Radiology: Imaging Trauma Patients in a Deployed Setting

Diagnostic utility of whole-body computed tomography/pan-scan in trauma: a systematic review and meta-analysis study

Trauma is a significant cause of mortality and morbidity. It is crucial to diagnose trauma patients quickly to provide effective treatment interventions in such conditions. Whole-body computed tomography (WBCT)/pan-scan is an imaging technique that enables a faster and more efficient diagnosis for polytrauma patients. The purpose of this systematic review and meta-analysis is to evaluate the efficacy of WBCT in diagnosing injuries in polytrauma patients. We will also assess its impact on the mortality rate and length of hospital stay among trauma centers between patients who underwent WBCT and those who did not (non-WBCT). Twenty-seven studies meeting our inclusion criteria were selected among PubMed, Scopus, Web of Science, and Google Scholar. The criteria were centered on the significance of WBCT/pan-scan application in trauma patients. Stata version 15 was used to perform statistical analysis on the data. The authors have also used I2 statistics to evaluate heterogeneity. Egger and Begg's tests were performed to rule out any publication bias. Total of twenty-seven studies including 68,838 trauma patients with a mean age of 45.0 ± 24.7 years were selected. Motor vehicle collisions were the most common cause of blunt injuries (80.0%). Head, neck, and face injuries were diagnosed in 44% (95% CI, 0.28-0.60; I2 = 99.8%), 6% (95% CI, 0.02-0.09; I2 = 97.2%), and 9% (95% CI, 0.05-0.13; I2 = 97.1%), respectively. Chest injuries were diagnosed by WBCT in 39% (95% CI, 0.28-0.51; I2 = 99.8%), abdominal injuries in 23% (95% CI, 0.03-0.43; I2 = 99.9%) of cases, spinal injuries 19% (95% CI, 0.11-0.27; I2 = 99.4%), extremity injuries 33% (95% CI, 0.23-0.43; I2 = 99.2%), and pelvic injuries 11% (95% CI, 0.04-0.18; I2 = 97.4%). A mortality odd ratio of 0.94 (95% CI, 0.83-1.06; I2 = 40.1%) was calculated while comparing WBCT and non-WBCT groups. This systematic review and meta-analysis provide insight into the possible safety, efficacy, and efficiency of WBCT/pan-scan as a diagnostic tool for trauma patients with serious injuries, regardless of their hemodynamic status. In patients with serious injuries from trauma, whether or not there are indicators of hemodynamic instability, our recommended approach is to, wherever possible, perform a WBCT without stopping the hemostatic resuscitation. By using this technology, the optimal surgical strategy for these patients can be decided upon without causing any delays in their final care or greatly raising their radiation dose.

Limiting Exposure to Scattered Radiation From a CT System Installed in a Two-Sided Deployable ISO-Shelter

INTRODUCTION

Diagnostic radiology in the deployed military environment (in-theater diagnostic radiology) was greatly improved in the early 1990s with the addition of CT systems installed in military-grade one-sided expandable ISO-shelters. These shelters were provided with limited radiation shielding by several flexible lead curtains covering only a small portion of the shelter walls, necessitating placement of deployed CT systems at substantial distances from the field medical facility to limit exposures to personnel from secondary radiation. The newest generation deployable CT system is housed in a two-sided ISO-shelter with radiation shielding applied to the shelter walls. To ensure compliance with military and national standards for protection against ionizing radiation, we developed a simple method to calculate safe distances based on workload, frequencies of the various CT exams performed, and occupancy of controlled and uncontrolled areas.

MATERIALS AND METHODS

Calculation of radiation air kerma rates outside a two-sided CT ISO-shelter was developed using guidance from the National Council on Radiation Protection and Measurements Report No. 147. The simplified formula included measured radiation transmission factors for the ISO-shelter wall and installed shielding, occupancy factors, fraction of all CT exams that covered the chest, abdomen, and/or pelvis, total number of CT exams per week, and shielding design goals for controlled and uncontrolled areas. The formula was modified subsequently to account for whole-body CT exams expected during armed conflict.

RESULTS

Calculated safe distances revealed that the shielded two-sided CT ISO-shelter can be positioned much closer to the surgical shelters of the field medical unit than the previously unshielded one-sided CT ISO-shelter. Tables of safe distances for controlled and uncontrolled areas for the two medical support environments of disaster relief/peacekeeping and combat are provided. For example, for a controlled area at 100% occupancy when 300 CT exams per week are performed and 50% of those exams are of the chest, abdomen, and/or pelvis, the safe distance between the nearest surgical shelter and the shielded CT ISO-shelter is 2.1 m. By comparison, the safe distance for an unshielded CT ISO-shelter is 8.5 m under the same conditions. For lower occupancy factors and lower weekly workload, safe distances from the nearest surgical shelter are often negligible.

CONCLUSIONS

The shielding in the new deployable CT ISO-shelter substantially reduces the distance between it and the surgical shelters of the field medical unit necessary to ensure radiation safety. Safe distances depend on several factors including workload, types and frequencies of CT exams, occupancy factors, and classification of the area around the ISO-shelter, i.e., controlled and uncontrolled.

Robust Multi-View Fracture Detection in the Presence of Other Abnormalities Using HAMIL-Net

INTRODUCTION

Foot and ankle fractures are the most common military health problem. Automated diagnosis can save time and personnel. It is crucial to distinguish fractures not only from normal healthy cases, but also robust against the presence of other orthopedic pathologies. Artificial intelligence (AI) deep learning has been shown to be promising. Previously, we have developed HAMIL-Net to automatically detect orthopedic injuries for upper extremity injuries. In this research, we investigated the performance of HAMIL-Net for detecting foot and ankle fractures in the presence of other abnormalities.

MATERIALS AND METHODS

HAMIL-Net is a novel deep neural network consisting of a hierarchical attention layer followed by a multiple-instance learning layer. The design allowed it to deal with imaging studies with multiple views. We used 148K musculoskeletal imaging studies for 51K Veterans at VA San Diego in the past 20 years to create datasets for this research. We annotated each study by a semi-automated pipeline leveraging radiology reports written by board-certified radiologists and extracting findings with a natural language processing tool and manually validated the annotations.

RESULTS

HAMIL-Net can be trained with study-level, multiple-view examples, and detect foot and ankle fractures with a 0.87 area under the receiver operational curve, but the performance dropped when tested by cases including other abnormalities. By integrating a fracture specialized model with one that detecting a broad range of abnormalities, HAMIL-Net's accuracy of detecting any abnormality improved from 0.53 to 0.77 and F-score from 0.46 to 0.86. We also reported HAMIL-Net's performance under different study types including for young (age 18-35) patients.

CONCLUSIONS

Automated fracture detection is promising but to be deployed in clinical use, presence of other abnormalities must be considered to deliver its full benefit. Our results with HAMIL-Net showed that considering other abnormalities improved fracture detection and allowed for incidental findings of other musculoskeletal abnormalities pertinent or superimposed on fractures.

Lower extremity reconstruction for limb salvage and functional restoration - The Combat experience

Evolution in extremity injury treatment often occurs during major conflicts, with lessons learned applied and translated among military and civilian settings. In recent periods of war, improvements in protective equipment, in-theater damage control resuscitation/surgery, delivery of antibiotics locally/systemically, and rapid evacuation to higher levels of medical care capabilities have greatly improved combat casualty survivability rates. Additionally, widespread application of lower extremity tourniquets also has prevented casualties from exsanguination, thus reducing hemorrhagic-related deaths. Secondary to these, a high number of combat casualties suffering lower extremity traumatic injuries have presented for functional limb reconstruction and restoration as well as residual limb care.

Point-of-Care Tomosynthesis Imaging of the Wrist

INTRODUCTION

Musculoskeletal injury to extremities is a common issue for both stateside and deployed military personnel, as well as the general public. Superposition of anatomy can make diagnosis difficult using standard clinical techniques. There is a need for increased diagnostic accuracy at the point-of-care for military personnel in both training and operational environments, as well as assessment during follow-up treatment to optimize care and expedite return to service. Orthopedic tomosynthesis is rapidly emerging as an alternative to digital radiography (DR), exhibiting an increase in sensitivity for some clinical tasks, including diagnosis and follow-up of fracture and arthritis. Commercially available digital tomosynthesis systems are large complex devices. A compact device for extremity tomosynthesis (TomoE) was previously demonstrated using carbon nanotube X-ray source array technology. The purpose of this study was to prepare and evaluate the prototype device for an Institutional Review Board-approved patient wrist imaging study and provide initial patient imaging results.

MATERIALS AND METHODS

A benchtop device was constructed using a carbon nanotube X-ray source array and a flat panel digital detector. Twenty-one X-ray projection images of cadaveric specimens and human subjects were acquired at incident angles from -20 to +20 degrees in various clinical orientations, with entrance dose calibrated to commercial digital tomosynthesis wrist scans. The projection images were processed with an iterative reconstruction algorithm in 1 mm slices. Reconstruction slice images were evaluated by a radiologist for feature conspicuity and diagnostic accuracy.

RESULTS

The TomoE image quality was found to provide more diagnostic information than DR, with reconstruction slices exhibiting delineation of joint space, visual conspicuity of trabecular bone, bone erosions, fractures, and clear depiction of normal anatomical features. The scan time was 15 seconds and the skin entrance dose was verified to be 0.2 mGy.

CONCLUSIONS

The TomoE device image quality has been evaluated using cadaveric specimens. Dose was calibrated for a patient imaging study. Initial patient images depict a high level of anatomical detail and an increase in diagnostic value compared to DR.

The London Major Trauma Network System: A Literature Review

Trauma is one of the leading causes of death and disability worldwide and is a major global public health problem. The provision of trauma care has been substandard in England and Wales prior to the implementation of an inclusive major trauma network system in London in 2010 and subsequently across the rest of England two years later. The implementation of the London trauma system has brought about improvements to the delivery of trauma care by decreasing the overall morbidity and mortality significantly. This framework encompasses the collaboration of emergency services, designated Major Trauma Centres (MTCs), Trauma Units (TUs) and community providers which have been optimized with the expertise and resources to provide the best outcomes for major trauma patients. Specific triage protocols, consultant-led trauma service and on-the-spot access to radiology services and operating theatres have played a pivotal role in the improvement of trauma care. In spite of several strengths, however, the London major trauma network system is by no means without its limitations. The emergence of the new coronavirus disease 2019 (COVID-19) pandemic has created major barriers to the smooth running of trauma services by exhausting resources due to infection control measures, reduced theatre space and re-deployment of medical staffs. In addition, the cancellation of elective surgeries has impacted directly on the training of surgical trainees by leaving them with significantly reduced surgical exposure. As a results of this ever changing surgical landscape, a need to urgently review these traditional surgical training methods with a view to modernize the curriculum. Although the London trauma system has evolved significantly since its implementation, its limitations should be recognized and addressed to enhance performance and improve patient outcomes.