Unenhanced dynamic mediastinal computed tomography in the selection of patients requiring thoracic aortography for the detection of acute traumatic aortic injury

In our institution, the selection of patients who require thoracic aortography to evaluate for acute traumatic aortic injury (ATAI) is based upon an appropriate mechanism of injury and radiologic demonstration of a mediastinal hematoma. When plain chest or chest and/or mediastinal radiographs demonstrate a mediastinal hematoma, the patient undergoes thoracic aortography as promptly as is clinically feasible. If the plain film studies are negative for mediastinal hematoma, thoracic aortography is not performed because the patient is presumed not to have an ATAI. When the plain film studies are equivocal and the patient is stable, unenhanced computed tomography (CT) of the mediastinum is used to evaluate for a mediastinal hematoma. CT signs of a mediastinal hematoma include a soft tissue density, representing the hematoma admixed with mediastinal fat, which obscures or obliterates the normal aortic-mediastinal fat interface; hematoma admixed with fat of the right paratracheal stripe causing increased width and density of the stripe; and hematoma surrounding, and frequently displacing, the esophagus to the right of its normal position. Six of 36 patients (17%) with mediastinal hematoma demonstrated by unenhanced mediastinal CT had ATAI by thoracic aortography and confirmed surgically. The thoracic aortograms of the remaining 30 of 36 patients (83%) were negative. Sixty-three of 100 patients (63%) with equivocal plain chest or mediastinal radiographs had negative mediastinum by unenhanced CT. All 63 patients (100%) with normal mediastinal CT and who did not have thoracic aortography were discharged from the hospital 1–42 days (mean, 9.3 days) post-injury without clinical or radiographic signs of aortic rupture. Supported in part by the John S. Dunn Research Foundation.     

Evaluation of traumatic aortic injury: does dynamic contrast-enhanced CT play a role?

To investigate the value of 5-mm contrast material-enhanced computed tomography (CT) in patients with moderate to low probability of aortic laceration after a substantial deceleration injury, scans were obtained through the upper mediastinum in 160 consecutive patients. Thoracic angiography and aortography were performed in patients with evidence of mediastinal hemorrhage at CT. There was no evidence of mediastinal hemorrhage in 132 patients with normal admission chest radiographs. In the 28 patients with abnormal admission chest radiographs, CT helped exclude mediastinal hemorrhage in 22 patients (78%), and 19 patients (68%) were treated without undergoing angiography. Six patients had mediastinal hematoma at CT. Only one had an aortic laceration at angiography. The authors conclude that 5-mm contrast-enhanced CT can help exclude mediastinal hemorrhage and reduce the angiography rate in low-to-moderate-risk patients with a widened or indeterminate mediastinum. There were no unsuspected cases of mediastinal hemorrhage in patients with normal chest radiographs. Angiography is recommended for patients considered to be at high risk for aortic laceration.     

Classification of parenchymal injuries of the lung

Pulmonary contusion, implying interstitial and alveolar injury without significant laceration, has been accepted as the primary lung injury in nonpenetrating chest trauma. Computed tomographic (CT) findings were compared with those of chest radiography in 85 consecutive patients with chest trauma in which there was a pulmonary radiodensity consistent with pulmonary contusion or patients with a history of severe chest trauma with normal parenchyma despite rib fractures, hemothorax, pneumothorax, or widened mediastinum. CT was found to be more sensitive than radiography in that 151 abnormalities (excluding rib fractures) were demonstrated on radiographs versus 423 abnormalities on CT scans, and 99 lacerations were seen on CT scans versus five on radiographs. Pulmonary lacerations were classified into four types on the basis of CT findings and mechanism of injury: compression rupture, compression shear, rib penetration, and adhesion tears. In these cases, pulmonary laceration was shown to be an integral component of the mechanism of injury in pulmonary contusion, pulmonary hematoma, pulmonary cyst or pneumatocele, or cavitation in pulmonary contusion.     

Thoracic aortic rupture: advantages of intraarterial digital subtraction angiography

Sixty-one consecutive patients with blunt thoracic trauma underwent intraarterial digital subtraction angiography (IA-DSA) of the thoracic aorta because of obscuration of the aortic knob or mediastinal widening on chest radiographs. Ten of these patients had aortic ruptures diagnosed by IA-DSA. Digital subtraction aortography proved 100% accurate as indicated by results of surgery, conventional arteriography, serial chest radiography, and clinical follow-up. The method was 50% faster compared with conventional aortography and saved significantly on film costs. The potential for use of smaller caliber catheters and a decrease in contrast requirements also make this method safer than conventional arteriography. We recommend IA-DSA as the procedure of choice when emergency aortography is warranted.     

Application of spiral computerized tomography in the study of traumatic lesions of the thoracic aorta

PURPOSE: Acute thoracic aortic injuries account for up to 10-20% of fatalities in high-speed deceleration road accidents and have an estimated immediate fatality rate of 80-90%. Untreated survivors to acute trauma (10-20%) have a dismal prognosis: 30% of them die within 6 hours, 40-50% die within 24 hours, and 90% within 4 months. We investigated the diagnostic accuracy of Helical Computed Tomography (Helical CT) in acute traumatic injuries of the thoracic aorta, and the role of this technique in the diagnostic management of trauma patients with a strong suspicion of aortic rupture. MATERIAL AND METHODS: We compared retrospectively the chest Helical CT findings of 256 trauma patients examined June 1995 through August 1999. All patients underwent a plain chest radiograph in supine recumbency when admitted to the Emergency Room. Chest Helical CT examinations were performed according to trauma score, to associated traumatic lesions and to plain chest radiographic findings. All the examinations were performed with no intravenous contrast agent administration and the pitch 2 technique. After a previous baseline study, contrast-enhanced scans were acquired with pitch 1 in 87 patients. All examinations were assessed for the presence of mediastinal hematoma, periaortic hematoma, traumatic pseudodiverticulum, irregular aortic wall or contour and intimal flap as signs of aortic rupture. RESULTS: Helical CT showed thoracic aortic lesions in 9 of 256 patients examined. In all the 9 cases we found a mediastinal hematoma and all of them had positive plain chest radiographic findings of mediastinal enlargement. Moreover, in 6 cases aortic knob blurring was also evident on plain chest film and in 5 cases depressed left mainstem bronchus and trachea deviation rightwards were observed. All aortic lesions were identified on axial scans and located at the isthmus of level. Aortic rupture was always depicted as pseudodiverticulum of the proximal descending tract and intimal flap. We also found periaortic hematoma in 6 cases and intramural hematoma in 1 case. There were no false positive results in our series: 7 patients with Helical CT diagnosis of aortic rupture were submitted to conventional aortography that confirmed both type and extension of the lesions as detected by Helical CT, and all findings were confirmed by gross inspection at surgery. No false negative results have been recorded so far: untreated aortic ruptures are fatal within 4 months in 90% of patients, or they may evolve into chronic pseudoaneurysm in about 5% of survivors. CONCLUSIONS: In our experience Helical CT had much higher diagnostic sensitivity and specificity than plain chest radiography. In agreement with larger published series, in our small one the diagnostic accuracy of Helical CT was 100% in the evaluation of traumatic aortic ruptures. Moreover, Helical CT is faster and less invasive than conventional aortography, which makes this diagnostic modality increasingly used and markedly improves the management of the serious trauma patient. The more widespread use of this diagnostic tool has permitted to standardize the technique and now Helical CT can be used not only as a screening modality for patients that undergo digital aortography, but also as a reliable diagnostic method for surgical planning.     

Role of contrast-enhanced helical CT in the evaluation of acute thoracic aortic injuries after blunt chest trauma

The purpose of this retrospective study was to determine the value of contrast-enhanced helical CT for detecting and managing acute thoracic aortic injury (ATAI). Between June 1995 and February 2000, 1419 consecutive chest CT examinations were performed in the setting of major blunt trauma. The following CT findings were considered indicative of ATAI: intimal flap; pseudoaneurysm; contour irregularity; lumen abnormality; and extravasation of contrast material. On the basis of these direct findings no further diagnostic investigations were performed. Isolated mediastinal hematoma on CT scans was considered an indirect sign of ATAI: In these cases, thoracic aortography was performed even if CT indicated normal aorta. Seventy-seven patients had abnormal CT scans: Among the 23 patients with direct CT signs, acute thoracic aortic injuries was confirmed at thoracotomy in 21. Two false-positive cases were observed. The 54 remaining patients had isolated mediastinal hematoma without aortic injuries at CT and corresponding negative angiograms. The 1342 patients with negative CT scans were included in the 8-month follow-up program and did not show any adverse sequela based on clinical and radiographic criteria. Contrast-enhanced helical CT has a critical role in the exclusion of thoracic aortic injuries in patient with major blunt chest trauma and prevents unnecessary thoracic aortography. Direct CT signs of ATAI do not require further diagnostic investigations to confirm the diagnosis: Isolated aortic bands or contour vessel abnormalities should be first considered as possible artifacts or related to non-traumatic etiologies especially when mediastinal hematoma is absent. In cases of isolated mediastinal hematoma other possible sources of bleeding should be considered before directing patients to thoracic aortography.     

The value of thoracic computed tomography in the detection of recurrent Hodgkin's disease

Fifty chest radiographs and concurrent thoracic computed tomography (CT) scans obtained in a total of 44 patients with 50 separate episodes of suspected recurrent Hodgkin's disease were reviewed. Recurrent disease was present in 18 episodes, involving the mediastinum in 12, the lung parenchyma in five and both mediastinum and lung parenchyma in one. In four episodes, mediastinal recurrence was demonstrated on both the chest radiograph and CT scan. In a further two cases, the chest radiograph appeared normal but CT detected recurrence in the mediastinum. In 20 cases, the mediastinal appearances on chest radiography were suspicious but not diagnostic of recurrence, usually because of previous radiotherapy resulting in residual mediastinal widening. Computed tomography diagnosed recurrent disease which was subsequently proven in seven of these cases. Recurrent disease was suggested by CT in a further case, subsequently shown to be radiation fibrosis. Of the 12 remaining chest radiographs in which the mediastinal assessment was indeterminate, CT was true negative for recurrent disease in 10 cases and was also indeterminate in two. Recurrent disease in the lung parenchyma was demonstrated on the chest radiograph and CT scan on five occasions. There was one incident in which the chest radiograph was normal but CT detected recurrent parenchymal disease. The appearances of the lung parenchyma were indeterminate for recurrent disease on three chest radiographs but CT was helpful in only one case in which radiation change alone was diagnosed. In eight cases the diagnosis of recurrent disease by CT resulted in a decision to initiate treatment. Computed tomography is of value in detecting relapse in patients with suspected recurrent Hodgkin's disease when the chest radiograph is inconclusive, and may enable differentiation of radiation change from recurrent disease in the mediastinum.     

Computed tomographic characteristics of the normal thymus gland: Relationship to mediastinal hematoma

Computed tomography (CT) is frequently used in the screening process to determine the need for angiography in patients with possible blunt thoracic aortic injury. Misinterpretation of normal mediastinal structures (particularly the thymus in patients under age 40 years) as mediastinal hematoma may result in a significant number of false-positive scans. During a 20-month period, we reviewed the chest CT examinations of 1247 patients to select two groups of patients: group I, in whom the mediastinum was normal by CT, and group II, in whom the CT identification of a mediastinal hematoma had been proven surgically. Two major mediastinal CT differences were noted between the groups. The first was a normal cleavage plane between the lateral aspect of the aortic arch and the soft tissue density of the thymus seen in 100% of patients with normal mediastinum (group I) and 0% of patients with known mediastinal hematoma (group II). The second difference relates to the anatomic fact that the thymus is normally present only in the anterior mediastinum. Thus, the presence of a soft tissue density throughout the right paratracheal region of the middle mediastinum, which was seen in 100% of group II (mediastinal hematoma) patients and in 0% of group I (normal) patients, represented blood and not thymus tissue. These results demonstrate fundamental differences in appearance between thymic tissue, regardless of its state of involution, and a mediastinal hematoma on unenhanced mediastinal CT (UMCT). It is important that these differences be recognized so that thymic tissue is not confused with a mediastinal hematoma resulting in unnecessary thoracic aortography. Supported in part by the John S. Dunn Research Foundation.     

Hemiazygous continuation of a left inferior vena cava: Misleading radiographic findings in chest trauma

A widened mediastinum was found on chest radiography following blunt chest trauma. Aortography alone could not adequately determine the etiology of the radiographic findings; on computed tomography (CT) benign mediastinal widening was confirmed owing to accessory hemiazygous continuation of a left inferior vena cava (IVC), with communication to the left brachiocephalic vein through an enlarged left superior (highest) intercostal vein. This unusual anatomic variant and its radiographic finding are reviewed, as well as the complementary role of CT in the evaluation of the traumatized thoracic aorta and mediastinum.     

Trauma of the chest

Trauma to the chest may cause a wide range of injuries including fractures of the thoracic skeleton, contusion or laceration of pulmonary parenchyma, damage to the tracheobronchial tree, diaphragmatic rupture or cardiac contusion. Conditions affecting primarily extrathoracic sites may have indirect effects on the lungs causing adult respiratory distress syndrome or fat embolism. Laceration of the aorta is the typical and likewise most life threatening complication of massive blunt chest trauma necessitating immediate diagnosis and repair.Conventional radiography rather than cross-sectional imaging is the mainstay in diagnosing thoracic trauma. During the critical phase with often concomitant shock, pelvic and spinal injuries tailored radiographic views or even upright chest radiographs are impractical. The severely traumatized patient is usually radiographed in the supine position and suboptimal roentgenograms may have to be accepted for several reasons. It is well documented that many abnormalities detected on CT were not apparent on conventional radiographs, but CT is reserved for hemodynamical stable patients. Nevertheless certain situations like aortic rupture require further evaluation by CT and aortography.The value of conventional radiography, CT, MRI and aortography in chest trauma is reviewed and typical radiographic findings are presented.     

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

The role of CT in the diagnosis of major vascular rupture following blunt decelerating chest trauma is controversial. Its value in excluding major arterial injury has not yet been determined. During a 12-month period we obtained dynamic enhanced thoracic CT studies in 20 patients with blunt decelerating thoracic trauma who had abnormal or equivocal mediastinal contours on chest radiographs. In all cases diagnosis was confirmed by either digital subtraction (18 patients) or conventional thoracic angiography (two patients). CT scans showed evidence of direct aortic injury in three patients and evidence of mediastinal hematoma in five others. Four of these eight patients had major arterial injury verified angiographically and at surgery. In two patients the CT scan was considered equivocal; both patients had normal thoracic angiograms. CT excluded direct vascular injury or mediastinal hematoma in 10 patients. All 10 had normal thoracic angiograms. This preliminary study suggests that, in patients sustaining blunt decelerating thoracic trauma, thoracic CT may be more valuable than chest radiography in excluding major vascular injury and, in some cases, may reduce the need for thoracic angiography.     

Blunt thoracic aortic injury in children

Thoracic aortic injury (TAI) in children secondary to blunt chest trauma is rare and less well documented than TAI in adults. To further establishe the incidence and radiographic manifestations of this severe injury, we reviewed our experimence with TAI in children over an 8-year period. We performed a computer search from the Trauma Registry at our level I trauma center for all cases of TAI among patients 16 years of age or younger who were admitted after sustaining blunt chest trauma between August 1984 and September 1992. We reviewed our records of all thoracic aortograms performed on children for blunt trauma during this same time period. Indication for angiography was determined by review of chest radiographs and medical records of all patients who underwent thoracic aortography. We reviewed medical records and all available chest radiographs, computed tomography (CT) examinations, and thoracic aortograms of children diagnosed with TAI. Of 308 children admitted with blunt chest trauma, 26 (8.4%) underwent angiography to exclude aortic or great vessel injury. Of these 26 patients, three (11.5%) were diagnosed with TAI, and one patient demonstrated a traumatic pseudoaneurysm of the proximal left subclavian artery. The incidence of TAI among children who sustained blunt chest trauma was 1.0% in our series. All three patients with TAI in our series were male, ages 10–12 (mean: 11 years). Chest radiographs on two of the patients with TAI revealed mediastinal widening, ill-defined aortic outline, shift of the trachea and nasogastric tube, and depression of the left main stem bronchus. The chest radiograph in one patient with TAI was technically inadequate. CT demonstrated abnormalities in two patients. Angiographic findings were similar to those seen in adults. TAI in children is rare, occurring in 1% of children sustaining blunt chest trauma in our series. Our findings support previous reports that the plain film, CT, and angiographic findings with this injury resemble those found in adults.     

Identification of tension hemopneumothorax on supine chest radiograph: Value of the visceral pleural line sign

Tension hemopneumothorax is a life-threatening condition produced by either blunt or penetrating chest or thoracoabdominal trauma. The purpose of this study is to describe and illustrate the signs of tension hemopneumothorax on the supine chest radiograph. Review of the initial supine chest radiograph of 11 patients who were thought to have tension hemopneumothorax secondary to major blunt chest trauma constitutes the method of the study. The results of the study indicate that signs of tension hemopneumothorax include the visceral pleural line sign and shift of the mediastinal structures to the opposite side with or without a deep sulcus sign. These observations on the supine chest radiograph were confirmed by erect chest radiography in one patient, axial computed tomography in two patients, and clinically at the time of tube thoracostomy and by postthoracostomy intubation supine chest radiographs in eight patients. We conclude, therefore, that tension hemopneumothorax is recognizable on supine chest radiographs by the visceral pleural line sign and contralateral mediastinal shift with or without a deep sulcus sign, that tension hemopneumothorax is distinguishable from hemopneumothorax, hemothorax, and extrapleural hematoma, and that the radiologic distinction is clinically significant.This study was supported, in part, by the John S. Dunn Foundation.     

Acute posttraumatic rupture of the thoracic aorta: The role of angiography in a 7-year review

Between 1983 and 1989, 15 patients with acute rupture of the thoracic aorta by blunt trauma were seen. Superior mediastinal widening and obscuration of the aortic arch were the most important findings on chest radiograph. Computed tomography examinations in 7 patients showed mediastinal hematomas but did not reveal aortic lesions. Definitive diagnosis of traumatic aortic rupture was established by aortography in all 15 patients. Intraarterial digital substraction angiography proved to be as accurate as conventional film aortography and saved time.     

Diagnostic imaging of mediastinal tumors. Sensitivity and specificity of sonography in comparison with computed tomography and conventional x-ray diagnosis

The purpose of this prospective study was to evaluate the sensitivity of mediastinal sonography compared to CT and chest radiography in the detection of mediastinal tumors. The sonograms, computed tomograms and chest radiographs of 182 patients were interpreted blindly by three observers and the results of all three procedures were compared. The proportion of diagnostic sonographic examinations varied in the different mediastinal compartments from 85% (subcarinal region) to 96% (supra-aortic region). The sensitivities of sonography and chest radiography (using CT as the gold standard) in the imaging of mediastinal tumors for each compartment were as follows: supra-aortic region: 98% and 67%; paratracheal region: 89% and 69%; aorticopulmonary window: 81% and 62%; prevascular region: 92% and 46%; subcarinal region: 69% and 31%; pericardial region: 100% and 67%; posterior mediastinum: 6% and 6%; paravertebral region: 11% and 44%. These results show that sonography is superior to chest radiography for the diagnosis of mediastinal tumors. In certain mediastinal regions (supra-aortic, pericardial, prevascular and paratracheal region), sonography is so sensitive that CT and MR examinations may be avoided in cases with equivocal radiographic findings.     

Mediastinal tumors: sensitivity of detection with sonography compared with CT and radiography

The purpose of this prospective study was to evaluate the sensitivity of mediastinal sonography compared with computed tomography (CT) and chest radiography in the detection of mediastinal tumors. The sonograms, CT scans, and chest radiographs of 182 patients were interpreted blindly by three observers, and the results were compared. The proportion of diagnostic sonographic examinations varied for the different mediastinal compartments from 85% (subcarinal region) to 96% (supraaortic region). The sensitivities of sonography and chest radiography, respectively, for each compartment, with CT as the reference method, were as follows: supraaortic region, 98% and 67%; paratracheal region, 89% and 69%; aorticopulmonary window, 81% and 62%; prevascular region, 92% and 46%; subcarinal region, 69% and 31%; pericardial region, 100% and 67%; posterior mediastinum, 6% and 6%; and paravertebral region, 11% and 44%. These results show that sonography is superior to chest radiography in the diagnosis of mediastinal tumors. In certain mediastinal regions (supraaortic, pericardial, prevascular, and paratracheal), sonography is so sensitive that CT and magnetic resonance examinations may be obviated in patients with equivocal radiographic findings.     

Value of chest radiography in excluding traumatic aortic rupture

A retrospective review of chest radiographs from 205 patients with blunt chest trauma who also underwent aortography was performed. Forty-one of the 205 had aortographically proved aortic rupture. Discriminant analysis of 16 radiographic signs indicated that the most discriminating signs were loss of the aorticopulmonary window, abnormality of the aortic arch, rightward tracheal shift, and widening of the left paraspinal line without associated fracture. No single or combination of radiographic signs demonstrated sufficient sensitivity to indicate all cases of traumatic aortic rupture on plain chest radiographs without the performance of a large number of aortographically negative studies. The bedside anteroposterior "erect" view of the chest proved far more valuable than the supine view in detecting true-negative studies. Despite significant reader variability in the interpretation of the various radiographic signs, in general the analysis confirmed the role of chest radiography in this clinical situation, but suggests that its most beneficial use is in excluding the diagnosis and eliminating unwarranted aortography rather than in predicting aortic rupture.     

Mediastinal imaging in myasthenia gravis: correlation of chest radiography, CT, MR, and surgical findings

Chest radiographs and CT and MR images of the mediastinum were studied in 16 patients with myasthenia gravis who underwent thymectomy (two with a final diagnosis of thymoma, seven with hyperplasia, and seven with a normal thymus). The anterior mediastinum was analyzed on imaging studies for thymic morphology and the presence of mass lesions, and the findings were then correlated with the results of surgical resection and pathologic examination. The chest radiographs detected an anterior mediastinal mass in two patients consistent with thymoma on subsequent CT and MR examinations. Chest radiographs in the other 14 patients were normal. In seven patients with a final diagnosis of thymic hyperplasia, both CT and MR demonstrated normal thymic morphology in five, an enlarged thymus in one, and a small thymus in one that was easily identified on CT but was difficult to define on MR. In the other seven patients with a normal thymus on pathologic examination, both CT and MR showed an involuted thymus in four, a normal thymus in two, and an enlarged thymus in one. While both CT and MR were superior to chest radiography for studying the thymus, CT provided better spatial resolution and thymic definition in a much shorter scanning time than MR did. This study suggests that CT should remain the procedure of choice when further imaging of the thymus is needed after the initial chest radiographs in patients with myasthenia gravis.     

Routine chest radiographs after central line insertion: Mandatory postprocedural evaluation or unnecessary waste of resources?

Purpose: To study the cost and impact on patient management of the routine performance of chest radiographs in patients undergoing imaged-guided central venous catheter insertion. Methods: Six hundred and twenty-one catheters placed in 489 patients over a 42-month period formed the study group. Catheters were placed in the right internal jugular vein (425), left internal jugular vein (133), and subclavian veins (63). At the end of the procedure fluoroscopy was used to assess catheter position and check for complications. A postprocedural chest radiograph was obtained in all patients. Results: Postprocedural chest fluoroscopy showed no evidence of pneumothorax, hemothorax, or mediastinal hematoma. Inappropriate catheter tip position or catheter kinks were noted with 90 catheters. These problems were all corrected while the patient was on the interventional table. Postprocedural chest radiographs showed no complications but proximal catheter tip migration was noted in six of 621 catheters (1%). These latter six catheters required further manipulation. The total technical and related charges for the postprocedural chest radiographs in this series were estimated at ￡15,525. Conclusion: Postprocedural chest radiographs after image-guided central venous catheter insertion are not routinely required. A postprocedural chest radiograph can be performed on a case-by-case basis at the discretion of the interventional radiologist.     

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

OBJECTIVE: The purpose of this study was to show that helical CT could be used at our center in lieu of routine aortography to examine patients who have had serious blunt chest trauma. We also wanted to assess the potential savings of using CT to avoid unnecessary aortography. MATERIALS AND METHODS: The institutional review board approved the parallel imaging-CT immediately followed by aortography-of patients presenting with blunt chest trauma between August 1997 and August 1998. To screen patients for potential aortic injuries, we performed parallel imaging on 142 patients, and these patients comprised our patient population. CT examinations of the patients were reviewed for signs of injury by radiologists who were unaware of each other's interpretations and the aortographic results. Findings of CT examinations were classified as negative, positive, or inconclusive for injury. Aortography was performed immediately after CT. The technical and professional fees for both transcatheter aortography and helical CT were also compared. RESULTS: Our combined kappa value for all CT interpretations was 0.714. The aortographic sensitivity and negative predictive value were both 100%. Likewise, the sensitivity and negative predictive value of CT were 100%. The total costs of performing aortography were estimated at approximately $402,900, whereas those for performing helical CT were estimated at $202,800. CONCLUSION: Helical CT has a sensitivity and negative predictive value equivalent to that of aortography. Using CT to eliminate the possibility of mediastinal hematoma and to evaluate the cause of an abnormal aortic contour in a trauma patient allows us to use aortography more selectively. Avoiding the performance of unnecessary aortography will expedite patient care and reduce costs. We report the results of our experience with CT and how our center successfully made this transition in the initial examination of patients with serious thoracic trauma.