Spiral CT aortography: an efficient technique for the diagnosis of traumatic aortic injury

Traumatic Aortic Injury: Sailing Close to the Wind

Blunt aortic injuries are lethal and only a few patients survive. Most of the patients die at the site of accidents and only a few reach the hospital. Those who reach hospitals usually have small tears or pseudo-aneurysm of the aorta. Immediate imaging and intervention play a major role in the survival of these patients. We report this case as only a few patients report to the hospital with aortic injury and our patient was taken up for surgery immediately and a life-saving procedure was done.

Blunt Thoracic Aortic Injury: Current Therapies, Outcomes, and Challenges

Blunt thoracic aortic injuries are rare occurrences but carry an increased risk of mortality. Over the last two decades, however, major advances in diagnostic imaging, staging, and treatment have significantly improved outcomes. Modern imaging paved the way for a new staging system based on the anatomical layers of the aortic wall. This staging system, in turn, allowed for refinement of treatment, which now includes nonoperative management with anti-impulse therapy, endovascular intervention, and, if needed, open surgical repair. As is the case with any other rapidly evolving therapy, however, new challenges and controversies arise. The resolution of these challenges will rely on a broad, international, and multidisciplinary effort. (This is a review article based on the invited lecture of the 46th Annual Meeting of Japanese Society for Vascular Surgery.)

Is endovascular repair the first choice for all blunt aortic injury? A real-world assessment

Blunt thoracic aortic injury (BTAI) represents an infrequently encountered but lethal traumatic injury. Minimal aortic injuries are appropriately treated by medical management, while more severe injuries require endovascular or open repair. Rapidly evolving endovascular technology has largely supplanted open repair as first line operative intervention, however, the complexity of the severely injured blunt trauma patient can complicate management decisions. The development and implementation of an optimal consensus grading system and treatment algorithm for the management of BTAI is necessary and will require multi-institutional study.

Case Report of Traumatic Aortic Disruption: A Lethal Injury Requiring Rapid and Accurate Diagnosis to Lower Mortality

Traumatic aortic disruption is an uncommon but frequently emphasised condition in trauma management in the emergency department. We report a case in which a middle aged woman was hit by a moving vehicle, sustaining multiple severe injuries. Multidetector computed tomography revealed an unexpected but potentially fatal condition – traumatic aortic disruption. A pseudoaneurysm was detected over the aortic arch. In view of the multiple trauma, she was put on conservative treatment. Traumatic aortic disruption should be borne in mind during the emergency evaluation and management of unstable trauma victims, especially those with significant trauma mechanisms. Radiological evaluation plays an important diagnostic role.

Man with a forehead mass: detection of a forehead pseudoaneurysm with bedside ultrasonography

A vascular pseudoaneurysm can present similarly to an abscess; yet incision and drainage of a pseudoaneurysm can lead to uncontrolled bleeding and expose the patient to further morbidity. This is a case of a patient with a forehead pseudoaneurysm who presented to our emergency room after blunt head trauma. Here we review different diagnostic modalities as well as some of the treatment options that are described in the literature.

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.

Diagnostic imaging of traumatic pseudoaneurysm of the thoracic aorta

Background

The purpose of the study was the presentation of findings and diagnostic imaging in patients with traumatic pseudoaneurysms of the thoracic aorta, as a rare consequence of road traffic accidents.

Patients and methods

In 22 years we have found 8 traumatic pseudoaneurysms of the thoracic aorta, out of which 7 (87.5%) in male and 1 (12.5%) in female patients. At the time of accidents the youngest patient was 21 and the oldest was 55 (mean age 33.8 years), and at the moment of diagnosing a pseudoaneurysm they were 26 and 55 years old, respectively (mean age 38.7 years). In all patients chest radiography was performed as well as CT scan, in 6 (75%) patients intra-venous digital subtraction angiography was performed (i.v. DSA) and in 1 (12.5%) MRI. CT was performed with the application of 120 ml, and i.v. DSA with 60 ml of contrast medium, respectively.

Results

In 8 (100%) patients, who suffered a road traffic accident, and whose chest radiograph showed the enlargement of the aortic knob and widening of the mediastinum, CT, i.v. DSA and MRI revealed a traumatic pseudoaneurysm of the thoracic aorta. Periods of time between the accidents and the initial diagnosis of the pseudoaneurysm varied from 7 days to 18 years (median 2.0 years). The diameter of the pseudoaneurysm was from 4.5 to 9.2 cm (median 5.5 cm). In 7 (87.5%) isthmus was involved, and in 1 (12.5%) descending thoracic aorta, respectively. The chest radiograph revealed marginal calcifications in 4 (50%), and on the CT in 5 (62.5%) patients. Intraluminal thrombosis was found by CT in 2(25%) traumatized patients.

Conclusions

Traumatic pseudoaneurysm should be taken into consideration in blunt chest trauma, where a chest radiograph shows suspicious regions. A multislice CT is a diagnostic method of choice.

Traumatic aortic injury: computerized tomographic findings at presentation and after conservative therapy

OBJECTIVE

To determine the computerized tomographic (CT) findings in traumatic aortic injury (TAI) at presentation and after conservative management.

METHODS

Institutional review board-approved retrospective review of trauma registry during a 6-year period identified class 1 or 2 trauma patients with TAI. The CT findings were correlated with patient outcome.

RESULTS

Forty-eight of 3350 patients had TAI. Seven had TAI limited to the abdominal aorta. Twenty-nine of 48 had early (12) or delayed (17) aortic repair. Common abnormalities were pseudoaneurysms (69%) and intramural hematoma (IMH) (65%). Forty-one of 48 TAI were confirmed on endovascular imaging or surgery. Subsequent CT was available in those who had delayed repair (n = 9) or conservative management (10) and showed stable pseudoaneurysms with resolving IMH (n = 11), resolving IMH (n = 4), intimal flap (n = 2), aortic thrombus (n = 1), and dissection (n = 1).

CONCLUSIONS

Traumatic aortic injury is rare. It commonly involves thoracic aorta with pseudoaneurysm and IMH. Significant TAI in stable patients remains stable on follow-up imaging. Minor TAI may resolve with conservative therapy.

Dissection properties of the human aortic media: an experimental study

Aortic dissection occurs frequently and is clinically challenging; the underlying mechanics remain unclear. The present study investigates the dissection properties of the media of 15 human abdominal aortas (AAs) by means of direct tension tests (n=8) and peeling tests (n=12). The direct tension test demonstrates the strength of the media in the radial direction, while the peeling test allows a steady-state investigation of the dissection propagation. To explore the development of irreversible microscopic changes during medial dissection, histological images (n=8) from four AAs at different peeling stages are prepared and analyzed. Direct tension tests of coin-shaped medial specimens result in a radial failure stress of 140.1+/-15.9 kPa (mean+/-SD, n=8). Peeling tests of rectangular-shaped medial strips along the circumferential and axial directions provide peeling force/width ratios of 22.9+/-2.9 mN/mm (n=5) and 34.8+/-15.5 mN/mm (n=7); the related dissection energies per reference area are 5.1+/-0.6 mJ/cm(2) and 7.6+/-2.7 mJ/cm(2), respectively. Although student's t-tests indicate that force/width values of both experimental tests are not significantly different (alpha=0.05, p=0.125), the strikingly higher resisting force/width obtained for the axial peeling tests is perhaps indicative of anisotropic dissection properties of the human aortic media. Peeling in the axial direction of the aorta generates a remarkably "rougher" dissection surface with respect to the surface generated by peeling in the circumferential direction. Histological analysis of the stressed specimens reveals that tissue damage spreads over approximately six to seven elastic laminae, which is about 15-18% of the thickness of the abdominal aortic media, which forms a pronounced cohesive zone at the dissection front.

The role of 3D-CTA in the assessment of peripheral vascular lesions in trauma patients

PURPOSE

The goal of any imaging in the setting of a level 1 trauma center is to assess the injuries of a patient as fast as possible with the least amount of time spend to move the patients between rooms or scanners in order to reduce the time till final diagnosis. CT-angiography (CTA) has become increasingly used to analyze peripheral vascular lesions in blunt and penetrating trauma.

METHODS

Diagnostic angiography and CTA are competing methods for the display of peripheral vascular lesions. The specific advantages and shortcomings of both techniques for the routine use in a trauma center are discussed.

RESULTS

The inherent limitations of the spatial and temporal resolution of a CTA are compensated by the availability of the procedure and reduced time needed for the final diagnosis.

CONCLUSION

3D-CTA with multislice CT (MSCT) can be used to replace the diagnostic angiography in patients with blunt or penetrating extremity injuries.

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.

Traumatic arterial injuries of the extremities: initial evaluation with MDCT angiography

OBJECTIVE

The purpose of this study was to retrospectively assess the accuracy of MDCT angiography as the initial diagnostic technique to depict arterial injury in patients with extremity trauma.

MATERIALS AND METHODS

Over 36 months, 87 patients (16 females and 71 males; age range, 16-87 years) with clinically suspected arterial injury after extremity trauma underwent 4-MDCT angiography and 67 ultimately underwent surgery. Eighty patients had blunt injuries, and seven had penetrating injuries. The presence of arterial involvement was investigated prospectively by the radiologist in charge and retrospectively by two independent radiologists. Each detected arterial lesion was then characterized as a spasm, stenosis, occlusion, or rupture. The standard of reference was surgery in 67 patients, angiography in two patients, and clinical and radiologic follow-up findings in 18 patients. MDCT angiography was assessed by means of receiver operating characteristic (ROC) curve analysis for lesion detection and Spearman's rank correlation test for lesion characterization. Image quality, lesion depiction, and artifacts were subjectively assessed.

RESULTS

Sixty-two traumatic arterial lesions were confirmed at surgery in 55 patients. MDCT angiography yielded high accuracy in detection (area under the ROC curve [Az] = 0.96; p < 0.001) and characterization (r = 0.94; p < 0.001) of traumatic arterial injuries and in recognizing an underlying dissection (Az= 0.82; p < 0.001). Prospective sensitivity and specificity were 95% and 87%, respectively, and retrospective sensitivity and specificity were 99% and 87%, respectively. MDCT angiography was considered to be sufficient for a reliable diagnosis in 83 patients (p < 0.001). Image quality and lesion depiction on MDCT angiograms were considered to be good and artifacts were considered mild with substantial interobserver agreement (kappa, 0.62-0.69).

CONCLUSION

MDCT angiography provides significant and reproducible technique for the detection and characterization of arterial injuries to the extremities with high image quality and vascular delineation.

[Emergency pediatric thoracic radiology]

Pediatric thoracic emergencies are frequent and may be due to a large spectrum of lesions including traumatic and non traumatic pathologies, such as foreign bodies, mediastinal tumors, pulmonary infections, asthma, pneumothorax and delayed manifestations of congenital chest malformations. Emergencies require rapid diagnosis to make a treatment plan and in most cases, radiology plays an essential role. Plain chest radiographs remain the initial study with inspiratory films. In certain circumstances, the use of expiratory films is absolutely necessary. Ultrasonogragraphy is the primary modality for evaluation of pleural effusions. Computed tomography (CT), with volume acquisition and more rapid scanning, is a technique capable of imaging the lungs and mediastinum with excellent spatial resolution in the pediatric population. CT provides more information than chest radiographs. This explains the increasing indications of CT in the evaluation of pediatric thoracic emergencies, more particularly traumatic emergencies.

Multislice computed tomography angiography of the abdominal arteries: Comparison between computed tomography angiography and digital subtraction angiography findings in 52 cases

Since the introduction of multislice CT scanners, CT angiography (CTA) has become a powerful tool for imaging the vascular system. We compare conventional angiography to CTA in the diagnosis of morphological changes in the abdominal aorta and its branches. A retrospective analysis of 52 patients who underwent both multislice CT angiography (MSCTA) and digital subtraction angiography before surgical treatment is presented. All CT examinations were performed after administration of 100 mL contrast medium with a collimation of 4 x 1 mm and a pitch of 7. A standardized evaluation of the axial, multiplanar and 3D reconstructions was performed by two experienced radiologists. Stenoses were classified as high-grade and low-grade, and aneurysms, occlusions and arteriosclerosis were evaluated. The CTA findings were compared with conventional angiography. All aneurysms, occlusions, stenoses and calcifications were diagnosed correctly by CTA in axial and multiplanar projections (sensitivity 1.0; specificity 1.0). The degree of stenosis was overestimated in three cases when using axial projections. Three-dimensional volume-rendered CTA showed a sensitivity of 0.91 for aneurysms, 0.82 for stenoses, 0.75 for occlusions and 0.77 for calcifications. The specificity was 1.0 in all cases. Multislice CT angiography seems to be similar to conventional digital subtraction angiography for abdominal vessels if multiplanar projections are used.

Assessment of inter- and intraobserver agreement between intravascular US and aortic angiography of thoracic aortic injury

PURPOSE

To compare inter- and intraobserver agreement at thoracic aortic angiography with that at intravascular ultrasonography (US) in the work-up of patients suspected of having thoracic aortic injury.

MATERIALS AND METHODS

Three blinded readers performed a retrospective review of 95 thoracic aortic angiograms and 23 intravascular US images obtained in patients suspected of having traumatic aortic injury. Inter- and intraobserver agreement in the interpretation of the thoracic aortic angiograms and intravascular US images were determined by using Cohen kappa statistics. In addition, differences among demographic groups were evaluated by using bivariate analysis.

RESULTS

Interobserver agreement was lowest in the interpretation of indeterminate angiograms (kappa = 0.55) and highest in the interpretation of determinate angiograms (kappa = 0.71). In contrast, interobserver agreement in the interpretation of intravascular US images was excellent. For all groups, intraobserver agreement in the interpretation of aortic angiograms was substantial and overall agreement was good (kappa = 0.88). Intraobserver agreement in the interpretation of intravascular US images was excellent (kappa = 1.00). Differences among demographic groups were not found to be significant.

CONCLUSION

Intravascular US is an adjunct to aortic angiography and yields excellent overall inter- and intraobserver agreement. Subgroups of patients who are suspected of having aortic injury and have indeterminate angiograms may benefit from undergoing intravascular US.

Traumatic rupture of the thoracic aorta: third decade of experience

BACKGROUND

Traumatic rupture of the thoracic aorta is a relatively common injury of deceleration accidents, usually high-speed motor vehicle accidents. Spinal cord injury has been a well-documented complication of surgical management. The use of nonheparinized partial bypass with a centrifugal pump was evaluated for protection against spinal cord injury and reduction of risk of associated injuries.

METHODS

From 1989 to 1999, the third decade of the authors' experience, traumatic rupture was diagnosed in 58 patients (male 46 and female 12; mean age 39.9 years, range 17 to 85). Associated injuries were documented in 98.3% (57 patients). In all, 45 patients (77.6%) had the opportunity for definitive surgical management; 42 (93.3%) were managed with partial cardiopulmonary bypass, 35 without the use of heparin. Full cardiopulmonary bypass was utilized in 1 patient while 2 had repair without cardiopulmonary bypass support. Thirteen patients did not have the opportunity for definitive surgical management, 1 death on arrival, 8 (61.5%) suspected, and 4 (30.8%) diagnosed.

RESULTS

There were 6 deaths in the surgical group, 5 in nonheparinized patients. The causes were intraoperative hypovolemia (2), anoxic brain death after intraoperative cardiac arrest (1), sepsis (1), and adult respiratory distress syndrome (1). The other was in the simple aortic cross-clamp group from intraoperative pulmonary compromise. There was one spinal cord injury, paraparesis in 1 of the 2 patients managed without bypass support. The total hospital stay ranged from 8 to 112 days, primarily owing to management of associated injuries. Of the 13 patients who did not have the opportunity for definitive surgical management, 5 had unsuccessful emergency thoracotomy and 3 survived the hospital course without surgery. Of the total population, the overall mortality was 27.6%, whereas the mortality of the potentially operable patients was 25.8%. Of the surgical group, the intraoperative mortality was 6.7% and 30-day mortality was 13.3%.

CONCLUSIONS

Spinal cord injury was prevented by the use of partial cardiopulmonary bypass. Nonheparinized bypass was likely to be a contributory factor to lack of mortality directly related to associated injuries.

Direct findings of aortic injury on contrast-enhanced CT in surgically proven traumatic aortic injury: a multi-centre review

OBJECTIVE

To review the contrast-enhanced CT findings in surgically proven traumatic aortic injury (TAI).

MATERIALS AND METHODS

We searched the trauma registries of three academic medical centres from 1994 to 2000 and found 34 patients with surgically proven TAI that received pre-operative contrast-enhanced chest CT. Two chest radiologists recorded by consensus the size and location of direct (pseudoaneurysm, intimal flap) and indirect (mediastinal haematoma) findings of TAI. The imaging findings were correlated with surgical reports.

RESULTS

Direct findings of aortic injury (pseudoaneurysm or intimal flap) were seen on contrast enhanced CT in all patients and confirmed at surgery. Specifically, a pseudoaneurysm was seen in 33 (97%), presenting either as a focal bulge in 22 (65%) or as more diffuse aneurysmal enlargement in 11 (32%). An intimal flap was identified in 31 cases (91%). A periaortic haematoma was seen in 31 cases (91%). In the three patients without periaortic haematoma, the only indications of aortic injury were a focal pseudoaneurysm in two (6%) and an intimal flap in one (3%).

CONCLUSION

In this series of surgically proven TAI, direct findings of aortic injury were seen in all cases. Aortic tear occurred without mediastinal haematoma in 9% (3/34) of patients.

Recent advances in trauma management

Twenty-three thousand doctors in the UK have undertaken The Advanced Trauma Life Support Course for doctors over the past 12 years. The course was never designed to provide anything more than a framework within which inexperienced doctors could safely manage multiple injured patients until expert help arrived. Its critics will say that the course is didactic and its treatment protocols are not always up to date. Since its inception in 1976 in Nebraska it has undergone constant revision and the seventh edition of the course will appear in 2002. With each revision, evidence for new methods of management for the trauma victims are reviewed; some of these are discussed in this paper.

Guidelines for the diagnosis and management of blunt aortic injury: an EAST Practice Management Guidelines Work Group

In summary, BAI is a lethal result of severe blunt trauma. It should be considered in all patients who sustained injury by a deceleration or acceleration mechanism, especially in the face of physical or radiographic findings suggestive of mediastinal injury. Angiography remains the "gold standard" for diagnosis, although CT scanning is taking more of a role, especially for screening. Diagnosis should be followed by prompt surgical repair using some method of distal perfusion to minimize renal and spinal cord ischemia. If prompt repair is not feasible because of other injuries or comorbidities, medical control of blood pressure is warranted in the interim.

Helical (spiral) CT in the evaluation of emergent thoracic aortic syndromes. Traumatic aortic rupture, aortic aneurysm, aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer

For the near future, CT will play the critical and dominant role in the evaluation of patients presenting with emergent aortic syndromes. Its convenience, accuracy, and utility in the rapid evaluation of not just the aorta, but the entire thorax, make it ideally suited for use in emergency settings. Further benefits are likely to be realized in speed and resolution with multislice CT, although it is as yet not widely available.

Helical CT grading of traumatic aortic injuries. Impact on clinical guidelines for medical and surgical management

Helical CT is a reliable method for screening patients with blunt chest trauma for vascular and visceral injuries. Thoracic aortic injuries detected by CT examination affect the immediate clinical management and patient triage. This article describes the clinical indications and imaging protocols for helical CT of the chest used to detect aortic injuries, provides a grading system of the range of aortic injuries demonstrated by CT, and discusses the clinical management decisions that should be considered based on the CT grade of the aortic injury.