|Year : 2019 | Volume
| Issue : 4 | Page : 1513-1520
Role of multidetector computed tomography imaging in the management of patients with blunt chest trauma
Basma Abdel-Moneim Dessouky1, Shaimaa Abdel-Hamid Hassanein1, Mohammed M Salaheldin Abdelrehim2
1 Department of Radio-diagnosis, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Radio-diagnosis, Ministry of Health, Al-Haram Hospital, Giza, Egypt
|Date of Submission||15-Jan-2019|
|Date of Decision||10-Mar-2019|
|Date of Acceptance||14-Mar-2019|
|Date of Web Publication||31-Dec-2019|
Mohammed M Salaheldin Abdelrehim
Mostafa Mounir Adham Street, Elzahraa, Misr Elkadima, Cairo 11441
Source of Support: None, Conflict of Interest: None
To demonstrate the capabilities of multidetector computed tomography (MDCT), in revealing injuries and guiding management of patients with blunt chest trauma.
MDCT has become a cornerstone tool for evaluating blunt chest trauma owing to quick scanning, identification of concealed injuries, viewing images in many planes, providing three-dimensional images, ability to clarify tracheobronchial or vascular injuries, usage of contrast media, and detection of coexisting nonthoracic injuries.
Patients and methods
This study included 40 patients referred from Emergency Department with blunt chest trauma presented mainly with chest pain and dyspnea. All were subjected to clinical history, general and local examination, chest radiography (CXR), and MDCT studies for diagnostic evaluation and received intravenous water-soluble contrast.
MDCT showed superior sensitivity, detecting more injuries than CXR and detecting other injuries that were totally missed such as sternal, dorsal spinal fractures, lung lacerations, herniation, and trachea-bronchial injuries. CXR sensitivity was low regarding detection of many injuries such as chest wall, pleural, parenchymal, and mediastinal injuries. Accuracy of MDCT was superior to CXR for positive findings providing more details about them with subsequent changes in the management plans.
Our results support that MDCT is the imaging modality of choice for blunt thoracic trauma in hemodynamically stable patients, being more sensitive and accurate, being rapid, showing injuries that are well clarified with contrast media, and enabling postprocessing reformatted images with subsequent more diagnostic findings that would change patient management plan.
Keywords: blunt trauma, chest, computed tomography, patient management, radiographs
|How to cite this article:|
Dessouky BA, Hassanein SA, Salaheldin Abdelrehim MM. Role of multidetector computed tomography imaging in the management of patients with blunt chest trauma. Menoufia Med J 2019;32:1513-20
|How to cite this URL:|
Dessouky BA, Hassanein SA, Salaheldin Abdelrehim MM. Role of multidetector computed tomography imaging in the management of patients with blunt chest trauma. Menoufia Med J [serial online] 2019 [cited 2020 Aug 7];32:1513-20. Available from: http://www.mmj.eg.net/text.asp?2019/32/4/1513/274278
| Introduction|| |
The thorax is the third common site of posttraumatic injury, with high morbidity and mortality rates . Thoracic injuries account for 25% of trauma-related deaths directly  and 50% indirectly . This explains the importance of thoracic trauma imaging and its effect on life saving .
Chest radiography (CXR) is the primary screening tool; however, multidetector computed tomography (MDCT) importance has emerged, with significant more injuries detected in patients with normal initial radiographs, or more extensive injuries discovered compared with initial abnormal radiographs, resulting in change in management plans for many patients .
Technical developments in CT have helped fast scanning, higher accuracy, more sensitivity, and generation of postcontrast and postprocessed reformatted images . All these factors have established CT as a reliable effective modality for imaging patients accurately and rapidly, allowing more time for postdiagnosis care .
This study aims to clarify the role of various capabilities of MDCT in demonstration of blunt chest trauma.
| Patients and Methods|| |
This study was conducted according to the guidelines of ethics committee of Menoufia University and was approved by the institutional review board of the study site. All patients or first-degree relatives of unconscious patients gave written informed consent to be imaged in our study.
This prospective study included 40 patients referred from Emergency Department to Radio-diagnosis Department with blunt chest trauma for radiological workup. There were 31 male and nine female patients. They presented with different clinical complaints such as chest pain and dyspnea, and some of them were unconscious. This study was conducted over a period of 8 months from January 2018 till August 2018.
Patients who had experienced blunt chest trauma, either in isolation or as a part of polytrauma accident, and were hemodynamically stable were included.
Patients in need for emergency transfer to operating theater, those who were hemodynamically unstable, pregnant and lactating women, those with penetrating injuries, those with known contrast allergy, or those with impaired renal functions were excluded.
All patients were subjected to thorough full history taking regarding the injury type and mechanism; general and local clinical examination, with emphasis on main clinical presentation; routine laboratory investigations, with emphasis on kidney functions tests; and radiological workup, including CXR and contrast-enhanced CT for the chest.
CXR for all patients was done in posteroanterior views, or anteroposterior supine views for patients unable to obtain anteroposterior film.
MDCT studies were performed using multidetector 16-row helical CT scanner (Alexion 16 Slice; Toshiba, Irvine, California, USA). Patients were laid supine; head- first, scout projections were made first, followed by scanning from base of the neck down to level of diaphragm in a craniocaudal direction.
Parameters were 120 Kv and 200 mA, field of view was 30 × 25 cm, beam collimation was 16 × 1 mm, gantry rotation time was 0.5 s, and scan time was 5–7 s; thin-section images (1.25-mm slice thickness) were reconstructed to 5-mm thickness with 1-cm reconstruction interval for axial display.
Intravenous contrast included 100 ml of Ultravist 370 (Schering AG, Germany, Wedding, Berlin), at concentration of 350–400 mg/ml and flow rate 3 ml/s, with scanning delay of 25–40 s, administered using bolus tracking software.
Data were transferred to the workstation for processing to generate multiplanar reformatting/multiplanar reformatted (MPR), three-dimensional (3D), and volume rendering/volume rendered (VR) images using original slice thickness with 2.5-mm interval for reconstructing, with axial cuts being the primary step in MDCT assessment.
All MDCT images were carefully revised, and chest injuries were reported as a trauma-related finding and were categorized as either chest wall, pleural, lung, diaphragmatic, or mediastinal structures-related injuries. Each patient had been reviewed for both his/her CXR and MDCT findings.
The data acquired were of the descriptive type and were expressed as numbersand percentage. Quantitative data were also expressed as mean values and SD.
All statistical analyses were carried out using the statistical packages for social science (SPSS), version 18 (IBM Corp., Armonk, New York, USA).
| Results|| |
This study included 40 patients with blunt chest trauma. Males were 31 (77.5%) and females were nine (22.5%), with age range from 12 to 60 years, with a mean ± SD of 40.9 ± 10.96 years. Most patients fall between 31 and 50 years (62.5%). Chest pain and dyspnea were the most common clinical presentation, seen in 26 and 25 patients, respectively.
Most patients (26 patients, 65%) were injured in motor vehicle accidents (either pedestrians or car drivers/passengers), and the remaining were owing to fall from height.
Blunt thoracic injuries were categorized into chest wall, pleural, lung parenchymal, mediastinal, tracheobronchial, and diaphragmatic injuries. We found that more than one injury was detected in the same patient.
Pleural injuries were found on CXR in 15 (37.5%) patients, whereas on MDCT in 34 (85%) patients; lung parenchymal injuries were detected on CXR in 13 (32.5%) patients, whereas on MDCT in 34 (85%) patients; chest wall injuries were found on CXR in 11 (27.5%) patients, whereas on MDCT in 17 (42.5%) patients; mediastinal injuries were detected on CXR in two (5%) patients, whereas on MDCT in six (15%) patients; diaphragmatic injuries were detected on both CXR and MDCT in two (5%) patients; tracheobronchial injuries were not detected on CXR, whereas MDCT detected one (2.5%) patient. These data, which are summarized in [Table 1], showed that CXR was of lower sensitivity compared with MDCT in detecting most of these injuries, except for diaphragmatic injuries.
|Table 1: Numbers and percentage of injured patients with thoracic injuries as detected by chest radiography compared with multidetector computed tomography|
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In chest wall injuries, MDCT detected injuries missed on CXR, such as the nondisplaced sternal fracture, the spinal fracture, and chest wall hematomas.
MDCT had shown increased detection for most of other injuries, for example, in surgical emphysema. MDCT effectively depicts nine missed cases and excludes two false-positive cases [Table 1].
With the use of contrast medium, MDCT confidently excluded any possible subclavian vessel injuries, in upper rib fractures cases, whereas in lower rib fractures, in two of six cases, CT detected hemoperitoneum and assigned that to splenic laceration in one patient [Figure 1] and shuttered kidney in the second.
|Figure 1: Lower rib fractures and splenic injury. (a and b) Three-dimensional images, posterior views for bony thorax show left fractures from sixth down to tenth ribs, and (c) contrast-enhanced CT axial image for upper abdomen shows splenic laceration with perisplenic hemorrhage. CT, computed tomography.|
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3D images for bony thorax exhibit more information than axial and MPR images in rib fractures, providing an image rich in valuable information regarding number, site, any displacements, flail chest, and other nonrib fractures, all in a single image that can be rotated around any chosen axis. It served in similar way for other bony fractures, had detected shoulder girdle rotation in one patient, and excluded sternoclavicular joint dislocation.
MPR images served with axial in excluding possible subclavian vessel injuries (none were found) and with 3D images in assessment of detected sternal fractures (one case with two nondisplaced horizontally oriented fracture, which are hard to detect on axial), and inspection for pericardial and dorsal spine injuries, known to be associated with sternal fractures; such task is hard to achieve on CXR.
Dorsal spinal fracture at D5 was seen on axial, yet detailed information such as type, displacement, associated hematomas, and spinal cord injury was accurately obtained by MPR images 'especially sagittal' and the 3D (our case was burst type, without displacement inside spinal canal, with intact spinal cord).
In pleural injuries, MDCT showed increased detection of injuries [Table 1]. Four cases with pneumothoraxes were missed on CXR. This is clinically important for patients going for intubation for mechanical ventilation or surgeries.
Hounsfield unit (HU) value in MDCT for pleural collections was used to differentiate hemothorax from hydrothorax, especially in small collections; this affected the management, which was to be conservative in hydrothorax, whereas in hemothorax, interventions were made.
In pneumothoraces, axial and MPR images helped evaluating chest tubes' position, where CXR was not accurate. For example, one case had the chest tube tip adjacent to pericardium anteriorly off the midline, whereas in another case, the chest tube ended inside lung parenchyma impending complete re-expansion of the collapsed lung [Figure 2] with subsequent corrective clinical measures.
|Figure 2: Right-side pneumothorax. (a) Chest radiographs shows right pneumothorax; (b) multidetector CT axial image, after insertion of chest tube, seen ending into lung parenchyma surrounded by lung contusions; and (c) volume-rendered posterior aspect shows incomplete re-expansion of right lung. CT, computed tomography.|
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The main role of 3D images was indirect, searching for any bony fracture as a possible cause for hemothorax or pneumothorax.
External VR images were valuable in pleural injuries by demonstrating the exact size of the underlying lung collapse, alerting the medical team to the degree of respiratory compromise, allowing comparison between both lungs or the affected side to the ipsilateral hemithorax, in a single volumetric image.
MDCT in lung parenchymal injuries diagnosed laceration in two cases and a single lung herniation (missed on CXR and considered false negative) [Table 1]. The number of detected cases on CXR was low, with little details provided for parenchymal injuries in general, especially in cases with multiple coexisting thoracic injuries, where some injuries had masked others, with subsequent effect on patient's management.
MDCT detected two pericardial injuries considered false negatives on CXR [Table 1]. Axial images played the main role, aided by MPR images, helping evaluating type, amount, and any possible tamponade effect that could result in heart failure, and efficiently excluded other cardiac injuries. Such information was not possible by CXR.
MDCT did not diagnose any great vessel injuries.
Two (5%) patients with left-sided, diaphragmatic injuries were detected on CXR and MDCT, with intrathoracic herniation of abdominal contents [Figure 3] and [Figure 4]. However MDCT, using axial and VR images showed more details regarding extent of herniation and the degree of underlying lung compression and excluded any complications within the herniated viscus (not seen in this study). In one case, the stomach reached the apex of left hemithorax, whereas in the second, the transverse colon, splenic flexure, and the stomach were seen, with subsequent considerable left lung collapse in both cases.
|Figure 3: Left diaphragmatic tear. (a) Chest radiographs for a polytrauma patient not providing much details about the injury, whereas multidetector CT axial image (b) easily depicted it and showed herniation of the stomach into the left hemithorax and posterior mediastinum, which was confirmed on the volume-rendered image (c). CT, computed tomography|
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|Figure 4: Numbers of injured patients with thoracic injuries as detected on CXR and on MDCT. CXR, chest radiography; MDCT, multidetectors computed tomography.|
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We identified single tracheal wall injury, in which CXR showed only pneumomediastinum. It was basically detected on axial images, with the VR image being lower in value owing to marked pneumomediastinum masking the injury except inferiorly.
In this study, sensitivity of CXR was significantly low compared with MDCT regarding pleural, parenchymal, chest wall, and mediastinal injuries, detecting in only 44, 38, 65, and 33% of the injuries detected by MDCT, respectively, being low in value to predict presence of mediastinal and pleural injuries compared with MDCT.
| Discussion|| |
Thoracic trauma is a significant cause of morbidity, representing the third common cause for trauma-related injuries , with the blunt type being the major contributor (up to 98%) compared with penetrating .
Imaging plays a pivotal role and could change the patients' management plans, with MDCT becoming the imaging modality of choice for trauma assessment, driven by the continuous technical development, allowing accurate diagnosis and better outcome of patients .
This study included 40 patients with blunt chest trauma referred to Radiology Department for CXR and CT scan for the chest.
In this study, there was a statistically significant difference regarding sex, as males represented 31 (77.5%) patients, whereas females were only nine (22.5%) patients, with male to female ratio of 3.4: 1. This results goes with the study by Magus et al. , who reported that more than 80% of their study were males.
Mean age for this study was 40.9 years, with most patients (25 patients, 62.5%) patients falling between 31 and 50 years of age. This was different from the study of Palas et al. , which stated that trauma is the leading cause of death in persons younger than 45 years.
Motor vehicle accidents were the leading cause of injuries, seen in 26 (65%) patients, followed by fall from height. This agrees with Geyer and Linsenmaier , who stated that most blunt thoracic injuries are due to motor vehicle accidents (63–78%), which could be explained by the massive spread of motor vehicles with subsequent increase in risk of related injuries.
Chest pain and dyspnea were the leading clinical presentations that occurred in 26 (65%) and 25 (62.5%) patients, respectively.
Rib fractures were the most common chest wall injuries, seen in 12 (30%) patients, and accounting for 70% of overall fractures. This coincided with the study of Talbot et al. , which referred to rib fractures as common injuries in blunt chest trauma and stated that CT remains the mainstay for accurately diagnosing them, any complications, or other associated thoracic and nonthoracic injuries. Rib fractures can jeopardize lungs as well as vital thoracic or abdominal organs, with significant morbidity and mortality rates, which increased with the increase in the number of fractured ribs. Any discovered other nonrib injuries may change the patient's management plan.
Scapular fractures were not detected in our study. Peters et al.  stated that scapular fractures are relatively uncommon, as the scapula is protected by the surrounding muscles.
A single dorsal vertebral injury was detected on MDCT. This agrees with Palas et al. , who reported spinal fractures to occur in approximately 3% of blunt thoracic trauma, with MDCT being the modality of choice for detection. This appeared clearly in our study, where the fracture was missed on CXR but detected by MDCT. It was T5 injury, which was different from the usual site between T9 and T11 vertebral bodies .
Clavicular fractures seen in two (5%) patients were detected on both CXR and MDCT, which goes with the study by Magus et al.'s , in which clavicular fractures were only 10% and were seen on both CXR and CT studies.
Sternal fractures occurred in a single patient (2.5%), which did not vary a lot from the results of Mirka et al.  (8–10%), adding that they are usually caused by direct impact to the anterior chest wall and are often accompanied by other cardiac or mediastinal injuries, and a nondislocated transverse sternal fracture, 'as in our case,' can be missed on the supine CXR or overlooked at the axial MDCT, which augments the value of sagittal and 3D reformatted images.
Chest wall hematomas were detected in two (5%) patients on MDCT, and were associated with other injuries, mainly rib fractures. This goes with Chung et al. , who stated that all patients with chest wall hematomas had additional injuries, with rib fractures being the most common (81%) among hematoma cases.
The importance of hematomas is that they may be arterial in origin as they are commonly associated with rib fractures that may injure the intercostal, internal mammary, or subclavian arteries , with subsequent complications.
Subcutaneous emphysema were seen in nine (22.5%) patients, and according to Liman et al. , it is essential to identify them and treat the underlying cause, as massive subcutaneous emphysema can cause acute respiratory failure.
In pleural injuries, hemothorax was detected in 15 (37.5%) patients, which goes with Błasińska-Przerwa et al. , who stated that hemothorax is a frequent finding (50% of major trauma victims). In this study, half of the cases were missed on CXR. When hemothorax is due to lung lacerations or mediastinal lesions, it is often massive and protracted and may need interventional measures. MDCT helps in guiding management between selective embolization versus open surgery according to size of the bleeding vessel.
Pneumothorax and fluid-pneumothorax were detected in 20 (50%) patients. This agrees with Sangster et al. , who stated that pneumothorax had been reported in 30–39% in blunt thoracic trauma cases, and that pneumothorax diagnosis is challenging on supine CXR, especially small ones, as air tends to be located anteriorly and at the pleural base. Several studies showed that a large number of pneumothoraces diagnosed by CT were already missed on the initial CXR. In addition, although most pneumothoraces are small, their diagnosis is important because they may enlarge and become symptomatic if the patient undergoes mechanical ventilation or general anesthesia.
In lung parenchymal injuries, lung compression was the common followed by contusions, seen in 21 (52.5%) patients and 14 (35%) patients, respectively. This is different from Morley et al. , who stated that most blunt chest injuries are contusions.
In this study, CXR missed half of contusions. Clinical importance is that massive contusion may lead to adult respiratory distress syndrome and/or pneumonia. MDCT is very sensitive for them and can predict the need for mechanical ventilation.
Lung lacerations were found in two patients on MDCT, which is a little different from Palas et al. , who stated that lung lacerations nowadays are detected frequently. Lacerations most commonly resolve without intervention, but if they persist owing to bleeding or bronchovascular fistulae, surgery is required , hence, the role of MDCT in identifying those findings and guiding patient management accordingly.
The variation between MDCT and CXR in lung parenchymal injuries is attributed to the 2D nature of CXR causing structure overlapping, detecting lung compression by pleural collections, and little details provided by CXR especially with multiple chest injuries.
Pneumomediastinum was diagnosed on MDCT in four (10%) patients, showing higher sensitivity than CXR, which detected in only one (2.5%) patient. Low number of pneumomediastinum detection goes with Chouliaras et al. , who stated that the incidence of pneumomediastinum detection has been described to be 4–10% after blunt thoracic trauma.
Pneumopericardium was seen in only two (5%) patients on MDCT, which agrees with Mirka et al.  as they stated that pneumopericardium can be seen but rarely, and if large, may also result in cardiac tamponade.
Single tracheobronchial injury was diagnosed on MDCT but was missed on CXR. Such scarcity goes with Scaglione et al. , who stated that acute tracheobronchial injuries are rare, and added that 'In our series, chest film proved to be of limited, and it's frequently inconclusive.' MDCT can diagnose 'unsuspected' injuries, leading to early treatment, as 50% of trachea-bronchial related fatalities occur within the first hour.
Diaphragmatic ruptures were seen in two (5%) patients. Fair et al.  stated that blunt traumatic diaphragmatic ruptures are uncommon. They were left sided, which agrees with the Scaglione et al. , who stated that they occur more frequently on the left side in 56–86% of cases.
| Conclusion|| |
Chest radiographs are the primary screening tool for patients with trauma; however, MDCT became the imaging modality of choice owing to advances in technology, various capabilities, wide spread, fast scanning, contrast-enhanced studies, better details, and the ability to generate postprocessed images such as MPR, the 3D, VR, maximum intensity projection, and the unfolded rib images. All these factors had significantly improved diagnostic accuracy for the chest and any other nonthoracic injuries, with subsequent changes in the management plans according to MDCT findings, allowing for proper care, time, and lifesaving.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]