Chest wall, lung, and pleural space trauma

Chest radiographs frequently underestimate the severity and extent of chest trauma and, in some cases, fail to detect the presence of injury. CT is more sensitive than chest radiography in the detection of pulmonary, pleural, and osseous abnormalities in the patient who has chest trauma. With the advent of multidetector CT (MDCT), high-quality multiplanar reformations are obtained easily and add to the diagnostic capabilities of MDCT. This article reviews the radiographic and CT findings of chest wall, pleural, and pulmonary injuries that are seen in the patient who has experienced blunt thoracic trauma.     

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.     

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.     

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.     

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.     

¿Está indicado realizar una tomografía computarizada torácica urgente en el traumatismo leve-moderado?

Mild-moderate blunt chest trauma is defined as a blunt chest trauma that is not caused by a high-energy mechanism, causing thoracic tenderness with or without rib fractures and that has no immediate life-threatening consequences for the patient. It is a frequent clinical situation in the emergency department. The most common radiological techniques that are used in this context are chest X-ray and thoracic computed tomography (CT). The CT scan is set as the gold standard. However, there are no current clinical-radiological guidelines that establish the adequacy of the requests of the CT scan. Therefore, we decided to search for evidence-based recommendations to improve the adequacy of the chest X-ray and CT scan in our daily practice in order to reduce the costs and avoid unnecessary radiation exposure.     

Diaphragmatic rupture due to blunt trauma: sensitivity of plain chest radiographs

Preoperative diagnosis of diaphragmatic rupture caused by blunt injury is often difficult because of serious concurrent injuries, a lack of specific clinical signs, and simultaneous lung disease that may mask or mimic the diagnosis radiologically. Previous reports have suggested that a preoperative diagnosis is established on the basis of chest radiographs in only one third of patients. In order to assess the value of chest radiographs and other imaging techniques in diagnosing traumatic rupture of the diaphragm, we retrospectively reviewed all preoperative diagnostic imaging performed in 50 patients with surgically proved hemidiaphragmatic rupture due to blunt trauma. Chest radiographs were diagnostic in 20 (46%) of 44 patients with left-sided rupture and were considered suspicious enough to warrant further diagnostic studies in an additional eight patients (18%). Five patients with initially normal findings on chest radiographs had diagnostic findings on delayed chest radiographs. Chest radiographs were strongly suggestive in only one (17%) of six patients with right-sided hemidiaphragmatic rupture. CT was diagnostic for diaphragmatic rupture in only one (14%) of seven instances in which it was performed. MR was diagnostic in both patients in whom it was performed. Our experience indicates that chest radiographs obtained at admission and repeated soon after are more valuable in suggesting the diagnosis of traumatic rupture of the diaphragm than previously reported, particularly in the more frequent, left-sided injuries. This increased sensitivity may be due to a greater level of suspicion maintained in a trauma referral center in which this injury is not uncommon.     

Blunt nonaortic chest trauma: radiographic and CT findings

Following initial clinical evaluation and stabilization of a patient who has sustained blunt chest trauma, imaging has an important role in the evaluation of thoracic injuries. The initial study is the chest radiograph. However, chest CT is being used with increased frequency in the evaluation of blunt chest trauma. Although CT is used primarily to assess for traumatic aortic injuries, it is also useful in the evaluation of pulmonary and bronchial, airway, skeletal and diaphragmatic injury. The aim of this article is to review the characteristic imaging findings of pulmonary and bronchial, esophageal, thoracic, skeletal and diaphragmatic injuries. Electronic Publication     

Thoracic CT in detecting occult disease in critically ill patients

Bedside chest radiography is important in the detection of thoracic disease in critically ill patients. Unfortunately these studies are often of poor technical quality and are frequently difficult to interpret. Eighty-seven bedside chest radiographs and concurrent thoracic CT scans obtained in 56 critically ill patients over a 20-month period were interpreted retrospectively and independently. In most cases, the studies were obtained to search for a source of sepsis, fever, or unexplained clinical deterioration. In this series, thoracic CT added significantly more diagnostic information in 61 (70%) of these studies than was available from the corresponding bedside radiographs. Despite the difficulties of transporting critically ill patients for CT and the significant cost, our results suggest that the improved rate of detection of unsuspected thoracic disease justifies the use of CT when bedside radiographic examinations fail to adequately explain the clinical findings.     

Gas in the sternoclavicular joints of patients with blunt chest trauma: significance and frequency of CT findings.

OBJECTIVE: In trauma patients, gas (vacuum phenomenon) in the sternoclavicular joints could represent sequelae of significant distraction forces and thus serve as a potential marker for severe intrathoracic injury. We evaluated the significance and frequency of the finding of gas in the sternoclavicular joints on chest CT of patients with blunt trauma. SUBJECTS AND METHODS: We prospectively studied all chest CT examinations performed at our institution over a 14-week period for the finding of gas in the sternoclavicular joints. Chest CT examinations (n = 267) were performed in 234 patients. We excluded data from follow-up CT examinations (n = 33), limiting our evaluation to the initial CT examination for each patient. Of the study population, 103 patients (83 men and 20 women) who ranged in age from 14 to 79 years (mean, 40 years) had sustained blunt chest trauma. For all trauma patients, we recorded the mechanism of injury and the associated thoracic injuries. RESULTS: CT revealed gas in the sternoclavicular joints in 47 patients (21%). Gas was unilateral in 27 patients and bilateral in 20 patients. Sternoclavicular joint gas was seen in 39 (38%) of the 103 trauma patients but was found in only eight (6%) of the 131 nontrauma patients (p < .0001). In the 39 trauma patients with sternoclavicular joint gas, associated thoracic injuries were seen in 17 patients (44%); either a sternal fracture or a retrosternal hematoma was seen in three patients. Radiographically evident thoracic injury was revealed in 20 (31%) of the 64 trauma patients who had no gas in the sternoclavicular joint; however, 10 of these 20 patients had either a sternal fracture or a mediastinal hematoma. CONCLUSION: Although gas in the sternoclavicular joints is more frequently seen in patients with blunt chest trauma than in patients undergoing chest CT for other indications, this finding does not indicate a greater risk of significant mediastinal or thoracic injury.     

Value of CT in determining the need for angiography when findings of mediastinal hemorrhage on chest radiographs are equivocal

The role of CT in determining the need for angiography in patients with possible thoracic vascular injury resulting from blunt trauma is controversial. During a 24-month period, we prospectively evaluated the results of CT to screen 90 patients with a history of decelerating thoracic trauma for evidence of mediastinal hemorrhage or great vessel abnormality. All patients either had equivocally abnormal mediastinal contours on chest radiographs (64%) or had technically suboptimal chest radiographs owing to body habitus or restriction to the supine projection (36%). Patients with unequivocal signs of mediastinal hemorrhage on chest radiographs underwent immediate arteriography without prior CT. Thoracic CT was interpreted as normal in 63 (77%) patients and no further imaging was performed. Five patients had technically suboptimal CT studies, and CT scans were interpreted as equivocal in six. These 11 patients had normal arteriograms. Sixteen CT scans (18%) demonstrated evidence of mediastinal hemorrhage and/or great vessel contour abnormality. Four (27%) of 15 patients who underwent arteriography had injury to the great vessels. One patient refused to undergo angiography. In 11 patients with CT evidence of mediastinal hemorrhage, major vascular injury was not seen on arteriography. These results suggest a valuable role for CT in determining the need for arteriography to detect potential great vessel injury in patients with blunt decelerating thoracic trauma and equivocally abnormal mediastinal contours on chest radiographs.     

Chest injury in children with blunt abdominal trauma: evaluation with CT

One or more significant chest injuries were identified in 62 of 512 children (12%) examined with computed tomography (CT) after blunt abdominal trauma. Thirty-eight percent of all abnormalities identified on CT scans were underestimated or missed on the initial chest radiograph. Pleural and parenchymal abnormalities were missed in 50% and 34% of initial chest radiographs, respectively. Chest injuries occurred more frequently in children less than 7 years of age than in older children (62% vs 38%, P less than .02). Children with chest injuries tended to be more physiologically unstable than children without, as determined with lower (worse) mean trauma scores (P less than .001). Both the presence and severity of chest injuries strongly affected outcome. Mortality was 1.3% in children with no chest injury, 10.8% in children with significant unilateral chest injury, and 40% in children with significant bilateral or mediastinal chest injury (P less than .0001). Significant unsuspected or underestimated thoracic injuries are relatively common in children, and CT scans of the chest obtained while examinations of the upper abdomen are being performed can be helpful in the early recognition of such injuries.     

Lung parenchymal injury and its frequency in blunt thoracic trauma: the diagnostic value of chest radiography and thoracic CT

PURPOSE: The aims of this study were to determine the value of chest radiography in diagnosing lung parenchymal injury in patients with thoracic trauma, and to evaluate the frequency of lung parenchymal injury by using thoracic computed tomography (CT). MATERIALS AND METHODS: Between January 2005 and June 2006, we retrospectively evaluated the anteroposterior chest radiographs and thoracic CTs of 60 patients that presented to our emergency department and were hospitalized due to multi-organ trauma. RESULTS: Chest radiography revealed parenchymal injury in 32 of the patients, while thoracic CT confirmed parenchymal injury in only 27 of these 32 patients. Chest radiographs did not reveal any parenchymal injury in 28 of the patients, whereas thoracic CT detected parenchymal injury in 12 of these 28 patients. Thoracic CT results were accepted as the gold standard in the evaluation of patients with chest trauma and showed that the sensitivity, specificity, positive predictive value, and negative predictive value of chest radiography in determining parenchymal injury were 69%, 76%, 84%, and 57%, respectively. In addition, thoracic CT revealed that 65% of the patients with blunt thoracic trauma suffered parenchymal injury. CONCLUSION: The sensitivity of anteroposterior chest radiography in identifying lung parenchymal injury was low, with a high false negative rate; therefore, we think that early evaluation with thoracic CT is extremely helpful in the diagnosis and treatment of patients with thoracic trauma, adding to the cooperative work that exists between radiologists and emergency physicians.     

Early detection of thoracic spine fracture in the multiple trauma patient: Role of the initial portable chest radiograph

Early detection of thoracic spine fracture in the often unconscious multiple trauma patient is of utmost importance. Failure to recognize thoracic spine fracture early could result in neurologic injury during certain radiologic and therapeutic procedures that may be indicated for other injuries. In most trauma centers, the initial evaluation of the multiple trauma patient includes a portable chest radiograph, which may show signs of thoracic injury.To determine the value of the initial portable chest radiograph in the detection of thoracic spine fracture, 34 cases of multiple trauma patients with proven thoracic spine fractures were studied. The initial portable chest radiograph was reviewed for signs of thoracic fracture and compared with the findings on plain bone radiographs and computed tomographic scans and with the patient's medical record.Of the 34 cases, radiologic signs of fracture were initially reported in 18 patients (53%). On re-review, positive signs of fracture were seen in 27 patients (79%). The authors conclude that the initial portable chest radiograph in the multiple trauma patient must be carefully studied for subtle signs of thoracic spine fracture. The most frequent chest radiographic findings were paraspinal hematoma, decreased vertebral body height, and lateral translation of vertebral bodies. Apical pleural cap, increased interpediculate distance, increased interspinous distance (empty vertebral body sign), and rib disarticulation were also noted.     

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.     

Computerized tomography in thoracic trauma

Chest CT scans were obtained in 86 patients suffering from serious blunt or penetrating chest trauma. The finding of mediastinal widening was by far the most common CT indication. CT proved to be a more sensitive method for detection of parenchymal lung lesions and occult pneumothorax than bedside radiographs. CT contributed substantially in differentiation of lung abscess and empyema, exclusion of mediastinal pathology and spinal injuries. Aortography is still indicated, even when CT findings are normal if aortic laceration is clinically suspected. Despite all of the technical problems combined with CT examinations in the critically ill patient, we consider CT a valuable diagnostic tool for certain problems in the traumatized patient.     

Imaging of chest trauma: radiological patterns of injury and diagnostic algorithms

In patients after chest trauma, imaging plays a key role for both, the primary diagnostic work-up, and the secondary assessment of potential treatment. Despite its well-known limitations, the anteroposterior chest radiograph remains the starting point of the imaging work-up. Adjunctive imaging with computed tomography, that recently is increasingly often performed on multidetector computed tomography units, adds essential information not readily available on the conventional radiograph. This allows better definition of trauma-associated thoracic injuries not only in acute traumatic aortic injury, but also in pulmonary, tracheobronchial, cardiac, diaphragmal, and thoracic skeletal injuries. This article reviews common radiographic findings in patients after chest trauma, shows typical imaging features resulting from thoracic injury, presents imaging algorithms, and recalls to the reader less common but clinically relevant entities encountered in patients after thoracic trauma.     

Evaluation of the role of chest computed tomography in the management of trauma patients

The role of chest computed tomography (CT) in the management of trauma patients is evolving. The present study reviews the chest radiographic and chest CT findings in a group of trauma patients to determine the clinical impact of findings noted exclusively on chest CT.Fifty-five trauma patients examined with chest radiography and chest CT and whose clinical charts were available for review were retrospectively identified. There were 46 men and 9 women, with a mean age of 39 years. The presence (and size) of pneumothorax, hemothorax, pulmonary contusion, and fractures was tabulated for the chest radiographs and CT scans. The presence of mediastinal widening on chest radiographs and all mediastinal findings on CT were noted. The results of aortography, when applicable, were correlated. The clinical charts were reviewed to assess the impact of CT findings on patient management.Pneumothorax (P<0.05), hemothorax (P<0.05), pulmonary contusions, and fractures were noted more frequently on chest CT than on chest radiography. However, clinical management was affected in only three (5%) of these patients. Chest CT findings related to the mediastinum affected patient management in 13 (24%) patients. CT obviated the need for aortography in 7 of 10 patients with mediastinal widening on chest radiographs. Six other patients had aortography, four for mediastinal hematoma with a normal-appearing aorta on contrast medium-enhanced CT, and two for mediastinal hematoma and aortic injury on CT.Despite detection of significantly more pneumothoraces and hemothoraces on chest CT, clinical management was affected in only a small minority (5%) of cases. CT did prove useful in evaluating the mediastinum, obviating the need for aortography in 7 of 10 patients with a widened mediastinum on chest radiography and accurately diagnosing the presence and site of aortic injury in the two patients with that diagnosis.     

X线平片与CT扫描对胸部外伤的诊断价值

目的分析胸部外伤的X线与CT表现类型并评价其诊断价值。方法回顾性分析60例临床胸部外伤患者的X线平片及CT表现。结果 60例中,皮下气肿见于38例,骨折55例,胸膜伤38例,肺损伤48例,创伤湿肺22例,肺不张9例,纵隔伤15例。伴发其他部位的损伤包括颅脑损伤42例,椎体及附件骨折20例,腹腔积血32例。结论 X线平片及CT扫描在胸部外伤中具有重要的诊断价值,X线平片可作为常规检查及随访的最主要影像技术,而CT对探测或判定胸外伤具有更高的敏感性和特异性,应作为重要补充。     

Thoracic computed tomography in victims of blunt trauma: changes in utilization after the introduction of helical technology

Purpose: In blunt trauma, CT of the thorax is often performed because of the limitations of plain film chest radiography in accurately depicting injuries to the thoracic aorta. The advent of helical CT has allowed the entire chest to be imaged more expeditiously. We will evaluate the extent to which this ability to rapidly obtain additional images of the thorax has increased the utilization of chest CT in blunt trauma. Methods: The radiologic records of all victims of blunt trauma who underwent total body CT (TBCT), which included abdomen, pelvis, and chest images, in the 10 months before and 10 months after our institution acquired helical CT (HCT), were retrospectively evaluated. Results: In the 10 months before we obtained HCT, 520 conventional CT of the abdomen and pelvis were completed, of which only 11 (2.1 %) included images of the full thorax. After HCT was instituted, 684 abdomen and pelvis CT were performed, of which 59 (8.6 %) were ordered with the entire chest. Of the 11 conventional TBCT, 6 (55 %) showed findings in the chest; in 2 of these cases (18 %) the abnormalities were confined exclusively to the thorax. Similarly, of the 59 helical TBCT, 31 (53 %) depicted traumatic abnormalities in the thorax, and in 23 of these cases (39 %) injuries were only within the chest. In 4 of the latter the injuries were mediastinal hematomas, 1 of which (25 %) was confirmed angiographically to represent an aortic laceration. Conclusion: The speed and ease with which additional images can be obtained by HCT has greatly increased utilization of cross-sectional imaging of the thorax after blunt trauma (approximately four-fold). Over half of these depict traumatic injuries.