control of bleeding was lastly obtained with hemostatic devices and selective cross-clamping of the right hepatic artery. The patient was then transferred to intensive care unit where, despite absence of further hemorrhage, hemodynamic instability, anuria, severe lactic acidosis together with liver necrosis indices appeared. A new CTA demonstrated massive parenchymal disruption within the right lobe of the liver and multiple hematomas in the left lobe. Considering the high-grade lesions of the hepatic vascular tree and liver failure, patient was listed for emergency liver transplantation (LT). LT occurred few hours later, and patient's clinical conditions rapidly improved even if the subsequent clinical course was characterized by a severe fungal infection because of immunosuppression. Evaluation of life-threatening lesions and treatment priorities, availability of different excellence skills, and multidisciplinary collaboration have a key role to achieve clinical success in such severe cases.

Delay of computed tomography is associated with poor outcome in patients with blunt traumatic aortic injury: A nationwide observational study in Japan

According to guidelines from the Eastern Association for the Surgery of Trauma, computed tomography (CT) with intravenous contrast is strongly recommended to diagnose clinically significant blunt traumatic aortic injury (BTAI). However, it remains unclear whether the timing of CT scanning is associated with the prognosis of BTAI patients.We extracted data on emergency patients who suffered a BTAI in the chest and/or the abdomen from 2004 to 2015 from the Japanese Trauma Data Bank, a nationwide trauma registry. The primary outcome was death in the emergency department (ED) and secondary outcome was discharge to death. In addition, we assessed the relationship between death in the ED and the timing of CT scanning by shock status in subgroup analysis. We divided these patients into the tertile groups of early (≤26 minutes), middle (27-40 minutes), and late (≥41 minutes) phases based on the time interval from hospital arrival to start of first CT scanning, and assessed death of BTAI patients in the ED by CT scanning time with the use of a multivariable logistic regression model.In total, 421 patients who suffered BTAI in the chest and/or the abdomen were eligible for our analysis. The proportion of patients dying at hospital admission was 7.7% (11/142) in the early group, 11.1% (15/135) in the middle group, and 17.6% (25/144) in the late group. In a multivariable logistic regression adjusted for confounding factors, the adjusted odds ratio (AOR) of death in the ED was 1.833 (95% confidence interval [CI]: 0.601-5.590, P = .287) in the middle group and 2.832 (95% CI: 1.007-7.960, P = .048) in the late group compared with the early group. Compared with the early group, the late group tended to have a higher rate of discharge to death (AOR: 1.438, 95% CI: 0.735-2.813). In the patients with shock, the AOR was 3.292 (95% CI: 0.495-21.902) in the middle group and 6.039 (95% CI: 0.990-36.837) in the late group compared with the early group.This study revealed that a longer time interval from hospital arrival to CT scanning was associated with higher mortality in the ED in patients with BTAI.

Evaluation and management of blunt traumatic aortic injury: a practice management guideline from the Eastern Association for the Surgery of Trauma

BACKGROUND

Blunt traumatic aortic injury (BTAI) is the second most common cause of death in trauma patients. Eighty percent of patients with BTAI will die before reaching a trauma center. The issues of how to diagnose, treat, and manage BTAI were &filig;rst addressed by the Eastern Association for the Surgery of Trauma (EAST) in the practice management guidelines on this topic published in 2000. Since that time, there have been advances in the management of BTAI. As a result, the EAST guidelines committee decided to develop updated guidelines for this topic using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework recently adopted by EAST.

METHODS

A systematic review of the MEDLINE database using PubMed was performed. The search retrieved English language articles regarding BTAI from 1998 to 2013. Letters to the editor, case reports, book chapters, and review articles were excluded. Topics of investigation included imaging to diagnose BTAI, type of operative repair, and timing of operative repair.

RESULTS

Sixty articles were identi&filig;ed. Of these, 51 articles were selected to construct the guidelines.

CONCLUSION

There have been changes in practice since the publication of the previous guidelines in 2000. Computed tomography of the chest with intravenous contrast is strongly recommended to diagnose clinically signi&filig;cant BTAI. Endovascular repair is strongly recommended for patients without contraindications. Delayed repair of BTAI is suggested, with the stipulation that effective blood pressure control must be used in these patients.

CT Chest with IV Contrast Compared with CT Angiography after Blunt Trauma

Blunt aortic injury (BAI) after chest trauma is a potentially lethal condition. Rapid diagnosis is important to appropriately treat patients. The purpose of this study was to compare CT with intravenous contrast (CTI) to CT with angiography (CTA) in the initial evaluation of blunt chest trauma patients. This was a retrospective review of all blunt trauma patients who received a CTI or CTA during the initial evaluation at an urban Level I trauma center from January 1, 2010 to December 31, 2013. Two-hundred and eighty-one trauma patients met inclusion criteria. Most, 167/281 (59%) received CTI and 114/281 (41%) received CTA. There were no differences between cohorts in age, gender, initial heart rate, systolic blood pressure, and Glasgow Coma Scale in emergency department. Mortality rates were similar for CTI and CTA (4% vs 8%, P = 0.20). CTI identified an injury in 54 per cent compared with 46 per cent in CTA ( P = 0.05). Overall, 2 per cent of patients had BAI with similar rates in CTI and CTA (2% vs 2%, P = 0.80). BAI was not missed using either CTI or CTA. Trauma patients studied with CTI had similar diagnostic findings as CTA. CTI may be preferable to CTA during the initial assessment for possible BAI because of a single contrast injection for whole body CT.

CT Chest with IV Contrast Compared with CT Angiography after Blunt Trauma

Blunt aortic injury (BAI) after chest trauma is a potentially lethal condition that requires rapid diagnosis for appropriate treatment. We compared CT with IV contrast (CTI) with CT with angiography (CTA) during the initial phase of care at an urban Level I trauma center from January 1, 2010 to December 31, 2013. Overall, 281 patients met inclusion criteria with 167 (59%) CTI and 114 (41%) CTA. There were no differences between cohorts in age, gender, initial heart rate, systolic blood pressure, and Glasgow Coma Scale. Mortality rates were similar for CTI and CTA (4% vs 8%, P = 0.20). CTI identified any chest injury in 54 per cent of patients compared with 46 per cent with CTA ( P = 0.05). The rate of BAI was similar with CTI and CTA (2% vs 2%, P = 0.80), and neither modality was falsely negative. We conclude that CTI and CTA are similar at evaluating trauma patients for BAI, although CTI may be preferable during the initial assessment phase because the contrast injection may be combined with abdominal scanning and image time is reduced when whole-body CT is required.

Diagnosis and treatment planning of acute aortic emergencies using a handheld DICOM viewer

Acute aortic syndromes and traumatic aortic injury are often diagnosed on CT angiography, possibly requiring emergent intervention. Advances in handheld computing have created the possibility of viewing full DICOM datasets from a remote location. We evaluated the ability to diagnose and characterize acute aortic pathologies on CT angiograms of the thorax using an iPhone-based DICOM viewer. This study was performed after Institutional Review Board approval. Fifteen CT angiograms of the thorax in suspected acute aortic syndromes were evaluated by three blinded radiologists on a handheld device using a DICOM viewer. Studies were evaluated for the ability to identify and classify aortic dissection, transection, or intramural hematoma, measure aortic dimensions, and identify mediastinal hematoma, arch variants, and pulmonary pathology. Studies were compared to blinded interpretations on a dedicated PACS workstation. The aortic pathology was correctly identified as aortic transection/pseudoaneurysm (n = 5), type A dissection (n = 2), and type A intramural hematoma (n = 1) by all reviewers, with no false-positive interpretations. This represents a sensitivity and specificity of 100 %. Mediastinal hematoma (n = 6), pneumothorax (five right, three left), and arch vessel involvement (n = 2) were identified in all cases. There was 88.5 % accuracy in identifying arch variants. Measurement of the size of the involved aortic segment was similar on handheld device and PACS workstation; however the adjacent normal aorta was 1.2 ± 1.0 mm larger on the handheld device (p = 0.03). Handheld DICOM viewers may be useful for emergent consultations and triage, and may expedite preprocedure planning to reduce the time interval between diagnostic scan and therapeutic intervention.

ACR Appropriateness Criteria(®) blunt chest trauma--suspected aortic injury

The purpose of these guidelines is to recommend appropriate imaging for patients with blunt chest trauma. These patients are most often imaged in the emergency room, and thus emergency radiologists play a substantial role in prompt, accurate diagnoses that, in turn, can lead to life-saving interventions. The ACR Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. Imaging largely focuses on the detection and exclusion of traumatic aortic injury; a large proportion of patients are victims of motor vehicle accidents. For those patients who survive the injury and come to emergency radiology, rapid, appropriate assessment of patients who require surgery is paramount.

Initial management and resuscitation of severe chest trauma

Severe chest trauma, blunt or penetrating, is responsible for up to 25% of traumatic deaths in North America. Respiratory compromise is the most frequent dramatic presentation in blunt trauma, while injuries to the heart and great vessels pose the greatest risk of immediate death following penetrating trauma. More than 80% of patients will be managed with interventions that can be performed in the emergency department. This article reviews the presentation, diagnosis, and management of the most important thoracic injuries. A structured approach to the acutely unstable patient is proposed to guide resuscitation decisions.

Imaging vascular trauma

Background

Over the past 50 years the management of vascular trauma has changed from mandatory surgical exploration to selective non-operative treatment, where possible. Accurate, non-invasive, diagnostic imaging techniques are the key to this strategy. The purpose of this review was to define optimal first-line imaging in patients with suspected vascular injury in different anatomical regions.

Methods

A systematic review was performed of literature relating to radiological diagnosis of vascular trauma over the past decade (2000–2010). Studies were included if the main focus was initial diagnosis of blunt or penetrating vascular injury and more than ten patients were included.

Results

Of 1511 titles identified, 58 articles were incorporated in the systematic review. Most described the use of computed tomography angiography (CTA). The application of duplex ultrasonography, magnetic resonance imaging/angiography and transoesophageal echocardiography was described, but significant drawbacks were highlighted for each. CTA displayed acceptable sensitivity and specificity for diagnosing vascular trauma in blunt and penetrating vascular injury within the neck and extremity, as well as for blunt aortic injury.

Conclusion

Based on the evidence available, CTA should be the first-line investigation for all patients with suspected vascular trauma and no indication for immediate operative intervention.

Is chest x-ray an adequate screening tool for the diagnosis of blunt thoracic aortic injury?

BACKGROUND

Blunt thoracic aortic injuries (BTAI) have a high mortality rate. For survivors, chest X-ray (CXR) findings are used to determine the need for further diagnostic testing with chest computerized tomography with angiography (CTA) or conventional angiography. We set to determine the adequacy of utilizing CXR alone as a screening tool for BTAI.

METHODS

All patients diagnosed with BTAI at a level I trauma-center during a 7-year-period were identified. CXRs of these patients and those of a control group of blunt trauma patients with an injury severity score >15 were reviewed by four trauma surgeons blinded to the diagnosis. Based on each CXR viewed, the surgeons decided if they would have proceeded to chest CTA, angiography, or required no further studies to rule out BTAI.

RESULTS

In the 7-year-period, 83 patients had BTAI. CXRs were available in 45 patients. The four surgeons viewed 96 CXRs including those of 51 controls. Based on the CXR appearance in patients with BTAI, the surgeons chose to proceed to chest CTA in 38 patients (84.4%), conventional aortography in two patients (4.4%), and no further testing in five patients (11.2%). A widened mediastinum (75%) and loss of the aorto-pulmonary window (40%) were the most frequent CXR abnormalities. Patients with BTAI were more likely to have an abnormal CXR-40 of 45 (88.8%) patients when compared with the controls-25 of 51 (49%)patients-p < 0.001.

CONCLUSIONS

Although CXR is a sensitive screening modality, it failed to identify the possibility of BTAI in 11% of patients. The liberal use of chest CTA after high speed motor vehicle crashes is recommended to minimize the incidence of missed BTAI.

[Blunt traumatic aortic injury: importance of transesophageal echocardiography]

Traumatic injury of the aorta can be a fatal complication of blunt thoracic trauma and if it is survived and diagnosed, surgery will be necessary. A prerequisite is a prompt imaging diagnosis of the injury in order to plan an optimal therapeutic procedure for the patient, depending on the severity of the injury. Digital angiography has now been replaced by non-invasive methods, such as computer tomography (CT) or transesophageal echocardiography (TEE). Using TEE it is possible to carry out a staging of the injury and this classification together with the corresponding clinical symptoms determines the therapeutic treatment regime. In many cases a staged treatment is standard procedure. In addition to the establishment of an adequate blood pressure (for prophylaxis of the open rupture), monitoring during the course of treatment may be necessary. The main advantage of TEE is that the examination of these mostly multiple traumatised patients can be carried out at the bedside. This review describes the use of TEE as a diagnostic tool in the early phase and for continuous monitoring of an initially conservative treatment regime.

CT diagnosis of Rib fractures and the prediction of acute respiratory failure

BACKGROUND

The number of rib fractures has been reported to correlate with mortality after blunt chest trauma. These reports, however, predate routine truncal helical computed tomographic (CT) scanning and their conclusions are based on data derived from plain chest radiographs (CXR). CT scan provides better anatomic definition of chest injuries than plain CXR, and we hypothesized CT evaluation of rib fracture number and patterns would provide a better prediction of respiratory failure and mortality after chest injury than the data derived from the initial CXR.

METHODS

The charts on all patients of 16 years or older with one or more rib fractures after blunt trauma admitted from January 2003 through December 2005 were reviewed. Both the initial CXR and the helical CT scans were systematically re-read for the number and location of rib fractures and presence of pulmonary contusions. Anatomic fracture location (anterior, posterior, lateral) was determined using a standardized template. Outcomes data included pneumonia, respiratory failure (>/=3 ventilator days), need for trachestomy, and mortality. Logistic regression was performed to identify factors that predicted pulmonary morbidity.

RESULTS

Three hundred and eighty eight patients had >/=1 rib fracture. The mean (+/-standard deviation) age was 44 +/- 18. injury severity score was 21 +/- 11. Mortality was 6% (22 of 388). Sixty-three (16%) patients developed respiratory failure. The mean number of rib fractures per patient was four (range, 1-23); 21% of patients had one rib fracture and 17% had six or more fractures. 208 (54%) of the initial CXRs were read as having no rib fractures. The mean number of rib fractures per patient in this group was 3.1 (CI95 2.9-3.2). In 43% (179 of 388) of patients, the CT radiology report incorrectly identified the number and location of the fractured ribs. Of these reports, 72% (129 of 179) differed from the prospective review by more than one fracture. The number of fractures was higher in patients who died (7 +/- 5 vs. 4 +/- 3; p = 0.02) and in those developing respiratory failure (6 +/- 4 vs. 3 +/- 3; p = 0.02). Any rib fracture or pulmonary contusion visible on the initial plain CXR significantly increased the incidence of pulmonary morbidity or mortality. CT determination of fracture location had no effect on respiratory failure, pneumonia, or mortality when fractures were confined to one anatomic location. The presence of rib fracture in more than anatomic region doubled the incidence of respiratory failure (24% vs. 12%; p = 0.002) but had no effect on mortality. Logistic regression identified only injury severity score and presence of a parenchymal injury on plain CXR as independent predictors of subsequent respiratory failure.

CONCLUSIONS

Rib fracture mortality was lower than that in the previously published studies and is likely reflect the increased sensitivity of CT scan in diagnosing rib fractures. Screening CXRs miss rib fractures more than 50% of the time. Radiology reports are often not sufficiently descriptive or are incomplete with respect to the number and location fracture and reliance on these data will lead to erroneous conclusions. Using CT scanning, only the finding of rib fractures in multiple locations was associated with increased incidence of respiratory failure. In contrast, the presence of any parenchymal injury or visible rib fracture on the screening CXR significantly increases the risk for subsequent pulmonary morbidity (odds ratio, 3.8; CI95, 2.2-6.6). Although truncal CT scanning markedly improved the diagnosis and delineation of rib fractures, the screening CXR was a better predictor of subsequent pulmonary morbidity and mortality.

Diagnostic Dilemmas and Current Controversies in Blunt Chest Trauma

Blunt chest injuries are common encounters in the emergency department. Instead of a comprehensive review of the management of all chest injuries, this review focuses on injuries that can be difficult to diagnose and manage, including blunt aortic injury, cardiac contusion, and blunt diaphragmatic injury. This review also discusses some recent controversies in the literature regarding the use of prophylactic antibiotics for tube thoracostomy and the optimal management of occult pneumothorax. The article concludes with a discussion of the management of rib fractures in the elderly.

Thoracic aortic and great vessel trauma and its management

Interventional radiologists (IRs) now play a major role in the management of thoracic aortic and great vessel trauma. The recent availability of a wide range of stent grafts able to treat vessels from 3 to 46 mm in diameter is clearly a significant contributor to this change. Stent grafts can now treat the majority of incomplete aortic injuries with much lower morbidity and mortality than open surgery. Short- to medium-term follow-up is encouraging, but the long-term durability is unknown, and close monitoring of these patients must continue. In great vessel trauma, stent grafts are a useful adjunct to balloon tamponade, embolization, and bare stents. As a result, a wide range of head neck and upper limb vascular injuries can be managed with less local trauma, blood loss, and physiological stress. The increased involvement of IR in the management of vascular trauma is not simply the result of technological advances. IRs have increasingly made themselves available to carry out these emergency procedures. IRs should assist in the development of trauma protocols and management algorithms that involve endovascular expertise early in the assessment of the major trauma patient.

[Echocardiography during acute hemodynamic instability]

In light of the growing proportion of illness in the general population, the complexity of modern surgery requires precise perioperative hemodynamic monitoring. Echocardiography has emerged over the past 15 years as an especially valuable diagnostic instrument for intensive medicine. No other monitoring technique provides in such a short time, with so little invasiveness, so much additional anatomic information for determining the cause of acute hemodynamic instability. There is of course the possibility of proceeding transthoracally at first, with poor imaging quality but noninvasively, or transesophageally. However, perioperative hemodynamic monitoring allows even less experienced operators to detect the various differential diagnoses of acute hemodynamic instability with an easily managed number of standard images. Starting from the first standard settings, depending on pathology the imaging should continue selectively with transthoracal echocardiography in the short parasternal axis or transesophageal echocardiography in the transgastral short midpapillary axis.

Aortic rupture: comparison of three imaging modalities

We report a case of a 56-year-old man with traumatic aortic rupture (TAR) sustained in a motor vehicle accident diagnosed by helical computed tomography, aortography, and transesophageal echocardiography. A large majority of patients with TAR never make it to the hospital, and for those who do, a timely diagnosis is critical for survival. We discuss the merits and pitfalls of the three imaging modalities.

Diagnostic value of the helical CT scan for traumatic aortic injury: Correlation with mortality and early rupture

To evaluate the value of helical computed tomography of the thorax (HCTT) as a definitive tool for diagnosing traumatic aortic injury, this study retrospectively examined 53 patients with blunt thoracic injuries and HCTT during a 5-year period. All CT scans were reviewed for direct signs of aortic injury and correlated with aortography or surgery. Correlations between clinical parameters, as well as combinations of direct signs and individual signs, and mortality were analyzed in all traumatic aortic injury (TAI) cases. Direct signs were seen on the HCTT in 25 cases and 22 had TAI. All false positive results came from the group with only a single direct sign depicted on HCTT. Among individual direct signs examined, intimal flap and luminal thrombus were the most specific (100%), whereas irregular aortic contour was the most sensitive (100%). A combination of > or = 3 direct signs (p = 0.006) and periaortic contrast material extravasation significantly correlated with early rupture and mortality (p = 0.002). In conclusion, intimal flap on HCTT is both the most specific and sensitive sign for TAI. TAI patients with > or = 3 direct signs, including periaortic contrast material extravasation, may not require aortography before immediate surgery.

Management Options in Blunt Aortic Injury: A Case Series and Literature Review

Blunt aortic injury (BAI) is a devastating consequence of high-energy trauma. The majority of its victims do not survive; those who do generally have significant associated injury. The standard treatment of BAI has been emergent replacement or repair of the damaged aorta via a posterolateral thoracotomy, with or without perfusion adjuncts. In addition to the substantial morbidity and mortality secondary to multisystem traumatic injuries, patients surviving to reach the operating room have been exposed to the risks related to their surgical treatment, namely death, paraplegia, hemorrhage, transfusion, organ dysfunction, prolonged intensive care unit stays, and extensive rehabilitation requirements. Contributions to the literature over the past several years have provided support for changing practice patterns in the management of BAI. Aggressive control of blood pressure has made it safe to delay high-risk interventions in patients with complex injuries. Advanced perfusion strategies using little or no anticoagulation appear to have positively affected bleeding complications and neurologic risk. Finally, endovascular stent grafting, though not yet rigorously evaluated in BAI, has been shown to be feasible and effective in the short term. This case presentation and literature review will examine treatment options and propose a management algorithm.

Decision Making in the Face of Uncertainty and Resource Constraints: Examples from Trauma Imaging

The purpose of this review is to illustrate how tools and concepts from decision and cost-effectiveness analyses can be used to help make decisions in the face of uncertainty and resource constraints, select appropriate subjects for imaging, choose between competing imaging modalities, and prioritize future research. Examples from trauma imaging illustrate the use of the presented tools. The author advocates the PROACTIVE approach in deciding which imaging strategies are cost-effective (PRO for defining the problem, reframing the problem from multiple perspectives, and focusing on the objective; ACT for expanding the alternatives, considering the consequences and associated chances of each alternative, and identifying the trade-offs involved; IVE for integrating the evidence and values, optimizing the value of interest, and exploring uncertainty). Simulation models play an important role in the assessment of imaging strategies by helping to identify alternative strategies and to integrate the best-available evidence related to risks, benefits, patient values, and costs. Exploring the uncertainty in the evidence and assessing the value of obtaining more information can help prioritize future research and guide study design.

Review of branch aortic injuries in blunt chest trauma

OBJECTIVES

To review the incidence, mechanisms of injury, diagnosis and treatment of injuries to the major branches of the thoracic aorta within the thoracic cavity following blunt trauma.

METHODS

Medline, Embase and Cochrane were searched using appropriate key word and MeSH headings. Full text articles were retrieved where there was any information relating to the mechanism of injury, incidence of injury, diagnosis, treatment or outcome in patients with injuries to the brachiocephalic, subclavian or carotid arteries within the thoracic cavity following blunt chest trauma.

RESULTS

The reported incidence of these injuries varied widely, most injuries were related to rapid deceleration injuries or falls. Diagnosis depends on a high level of clinic suspicion and appropriate investigations include helical CT scanning and arteriography. Treatment options have expanded in recent years with the use of endovascular stents; however, the optimal treatment remains uncertain.

CONCLUSIONS

Aortic branch injuries must be actively excluded in patients with suspicious mechanisms of injury. Guidelines determining appropriate investigative pathways and methods of treatment should be developed at all trauma centres.

[Diagnosis and immediate therapeutic management of chest trauma. A systematic review of the literature]

OBJECTIVE

Injuries to the chest contribute significantly to the morbidity and mortality in multiple injured patients. This systematic review focuses on evidence based initial diagnostics and emergency room management of chest trauma.

METHODS

Clinical trials was systematically collected (Medline, Cochrane and hand searches) and classified into evidence levels (1 to 5 according to the Oxford system).

RESULTS

There are only a few studies that document the impact of injury mechanism and clinical examination of the patient. There is a positive correlation between crash severity or lateral impact with injury severity. Auscultation was found to be very sensitive in the detection of pneumothorax. Helical CT of the chest is most important in the initial work-up. Aortography is only indicated in selected cases. Whether tube thoracostomy is necessary in patients with occult pneumotharaces is still a matter of discussion. Indications for endotracheal intubation are poorly investigated and predominantly based on expert opinion.

CONCLUSION

Numerous comparative studies (LE 2) dealing with emergency diagnostics and therapy of chest trauma are available, however only a few randomized studies do exist. Based on the available data a rational therapy of chest trauma is possible.

Use of 3D imaging in CT of the acute trauma patient: impact of a PACS-based software package

To evaluate the impact of a picture archiving and communication systems (PACS)-based software package on the requests for 3D reconstructions of multidetector CT (MDCT) data sets in the emergency radiology of a level 1 trauma center, we reviewed the number and type of physician requests for 3D reconstructions of MDCT data sets for patients admitted after sustaining multiple trauma, during a 12-month period (January 2003-December 2003). During the first 5 months of the study, 3D reconstructions were performed in dedicated workstations located separately from the emergency radiology CT interpretation area. During the last 7 months of the study, reconstructions were performed online by the attending radiologist or resident on duty, using a software package directly incorporated into the PACS workstations. The mean monthly number of 3D reconstructions requested during the two time periods was compared using Student's t test. The monthly mean +/- SD of 3D reconstructions performed before and after 3D software incorporation into the PACS was 34+/-7 (95% CI, 10-58) and 132+/-31 (95% CI, 111-153), respectively. This difference was statistically significant (p<0.0001). In the multiple trauma patient, implementation of PACS-integrated software increases utilization of 3D reconstructions of MDCT data sets.

Bedside echocardiography in chest trauma

Bedside US has an established role in the evaluation of chest trauma patients. Transthoracic echocardiography and TEE can be used to obtain critical information at the bedside for many emergent conditions, including the immediate detection of hemopericardium and acute aortic injury. More recent work has demonstrated that US also can be used to detect hemothoraces and pneumothoraces with accuracy. These diagnostic techniques can improve patient outcome and are within the scope of practice of emergency physicians and trauma surgeons. Physicians caring for trauma patients should be familiar with these techniques.

Left Mediastinal Width and Mediastinal Width Ratio Are Better Radiographic Criteria Than General Mediastinal Width for Predicting Blunt Aortic Injury

BACKGROUND

General mediastinal width, left mediastinal width, and mediastinal width ratio were compared as radiographic predictors of aortic injury.

METHODS

A retrospective study investigated the chest radiographs of 51 patients admitted to a level 1 trauma center during a 6-year period for a thorough survey of aortic injury. Mediastinal width (MW >/= 8 cm), left mediastinal width (LMW >/= 6 cm), mediastinal width ratio (MWR >/= 0.60), and a combination of LMW and MWR were compared as predictors of aortic injury. The cutoff points were predetermined by receiver-operator-curve to accommodate 100% sensitivity for each criterion.

RESULTS

Of the 51 patients, 21 had aortic injuries and 30 had normal imaging studies. All criteria had 100% negative predictive value. The specificities and positive predictive values, respectively, were 13.3% and 44.7% (MW), 40.0% and 53.8% (LMW), 43.3% and 55.3% (MWR), and 66.7% and 67.7% (combined LMW and MWR). The positive likelihood ratio of aortic injury was 3.00 when LMW was 6 cm or more and MWR was 0.60 or more.

CONCLUSIONS

Both an LMW of 6 cm or more and an MWR of 0.60 or more are better radiographic criteria than an MW of 8 cm or more for predicting blunt aortic injury. Trauma patients with positive test results based on the combined LMW and MWR criteria should proceed immediately to aortography or helical computed tomography.

CT and MR imaging of the thoracic aorta: current techniques and clinical applications

Disease of the thoracic aorta can present with a broad clinical spectrum of symptoms and signs. The accepted diagnostic gold standard, selective digital subtraction angiography, is now being challenged by state-of-the-art CT angiography (CTA) and MR angiography(MRA). Currently, in many centers, cross-sectional imaging modalities are being used as the first line of diagnosis to evaluate the cardiovascular system, and conventional angiography is reserved for therapeutic intervention. Understanding the principles of CTA and MRA techniques is essential to acquire diagnostic images consistently. This article reviews current CTA and MRA methods used in the evaluation of thoracic aortic disease.

The Trend of Using Computed Tomography in the Detection of Acute Thoracic Aortic and Branch Vessel Injury after Blunt Thoracic Trauma: Single-Center Experience Over 13 Years

BACKGROUND

The purpose of this study was to review the trend of using chest computed tomography (CT) and aortography in evaluating patients with blunt thoracic trauma.

METHODS

A total of 85 patients who had blunt aortic injury diagnosed by chest CT, aortography, or both were included in this study.

RESULTS

Aortography was the dominant modality before 1998, and the use of chest CT has increased to 50% of patients with aortic injuries as of 2001. Isolated aortic, branch vessel, or combined injuries were found in 71 (84%), 11 (13%), and 3 (4%) patients, respectively. All 14 patients with branch vessel injuries were diagnosed by aortography. Ninety-eight percent of patients with aortography were true-positives, and 20% of patients with chest CT had indirect signs of aortic injury.

CONCLUSION

Our institution has increased the use of chest CT to evaluate blunt thoracic trauma. Patients with indirect signs of aortic injuries shown on chest CT require further evaluation. In our experience, angiography remains the optimal diagnostic modality for evaluating aortic branch vessel injuries.

Periaortic Hematoma at Diaphragmatic Crura at Helical CT: Sign of Blunt Aortic Injury in Patients with Mediastinal Hematoma

PURPOSE

To evaluate periaortic hematoma (PH) near the level of the diaphragm at abdominal computed tomography (CT) as an indirect sign of acute traumatic aortic injury after blunt trauma in patients with mediastinal hematoma.

MATERIALS AND METHODS

From 1998 to 2001, 97 patients with CT evidence of mediastinal hematoma after blunt thoracic trauma were retrospectively identified at two level 1 trauma centers. The presence or absence of PH near the level of the diaphragmatic crura was retrospectively established by a blinded reviewer at each institution. Aortic injury status was determined by reviewing angiographic, surgical, and clinical records. Sensitivity, specificity, positive and negative productive values, and positive and negative likelihood ratios were calculated.

RESULTS

Among the 97 patients with mediastinal hematoma, 14 had both PH near the level of the diaphragm and aortic injury; six had aortic injuries without PH, five had PH near the level of the diaphragm without aortic injury, and 72 had no evidence of PH near the diaphragm and no aortic injury. Sensitivity for PH near the level of the diaphragm as a sign of aortic injury was 70%; specificity, 94%; positive predictive value, 74%; and negative predictive value, 92%. The positive likelihood ratio for the presence of aortic injury was 10.8, and the negative likelihood ratio was 0.3.

CONCLUSION

PH near the level of the diaphragmatic crura is an insensitive but relatively specific sign for aortic injury after blunt trauma. The presence of this sign at abdominal CT should prompt imaging of the thoracic aorta to evaluate potential thoracic aortic injury.

Role of computed tomography and magnetic resonance imaging in assessment of acute aortic syndromes

Acute aortic syndromes refer to the spectrum of aortic emergencies that include nontraumatic diseases of the aorta, such as aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, aortic aneurysm leak, as well as traumatic aortic transection. Patients presenting with nontraumatic acute aortic syndromes usually have a similar clinical profile; hence, clinical diagnosis is difficult. Computed tomography (CT) and magnetic resonance imaging (MRI) allow for specific diagnosis of the underlying condition. Traumatic rupture of the aorta is one of the most dreaded complications of blunt chest trauma; therefore, in patients with high-risk deceleration injuries, radiographic assessment of the aorta is crucial. Imaging methods should detect even subtle aortic wall disruption and should provide a mechanism for communicating the findings to the surgical team. Noninvasive, cross-sectional imaging techniques have proven efficacy in the diagnosis of aortic pathology and have largely replaced aortography. Both CT and MR imaging provide aortogram-like reconstruction of the original data sets, and in addition to assessing the aortic lumen, permit detailed evaluation of the aortic wall, as well as comprehensive assessment of thoracic and abdominal viscera. This article addresses the role of different imaging modalities in assessment of acute aortic syndromes, with focus on CT and MRI, and with discussion of the key imaging findings that allow distinction among the various aortic pathologies.