Multislice CT in thoracic trauma

Hybrid emergency room shows maximum effect on trauma resuscitation when used in patients with higher severity

BACKGROUND

The hybrid emergency room (ER) system is a novel trauma workflow that uses angio-computed tomography equipment in a trauma resuscitation room. Although the hybrid ER system decreases time to start surgery and endovascular treatments and improves mortality, the optimal target benefitting from this system remained unclear. We aimed to identify a subset of trauma patients likely to receive the greatest benefits from the hybrid ER.

METHODS

This retrospective cohort study was conducted in a tertiary hospital in Japan from August 2007 to January 2020. We consecutively included severe adult blunt trauma patients (Injury Severity Score [ISS], ≥16) and divided them into two groups: conventional group (August 2007 to July 2011) and hybrid ER (August 2011 to January 2020) group. We evaluated the association between the hybrid ER group and 28-day mortality using multivariable logistic regression analysis. The 28-day mortality trend during the study period was evaluated with restricted cubic spline analysis. To evaluate heterogeneity of effects within various patient severities, we evaluated whether the patients' ISS modified the effect of the hybrid ER on survival.

RESULTS

Among 1,050 trauma patients, the conventional group comprised 360 patients and the hybrid ER group comprised 690 patients. Injury Severity Score and probability of survival (Ps) were not significantly different between the groups. Twenty-eight-day mortality was significantly lower in the hybrid ER group (Ps-adjusted odds ratio, 0.48; 95% confidence interval, 0.32-0.71; p < 0.001). Restricted cubic spline analysis revealed that Ps-adjusted 28-day mortality sharply decreased approximately 200 days after installation of the hybrid ER. Increase of survival probabilities according to the increase of ISS was significantly improved in hybrid ER group (p = 0.014). Because ISS increased to >25, survival probabilities in the hybrid ER group were higher compared with those in the conventional group.

CONCLUSION

The hybrid ER may improve posttraumatic mortality, especially in patients with higher baseline severity.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Non-aortic vascular findings on chest CT angiogram: including arch vessels and bronchial arteries

CT angiogram (CTA) has become the modality of choice for imaging of thoracic vascular pathologies, involving the aorta and the pulmonary arteries. Apart from showing exquisite details of these large arteries, pathologies and anatomic variants of their branches can also be studied to a great extent. The major branches of aortic arch can be affected by a wide variety of pathologies ranging from atherosclerosis to trauma and vasculitis. Bronchial arteries in spite of supplying only 1% of lung parenchyma can become hypertrophied in various congenital and acquired conditions, becoming an important source of collateral circulation as well as a source for life threatening hemoptysis. CT also plays an important role in diagnosis of vascular compression at the thoracic outlet. With advances in CT technology, the acquisition, interpretation and clinical applications of CT angiography will continue to grow in the years to come.

The Utility of Additional Imaging in Trauma Consults with Mild to Moderate Injury

Limiting CT imaging in the ED has gained interest recently. After initial trauma workup for consultations in the ED, additional CT imaging is frequently ordered. We assessed the benefits of this additional imaging. Our hypothesis was that additional imaging in lower acuity trauma consults results in the diagnosis of new significant injuries with a change in treatment plan and increased Injury Severity Score (ISS). The registry at our Level I trauma center was queried from November 2015 to November 2016 for trauma consults initially evaluated by ED physicians. Patients with mild to moderate injuries were included. Injury findings before and after additional imaging were determined by chart review and pre- and postimaging ISS were calculated. Blinded trauma surgeons assessed the findings for clinical significance and changes in treatment. Four hundred and twenty-one patients were evaluated, 41 were excluded. One hundred and forty patients (37%) underwent additional CT imaging. Forty-seven patients (34%) had additional injuries found, with 16 (12%) increasing their ISS (mean 0.54, SD 1.66). Ninety-three per cent of cases resulted in at least one physician finding the new injuries clinically significant; however, agreement was low (κ = 0.095). For 70 per cent, at least one physician felt the findings warranted a change in treatment plan (κ = 0.405). Additional imaging in ED trauma consults resulted in the identification of new injuries in 1/3 of our patient sample. This suggests that current efforts to limit the use of CT imaging in trauma patients may result in significant injuries going undiscovered and undertreated. Further research is needed to determine the risk of attempts to limit imaging.

Complementary exams in blunt torso trauma. Perform only radiographs and fast: is it safe?

OBJECTIVE

to evaluate effectiveness of using chest X-ray (CXR), pelvis X-ray (RXP) and FAST (Focused Abdominal Sonography on Trauma) to exclude significant lesions of the body in blunt trauma.

METHODS

a prospective study involving 74 patients whom made the three tests (CXR, RXP and FAST) during the initial evaluation between October 2013 and February 2014. The results were compared to the tomography of the same patients or clinical outcome. If the patient did not have alterations on the CT scans or during the observation time, the initial workup was considered safe. All patients were evaluated at the Hospital João XXIII, Belo Horizonte, Brazil.

RESULTS

of the 74 patients studied the average age was 33 years, RTS: 6.98, ECG: 12. From 44 (59.45%) patients with exams (radiographs and FAST) unchanged, three had significant injuries (two splenic injuries and one liver injury) diagnosed by clinical monitoring. The remaining patients - 30 (40.55%) - had at least one alteration in conventional tests. Of these group 27 (90%) had significant injuries and three (10%) minor injuries. The sensitivity of all three tests for screening considerable lesions was 90% and the specificity was 93%. The negative predictive value was 93% and the positive predictive value 89%.

CONCLUSION

this research showed that all the three exams - chest X-ray, pelvis and FAST - are safe to lead with the blunt trauma if well used and associated with clinical examination.

Thoracic computed tomography is an effective screening modality in patients with penetrating injuries to the chest

BACKGROUND

The precise role of thoracic CT in penetrating chest trauma remains to be defined. We hypothesized that thoracic CT effectively screens hemodynamically normal patients with penetrating thoracic trauma to surgery vs. expectant management (NOM).

METHODS

A ten-year review of all penetrating torso cases was retrospectively analyzed from our urban University-based trauma center. We included hemodynamically normal patients (systolic blood pressure ≥90) with penetrating chest injuries that underwent screening thoracic CT. Hemodynamically unstable patients and diaphragmatic injuries were excluded. The sensitivity, specificity, positive predictive value and negative predictive value were calculated.

RESULTS

A total of 212 patients (mean injury severity score=24, Abbreviated Injury Score for Chest=3.9) met inclusion criteria. Of these, 84.3% underwent NOM, 9.1% necessitated abdominal exploration, 6.6% underwent exploration for retained hemothorax/empyema, 6.6% underwent immediate thoracic exploration for significant injuries on chest CT, and 1.0% underwent delayed thoracic exploration for missed injuries. Thoracic CT had a sensitivity of 82%, specificity of 99%, positive predictive value of 90%, a negative predictive value of 99%, and an accuracy of 99% in predicting surgery vs. NOM.

CONCLUSIONS

Thoracic CT has a negative predictive value of 99% in triaging hemodynamically normal patients with penetrating chest trauma. Screening thoracic CT successfully excludes surgery in patients with non-significant radiologic findings.

Delayed Traumatic Diaphragmatic Hernia With Bacterial Pleuritis

Thoraco-abdominal blunt trauma may cause traumatic diaphragmatic hernia. Here, we report a case of delayed traumatic diaphragmatic rupture with herniation of multiple viscera along with bacterial pleuritis without perforation or necrosis. A 72-year-old man presented with severe left-sided chest pain and dyspnea following a fall in the bathroom on the previous day; he had hit the left side and back of the chest against a faucet. Computed tomography (CT) revealed pneumoderma, mediastinal emphysema, pneumothorax, and fractures of the 8th–11th left ribs. We diagnosed traumatic pneumothorax, which was treated by a thoracostomy tube inserted into the pleural space. Approximately 6 months later, he presented again with fever (39.2°C), dyspnea, and coughing. The white blood cell count and C-reactive protein were elevated at 20.3 × 103/μL and 28.7 mg/dL, respectively. A CT scan revealed left-sided pleural effusion and diaphragmatic hernia. Thoracocentesis was performed for the pleural effusion, and bacterial cultivation tests revealed Bacteroides fragilis; therefore, antibiotics were administered for 3 weeks. Subsequently, diaphragmatic hernia repair was performed. Laparotomy via a left subcostal incision revealed a defect measuring 60 × 60 mm; this was repaired with uninterrupted absorbable sutures without using a hernia mesh to avoid infection. The postoperative course was uneventful, and no recurrence was noted at the 1-year follow-up. We repaired delayed traumatic diaphragmatic rupture with herniation of multiple viscera by simple suturing without using a hernia mesh following the treatment of associated bacterial pleuritis.

Massive hemothorax: A rare complication after supraclavicular brachial plexus block

Plexus block is the preferred anesthesia plan for upper limb surgeries. Among the known complications, hematoma formation following the vascular trauma is often occur but this complication is frequently underreported. We present a case where a massive hemothorax developed post operatively in a patient who underwent resection of giant cell tumor of the right hand radius bone followed by arthroplasty under brachial plexus block using supraclavicular approach. This case report attempts to highlight the essence of remaining vigilant postoperatively for first initial days after brachial plexus block, especially after failed or multiple attempts. Ultrasound guided technique in combination with nerve stimulator has proven to be more reliable and safer than traditional techniques.

Intensive care unit imaging

Chest radiography serves a crucial role in imaging of the critically ill. It is essential in ensuring the proper positioning of support and monitoring equipment, and in evaluating for potential complications of this equipment. The radiograph is useful in diagnosing and evaluating the progression of atelectasis, aspiration, pulmonary edema, pneumonia, and pleural fluid collections. Computed tomography can be useful when the clinical and radiologic presentations are discrepant, the patient is not responding to therapy, or in further defining the pattern and distribution of a radiographic abnormality.

Multidetector computer tomography: evaluation of blunt chest trauma in adults

Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall.

Delayed massive hemothorax complicating simple rib fracture associated with diaphragmatic injury

Traumatic hemothorax is potentially life threatening. Rib fractures are the commonest injury after chest trauma, which accounts for 10% of patients after trauma. A delayed massive hemothorax after simple rib fracture is rare. The possibility of delayed sequelae after chest trauma should be considered, and patients should be informed of this possibility. We present a case of this uncommon situation with delayed massive hemothorax caused by simple fracture of the lower ribs. Admission should be considered for close observation when presenting with fracture of the lower ribs because of the possibility of diaphragmatic injury or intra-abdominal injury, even if a simple rib fracture is found initially.

Diaphragmatic hernia mimicking hydropneumothorax: common error in emergency department

Detection of diaphragmatic hernia in the acute setting is problematic and diagnosing diaphragmatic hernia as hydropneumothorax is not an uncommon mistake. We present a series of four such cases diagnosed over a 7-year period, from December 2004 to January 2011 and analyse them for how this mistake can be avoided. In case of all the patients reported by us the initial radiographs were technically compromised because the patient could not be positioned properly. Also they were examined by non-radiologists. We feel that treating surgeons in emergency department tend to overdiagnose pneumothorax as it is a life-threatening condition. We feel that in the appropriate setting suspicion of diaphragmatic hernia should be raised in patients having fractured ribs associated with homogenous opacity, which cannot be differentiated from the diaphragm. Evidence of loculation of hydropneumothorax in the appropriate setting should also raise the possibility of diaphragmatic hernia.

El uso de las imágenes en el trauma de tórax

El  trauma  de  tórax  produce  un  desenlace  fatal  en aproximadamente un 25% de los traumatismos en general. Constituye  la  principal  causa  de  morbilidad  y  mortalidad después  del  trauma  craneoencefálico  y  las  lesiones  de  la médula ósea; puede afectar cualquiera o la totalidad de las estructuras del  tórax, desde los tejidos blandos, la pleura, los pulmones y el diafragma hasta las estructuras mediastinales incluyendo el corazón. Constituye una urgencia médica que requiere de un rápido y oportuno manejo. Su diagnóstico temprano  y  un  adecuado  tratamiento  en  los  servicios  de urgencias  evitarán  una  resolución  fatal  en  la  mayoría  de pacientes  que  ha  sufrido  un  trauma  de  tórax  teniendo  en cuenta que aproximadamente solo de un 10 a 15 % requiere manejo  quirúrgico.  Es  de  vital  importancia  establecer  un diagnóstico, por  lo cual  las  imágenes diagnósticas, entre ellas la  radiografía  convencional  y  la  tomografía  computarizada multidetector juegan un papel fundamental ya que cada vez se están  utilizando  con  mayor  frecuencia  porque  brindan información rápida y precisa en  la variedad de  lesiones de  los pacientes que han sufrido trauma; además las imágenes de tomografía  computada  multiplanar  y  volumétricas proporcionan una mejor visualización de las lesiones con un aumento en la comprensión de estas para así poder ofrecer un tratamiento a  las  lesiones  secundarias a un  trauma de tórax. Por  lo  tanto, el profesional de  la medicina debe  tener un conocimiento claro acerca de la ayuda diagnóstica de mejor elección y de  la  interpretación de  la misma. Para la realización del presente artículo se hizo una búsqueda sistemática de la literatura en relación al trauma de tórax, su epidemiología, fisiopatología,  clasificación  y  los  métodos  de  ayudas diagnósticas por  imagen que se utilizan para su adecuado diagnóstico y manejo. 

Impact of whole-body computed tomography on mortality and surgical management of severe blunt trauma

Introduction

The mortality benefit of whole-body computed tomography (CT) in early trauma management remains controversial and poorly understood. The objective of this study was to assess the impact of whole-body CT compared with selective CT on mortality and management of patients with severe blunt trauma.

Methods

The FIRST (French Intensive care Recorded in Severe Trauma) study is a multicenter cohort study on consecutive patients with severe blunt trauma requiring admission to intensive care units from university hospital trauma centers within the first 72 hours. Initial data were combined to construct a propensity score to receive whole-body CT and selective CT used in multivariable logistic regression models, and to calculate the probability of survival according to the Trauma and Injury Severity Score (TRISS) for 1,950 patients. The main endpoint was 30-day mortality.

Results

In total, 1,696 patients out of 1,950 (87%) were given whole-body CT. The crude 30-day mortality rates were 16% among whole-body CT patients and 22% among selective CT patients (p = 0.02). A significant reduction in the mortality risk was observed among whole-body CT patients whatever the adjustment method (OR = 0.58, 95% CI: 0.34-0.99 after adjustment for baseline characteristics and post-CT treatment). Compared to the TRISS predicted survival, survival significantly improved for whole-body CT patients but not for selective CT patients. The pattern of early surgical and medical procedures significantly differed between the two groups.

Conclusions

Diagnostic whole-body CT was associated with a significant reduction in 30-day mortality among patients with severe blunt trauma. Its use may be a global indicator of better management.

Multidetector-row computed tomography of thoracic trauma

Imaging in trauma patients has dramatically evolved since the advent of computed tomography (CT), particularly multidetector CT (MDCT) technology. Axial MDCT images of the body can be acquired in seconds and shown any plane, allowing immediate viewing and interpreting. These factors make CT an invaluable means to detect many injuries not previously visible by any other noninvasive imaging techniques. Potentially subtle, but significant, thoracic injuries such as pneumothorax, haemothorax, aortic injury, sternal and spinal fractures can be detected on MDCT easily. In this article, the author will discuss the use of MDCT in the diagnosis of various thoracic injuries.

Computed Tomography in the Evaluation of Diaphragmatic Hernia following Blunt Trauma

Diagnosis of traumatic diaphragmatic hernia due to blunt abdominal trauma requires a high index of suspicion. This study was conducted to assess the accuracy of multidetector computed tomogram (MDCT) in the diagnosis of traumatic diaphragmatic hernia. All patients with thoracoabdominal blunt trauma with diaphragmatic hernia diagnosed on radiologic evaluation during a 3-year period (i.e., from June 2004 to June 2007) were analyzed. Nineteen patients with diaphragmatic injuries in 117 patients with blunt thoracoabdominal injury (16.23%) were studied. Age range was 8-60 years (mean 34 years). Male-female ratio was 18:1. Various features seen on CT scan were diaphragmatic discontinuity in 13 (68.42%), thickened diaphragm in 10 (52.63%), "collar sign" in 8 (42.10%), visceral herniation in 12 (63.15%), dependent viscera sign in 8 (42.10%), and segmental nonrecognition of the diaphragm in 1 patient (5.88%). Two patients presented with delayed rupture. In the rest mean duration between time of injury and performance of CT scan was 44.35 h (range 3-288 h). Fourteen patients underwent operative management. Sensitivity, specificity, and accuracy of MDCT scan were 100, 93, and 95%, respectively. Three patients (15.78%) expired. MDCT is a highly accurate modality for detecting traumatic diaphragmatic hernia.

CT imaging of blunt chest trauma

BACKGROUND: Thoracic injury overall is the third most common cause of trauma following injury to the head and extremities. Thoracic trauma has a high morbidity and mortality, accounting for approximately 25% of trauma-related deaths, second only to head trauma. More than 70% of cases of blunt thoracic trauma are due to motor vehicle collisions, with the remainder caused by falls or blows from blunt objects. METHODS: The mechanisms of injury, spectrum of abnormalities and radiological findings encountered in blunt thoracic trauma are categorised into injuries of the pleural space (pneumothorax, hemothorax), the lungs (pulmonary contusion, laceration and herniation), the airways (tracheobronchial lacerations, Macklin effect), the oesophagus, the heart, the aorta, the diaphragm and the chest wall (rib, scapular, sternal fractures and sternoclavicular dislocations). The possible coexistence of multiple types of injury in a single patient is stressed, and therefore systematic exclusion after thorough investigation of all types of injury is warranted. RESULTS: The superiority of CT over chest radiography in diagnosing chest trauma is well documented. Moreover, with the advent of MDCT the imaging time for trauma patients has been significantly reduced to several seconds, allowing more time for appropriate post-diagnosis care. CONCLUSION: High-quality multiplanar and volumetric reformatted CT images greatly improve the detection of injuries and enhance the understanding of mechanisms of trauma-related abnormalities.

Effect of whole-body CT during trauma resuscitation on survival: a retrospective, multicentre study

BACKGROUND

The number of trauma centres using whole-body CT for early assessment of primary trauma is increasing. There is no evidence to suggest that use of whole-body CT has any effect on the outcome of patients with major trauma. We therefore compared the probability of survival in patients with blunt trauma who had whole-body CT during resuscitation with those who had not.

METHODS

In a retrospective, multicentre study, we used the data recorded in the trauma registry of the German Trauma Society to calculate the probability of survival according to the trauma and injury severity score (TRISS), revised injury severity classification (RISC) score, and standardised mortality ratio (SMR, ratio of recorded to expected mortality) for 4621 patients with blunt trauma given whole-body or non-whole-body CT.

FINDINGS

1494 (32%) of 4621 patients were given whole-body CT. Mean age was 42.6 years (SD 20.7), 3364 (73%) were men, and mean injury-severity score was 29.7 (13.0). SMR based on TRISS was 0.745 (95% CI 0.633-0.859) for patients given whole-body CT versus 1.023 (0.909-1.137) for those given non-whole-body CT (p<0.001). SMR based on the RISC score was 0.865 (0.774-0.956) for patients given whole-body CT versus 1.034 (0.959-1.109) for those given non-whole-body CT (p=0.017). The relative reduction in mortality based on TRISS was 25% (14-37) versus 13% (4-23) based on RISC score. Multivariate adjustment for hospital level, year of trauma, and potential centre effects confirmed that whole-body CT is an independent predictor for survival (p </= 0.002). The number needed to scan was 17 based on TRISS and 32 based on RISC calculation.

INTERPRETATION

Integration of whole-body CT into early trauma care significantly increased the probability of survival in patients with polytrauma. Whole-body CT is recommended as a standard diagnostic method during the early resuscitation phase for patients with polytrauma.

FUNDING

None.

The role of chest computed tomography in trauma

Chest computed tomography (CCT) evaluation for trauma encompasses two main objectives: (1) The evaluation of the acutely injured in the search for diagnoses and (2) follow up assessment or diagnosis of pulmonary complications in the hospitalised patient. In the acute phase of evaluation, CCT has become particularly helpful for the diagnosis of blunt thoracic aortic injury (BAI), great vessel injury, extent of lung contusion, occult hemothorax, occult pneumothorax, spinal fractures and spinal cord injuries and to determine the tract of transmediastinal gun shot wounds. In the subacute phase, CCT has gained popularity for diagnosing pulmonary embolism and evaluation of retained hemothorax. Technological advances have lead to better diagnostic capabilities that can be obtained quickly but, particularly in the trauma patient, there is little consistent data supporting an outcome improvement in the majority of patients despite changes in clinical management. Further data is needed to support use of CCT in select trauma patient populations to increase useful diagnostic yield and cost effectiveness.

Postmortem imaging of blunt chest trauma using CT and MRI: comparison with autopsy

OBJECTIVE

Postmortem examination of chest trauma is an important domain in forensic medicine, which is today performed using autopsy. Since the implementation of cross-sectional imaging methods in forensic medicine such as computed tomography (CT) and magnetic resonance imaging (MRI), a number of advantages in comparison with autopsy have been described. Within the scope of validation of cross-sectional radiology in forensic medicine, the comparison of findings of postmortem imaging and autopsy in chest trauma was performed.

METHODS

This retrospective study includes 24 cases with chest trauma that underwent postmortem CT, MRI, and autopsy. Two board-certified radiologists, blind to the autopsy findings, evaluated the radiologic data independently. Each radiologist interpreted postmortem CT and MRI data together for every case. The comparison of the results of the radiologic assessment with the autopsy and a calculation of interobserver discrepancy was performed.

RESULTS

Using combined CT and MRI, between 75% and 100% of the investigated findings, except for hemomediastinum (70%), diaphragmatic ruptures (50%; n=2) and heart injury (38%), were discovered. Although the sensitivity and specificity regarding pneumomediastinum, pneumopericardium, and pericardial effusion were not calculated, as these findings were not mentioned at the autopsy, these findings were clearly seen radiologically. The averaged interobserver concordance was 90%.

CONCLUSION

The sensitivity and specificity of our results demonstrate that postmortem CT and MRI are useful diagnostic methods for assessing chest trauma in forensic medicine as a supplement to autopsy. Further radiologic-pathologic case studies are necessary to define the role of postmortem CT and MRI as a single examination modality.

ICU imaging

Chest radiography serves a crucial role in imaging of the critically ill. Its uses include diagnosis and monitoring of commonly encountered pulmonary parenchymal and pleural space abnormalities. It is also important in evaluating monitoring and support devices and associated complications. CT, another useful imaging modality in select patients, can better characterize pulmonary parenchymal and pleural space disease.

The Increasing Use of Chest Computed Tomography for Trauma: Is it Being Overutilized?

OBJECTIVE

Chest computerized tomography (CCT) has gained popularity in trauma evaluation, but it is expensive, increases exposure to radiation, and leads to findings of debatable clinical significance. The objective of this study was to determine the change in usage of CCT over time and the number of injuries missed on plain chest radiograph (CXR) with normal findings that required therapy.

METHODS

Data on all patients evaluated with a screening CXR during a 7-year period were extracted from a Level I center trauma registry. The incidence of CCT utilization during the duration of the study was identified. Patients who had CCT done after the initial CXR were analyzed separately for the presence of occult injuries. The association of these findings with demographic and injury data were examined.

RESULTS

There were 2,326 CCT performed, and 1,873 (80.5%) of them were after negative CXRs. The percentage of patients studied with CCT increased incrementally from 2.7% to 28.7% for blunt and from 0.4% to 2.9% for penetrating injury. The identification of occult pneumothorax, hemothorax, rib fractures, and lung contusions significantly increased during the study period with the increased frequency of CCT use. There were 102 occult pneumothoraces and/or hemothoraces identified, but only 12 patients underwent tube thoracostomy during the 7-year period. There were 43 patients with blunt aortic injury (BAI) and 6 (13.9%) of these patients had normal CXR findings. There was no trend in increased BAI diagnosed during the study period, although the utilization of CCT was increased.

CONCLUSIONS

There has been a 10-fold increase in use of CCT for trauma evaluation. Although occult findings increased, the number of patients who needed treatment was small. The excess utilization of CCT after negative CXR needs continued refinement to identify the small number of potentially lethal injuries while reducing the number of trivial findings.

Isotropic chest CT examination: diagnostic quality of reformats

AIM

To evaluate the image quality of axial and coronal reformats obtained from isotropic resolution 40-channel chest computed tomography (CT) examinations.

METHODS AND MATERIALS

Thirty consecutive patients with intravenous contrast-enhanced chest CT examinations using a 40-channel CT machine were enrolled for the study. The raw data were reconstructed into two sets of source axial images: 0.9 mm section width and 0.45 mm reconstruction interval (isotropic resolution) and 4mm section width with 3 mm reconstruction interval (anisotropic resolution; group A). The isotropic data set was reformatted into axial and coronal stacks (groups B and C, respectively) with 4 mm section width and 3 mm interval. Three independent readers evaluated stacks A to C using a three-point scale for resolution of right lower lobe segmental bronchi, edge sharpness of major and minor fissures, respiratory motion artefact, reconstruction artefact, noise and overall image quality.

RESULTS

The sharpness of fissures scored significantly higher with the coronal reformats (group C) compared with the axial image sets (groups A and B) (p<0.01). Noise in group A scored significantly lower than groups B or C (p<0.01). For other parameters there was no statistical difference between the groups. There was substantial or excellent agreement between the reviewers.

CONCLUSION

Isotropic imaging of the chest allows creation of reformats with similar image quality as similar thickness axial source images. These reformats are probably of sufficient quality to form the basis of clinical interpretation.

The role of the radiologist in the management of politrauma patients

The management of trauma patients has become a very relevant issue and one of the major challenges in the western countries. In the assessment of politrauma patients, since the last 2 decades, radiological imaging methods have been increasingly used in order to provide a quick and thorough survey of craniocerebral, cervical, abdominal, pelvic and limb traumatic injuries. Among imaging methods, conventional radiographs (CR) have precise but limited indications. In most European hospitals, UltraSonography (US) represents the method of choice for patients referred following blunt abdominal trauma, whereas multislice computed tomography (MSCT) remains a second-line method of investigation, although it provides a fully comprehensive assessment of their injuries and allows for their categorization according to the severity of traumatic injuries. In fact, injury prevalence, radiation dose exposure, and costs represent important considerations in all of the emergency departments, where a growing number of patients seeking medical attention is seen. The radiologist's task is to decide which imaging method is mostly appropriate after initial patient presentation. In the severe politrauma patient, the diagnostic endpoint is to identify the nature and extent of the various injuries in order to execute a more tailored therapeutic approach: this is the patient in whom a total-body MSCT has to be performed in order to provide rapid and accurate information for a correct management. In the large majority of our patients, who do not show the need for a formal hospital admission, after the physical examination has revealed the clinical suspicion of minimal single-organ injury, US provides an adequate assessment of abdominal traumatic injuries and triage those few who are subsequently to be evaluated by means of MSCT. In the majority of this patients category, with low to very-low grade of potential injuries, CR can detect all types of skeletal fractures (except for the skull and the hips). Overall, the role of the emergency radiologist has become of primary importance in the management of trauma patients, and this all the more so since development of interventional radiology affords therapeutic procedures alternative to surgery.

Multi-slice CT angiography for arterial evaluation in the injured lower extremity

BACKGROUND

With the evolution of multi-slice helical computed tomographic angiography (MCTA), the optimal imaging modality for arterial injury in the traumatized lower extremity has been challenged. The objective of this study was to evaluate the ability of MCTA to detect arterial injury in the traumatized lower extremity. Our hypothesis was that MCTA is a sensitive and specific test for the non-invasive evaluation of lower extremity arterial injury.

METHODS

After Institutional Review Board approval, we reviewed all patients at our Level I trauma center who sustained lower extremity trauma and underwent initial evaluation by MCTA over a 3-year period ending in February 2005. MCTA accuracy was tested against a gold standard of operative intervention, duplex ultrasonography, catheter-based angiography, or clinical follow-up.

RESULTS

Sixty-three MCTAs were performed in 59 patients. MCTA was diagnostic in 62 of the 63 scans (98.4%). The mechanism was penetrating in 45.8%. Lower extremity fractures were present in 38.7% of patients studied. There were 22 positive studies. Out of this group, 19 were confirmed at operation and 3 were managed non-operatively. In the 19 injuries confirmed in the operating theater, there were 5 superficial femoral, 2 profunda, 10 popliteal, 1 posterior tibial, and 1 injury to all 3 mid-calf arteries. There were two injuries below the trifurcation managed non-operatively and there was one popliteal occlusion with distal reconstitution that was confirmed by duplex and managed non-operatively because of patient refusal of surgery. Forty studies were negative for arterial injury, with clinical follow up available in 89.5%, for a mean of 48.2 days (range, 5-287 days). No missed injuries were identified during the follow-up period. MCTA was non-diagnostic in 1 patient (1.6%), secondary to artifact from retained missile fragments. MCTA achieved 100% sensitivity and 100% specificity in detecting clinically significant arterial injury.

CONCLUSION

MCTA is a sensitive and specific non-invasive imaging modality for arterial evaluation in the injured lower extremity that may replace catheter-based angiography in most patients.

Visceral Torso Computed Tomography for Clearance of the Thoracolumbar Spine in Trauma: A Review of the Literature

BACKGROUND

Accurate screening of the thoracolumbar spine (TLS) remains problematic in the care of trauma patients. The current standard of care for TLS screening is not clearly defined. In trauma patients undergoing computed tomography (CT) of the chest and or abdomen, compelling supportive evidence for reformatting and reusing this CT data to clear the thoracolumbar spine has accumulated over the last 3 years. The objective of this review was to identify and review all published studies comparing reformatted CT to traditional plain radiography for TLS clearance.

METHODS

A Medline search for all English language articles published on this subject since 1980 identified seven studies. Each was classified according to the levels of evidence classification of the Agency for Health Care Policy and Research. The methodology of each study was reviewed for the CT protocol, utilization of radiologist blinding and whether historical dictated reports or de novo image readings were used for comparison. The sensitivity and specificity of each study and the gold standard utilized in its calculation was noted. Where available, detailed information regarding the missed injuries and their clinical relevance was abstracted for each study.

RESULTS

All evaluated studies demonstrated superior sensitivity and interobserver variability for reformatted CT compared with plain radiographic screening. CT was also more accurate in localizing, classifying, and delineating the age, bony intrusion, and soft-tissue damage associated with the fracture. For studies with time-motion components, a protocol utilizing CT clearance was not only more accurate but faster and more economical. Screening with reformatted visceral CT data required no additional scan time or radiation exposure.

CONCLUSION

The evidence to date demonstrates the superior sensitivity of reformatted visceral CT for detecting thoracolumbar spine injury. With no further patient movement, radiation exposure, cost, or time, trauma patients undergoing visceral CT can have their thoracolumbar spine promptly evaluated. Further prospective evaluation of the CT protocols to optimize visualization of both the viscera and the bone is warranted.

Imaging Evaluation of Pediatric Chest Trauma

Following a discussion of the various imaging manifestations of pediatric chest trauma by anatomic location, the authors discuss their diagnostic approach to the pediatric multitrauma patient with an emphasis on chest imaging.

Three-dimensional imaging of thoracic diseases with multi-detector row CT

The benefits of multi-detector row CT (MDCT) relative to single-detector row helical CT are considerable. Multi-detector row CT allows shorter acquisition times, greater coverage, and superior image resolution. These factors substantially increase the diagnostic accuracy of the examination. Three-dimensional (3D) volume data from MDCT provides various unique applications on thoracic diseases. These includes isotropic viewings, use of multiplanar reformation (MPR), maximum and minimum intensity projections (MIP and minIP), and volume rendering performed from external and internal perspectives allowing the user to "fly around" and "fly through" the structures. Recent advances in 3D volume rendering put real-time, interactive virtual reality guidance of the procedures such as bronchoscopy and surgery into practice.

Multidetector computed tomography imaging of the spine

This article discusses applications of multidetector computed tomography imaging of the spine as they were presented at the "Advances in Multidetector CT" meeting held in Washington, DC, September 13-14, 2003. These include imaging the spine in the setting of trauma, postoperative fusion, chronic pain, radiculopathy, or bony lesions and performing image-guided biopsies.