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.     

Diaphragmatic injuries after blunt trauma: are they still a challenge?

Traumatic diaphragmatic rupture is a life-threatening injury that may occur in patients with blunt trauma. At present, supine chest radiographs is the initial, most commonly performed imaging test to evaluate a traumatic injury of the thorax. However, computed tomography (CT) is the imaging tool of choice, as it is the 'gold standard' for the detection of diaphragmatic injury after trauma. In particular, recent literature indicates that multidetector CT with multiplanar reformations has significantly improved in accuracy. Radiologists working in the emergency room should keep in mind the possibility of diaphragmatic injuries and should routinely integrate the axial images CT with multiplanar reformations in order to detect any potential, subtle or doubtful sign of incomplete diaphragmatic injury.     

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.     

Diagnostic Imaging in pediatric thoracic trauma

Thoracic trauma accounts for approximately 14% of blunt force traumatic deaths, second only to head injuries. Chest trauma can be blunt (90% of cases) or penetrating. In young patients, between 60 and 80% of chest injuries result from blunt trauma, with over half as a consequence of impact with motor vehicles, whereas in adolescents and adults, penetrating trauma has a statistically more prominent role. Pulmonary contusions and rib fractures are the most frequent injuries occurring. Chest X-ray is the first imaging modality of choice to identify patients presenting with life-threatening conditions (i.e., tension pneumothorax, huge hemothorax, and mediastinal hematoma) and those who require a CT examination. Multi-Slice Computed Tomography is the gold standard to evaluate chest injuries. In fact, the high spatial resolution, along with multiplanar reformation and three-dimensional (3D) reconstructions, makes MDCT the ideal imaging method to recognize several chest injuries such as rib fractures, pneumothorax, hemothorax, lung contusions and lacerations, diaphragmatic rupture, and aortic injuries. Nevertheless, when imaging a young patient, one should always keep into account the ALARA concept, to balance an appropriate and low-dose technique with imaging quality and to reduce the amount of ionizing radiation exposure. According to this concept, in the recent years, the current trends in pediatric imaging support the rising use of alternative imaging modalities, such as US and MRI, to decrease radiation exposure and to answer specific clinical questions and during the observation period also. As an example, ultrasound is the first technique of choice for the diagnosis and treatment of pleural and pericardial effusion; its emerging indications include the evaluation of pneumothoraces, costocondral and rib fractures, and even pulmonary contusions.     

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.     

Computed tomography of blunt and penetrating diaphragmatic injury: sensitivity and inter-observer agreement of CT Signs

Diaphragmatic injury is an uncommon but clinically important entity in the setting of trauma. Computed tomography (CT) is widely used to evaluate hemodynamically stable trauma patients. While prior studies have identified CT signs of diaphragm injury in blunt or penetrating trauma, no study has directly compared signs across these two types of injuries. We identified patients with surgically proven diaphragm injuries who underwent CT at presentation. Three reviewers examined each for 12 signs of diaphragm injury, as well as for an overall impression of diaphragm injury. We reviewed a total of 84 patients (37 % blunt trauma, 63 % penetrating). The initial interpreting radiologists discovered 77 % of blunt and 47 % of penetrating injuries (p?=?0.01). We found that the majority of signs of diaphragmatic injury were split between those common in blunt trauma and those common in penetrating trauma, with minimal overlap. The presence of at least one blunt injury sign has 90 % sensitivity for diaphragm injury in blunt trauma; the presence of a wound tract traversing the diaphragm has 92 % sensitivity in penetrating trauma. Inter-observer reliability of these signs is also high (κ?>?0.65). Penetrating diaphragm injuries present a different spectrum of imaging findings from those in blunt trauma and are underdiagnosed at CT; looking for a wound tract traversing the diaphragm is highly sensitive for diaphragm injury in these cases. Signs of organ or diaphragm fragment displacement are sensitive for blunt diaphragm injuries, consistent with these injuries being caused by increased intra-abdominal pressure.     

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.     

The role of MRI in traumatic rupture of the diaphragm. Our experience in three cases and review of the literature

PURPOSE: To evaluate the role and effectiveness of Magnetic Resonance Imaging (MRI) in blunt diaphragmatic injuries by reviewing the literature and our experience in three cases. MATERIALS AND METHODS: We reviewed the medical records and MRI findings of three patients with diaphragmatic injury due to blunt abdominal trauma. All patients were previously examined with chest X-ray and CT and later with MRI at our institution. Coronal and sagittal SE TI-w and fast SE T2-w sequence images were acquired. All patients underwent surgery. RESULTS: MRI showed a 5.5 cm tear in the left hemidiaphragmatic dome with herniation of the stomach and colon into the thoracic cavity in the first case; a 1 cm tear in the diaphragmatic dome with herniation of the stomach and posterior abscess in the second case; and an 8 cm breach in the left diaphragm with visceral herniation in the third case. CONCLUSIONS: The major advantage of MRI lies in its capability of directly acquiring coronal and sagittal images allowing evaluation of the entire diaphragm, both in normal and in pathological conditions. In our experience, MRI showed the exact site and size of the diaphragmatic rupture in all cases. However, this technique cannot be performed in emergency situations or in multitrauma patients. Therefore, in agreement with the literature, helical CT remains the modality of choice in traumatic patients. MR imaging is useful only in doubtful cases and in haemodynamically stable patients.     

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.     

Imaging of blunt pediatric thoracic trauma

The imaging evaluation of thoracic trauma is a central feature of the acute assessment and management of injured children. A reliable early clinical diagnosis of chest injury often is difficult. Cardiopulmonary symptoms may not be present in the first 24 hours, and there is no consistent relationship between external chest wall injury and underlying abnormalities. This is particularly evident in children, in whom increased compliance of the bony thorax allows major internal injury to occur without associated skeletal injury. Additionally, unlike the examination of injuries to the head and abdomen, which are often evaluated with computed tomography in the initial posttraumatic period, chest radiography remains the primary method for evaluation of chest injuries, although it may not demonstrate or may underestimate many abnormalities. This essay reviews the imaging appearance of common and uncommon thoracic injury in children.     

Imaging hemidiaphragmatic injury

The supine chest radiograph is the initial and most commonly performed imaging study to evaluate the thorax after trauma. Whenever the chest radiograph is equivocal or suspicious for acute diaphragmatic injury (DI), computed tomography (CT) is usually the next study of choice since it is both generally available and often used to examine other body regions in the patient after trauma. CT is usually diagnostic, particularly if supplemented by multiplanar reformation (MPR) obtained using thin-slice axial scanning and overlapping images for reformations. Magnetic resonance imaging (MRI) is potentially useful to assess the diaphragm if CT findings are indeterminate and the patient is stable enough to have the procedure. Simple T1-weighted spin-echo images in the sagittal and coronal orientation are usually sufficient to establish or exclude DI. This article reviews imaging modalities and strategies for diagnosing DI from blunt trauma.     

Acute tracheobronchial injuries: Impact of imaging on diagnosis and management implications

PURPOSE: To evaluate the role of chest radiography, single-slice CT and 16-row MDCT in the direct evidence of tracheobronchial injuries. METHODS: Patients with acute tracheobronchial injury were identified from the registry of our level 1 trauma center during a 5-year period ending July 2005. Findings at chest radiograph and CT were compared to those shown at bronchoscopy. RESULTS: Eighteen patients with tracheobronchial injury - three patients with cervical trachea injury, eight with thoracic trachea injury and seven with bronchial injury - were identified. Twelve patients had a blunt trauma (67%), six patients had a penetrating (iatrogenic) injury (33%). Chest radiograph directly identified the site of tracheal injury in four cases, showing overdistension of the endotracheal cuff in three cases and displacement of the endotracheal tube in one case. At the level of the bronchi, chest radiograph demonstrated only one injury. CT directly identified the site of tracheal injury in all the cases showing the overdistension of the endotracheal cuff at the level of the thoracic trachea (three cases), posterior herniation of the endotracheal cuff at the thoracic trachea (three cases), lateral endotracheal cuff herniation at the thoracic trachea (one case), tracheal wall discontinuity at the cervical (one case) and at the thoracic trachea (one case) and displacement of endotracheal tube at the cervical trachea (two cases). At the level of the bronchi, CT correctly showed the site of injury in six case including: discontinuity of the left main bronchial wall (two cases), the "fallen lung" sign (one case), right main bronchial wall enlargement (one case), discontinuity of the right middle bronchial wall (two cases). In one case, CT showed just direct "air leak" at the level of the carina suggesting main bronchus injury. This finding was confirmed by bronchoscopy. CONCLUSION: Chest radiograph was helpful for the assessment of iatrogenic tracheal injuries. CT detected the site of blunt tracheobronchial injuries in 94% of the cases. Multiplanar 16-row MDCT reconstructions, were essential for the optimal surgical approach.     

X-ray computed tomography of thoracic injuries. Apropos of 40 cases]

On chest radiographs, the precise assessment of thoracic injuries consecutive to blunt trauma is often compromised by the nonspecific appearance of many lesions. Furthermore, significant injuries are frequently overlooked. However, the management of the patients with chest trauma is still often based primarily upon clinical and radiographic findings and Computed Tomography (CT) is often performed secondarily on the basis of unexplained clinical signs or suspected radiographic abnormality. Some authors have reported that CT was a highly sensitive method for detecting thoracic lesions frequently not seen or underestimated on conventional supine chest radiographs. However, the value that these new CT findings could have in the therapeutic management of these patients, have not been systematically investigated to our knowledge, except in a limited series suggesting that the course of critically ill patients could be substantially altered after thoracic CT. In order to estimate the role of early CT in the management of patient care, we report the therapeutic consequences of CT findings in forty patients who we report the therapeutic consequences of CT findings in forty patients who had a thoracic CT within few hours following a chest injury. We showed that early thoracic CT scan in patients with blunt trauma detected significantly more lesions than did chest X-Ray and appreciably modified the treatment modalities in 70% of our patients. We then recommend that all the patients admitted in ICU after chest trauma undergo a thoracic CT scan as soon as possible in order to optimize their treatment modalities.     

Multidetector computed tomography and blunt thoracoabdominal trauma

Computed tomography has had an increasing role in the evaluation of patients after blunt trauma. Important findings in thoracic trauma include acute traumatic aortic injury, pneumothorax, hemothorax, pulmonary contusions and lacerations, mediastinal hematoma, and diaphragmatic rupture. The solid abdominal viscera may lacerate; infarct; or suffer vascular, ductal, or pyelocalyceal disruption. The bladder and intestines may rupture. In abdominal pelvic trauma, the direction of applied force often results in an identifiable constellation of injuries. This article reviews how multidetector computed tomography (MDCT) is used in the trauma patient. Technical advances of increased cephalocaudad coverage speed and improved z-axis resolution intrinsic to MDCT, together with effective contrast utilization, make MDCT invaluable in the setting of trauma.     

Coronal thick CT reconstruction: an alternative for initial chest radiography in trauma patients

It has been proposed that the imaging workup of trauma patients be accelerated by omitting the initial chest radiography (CR) and directly performing a computed tomography (CT); however, the baseline CR is then lacking. The purpose of this study was to assess if coronal thick reconstructions generated from chest CT could present an adequate alternative for CR. Sixty trauma patients underwent bedside CR and multidetector row chest CT in the emergency room. The image quality of thoracic anatomical structures, the diagnostic accuracy for chest pathology, and the depiction of indwelling devices were assessed on both modalities. Main pulmonary arteries and perihilar bronchi were equally visualized with both modalities. Central bronchi, retrocardial lung parenchyma, diaphragm, descending aorta, and vertebral pedicles were better visualized on thick CT reconstructions, whereas peripheral lung vessels were better depicted on CR (p<0.05). The accuracy to delineate various pathological findings did not differ between both modalities, except for a higher sensitivity to diagnose bronchial cuffing on CR (p<0.05). The location of indwelling devices was similarly and correctly depicted with both modalities. Coronal thick CT reconstructions provide a similar image quality and diagnostic accuracy compared with CR. These reconstructions may serve as an equivalent baseline image in trauma patients in whom emergency radiological evaluation has to be accelerated.     

Endovascular Repair of Traumatic Rupture of the Thoracic Aorta: Single-Center Experience

Purpose Traumatic rupture of the thoracic aorta secondary to blunt chest trauma is a life-threatening emergency and a common cause of death, usually following violent collisions. The objective of this retrospective report was to evaluate the efficacy of endovascular treatment of thoracic aortic disruptions with a single commercially available stent-graft. Methods Nine men (mean age 29.5 years) were admitted to our institution between January 2003 and January 2006 due to blunt aortic trauma following violent motor vehicle collisions. Plain chest radiography, spiral computed tomography, aortography, and transesophageal echocardiography were used for diagnostic purposes in all cases. All patients were diagnosed with contained extramural thoracic aortic hematomas, secondary to aortic disruption. One patient was also diagnosed with a traumatic thoracic aortic dissection, secondary to blunt trauma. All subjects were poor surgical candidates, due to major injuries such as multiple bone fractures, abdominal hematomas, and pulmonary contusions. All repairs were performed using the EndoFit (LeMaitre Vascular) stent-graft. Results Complete exclusion of the traumatic aortic disruption and pseudoaneurysm was achieved and verified at intraoperative arteriography and on CT scans, within 10 days of the repair in all patients. In 1 case the deployment of a second cuff was necessary due to a secondary endoleak. In 2 cases the left subclavian artery was occluded to achieve adequate graft fixation. No procedure-related deaths have occurred and no cardiac or peripheral vascular complications were observed within the 12 months (range 8–16 months) follow-up. Conclusions This is the first time the EndoFit graft has been utilized in the treatment of thoracic aortic disruptions secondary to chest trauma. The repair of such pathologies is technically feasible and early follow-up results are promising.     

Helical CT of diaphragmatic rupture caused by blunt trauma

OBJECTIVE: The purpose of this study was to determine the diagnostic sensitivity and specificity of helical CT with sagittal and coronal reformatted images in detecting diaphragmatic rupture after blunt trauma. MATERIALS AND METHODS: Chest and abdominal helical CT scans obtained in 41 patients with suspected diaphragmatic injury after major blunt trauma were reviewed by three observers who were unaware of surgical findings. Coronal and sagittal reformatted images were reviewed for each patient as well. Findings consistent with diaphragmatic injury, such as waistlike constriction of abdominal viscera (i.e., the "collar sign"), intrathoracic herniation of abdominal contents, and diaphragmatic discontinuity were recorded. Sensitivity and specificity of helical CT were calculated on the basis of surgical findings and clinical follow-up. RESULTS: Helical CT was performed preoperatively in 23 patients with diaphragmatic rupture (left, n = 17; right, n = 5; bilateral, n = 1). An additional 18 patients underwent helical CT to further evaluate suspicious findings seen on chest radiography at admission and were found to have an intact diaphragm. Sensitivity for detecting left-sided diaphragmatic rupture was 78% and specificity was 100%. Sensitivity for the detection of right-sided diaphragmatic rupture was 50% and specificity was 100%. The most common CT finding of diaphragmatic rupture was the collar sign, identified in 15 patients (sensitivity, 63%; specificity, 100%). Diaphragmatic discontinuity was seen in four patients. CONCLUSION: Helical CT, especially with the aid of reformatted images, is useful in the diagnosis of acute diaphragmatic rupture after blunt trauma. Helical CT can be used to detect 78% of left-sided and 50% of right-sided injuries.     

CT features of blunt abdominal aortic injury

Abdominal aortic injuries are uncommon following blunt trauma, with relatively few reported series in the radiology literature. This study was conducted to identify common locations and imaging features of blunt traumatic abdominal aortic injury, the presence of associated visceral and osseous injuries, and the mechanisms of trauma. A retrospective review of 9,213 trauma registry entries over a 7-year period yielded 103 patients with aortic injuries, 12 of which had direct signs of abdominal segment involvement (dissection flap, focal intimal injury, intramural hematoma, active extravasation of contrast, or pseudoaneurysm formation). The majority (75 %) was isolated to the abdomen-67 % of which was infrarenal, 33 % suprarenal-while the other 25 % was a contiguous extension from a thoracic injury. Abdominal aortic injuries were uncommonly seen in isolation: all but one patient (92 %) demonstrated either retroperitoneal blood or stranding, hemoperitoneum, and/or CT signs of hypoperfusion complex, and only one patient (8 %) had no associated solid organ or skeletal injuries. All patients had a mechanism of injury which involved direct trauma to the abdomen, most commonly a motor vehicle collision. Similar to other recent series, there was an increased rate of abdominal segment injury (11.7 % of all aortic injuries) in this series compared to more remote autopsy series. This difference is likely due to detection of injuries which went undiagnosed before the widespread use of multidetector CT, which has become the standard of care for both acute evaluation following blunt trauma and for follow-up.     

Periaortic hematoma at diaphragmatic crura at helical CT: sign of blunt aortic injury in patients with mediastinal hematoma

PURPOSE: To evaluate periaortic hematoma (PH) near the level of the diaphragm at abdominal computed tomography (CT) as an indirect sign of acute traumatic aortic injury after blunt trauma in patients with mediastinal hematoma. MATERIALS AND METHODS: From 1998 to 2001, 97 patients with CT evidence of mediastinal hematoma after blunt thoracic trauma were retrospectively identified at two level 1 trauma centers. The presence or absence of PH near the level of the diaphragmatic crura was retrospectively established by a blinded reviewer at each institution. Aortic injury status was determined by reviewing angiographic, surgical, and clinical records. Sensitivity, specificity, positive and negative productive values, and positive and negative likelihood ratios were calculated. RESULTS: Among the 97 patients with mediastinal hematoma, 14 had both PH near the level of the diaphragm and aortic injury; six had aortic injuries without PH, five had PH near the level of the diaphragm without aortic injury, and 72 had no evidence of PH near the diaphragm and no aortic injury. Sensitivity for PH near the level of the diaphragm as a sign of aortic injury was 70%; specificity, 94%; positive predictive value, 74%; and negative predictive value, 92%. The positive likelihood ratio for the presence of aortic injury was 10.8, and the negative likelihood ratio was 0.3. CONCLUSION: PH near the level of the diaphragmatic crura is an insensitive but relatively specific sign for aortic injury after blunt trauma. The presence of this sign at abdominal CT should prompt imaging of the thoracic aorta to evaluate potential thoracic aortic injury.