Clinical and radiographic indications for aortography in blunt chest trauma

To determine which clinical and radiographic findings are valuable in selecting patients with blunt chest trauma for aortography, we analyzed the medical records and admission chest radiographs of 76 consecutive victims of blunt chest trauma with suspected thoracic aortic rupture during the past 7 years. All patients were evaluated by history, physical examination, chest radiography, and aortography; a total of 70 clinical and radiographic findings were independently assessed in each patient. The following occurred with significantly greater frequency in patients with thoracic aortic rupture than in those without: history of significant hypotension (mean arterial pressure less than 80 mm Hg) (p less than 0.04); the presence of upper extremity hypertension, bilateral lower extremity pulse pulse deficits, or an initial chest tube output greater than 750 ml of blood (p less than 0.05); and greater incidence of myocardial contusions, intra-abdominal injuries, and pelvic fractures compared with patients without thoracic aortic rupture (p less than 0.05). Mediastinal widening (equal to or greater than 8 cm) shown on anteroposterior chest radiography occurred in all patients with thoracic aortic rupture; however, its specificity was only 10.6%. Radiographic signs that were helpful in indicating the presence of thoracic aortic rupture included paratracheal stripe greater than 5 mm, rightward deviation of the nasogastric tube or central venous pressure line, blurring of the aortic knob, and an abnormal or absent paraspinous stripe. Upper rib fractures and mediastinal to thoracic cage width ratios at any level did not increase diagnostic accuracy for thoracic aortic rupture in the present series. Six patients in the series died, two of whom had thoracic aortic rupture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mediastinal evaluation utilizing the reverse Trendelenburg radiograph

When thoracic aortic rupture is suspected, a 45-degree reverse Trendelenburg (RT) anteroposterior (AP) chest radiograph should place the mediastinal structures in a more appropriate position and allow a more accurate evaluation than a supine AP radiograph. One hundred ninety-one consecutive hemodynamically stable adult patients with major blunt thoracic trauma were initially evaluated for mediastinal abnormalities associated with aortic disruption by both supine AP chest radiograph and an AP chest radiograph with the patient in 45-degree RT position. One hundred four patients underwent contrast aortography based on mediastinal abnormalities detected on the supine AP chest radiograph. Twenty of these patients had abnormal aortograms demonstrating traumatic aortic disruption confirmed at surgery. Supine and RT chest radiographs were retrospectively compared in a blinded fashion to evaluate their specificity and positive predictive value for detection of traumatic thoracic aortic rupture. If RT chest radiographic findings had been used to determine the need for further assessment, 29 angiograms (26%) would have been eliminated, specificity would have increased from 52 per cent to 69 per cent, and positive predictive value would have increased from 19 per cent to 27 per cent. Both supine and RT chest radiographs demonstrated mediastinal widening in all 20 patients with abnormal aortograms, with no missed thoracic aortic disruptions (100% sensitivity). This study indicated that the RT chest radiograph may be used instead of the standard supine radiograph as the initial screen for mediastinal evaluation, maintaining a high sensitivity and eliminating the cost and morbidity of many unnecessary aortograms.     

Evaluation of transesophageal echocardiography for diagnosis of traumatic aortic injury

BACKGROUND: Traumatic aortic injury is a frequent cause of death after blunt trauma, but few patients survive to reach a trauma center. The role of transesophageal echocardiography (TEE) in the diagnosis of traumatic aortic injury remains debated. METHODS: Over a 9-yr period, 209 blunt trauma patients (mean age, 34 +/- 13 yr) were suspected of having traumatic aortic injury because of enlarged mediastinum and/or sudden deceleration, and underwent TEE and angiography (aortography and/or contrast-enhanced computed tomography. RESULTS: Traumatic aortic injury was diagnosed in 42 patients (20%). Angiography (aortography and/or contrast-enhanced computed tomography) was less accurate (sensitivity, 83%; specificity, 100%) than TEE (sensitivity, 98%; specificity, 100%) for the diagnosis of aortic injury because it failed to diagnose most minor injuries (intramural hematoma or limited intimal flap, n = 7). However, when considering only patients with major aortic injury (n = 33; i.e., those who might need surgery), angiography (sensitivity, 97%; specificity, 100%) and TEE (sensitivity, 97%; specificity, 100%) were equivalent. CONCLUSION: Transesophageal echocardiography is an accurate method for diagnosis of traumatic aortic injury. Nevertheless, the clinical implications of limited aortic injuries diagnosed by the technique have yet to be determined.     

Transesophageal echocardiography. Preliminary results in patients with traumatic aortic rupture

Eleven patients with blunt chest trauma at risk for traumatic aortic rupture underwent transesophageal echocardiography to image the descending aorta. Diagnoses were compared with the results of radiographic studies. Ten of the 11 patients underwent arch aortography, with positive results in six cases. In one patient, the results of a computed tomographic scan were interpreted as consistent with aortic rupture. The results of transesophageal echocardiography were positive for ruptured descending aorta in three of six patients with positive aortographic findings, and negative in eight patients. All three patients with positive findings had the diagnosis of ruptured descending aorta confirmed at surgery. The remaining eight patients demonstrated no aortic morbidity. These preliminary findings suggest that transesophageal echocardiography is a useful technique for the diagnosis of ruptured descending aorta following blunt chest trauma.     

Traumatic rupture of the aorta. Indications for aortography

The indications for thoracic aortography in the blunt chest trauma patient remain controversial. Clinical and radiographic findings in 102 patients seen at a Level I Trauma Center over a five-year period were reviewed to evaluate criteria predictive of major thoracic vascular injury. Five patients had positive aortograms. There was no significant correlation with Revised Trauma Score, symptoms, or associated thoracic injuries, although patients with aortic rupture did have a higher incidence of extrathoracic injuries (P less than 0.001). A blinded review of admitting chest radiographs for five major findings (widened mediastinum, aortic arch abnormalities, aortopulmonary window opacification, left apical capping, and right apical capping) revealed a significant difference between patients with and without aortic injury (0.98 +/- 1.24 findings in the negative aortogram group and 3.00 +/- 0.71 findings in the positive aortogram group) (P less than 0.001). All patients with aortic rupture had at least two major positive findings on admitting chest radiographs. Admission chest x-ray evidence of at least one major abnormality is a safe method of screening blunt chest trauma patients for thoracic aortography.     

Evaluation of Transesophageal Echocardiography for Diagnosis of Traumatic Aortic Injury

Background: Traumatic aortic injury is a frequent cause of death after blunt trauma, but few patients survive to reach a trauma center. The role of transesophageal echocardiography (TEE) in the diagnosis of traumatic aortic injury remains debated.

Methods: Over a 9-yr period, 209 blunt trauma patients (mean age, 34 +/- 13 yr) were suspected of having traumatic aortic injury because of enlarged mediastinum and/or sudden deceleration, and underwent TEE and angiography (aortography and/or contrast-enhanced computed tomography.

Results: Traumatic aortic injury was diagnosed in 42 patients (20%). Angiography (aortography and/or contrast-enhanced computed tomography) was less accurate (sensitivity, 83%; specificity, 100%) than TEE (sensitivity, 98%; specificity, 100%) for the diagnosis of aortic injury because it failed to diagnose most minor injuries (intramural hematoma or limited intimal flap, n = 7). However, when considering only patients with major aortic injury (n = 33;i.e., those who might need surgery), angiography (sensitivity, 97%; specificity, 100%) and TEE (sensitivity, 97%; specificity, 100%) were equivalent.     

Current Experience with Computed Tomographic Cystography and Blunt Trauma

We present our experience with computed tomographic (CT) cystography for the diagnosis of bladder rupture in patients with blunt abdominal and pelvic trauma and compare the results of CT cystography to operative exploration. We identified all blunt trauma patients diagnosed with bladder rupture from January 1992 to September 1998. We also reviewed the radiology computerized information system (RIS) for all CT cystograms performed for the evaluation of blunt trauma during the same time period. The medical records and pertinent radiographs of the patients with bladder rupture who underwent CT cystography as part of their admission evaluation were reviewed. Operative findings were compared to radiographic findings. Altogether, 316 patients had CT cystograms as part of an initial evaluation for blunt trauma. Of these patients, 44 had an ultimate diagnosis of bladder rupture; 42 patients had CT cystograms indicating bladder rupture. A total of 28 patients underwent formal bladder exploration; 23 (82%) had operative findings that exactly (i.e., presence and type of rupture) matched the CT cystogram interpretation. The overall sensitivity and specificity of CT cystography for detection of bladder rupture were 95% and 100%, respectively. For intraperitoneal rupture, the sensitivity and specificity were 78% and 99%, respectively. CT cystography provides an expedient evaluation for bladder rupture caused by blunt trauma and has an accuracy comparable to that reported for plain film cystography. We recommend CT cystography over plain film cystography for patients undergoing CT evaluation for other blunt trauma-related injuries.     

Use of CT for diagnosis of traumatic rupture of the thoracic aorta

CT imaging of traumatic aortic rupture has been both advocated and disparaged in the current literature as a reliable diagnostic modality. In a retrospective review of blunt chest trauma patients at our institution evaluated by both thoracic CT and arteriography, we found a 17% false negative rate and a 39% false positive rate. Although we feel CT is not sufficiently sensitive at present to evaluate traumatic rupture of the aorta directly, it is an invaluable adjunctive imaging modality for stable blunt chest trauma patients with equivocal chest radiographs or arteriograms.     

Computed tomographic evaluation to exclude traumatic aortic disruption.

Traumatic aortic disruption from blunt trauma remains a lethal injury. The role of computed tomographic (CT) scanning in the diagnosis of traumatic aortic disruption (TAD) has been debated and varying results have been reported. We reviewed our experience with 133 consecutive cases of blunt trauma with abnormal findings on chest x-ray films of sufficient concern to require further evaluation for TAD. Of the 105 patients who underwent CT scanning as the initial evaluation, 11 (10%) required aortography (Ao) for diagnosis; seven had TAD. Twenty-eight patients with highly suggestive signs of TAD underwent Ao as the initial diagnostic test; five had TAD. Ten of the 12 patients (83%) undergoing surgical repair had good results; one died of exsanguination at surgery and the other suffered a profound neurologic injury. Follow-up by phone or chart review at 6 months to more than 5 years after injury revealed no late mortalities from unrecognized TAD. We conclude that high quality CT evaluation of patients with worrisome chest x-ray films following blunt trauma can be used to exclude TAD in the majority of cases. Aortography is reserved for cases in which there is a high clinical suspicion of TAD and for those patients in whom TAD cannot be confidently excluded by CT scanning.     

Computerized tomography cystography for the diagnosis of traumatic bladder rupture

PURPOSE: We present our experience with computerized tomography (CT) cystography for diagnosing bladder rupture in patients with blunt abdominal and pelvic trauma, and compare the results of CT cystography with those of surgical exploration. MATERIALS AND METHODS: We identified all patients with blunt trauma diagnosed with bladder rupture from 1992 to September 1998. We reviewed the radiology computerized information system for all CT cystography performed to evaluate blunt trauma during the same period. We also reviewed the medical records and pertinent radiographic studies of patients with bladder rupture who underwent CT cystography as part of the hospital admission evaluation. Operative and radiographic findings were compared. RESULTS: CT cystography was performed in 316 patients as part of the initial evaluation of blunt trauma. Of the 44 patients with the ultimate diagnosis of bladder rupture CT cystography revealed bladder rupture in 42, while 23 of the 28 (82%) who underwent formal bladder exploration had operative findings that exactly matched the CT cystography interpretation in terms of the presence and type of rupture. In the 316 patients CT cystography detected bladder rupture with an overall sensitivity and specificity of 95% and 100%, respectively. For intraperitoneal rupture sensitivity was 78% and specificity was 99%. CONCLUSIONS: CT cystography provides expedient evaluation of bladder rupture due to blunt trauma and has accuracy comparable to that reported for plain film cystography. We recommend CT cystography over plain film cystography in patients undergoing CT for other injuries associated with blunt trauma.     

Role of CT in diagnosis of major arterial injury after blunt thoracic trauma

The role of computed tomography (CT) in the diagnosis of blunt thoracic vascular injury is controversial. Several recent reports have advocated the use of CT to exclude aortic and major branch injuries in hemodynamically stable patients with blunt trauma. This approach potentially avoids invasive angiography and unnecessary treatment delays in multiply injured patients but risks missed aortic transections if the CT or its interpretation is not accurate. We prospectively evaluated 153 consecutive trauma patients in whom we suspected blunt aortic injury between September 1985 and August 1988. All hemodynamically stable patients underwent contrast-enhanced chest CT followed by immediate aortic arch angiography. Forty-nine unstable patients underwent immediate angiography without chest CT, and 11 (22%) had major thoracic arterial injuries. Data from the remaining 104 stable patients indicate that the sensitivity of chest CT for diagnosis of major thoracic injury is 55%; specificity, 65%. If the chest CT had been used as a screening modality to perform aortic angiography, two transected aortas and three major aortic branch injuries would have been missed. We conclude that chest CT has no screening role in the evaluation of blunt trauma patients with possible major vascular injury.     

Derivation of a clinical decision rule to exclude thoracic aortic imaging in patients with blunt chest trauma after motor vehicle collisions

BACKGROUND: Thoracic aortic injury (TAI) is associated with high mortality. It is not practical to evaluate all patients with blunt chest trauma with dedicated aortic imaging. The purpose of this study was to define a group of patients with blunt chest trauma after motor vehicle collision (MVC) that do not require aortic imaging based on information available in the emergency department. METHODS: This was a secondary analysis of a prospectively-collected database. Consecutive patients with blunt chest trauma after MVC were included. Characteristics of mechanism, examination, and chest radiographic findings were collected for each patient. All patients underwent chest computed tomography (CT), aortography, or both for TAI evaluation. Binary recursive partitioning was used to derive and validate a clinical decision rule to predict exclusion of TAI. RESULTS: During the study period, 1,096 patients were included, and 22 (2.0%) were diagnosed with TAI. The decision rule for exclusion of TAI included findings from the chest radiograph, incorporating left paraspinous line displacement, obscured aortic knob, and mediastinal widening. The rule resulted in a sensitivity of 86% (95% confidence interval [CI]: 65% to 97%), a specificity of 77% (95% CI: 75% to 80%), a positive predictive value of 7% (95% CI: 4% to 11%), a negative predictive value (NPV) of 99.6% (95% CI: 99.0% to 99.9%), a positive likelihood ratio of 3.8 (95% CI: 1.1-12.9), and a negative likelihood ratio of 0.18 (95% CI: 0.05-0.61). This would potentially reduce aortic imaging by 76% (95% CI: 74% to 79%). CONCLUSION: We report a clinical decision rule with a high NPV for exclusion of TAI. This may standardize the approach to such patients and may reduce the need for CT.     

Aortic dissection associated with blunt chest trauma diagnosed by elevated D-dimer

IntroductionSimilar to spontaneous aortic dissection, traumatic aortic dissection is diagnosed with a careful history and physical exam, chest radiograph, and ultimately, dedicated aortic imaging. The diagnosis of spontaneous aortic dissection may be aided by using the serum D-dimer test. The use of D-dimer for diagnosing aortic injury in the setting of blunt trauma has not previously been reported.Presentation of caseWe present a case of aortic dissection in a 61-year-old male diagnosed when the patient presented with chest pain after blunt chest trauma.DiscussionThe patient had no known history or risk factors for aortic disease. None of the classic findings were present by history, physical examination or chest radiograph and the diagnosis was made as the result of an elevated D-dimer. We discuss how the D-dimer test fortuitously led to the diagnosis in this case, and the implications.ConclusionD-dimer could be helpful in diagnosing aortic injuries in low-risk chest trauma patients.     

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.     

External validation of the traumatic aortic injury score

Aim

Traumatic aortic injury (TAI) is a serious complication of blunt chest trauma. The traumatic aortic injury score (TRAINS) is a clinical tool for risk determination, with patients scoring <4 considered low risk. The aim of the present study was to determine the sensitivity of TRAINS on a population of blunt trauma patients with TAI at an Australian major trauma centre.

Patients and Methods

Patients diagnosed with thoracic TAI between 2006 and 2014 were identified from an institutional registry. Radiological studies (chest X‐ray) were reviewed, while blood pressure on arrival to hospital was extracted from the registry. Using abbreviated injury scale codes, the presence of the five associated injuries included in the TRAINS model was determined.

Results

A TRAINS ≥4 was observed in 28 out of 63 cases, with complete data available (sensitivity = 44.4 per cent; 95 per cent confidence interval: 32.8–56.7), with minimum and maximum possible sensitivities of 42.4 per cent and 47 per cent, respectively, as determined by two‐way sensitivity analysis.

Conclusions

This independent external validation of the TRAINS concluded a poor sensitivity for excluding TAI in the blunt chest trauma population. In the absence of reliable predictive tools, a low threshold for thoracic computed tomography imaging and clinical gestalt remain essential tools for the early diagnosis of TAI.     

Efficacy of Radiographic Imaging in Pediatric Blunt Renal Trauma

Purpose

We sought to determine whether radiographic imaging can effectively detect significant renal injuries in children with blunt trauma who do not have significant hematuria.

Materials and Methods

We reviewed the records of 180 children who presented to our hospital for suspected renal trauma between 1977 and 1995. Results of excretory urography or abdominal computerized tomography were correlated with urinalysis findings and clinical outcome.

Results

Of 147 patients with microscopic hematuria after blunt trauma 77 underwent imaging. Only 1 patient had a significant renal injury (grade 2 or greater) and 76 had normal findings or renal contusions only, including 11 with microscopic hematuria and shock. Of the 74 patients who did not undergo imaging a clinical diagnosis of renal contusion was made and followup was available for 57 (77 percent). All patients healed without adverse sequelae. Of 33 patients with gross hematuria significant renal injuries were found in 9, including 3 who required immediate surgical repair of a major renal laceration or vascular injury. Combining our results with those of other reported series revealed significant renal injuries in only 11 of 548 children (2 percent) with less than 50 red blood cells per high power field on presenting urinalysis after blunt abdominal trauma. These patients were likely to have multiple associated injuries.

Conclusions

Significant renal injuries are unlikely in pediatric patients with blunt renal trauma but no gross or substantial microscopic hematuria. Shock does not appear to be a clinically useful indicator.     

Traumatic diaphragmatic hernia. Occult marker of serious injury.

OBJECTIVE: Recent experience with traumatic diaphragmatic hernias at the Massachusetts General Hospital was reviewed to identify pitfalls in the diagnosis and treatment of this injury. SUMMARY BACKGROUND DATA: Traumatic diaphragmatic disruption is a common injury and a marker of severe trauma. It occurs in 5% of hospitalized automobile accident victims and 10% of victims of penetrating chest trauma. Numerous reports describe splenic rupture in 25% of patients with blunt diaphragmatic rupture, liver lacerations in 25%, pelvic fracture in 40%, and thoracic aortic tears in 5%. Diaphragmatic rupture is a predictor of serious associated injuries which, unfortunately, is itself often occult. METHODS: A chart review of all patients admitted to the Trauma Service with traumatic diaphragmatic hernias was undertaken for the period of January 1982 to June 1992. RESULTS: Data on 68 patients sustaining blunt (n = 25) and penetrating (n = 43) diaphragmatic rupture or laceration were presented. The diagnosis was made preoperatively in only 21 (31%). Associated injuries were frequent in those injured by either blunt or penetrating trauma. Sixty-six patients underwent repair, 54 (82%) through a laparotomy alone and 12 (18%) with the addition of a thoracotomy. There were five (7.4%) deaths that were caused by coagulopathy, hemorrhagic shock, multisystem organ failure, and pulmonary embolism. Complications were twice as frequent in the blunt-trauma group and included abscess, pneumonia, and the sequelae of closed head injuries. CONCLUSIONS: The recognition of diaphragmatic rupture is important because of the frequency and severity of associated injuries. The difficulties in reaching the diagnosis require an aggressive search in patients at risk.     

Comparison of multiplane transesophageal echocardiography and contrast-enhanced helical CT in the diagnosis of blunt traumatic cardiovascular injuries

BACKGROUND: Multiplane transesophageal echocardiography (TEE) and helical computed tomography (CT) of the chest have been validated separately against aortography for the diagnosis of acute traumatic aortic injuries (ATAI). However, their respective diagnostic accuracy in identifying blunt traumatic cardiovascular lesions has not been compared. METHODS: During a 3-yr period, 110 consecutive patients with severe blunt chest trauma (age: 41 +/- 17 yr; injury severity score: 34 +/- 14) prospectively underwent TEE and chest CT as part of their initial evaluation. Results of both imaging methods were interpreted independently by experienced investigators and subsequently compared. All cases of subadventitial acute traumatic aortic injury were surgically confirmed. RESULTS: Seventeen patients had vascular injury and 11 had cardiac lesions. TEE and CT identified all subadventitial disruptions involving the aortic isthmus (n = 10) or the ascending aorta (n = 1) that necessitated surgical repair. In contrast, CT only depicted one disruption of the innominate artery. TEE detected injuries involving the intimal or medial layer, or both, of the aortic isthmus in four patients with apparently normal CT results who underwent successful conservative treatment. All cardiac injuries but two were identified only by TEE. CONCLUSIONS: In patients with severe blunt chest trauma, TEE and CT have similar diagnostic accuracy for the identification of surgical acute traumatic aortic injuy. TEE also allows the diagnosis of associated cardiac injuries and is more sensitive than CT for the identification of intimal or medial lesions of the thoracic aorta.     

Prospective evaluation of the sensitivity of physical examination in chest trauma

BACKGROUND: Chest radiographs are routine for patients presenting with blunt and penetrating chest trauma. The accuracy of physical examination in the diagnosis of hemopneumothorax in these patients is unclear. A prospective study was performed to define the utility of routine portable chest radiographs in 676 trauma patients. METHODS: Over 19 months (January 2000-July 2001), 676 patients who presented with penetrating or blunt chest trauma were interviewed and examined for signs and symptoms of hemopneumothorax. The incidence of chest pain or tenderness and tachypnea was noted and both lung fields were auscultated. A portable chest radiograph was then performed on all the patients. RESULTS: All the patients were hemodynamically stable. Five hundred twenty-three patients sustained blunt trauma, with seven hemopneumothoraces (1.3%). The negative predictive values of auscultation, pain or tenderness, and tachypnea were 99& to 100%. One hundred fifty-three patients sustained penetrating chest trauma. Of these injuries, 68 were gunshot wounds and 85 were stab wounds. Twenty-four (16%) of these patients had hemopneumothoraces. The sensitivities of auscultation, pain or tenderness, and tachypnea were 50%, 25%, and 32%, respectively. The negative predictive values of these tests were < 91%. CONCLUSION: Blunt chest trauma patients who are hemodynamically stable with a normal physical examination do not require a routine chest radiograph. In contrast, all victims of penetrating trauma require chest radiographs because many will have hemopneumothorax in the absence of clinical findings.     

The potential effects of radiographic criteria to exclude aortography in patients with blunt chest trauma. Results of a study of 32 patients with proved aortic or brachiocephalic arterial injury

The purpose of this study was to test the effectiveness, in patients with known aortic or brachiocephalic arterial injury, of five previously published radiographic criteria for excluding aortography in patients with blunt chest trauma. These criteria were (1) normal findings on erect chest radiograph; (2) normal aortic arch and left subclavian artery; (3) normal aortic arch, descending aorta, aortopulmonary window, tracheal position, and left paraspinal interface; (4) normal right paratracheal stripe and nasogastric tube position, and (5) normal aortic arch and tracheal and nasogastric tube position. One or more of these criteria were met in 6% to 25% of patient with major thoracic arterial injury, depending on the criteria used. Interestingly, two (6%) patients had radiographs that showed no specific signs of mediastinal hemorrhage, which indicates that the chest radiograph is limited in its sensitivity to detect major thoracic arterial injury. Because of these results, we do not believe that attempts to limit aortography in patients with supine film evidence of mediastinal abnormality, based on the absence of certain signs of mediastinal hemorrhage, are warranted. Furthermore, an abnormal radiograph cannot be relied on as the sole criterion for aortography if the goal of care is to detect as close to 100% of vascular injuries as possible.