Cumulative strain-based metrics for predicting subconcussive head impact exposure-related imaging changes in a cohort of American youth football players.

OBJECTIVE: Youth football athletes are exposed to repetitive subconcussive head impacts during normal participation in the sport, and there is increasing concern about the long-term effects of these impacts. The objective of the current study was to determine if strain-based cumulative exposure measures are superior to kinematic-based exposure measures for predicting imaging changes in the brain. METHODS: This prospective, longitudinal cohort study was conducted from 2012 to 2017 and assessed youth, male football athletes. Kinematic data were collected at all practices and games from enrolled athletes participating in local youth football organizations in Winston-Salem, North Carolina, and were used to calculate multiple risk-weighted cumulative exposure (RWE) kinematic metrics and 36 strain-based exposure metrics. Pre- and postseason imaging was performed at Wake Forest School of Medicine, and diffusion tensor imaging (DTI) measures, including fractional anisotropy (FA), and its components (CL, CP, and CS), and mean diffusivity (MD), were investigated. Included participants were youth football players ranging in age from 9 to 13 years. Exclusion criteria included any history of previous neurological illness, psychiatric illness, brain tumor, concussion within the past 6 months, and/or contraindication to MRI. RESULTS: A total of 95 male athletes (mean age 11.9 years [SD 1.0 years]) participated between 2012 and 2017, with some participating for multiple seasons, resulting in 116 unique athlete-seasons. Regression analysis revealed statistically significant linear relationships between the FA, linear coefficient (CL), and spherical coefficient (CS) and all strain exposure measures, and well as the planar coefficient (CP) and 8 strain measures. For the kinematic exposure measures, there were statistically significant relationships between FA and RWE linear (RWEL) and RWE combined probability (RWECP) as well as CS and RWEL. According to area under the receiver operating characteristic (ROC) curve (AUC) analysis, the best-performing metrics were all strain measures, and included metrics based on tensile, compressive, and shear strain. CONCLUSIONS: Using ROC curves and AUC analysis, all exposure metrics were ranked in order of performance, and the results demonstrated that all the strain-based metrics performed better than any of the kinematic metrics, indicating that strain-based metrics are better discriminators of imaging changes than kinematic-based measures. Studies relating the biomechanics of head impacts with brain imaging and cognitive function may allow equipment designers, care providers, and organizations to prevent, identify, and treat injuries in order to make football a safer activity.

Nationwide Procedural Trends for Renal Trauma Management.

OBJECTIVE: To characterize national trends in procedural management of renal trauma. BACKGROUND: Management of renal trauma has evolved to favor a more conservative approach. For patients requiring intervention, there is a paucity of information to characterize the nature of procedural therapy administered. METHODS: A retrospective cross-sectional analysis was performed using data contained within the National Trauma Data Bank. The National Trauma Data Bank is a voluntary data repository managed by the American College of Surgeons, containing data regarding trauma admissions at 747 level I to V trauma centers throughout the United States and Canada. Participants included any patient with renal trauma requiring intervention from 2002 to 2012. They were identified according to International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes, with codes 866.00 through 866.03 for blunt renal trauma, and codes 866.10 through 866.13 for penetrating trauma. Cases were separated into those requiring nephrectomy, renorrhaphy, or endovascular repair based on ICD-9 procedure code. The number of cases performed each year and yearly trends as measured by linear regression. RESULTS: A total of 4296 cases were reported during the study period. Of these cases, 2635 involved blunt trauma and 1661 involved penetrating injury. There was a significant increase in the percentage of cases managed by endovascular means for both blunt and penetrating trauma (R = 0.92, P < 0.01; and R = 0.86, P < 0.01, respectively). This was primarily at the expense of nephrectomy, with cases showing significant decline in both groups. CONCLUSIONS: National trends for procedural management of renal trauma are toward less invasive interventions. These trends suggest favorable change towards renal preservation and decreased morbidity, potentially facilitated, in part, by improved radiographic staging and endovascular techniques, and also increased provider awareness of the safety and value of conservative management.

Post-Irradiation Treatment with a Superoxide Dismutase Mimic, MnTnHex-2-PyP5+, Mitigates Radiation Injury in the Lungs of Non-Human Primates after Whole-Thorax Exposure to Ionizing Radiation.

Radiation injury to the lung is the result of acute and chronic free radical formation, and there are currently few effective means of mitigating such injury. Studies in rodents indicate that superoxide dismutase mimetics may be effective in this regard; however, studies in humans or large animals are lacking. We hypothesized that post-exposure treatment with the lipophilic mitochondrial superoxide dismutase mimetic, MnTnHex-2-PyP5+ (hexyl), would reduce radiation-induced pneumonitis and fibrosis in the lungs of nonhuman primates. Rhesus monkeys (Macaca mulatta) received 10 Gy whole thorax irradiation, 10 Gy + hexyl treatment, sham irradiation, or sham irradiation + hexyl. Hexyl was given twice daily, subcutaneously, at 0.05 mg/kg, for 2 months. Animals were monitored daily, and respiratory rates, pulse oximetry, hematology and serum chemistry panels were performed weekly. Computed tomography scans were performed at 0, 2, and 4 months after irradiation. Supportive fluid therapy, corticosteroids, analgesics, and antibiotics were given as needed. All animals were humanely euthanized 4.5 months after irradiation, and pathologic assessments were made. Multifocal, progressive lung lesions were seen at 2 and 4 months in both irradiated groups. Hexyl treatment delayed the onset of radiation-induced lung lesions, reduced elevations of respiratory rate, and reduced pathologic increases in lung weight. No adverse effects of hexyl treatment were found. These results demonstrate (1) development of a nonhuman primate model of radiation-induced lung injury, (2) a significant mitigating effect of hexyl treatment on lung pathology in this model, and (3) no evidence for toxicity of hexyl at the dose studied.

Disability risk in pediatric motor vehicle crash occupants.

BACKGROUND: Mortality rates among children in motor vehicle crashes (MVCs) are typically low; however, nonfatal injuries can vary in severity by imposing differing levels of short- and long-term disability. To better discriminate the severity of nonfatal MVC injuries, a pediatric-specific disability risk (DR) metric was created. METHODS: The National Automotive Sampling System 2000 to 2011 was used to define the top 95% most common Abbreviated Injury Scale (AIS) 2+ injuries among pediatric MVC occupants. Functional Independence Measure scores were abstracted from the National Trauma Data Bank 2002 to 2006. Multiple imputation was used to account for missing data. The DR and coinjury-adjusted DR (DRMAIS) of the most common AIS 2+ MVC-induced injuries were calculated for 7-year-old to 18-year-old children by determining the proportion of those disabled after an injury to those sustaining the injury. DR and DRMAIS values ranged from 0 to 1, representing 0% to 100% DR. RESULTS: The mean DR and DRMAIS of all injuries were 0.290 and 0.191, respectively. DR and DRMAIS were greatest for injuries to the head (DR, 0.340; DRMAIS, 0.279), thorax (DR, 0.320; DRMAIS, 0.233), and spine (DR, 0.315; DRMAIS, 0.200). The mean DR and DRMAIS increased with increasing AIS severity but there was significant variation and overlapping values across AIS severity levels. Comparison of DRMAIS to coinjury-adjusted mortality risk (MRMAIS) revealed that among 118 injuries with MRMAIS of 0.000, DRMAIS ranged from 0.000 to 0.429. CONCLUSION: Incorporation of DR metrics into injury severity metrics may improve the ability to distinguish between the severity of different nonfatal injuries. This is especially crucial in the pediatric population where permanent disability can result in a high number of years lost due to disability. The accuracy of such severity metrics is crucial to the success of pediatric triage algorithms such as Advanced Automatic Crash Notification algorithms. LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level III.

Thoracoabdominal organ volumes for small women.

OBJECTIVE: Thoracoabdominal injuries commonly occur as a result of motor vehicle crashes. In order to design occupant protection systems that reduce risk of injury, researchers are using a variety of tools, including computational human body models. Though research has been conducted to provide morphological and volumetric data for the thoracoabdominal cavity of the average male, there is currently an interest in developing models for a wider range of occupants. One particular cohort of interest is the small female by stature and weight because of their use in restraint system development. Geometric data on thoracoabdominal organs are needed to construct accurate representations of female occupants. This study aimed to gather information on organ volumes from clinical medical imaging studies of small females. METHODS: Anonymized clinical computed tomography (CT) and magnetic resonance images were used to segment organs relevant to crash-induced injuries: namely, the liver, spleen, left kidney, right kidney, pancreas, gallbladder, lungs, and heart. Segmentations were conducted using semi-automatic techniques. Additionally, diametric measurements of the vena cava, aorta, trachea, and colon were obtained from the medical images at discrete locations using linear measurement tools. RESULTS: A total of 14 adult scans were selected with stature and weight ranges of 145.0 to 162.6 cm and 43.7 to 65.5 kg, respectively. The following are the average thoracoabdominal organ volumes: liver (1,224.5 ± 220.7 mL), spleen (151.6 ± 42.1 mL), left kidney (123.7 ± 20.1 mL), right kidney (115.4 ± 20.9 mL), heart (417.8 ± 36.6 mL), pancreas (54.1 ± 11.8 mL), and gallbladder (20.6 ± 13.4 mL). The average diameters were 19.7 ± 3.2 mm and 17.7 ± 5.1 mm for the vena cava and aorta, respectively. The colon had an average diameter of 37.9 ± 7.1 mm. CONCLUSION: Data characterizing the small female are important to validate the geometries used in computational models, including models derived from scaling techniques and those developed using subject-specific medical imaging. The goal of this study was to use a sample of subjects anthropometrically representative of small females to evaluate the average volume for organs commonly injured in motor vehicle crashes. Based on these data, the right and left lungs were strongly correlated with stature and the heart was strongly correlated with weight. Ultimately, these measurements will be useful for the validation of computational models of the small female.

Finite element model prediction of pulmonary contusion in vehicle-to-vehicle simulations of real-world crashes.

OBJECTIVE: Pulmonary contusion (PC) is a common chest injury following motor vehicle crash (MVC). Because this injury has an inflammatory component, studying PC in living subjects is essential. Medical and vehicle data from the Crash Injury Research and Engineering Network (CIREN) database were utilized to examine pulmonary contusion in case occupants with known crash parameters. METHOD: The selected CIREN cases were simulated with vehicle finite element models (FEMs) with the Total HUman Model for Safety (THUMS) version 4 as the occupant. To match the CIREN crash parameters, vehicle simulations were iteratively improved to optimize maximum crush location and depth. Fifteen cases were successfully modeled with the simulated maximum crush matching the CIREN crush to within 10%. Following the simulations, stress and strain metrics for the elements within the lungs were calculated. These injury metrics were compared to patient imaging data to determine the best finite element predictor of pulmonary contusion. RESULTS: When the thresholds were evaluated using volumetric criteria, first principal strain was the metric with the least variation in the FEM prediction of PC. CONCLUSIONS: A preliminary threshold for maximum crush was calculated to predict a clinically significant volume of pulmonary contusion.

Advanced age diminishes tendon-to-bone healing in a rat model of rotator cuff repair.

BACKGROUND: Advanced patient age is associated with recurrent tearing and failure of rotator cuff repairs clinically; however, basic science studies have not evaluated the influence of aging on tendon-to-bone healing after rotator cuff repair in an animal model. Hypothesis/ PURPOSE: This study examined the effect of aging on tendon-to-bone healing in an established rat model of rotator cuff repair using the aged animal colony from the National Institute on Aging of the National Institutes of Health. The authors hypothesized that normal aging decreases biomechanical strength and histologic organization at the tendon-to-bone junction after acute repair. STUDY DESIGN: Controlled laboratory study. METHODS: In 56 F344xBN rats, 28 old and 28 young (24 and 8 months of age, respectively), the supraspinatus tendon was transected and repaired. At 2 or 8 weeks after surgery, shoulder specimens underwent biomechanical testing to compare load-to-failure and load-relaxation response between age groups. Histologic sections of the tendon-to-bone interface were assessed with hematoxylin and eosin staining, and collagen fiber organization was assessed by semiquantitative analysis of picrosirius red birefringence under polarized light. RESULTS: Peak failure load was similar between young and old animals at 2 weeks after repair (31% vs 26% of age-matched uninjured controls, respectively; P > .05) but significantly higher in young animals compared with old animals 8 weeks after repair (86% vs 65% of age-matched uninjured controls, respectively; P < .01). Eight weeks after repair, fibroblasts appeared more organized and uniformly aligned in young animals on hematoxylin and eosin slides compared with old animals. Collagen birefringence analysis of the tendon-to-bone junction demonstrated that young animals had increased collagen fiber organization and similar histologic structure compared with age-matched controls (53.7 ± 2.4 gray scales; P > .05). In contrast, old animals had decreased collagen fiber organization and altered structure compared with age-matched controls (49.8 ± 3.1 gray scales; P < .01). DISCUSSION: In a rat model of aging, old animals demonstrated diminished tendon-to-bone healing after rotator cuff injury and repair. Old animals had significantly decreased failure strength and collagen fiber organization at the tendon-to-bone junction compared with young animals. This study implies that animal age may need to be considered in future studies of rotator cuff repair in animal models. CLINICAL RELEVANCE: With increasing age and activity level of the population, the incidence of rotator cuff tears is predicted to rise. Despite advances in rotator cuff repair technique, the retear rate remains specifically high in elderly patients. The findings of this research suggest that aging negatively influences tendon-to-bone healing after rotator cuff repair in a validated animal model.

Fibrin glue augmentation for flexor tendon repair increases friction compared with epitendinous suture.

PURPOSE: To compare the gliding resistance, repair gapping, and ultimate strength of a common suture construct with a modified construct with fibrin glue augmentation. METHODS: Twelve human cadaveric flexor digitorum profundus tendons were transected and repaired with a 4-strand core suture. Specimens were divided into 2 groups and augmented with epitendinous suture (n = 6) or fibrin glue (n = 6). We compared gliding resistance, 2-mm gapping, and ultimate strength of the repaired tendon between groups. RESULTS: The linear stiffness, force to produce a 2-mm gap, and ultimate failure were similar in both repair methods. However, the 4-strand suture repair with fibrin glue augmentation displayed significantly higher gliding resistance compared with the 4-strand suture with a running epitendinous suture. CONCLUSIONS: The significantly increased gliding resistance associated with fibrin glue raises questions regarding the use of this material for flexor tendon repair augmentation. CLINICAL RELEVANCE: In a human cadaveric study, fibrin glue augmentation to zone II flexor tendon repairs significantly increased friction in the tendon sheath compared with an epitendinous suture.

Investigation of pulmonary contusion extent and its correlation to crash, occupant, and injury characteristics in motor vehicle crashes.

BACKGROUND: Pulmonary contusion (PC) is a leading injury in blunt chest trauma and is most commonly caused by motor vehicle crashes (MVC). To improve understanding of the relationship between insult and outcome, this study relates PC severity to crash, occupant, and injury parameters in MVCs. METHODS: Twenty-nine subjects with PC were selected from the Crash Injury Research and Engineering Network (CIREN) database, which contains detailed crash and medical information on MVC occupants. Computed tomography scans of these subjects were segmented using a semi-automated protocol to quantify the volumetric percentage of injured tissue in each lung. Techniques were used to quantify the geometry and location of PC, as well as the location of rib fractures. Injury extent including percent PC volume and the number of rib fractures was analyzed and its relation to crash and occupant characteristics was explored. RESULTS: Frontal and near-side crashes composed 72% of the dataset and the near-side door was the component most often associated with PC causation. The number of rib fractures increased with age and fracture patterns varied with crash type. In near-side crashes, occupant weight and BMI were positively correlated with percent PC volume and the number of rib fractures, and the impact severity was positively correlated with percent PC volume in the lung nearest the impact. CONCLUSIONS: This study quantified PC morphology in 29 MVC occupants and examined the relationship between injury severity and crash and occupant parameters to better characterize the mechanism of injury. The results of this study may contribute to the prevention, mitigation, and treatment of PC.

An innovative approach to predict the development of adult respiratory distress syndrome in patients with blunt trauma.

BACKGROUND: Pulmonary contusion (PC) is a common injury associated with blunt chest trauma. Complications such as pneumonia and adult respiratory distress syndrome (ARDS) occur in up to 50% of patients with PC. The ability to predict which PC patients are at increased risk of developing complications would be of tremendous clinical utility. In this study, we test the hypothesis that a novel method that objectively measures percent PC can be used to identify patients at risk to develop ARDS after injury. METHODS: Patients with unilateral or bilateral PC with an admission chest computed tomographic angiogram were identified from the trauma registry. Demographic, infectious, and outcome data were collected. Percent PC was determined on admission chest computed tomography using our novel semiautomated, attenuation-defined computer-based algorithm, in which the lung was segmented with minimal manual editing. Factors contributing to the development of ARDS were identified by both univariate and multivariable logistic regression analyses. ARDS was defined as PaO2/FiO2 ratio of less than 200 with diffuse bilateral infiltrates on chest radiograph with no evidence of congestive heart failure. RESULTS: Quantifying percent PC from our objective computer-based approach proved successful. We found that a contusion size of 24% of total lung volume or greater was most significant at predicting ARDS, which occurred in 78% of these patients. Such patients also had a significantly higher incidence of pneumonia when compared with those with contusions less than 24%. The specificity of contusion size of 24% or greater was 94%, although sensitivity was 37%; positive predictive value was 78%, and negative predictive value was 72%. CONCLUSION: We developed and describe a software-based methodology to accurately measure the size of lung contusion in patients of blunt trauma. In our analyses, contusions of 24% or greater most significantly predict the development of ARDS. Such an objective approach can identify patients with PC who are at increased risk for developing respiratory complications before they happen. Further research is needed to use this novel methodology as a means to prevent posttraumatic lung injury in patients with blunt trauma. LEVEL OF EVIDENCE: Prognostic/epidemiologic study, level III; diagnostic study, level IV.

Correlating the extent of pulmonary contusion to vehicle crash parameters in near-side impacts.

Pulmonary contusion (PC) is the most common injury following blunt thoracic trauma with an associated mortality of 10% to 20%. The purpose of this study is to determine how crash parameters correlate to the volume of pulmonary contusion. The Crash Injury Research Engineering and Network (CIREN) database was queried to extract data on all occupants sustaining PC in a near-side crash. The selected CIREN data included all completed cases from 2005 through 2010. Cases involving a roll-over or without a thorax CT uploaded to the database were excluded. After all cases had been examined the study had 64 occupants with varying volumes of PC. Specific crash characteristics compiled included change in velocity due to the impact, energy, occupant characteristics, side airbag deployment, and crush profile measurements. Crush metrics quantifying the area of the crush profile and the location of the crush relative to the occupant were calculated. The thoracic CT scans from these cases were downloaded and segmented to determine the percent volume of high attenuation lung and PC as compared to the total volume of the lung. The results of the general linear model analysis suggest that maximum crush was the best predictor of high attenuation lung and lung location best predicted PC. An analysis of NASS and CIREN demonstrated that crashes with PC tended to have crash parameters that indicated higher severity. These correlations can be used in the future to develop an injury criterion for PC using finite element metrics.

Classic measures of hip dysplasia do not correlate with three-dimensional computer tomographic measures and indices.

UNLABELLED: Acetabular dysplasia is a precursor to osteoarthritis of the hip, and it causes acute and degenerative injuries of soft tissue stabilizers. Traditional radiographic assessments of dysplasia are useful in moderate and severe dysplasia, but they have questionable reliability in mild dysplasia. Computed tomography (CT) reconstruction provides a method for calculation of acetabular geometry and analysis of existing radiographic methods. We performed a retrospective radiographic review of anteroposterior pelvic films and their corresponding pelvic CT scans. Using 30 skeletally mature patients, we analyzed the following five measurements for 60 hips: lateral centre edge angle of Wiberg (LCE), Tönnis angle, Sharp angle, a modified Sharp angle, and the depth to width acetabular index. We also estimated hip surface areas, volumes, and ratios from 3-D reconstructions of a CT scan taken within 60 days of the plain radiograph. The Pearson Correlation Coefficient was used to evaluate the relationship between the plain film measurements and the computed hip indices. No moderate or strong correlation was found between the measured plain film indices and the calculated hip indices. Traditional 2-D measurements used to define acetabular dysplasia have little to no ability to quantify hip volumes and surface areas. CT reconstruction provides a better screening tool in the identification of subtle acetabular hip dysplasia in adults. LEVEL OF EVIDENCE: Level III.

Design, development, and analysis of a surrogate for pulmonary injury prediction.

Current anthropomorphic test devices (ATDs) measure chest acceleration and deflection to assess risk of injury to the thorax. This study presents a lung surrogate prototype designed to expand the injury assessment capabilities of ATDs to include a risk measure for pulmonary contusion (PC). The surrogate augments these existing measures by providing pressure data specific to the lung and its lobes. The prototype was created from a rendering of a 50th percentile male lung inflated to normal inspiration, obtained from clinical CT data. Surrogate size, lobe volume, and airway cross sections were selected to match the morphology of the lung. Elastomeric urethane was molded via rapid prototyping to create a functional prototype. Pressure sensors in each of the five terminal airways independently monitored pressure traces in the lobes during impacts to the surrogate. Software was created to analyze the surrogate impact pressure data, determine the lobe with the greatest pressure rise for a particular impact, and estimate the initial speed of surface deformation. Calibration testing indicates an approximately linear relationship between peak lobe pressure and surface impact speed. No type I or II errors were demonstrated during lobe detection testing. During repeatability testing, the standard deviation was between 2 and 4% of the mean peak pressure. Ongoing research will focus on correlating surrogate data, pressure pulses, or surface deformation, to risk functions for PC.

Finite element-based injury metrics for pulmonary contusion via concurrent model optimization.

This study explores the relationship between impact severity and resulting pulmonary contusion (PC) for four impact conditions using a rat model of the injury. The force-deflection response from a Finite Element (FE) model of the lung was simultaneously matched to experimental data from distinct impacts via a genetic algorithm optimization. Sprague-Dawley rats underwent right-side thoracotomy prior to impact. Insults were applied directly to the lung via an instrumented piston. Five cohorts were tested: a sham group and four groups experiencing lung insults of varying degrees of severity. The values for impact velocity (V) and penetration depth (D) of the cohorts were Group 1, (V = 6.0 m · s(-1), D = 5.0 mm), Group 2, (V = 1.5 m · s(-1),D = 5.0 mm), Group 3, (V = 6 m · s(-1), D = 2.0 mm), and Group 4, (V = 1.5 m · s(-1), D = 2.0 mm). CT scans were acquired at 24 h, 48 h, and 1 week post-insult. Contusion volume was determined through segmentation. FE-based injury metrics for PC were determined at 24 h and 1 week post-impact, based on the observed volume of contusion and first principal strain. At 24 h post-impact, the volume of high radiopacity lung (HRL) was greatest for the severe impact group (mean HRL = 9.21 ± 4.89) and was significantly greater than all other cohorts but Group 3. The concurrent optimization matched simulated and observed impact energy within one standard deviation for Group 1 (energy = 3.88 ± 0.883 mJ, observed vs. 4.47 mJ, simulated) and Group 2 (energy = 1.46 ± 0.403 mJ, observed vs. 1.50 mJ, simulated) impacts. Statistically significant relationships between HRL and impact energy are presented. The FEA-based injury metrics at 24 h post-contusion are ε(max) · ε(max) exceeding 94.5 s(-1), ε (max) exceeding 0.284 and ε(max) exceeding 470 s(-1). Thresholds for injury to the lung still present at 1 week post-impact were also determined. They are ε(max) · ε(max) exceeding 149 s(-1), ε (max) exceeding 0.343 and ε(max) exceeding 573 s(-1). A mesh sensitivity study found that thresholds based on strain rate were more sensitive to changes to mesh density than the threshold based on strain only.

Age thresholds for increased mortality of predominant crash induced thoracic injuries.

The growing elderly population in the United States presents medical, engineering, and legislative challenges in trauma management and prevention. Thoracic injury incidence, morbidity, and mortality increase with age. This study utilized receiver-operator characteristic analysis to identify the quantitative age thresholds associated with increased mortality in common isolated types of thoracic injuries from motor vehicle crashes (MVCs).The subject pool consisted of patients with a single AIS 3+ thorax injury and no injury greater than AIS 2 in any other body region. A logistic regression algorithm was performed for each injury to estimate an age threshold that maximally discriminates between survivors and fatalities. The c-index describing discrimination of the model and odds ratio describing the increased mortality risk associated with being older than the age threshold were computed.Twelve leading thoracic injuries were included in the study: unilateral and bilateral pulmonary contusion (AIS 3/4), hemo/pneumothorax, rib fractures with and without hemo/pneumothorax (AIS 3/4), bilateral flail chest, and thoracic penetrating injury with hemo/pneumothorax. Results are consistent with the traditional age threshold of 55, but were injury-specific. Pulmonary contusions had lower age thresholds compared to rib fractures. Higher severity pulmonary contusions and rib fractures had lower age thresholds compared to lower severity injuries.This study presents the first quantitatively estimated mortality age thresholds for common isolated thoracic injuries. This data provides information on the ideal 'threshold' beyond which age becomes an important factor to patient survival. Results of the current study and future work could lead to improvements in automotive safety design and regulation, automated crash notification, and hospital treatment for the elderly.

A method to measure acetabular metrics from three dimensional computed tomography pelvis reconstructions - biomed 2009.

Acetabular dysplasia is a proposed cause of osteoarthritis of the hip and techniques to identify acetabular dysplasia are important in early diagnosis and prevention of osteoarthritis of the hip. The aim of this study is to develop a method to measure acetabular coverage and volume using computed tomography (CT) images. A software program was used to create three-dimensional models of the acetabulum and femoral head and measure the acetabular volume of each hip from CT images. The three-dimensional models of the acetabulum and femoral head were imported into a post-processing software program to determine the surface areas for the femoral head covered by the acetabulum and the acetabular area covering the femoral head. Using CT scans gathered from 35 individuals, the results of this study demonstrated that the two surface area measurements were linearly correlated with the acetabulum volume. Positive linear relationships with R-squared values of 0.53 and 0.64 were found when comparing the acetabulum volume with the surface area of the femoral head covered by the acetabulum and the surface area of the acetabular area covering the femoral head. The method presented in this study for measuring acetabular coverage and volume using CT images could be used for the development of a more reliable method of diagnosing acetabular dysplasia.

Using a three dimensional model of the pediatric skull for pre-operative planning in the treatment of craniosynostosis - biomed 2009.

Spring mediated cranioplasty and cranial vault reconstruction are two surgical interventions for the treatment of craniosynostosis. The purpose of this study was to examine the use of three-dimensional models in pre-operative planning for these procedures. The methods for this study included the creation of the model and the integration of the model into pre-surgical planning. The patients in this study all received a pre-surgical computed tomography scan as part of the standard pre-operative procedure. The first step in model creation involved processing this image data. From the CT scans, using an automated thresholding command in an image analysis software, the bones of the cranial vault were isolated. Once the identification of the bone was complete a CAD file of the anatomy was created. Then, this geometry was imported into the pre-processing software of the three dimensional printer. The model was printed and hardened using cyanoacrylate. After the model was complete, it was used by the plastic surgery department in their pre-surgical planning. One of the primary uses for this model during the planning process was as a template for pre-bending the springs used in spring cranioplasty. The advantage of this technique was that the surgical procedure was less invasive since less of the skull had to be exposed. Additionally, the force characteristics of the spring could be better quantified. Based on the addition of this pre-surgical planning tool, the plastic surgeons have noted a shorter procedure time and a less invasive approach.

Characterization of crash-induced thoracic loading resulting in pulmonary contusion.

BACKGROUND: Pulmonary contusion (PC) is commonly sustained in motor vehicle crash. This study utilizes the Crash Injury Research and Engineering Network (CIREN) database and vehicle crash tests to characterize the occupants and loading characteristics associated with PC. A technique to match CIREN cases to vehicle crash tests is applied to quantify the thoracic loading associated with this injury. METHODS: The CIREN database and crash test data from the National Highway Traffic Safety Administration were used in this study. An analysis of CIREN data were conducted between three study cohorts: patients that sustained PC and any other chest injury (PC+ and chest+), patients with chest injury and an absence of PC (PC- and chest+), and a control group without chest injury and an absence of PC (PC- and chest-). Forty-one lateral impact crash tests were analyzed and thoracic loading data from onboard crash tests dummies were collected. RESULTS: The incidence of PC in CIREN data were 21.7%. Crashes resulting in PC demonstrated significantly greater mortality (23.9%) and Injury Severity Score (33.1 +/- 15.7) than the control group. The portion of lateral impacts increased from 27% to 48% between the control group and PC+ and chest+ cohort, prompting the use of lateral impact crash tests for the case-matching portion of the study. Crash tests were analyzed in two configurations; vehicle-to-vehicle tests and vehicle-to-pole tests. The average maximum chest compression and deflection velocity from the dummy occupants were found to be 25.3% +/- 2.6% and 4.6 m/s +/- 0.42 m/s for the vehicle-to-pole tests and 23.0% +/- 4.8% and 3.9 m/s +/- 1.1 m/s for the vehicle-to-vehicle tests. Chest deflection versus time followed a roughly symmetric and sinusoidal profile. Sixteen CIREN cases were identified that matched the vehicle crash tests. Of the 16 matched cases, 12 (75%) sustained chest injuries, with half of these patients presenting with PC. CONCLUSIONS: Quantified loading at the chest wall indicative of PC and chest injury in motor vehicle crash is valuable boundary condition data for bench-top studies or computer simulations focused on this injury. In addition, because PC often exhibits a delayed onset, knowing the population and crash modes highly associated with this injury may promote earlier detection and improved management of this injury.

Traumatic pulmonary pathology measured with computed tomography and a semiautomated analytic method.

The goal of this study is to develop a controlled approach to quantifying the amount of lung damage after blunt chest trauma. The presented method is used to analyze computed tomography scans and to assess patients' risk for developing acute respiratory distress syndrome (ARDS). When used to predict which patients were at risk for ARDS, the method presented in this study had a sensitivity of 57% and a specificity of 100%.

Method for identifying calcified plaque in contrast enhanced computed tomography.

Arteriosclerosis is the cause of many life threatening diseases which combine to cause many deaths and high health care costs. The thickness of the aortic wall and the volume of calcified plaque are both used to diagnose arteriosclerosis. Both "symptoms" can be assessed using computed tomography; however wall thickness measurements are typically made on contrast enhanced scans while plaque measurements are usually gathered from un-enhanced scans. A technique is described below that would allow for both diagnostic procedures to be performed using only one type of scan. The proposed technique is able to measure the volume of calcified plaque using contrast enhanced scans by adjusting for differences in contrast intensity on a slice by slice basis. This more robust approach is necessary because the intensity of contrast in the lumen varies by scan. Also, the contrast and calcified plaque have similar intensities. The validity of this new technique was assessed by comparing the results it generated to results from volumes calculated using un-enhanced scans. The volumes of calcified plaque produced by this technique are very similar to those obtained using un-enhanced scans (slope=1.0611, r-squared = 0.9974).