Original contributionDiagnostic value of the helical CT scan for traumatic aortic injury: Correlation with mortality and early rupture
Introduction
Traumatic aortic injury (TAI) is a potentially lethal condition. It accounts for 10–20% of mortality in high-speed deceleration accidents (1, 2). Among all victims of TAI, 80–90% die at the scene (1, 3). Of the remaining victims who arrive at the emergency department, the mortality rate of untreated TAI remains high; 30% of the mortality occurs within 6 h, 40–50% within 24 h (3, 4). However, patients receiving prompt recognition and surgery survive more than 70% of the time (4).
The diagnostic tool requirement in the Emergency Department, therefore, should be fast, timely, available, and highly specific. In recent years, helical computed tomography of the thorax (HCTT) has been advocated as a screening tool for TAI after blunt chest trauma, but its role in replacing catheter aortography as a definitive diagnostic tool remains controversial (2, 5, 6). Recently, reports showed that direct signs revealed on HCTT are specific and accurate in diagnosing TAI, and that aortography is not needed in patients with a clearly positive CT scan (7, 8, 9, 10). Despite evidence that HCTT can be as accurate and as effective as aortography, ambiguities regarding this recommendation still exist, especially in the surgical community, and some surgeons are reluctant to operate on the basis of HCTT alone. This is due in part to the perceived mandatory need for aortography before operation, and also, false positive results using direct signs have been reported (11, 12, 13). However, the requirement for aortography in patients with clearly positive CT scans may delay definite therapy and even result in death in some patients without obtaining additional information needed for surgery.
The purpose of this study was to evaluate the value of individual and combined direct signs revealed by HCTT in the diagnosis of traumatic aortic injury among patients in whom aortic injury was subsequently proven or excluded. The mortality risk correlated with these direct signs was also measured.
Section snippets
Materials and methods
During a period of 5 years, 479 patients who sustained blunt chest injuries underwent HCTT at a Level I trauma center. These patients were referred to HCTT if they presented with a significant injury mechanism that suggested deceleration injury, and chest radiographic findings of possible mediastinal hematoma. Patients whose chest radiographs did not show suspicious findings also underwent HCTT if aortic injury was suspected clinically or if contrast-enhanced helical CT scan of the abdomen or
Statistical analysis
Data are presented as means ± standard deviation (SD) or frequency (percentage). Because the sample size was small, Fisher’s exact test or the Wilcoxon rank-sum test was conducted to compare data between the mortality and surviving groups. The strength of association was presented as odds ratio (95% CI) for binary variables with survival status. All p values reported were one sided. Results were considered statistically significant if p < 0.05.
Results
Of the 53 patients, direct signs were found in 25 cases and not found in 28 cases. Among the 25 cases with direct signs revealed on HCTT, 22 had aortic injuries proved by subsequent aortography or surgical findings, and 3 did not show acute thoracic aortic injuries. Aortography in the 28 cases without direct signs was normal. None of these 31 patients died of mediastinal exsanguination during hospitalization or clinical follow-up for a median of 12.2 months. Of the 22 patients who had aortic
Discussion
Rapid exsanguination after TAI, if not promptly diagnosed and treated, is a threat to patients who survive long enough to reach a hospital. Patients with TAI often have multiple injuries and a wide range of signs and symptoms that are seldom specific (1, 6). The diagnosis of TAI is difficult, and therefore an imaging examination is critical in evaluating this injury. This imaging modality must be safe, efficient and reliable.
HCTT is an ideal imaging tool for TAI in the Emergency Department (ED)
References (18)
- et al.
Experience with spiral computed tomography as the sole diagnostic method for traumatic aortic rupture
Ann Thorac Surg
(2001) - et al.
Periaortic contrast medium extravasation on Chest CT in Traumatic aortic injury a sign for immediate thoracotomy
Am J Emerg Med
(2001) - et al.
Is helical computed tomography effective for diagnosis of blunt aortic injury?
Am J Emerg Med
(2002) - et al.
Traumatic rupture of the thoracic aortashould one always operate immediately?
Ann Vasc Surg
(1995) - et al.
Surgical indications and timings of repair of traumatic ruptures of the thoracic aorta
Ann Thorac Surg
(1998) - et al.
Prospective study of blunt aortic injuryMulticenter Trial of the American Association for the Surgery of Trauma
J Trauma
(1997) - et al.
Can chest CT be used to exclude aortic injury?
Radiology
(1999) - et al.
Thoracic aorta injuriesmanagement and outcome of 144 patients
J Trauma
(1996) - et al.
Nonpenetrating traumatic injury to the aorta
Circulation
(1958)
Cited by (19)
Evaluation of Thoracic Vascular Trauma With Multidetector Computed Tomography
2012, Seminars in RoentgenologyCitation Excerpt :Contrast extravasation into the mediastinum, indicating a full-thickness tear of the aortic wall with active bleeding, is rarely seen on CT; with little chance of survival.27 Once an aortic injury is diagnosed on CT, diagnostic conventional angiography is not necessary because it provides little or no additional information,46 is invasive, time consuming, and requires transferring the patient away from an optimal environment for direct monitoring and support.54 An unequivocally normal aortic CTA with regular aorta surrounded by normal fat and no mediastinal hematoma has a 100% negative predictive value for aortic injury.8
Chest Trauma in Children: Current Imaging Guidelines and Techniques
2011, Radiologic Clinics of North AmericaCitation Excerpt :Traditionally, when one suspected traumatic thoracic aortic injury based on clinical and chest radiographic findings, conventional aortography was considered the diagnostic gold standard, especially in hemodynamically unstable patients. There is a growing body of evidence supporting the use of MDCT as the primary diagnostic tool in this clinical setting.4,5,73–76 Because of the early mortality with the more typical aortic injuries, atypical locations may be encountered more commonly in those who survive long enough to be evaluated with a CT scan.
Management of thoracic aorta traumatism in 5 multiple traumatized patients
2008, Medicina IntensivaDiagnosis of blunt traumatic aortic injury 2007: Still a nemesis
2007, European Journal of RadiologyCitation Excerpt :As CT technology advanced, first with the introduction of helical CT, and later multi-row detector CT (MDCT), the quality of images obtained in the axial plane, multiplanar reformations, surface contour, and volume rendering techniques improved in step. Over the past decade, these advances have made CT the usual definitive screening test for major thoracic vascular injury, without the requirement of arteriography or transesophageal echocardiography to exclude or confirm the diagnosis, with the rare exception of an equivocal CT result or a technically inadequate study [9–11]. While the improved spatial resolution, better overall image quality, and supplemental post-processing techniques have been a great boon to the success of CT for the diagnosis of aortic-great vessel injury, these advances have also led to recognition of greater numbers of normal variants of vascular anatomy and subtler vascular injuries that were less likely to be appreciated using earlier conventional CT scans obtained with wider slice thickness, greater motion artifacts, poorer quality multiplanar reformations, and less consistent peak aortic contrast opacification.
Watch Out for the Early Killers: Imaging Diagnosis of Thoracic Trauma
2023, Korean Journal of RadiologyAortic rupture, traumatic (TAI)
2014, Rosen and Barkin's 5-Minute Emergency Medicine Consult: Fifth Edition