Postconcussive Symptoms After Early Childhood Concussion.

Importance: Research on postconcussive symptoms (PCS) following early childhood concussion has been hindered by a lack of measures suitable for this age group, resulting in a limited understanding of their evolution in young children. Objective: To document PCS in the first 3 months after early childhood concussion using a developmentally appropriate measure. Design, Setting, and Participants: This cohort study used data collected at 3 Canadian and 1 US urban pediatric emergency departments (EDs) and 8 Canadian daycares from December 2018 to December 2022 as part of the Kids' Outcomes and Long-Term Abilities (KOALA) project, a prospective, multicenter, longitudinal cohort study. Participants included children aged 6 to 72 months with early childhood concussion or orthopedic injury (OI) or uninjured children from the community to serve as controls. Data were analyzed from March 2023 to January 2024. Exposure: Concussion sustained between ages 6 and 72 months. Main Outcomes and Measures: Primary outcomes were cognitive, physical, behavioral and total PCS assessed prior to injury (retrospectively), acutely (within 48 hours), and at 10 days, 1 month, and 3 months after injury or recruitment through caregiver observations using the Report of Early Childhood Traumatic Injury Observations & Symptoms inventory. Group comparisons were analyzed using ordinal regression models. Results: The study included 303 children (mean [SD] age, 35.8 [20.2] months; 152 [50.2%] male). Of these, 174 children had a concussion (mean [SD] age, 33.3 [19.9] months), 60 children had an OI (mean [SD] age, 38.4 [19.8] months) and 69 children were uninjured controls (mean [SD] age, 39.7 [20.8] months). No meaningful differences were found between the concussion and comparison groups in retrospective preinjury PCS. Significant group differences were found for total PCS at the initial ED visit (concussion vs OI: odds ratio [OR], 4.33 [95% CI, 2.44-7.69]; concussion vs control: OR, 7.28 [95% CI, 3.80-13.93]), 10 days (concussion vs OI: OR, 4.44 [95% CI, 2.17-9.06]; concussion vs control: OR, 5.94 [95% CI, 3.22-10.94]), 1 month (concussion vs OI: OR, 2.70 [95% CI, 1.56-4.68]; concussion vs control: OR, 4.32 [95% CI, 2.36-7.92]), and 3 months (concussion vs OI: OR, 2.61 [95% CI, 1.30-5.25]; concussion vs control: OR, 2.40 [95% CI, 1.36-4.24]). Significant group differences were also found for domain-level scores (cognitive, physical, behavioral) at various time points. Conclusions and Relevance: In this early childhood cohort study, concussion was associated with more PCS than OIs or typical development up to 3 months after injury. Given the limited verbal and cognitive abilities typical of early childhood, using developmentally appropriate manifestations and behaviors is a valuable way of tracking PCS and could aid in concussion diagnosis in young children.

Improving outcome after paediatric concussion: challenges and possibilities.

The term concussion has permeated mainstream media and household vocabulary mainly due to awareness regarding the risks of concussion in professional contact sports, yet it occurs across a variety of settings and ages. Concussion is prevalent in infants, preschoolers, children, and adolescents, and is a common presentation or reason for referral to primary care providers, emergency departments, and specialised trauma clinics. Its broad range of symptoms and sequelae vary according to multiple individual, environmental, and clinical factors and can lead to health and economic burden. More than 20 years of research into risk factors and consequences of paediatric concussion has revealed as many questions as answers, and scientific work and clinical cases continue to expose its complexity and heterogeneity. In this Review, we present empirical evidence for improving outcome after paediatric concussion. We consider work pertaining to both sports and other injury mechanisms to provide a perspective that should be viewed as complementary to publications focused specifically on sports concussion. Contemporary challenges in prevention, diagnosis, prognosis, and intervention are discussed alongside pathways and future directions for improving outcome.

"What If?": Caregivers' Experiences Following Early Childhood Concussion.

OBJECTIVE: Little is known about the symptoms, signs, and management guidelines for children under the age of 6 years after they sustain a concussion. Caregivers of such young children may have unique concerns and encounter different challenges from those of school-age children given the distinctive developmental characteristics of the early childhood period. This study aimed to explore the experience of caregivers through semistructured interviews to inform clinical practice. METHODS: Fifty caregivers of children aged 6 months to 5.99 years were interviewed 3 months postinjury for this qualitative study to document their experience in relation to their child's accident, recovery, and healthcare provisions. RESULTS: Four main themes were identified: (1) visible changes associated with caregiver concerns, (2) a roller-coaster of emotions after the injury, (3) healthcare providers' role in addressing the need for reassurance, and (4) the need for better information after the injury. CONCLUSION: The findings provide critical insight into the unique experiences and information needs of caregivers of young children who sustain concussion. The challenges identified can inform healthcare professionals regarding the needs of caregivers after early concussion and contribute to building a knowledge base for the development of age-appropriate anticipatory guidance for caregiver mental health and child recovery.

Consumable Material Waste and Workflow Efficiency Comparison Between Multi-use Syringeless and Single-use Syringe-Based Injectors in Computed Tomography.

RATIONALE AND OBJECTIVES: Syringeless power injectors obviate the need for reloading iodinated contrast media (ICM) and plastic consumable pistons between exams. This study evaluates the potential time and material waste (ICM, plastic, saline, and total) saved using a multi-use syringeless injector (MUSI) compared to a single-use syringe-based injector (SUSI). MATERIALS AND METHODS: Two observers recorded technologist time spent using a SUSI and a MUSI over three clinical workdays. CT technologists (n = 15) were polled on their experience between the systems using a 5-point Likert scale survey. ICM, plastic, and saline waste data from each system were collected. A mathematical model was created to estimate total and categorical waste from each injector system over a 16-week period. RESULTS: On average, CT technologists spent 40.5 seconds less per exam with MUSI compared to SUSI (p < .001). Technologists rated MUSI work efficiency, user-friendliness, and overall satisfaction (strongly or somewhat improved) higher relative to SUSI (p < .05). Iodine waste was 31.3 L and 0.0 L for SUSI and MUSI, respectively. Plastic waste was 467.7 kg and 71.9 kg for SUSI and MUSI, respectively. Saline waste was 43.3 L and 52.5 L for SUSI and MUSI, respectively. Total waste was 555.0 kg and 124.4 kg for SUSI and MUSI respectively. CONCLUSION: Switching from SUSI to MUSI resulted in a 100%, 84.6%, and 77.6% reduction in ICM, plastic, and total waste. This system may fortify institutional endeavors toward green radiology initiatives. The potential time saved administering contrast using MUSI may improve CT technologist efficiency.

CT Number Accuracy and Association With Object Size: A Phantom Study Comparing Energy-Integrating Detector CT and Deep Silicon Photon-Counting Detector CT.

BACKGROUND. Variable beam hardening based on patient size causes variation in CT numbers for energy-integrating detector (EID) CT. Photon-counting detector (PCD) CT more accurately determines effective beam energy, potentially improving CT number reliability. OBJECTIVE. The purpose of the present study was to compare EID CT and deep silicon PCD CT in terms of both the effect of changes in object size on CT number and the overall accuracy of CT numbers. METHODS. A phantom with polyethylene rings of varying sizes (mimicking patient sizes) as well as inserts of different materials was scanned on an EID CT scanner in single-energy (SE) mode (120-kV images) and in rapid-kilovoltage-switching dual-energy (DE) mode (70-keV images) and on a prototype deep silicon PCD CT scanner (70-keV images). ROIs were placed to measure the CT numbers of the materials. Slopes of CT number as a function of object size were computed. Materials' ideal CT number at 70 keV was computed using the National Institute of Standards and Technology XCOM Photon Cross Sections Database. The root mean square error (RMSE) between measured and ideal numbers was calculated across object sizes. RESULTS. Slope (expressed as Hounsfield units per centimeter) was significantly closer to zero (i.e., less variation in CT number as a function of size) for PCD CT than for SE EID CT for air (1.2 vs 2.4 HU/cm), water (-0.3 vs -1.0 HU/cm), iodine (-1.1 vs -4.5 HU/cm), and bone (-2.5 vs -10.1 HU/cm) and for PCD CT than for DE EID CT for air (1.2 vs 2.8 HU/cm), water (-0.3 vs -1.0 HU/cm), polystyrene (-0.2 vs -0.9 HU/cm), iodine (-1.1 vs -1.9 HU/cm), and bone (-2.5 vs -6.2 HU/cm) (p < .05). For all tested materials, PCD CT had the smallest RMSE, indicating CT numbers closest to ideal numbers; specifically, RMSE (expressed as Hounsfield units) for SE EID CT, DE EID CT, and PCD CT was 32, 44, and 17 HU for air; 7, 8, and 3 HU for water; 9, 10, and 4 HU for polystyrene; 31, 37, and 13 HU for iodine; and 69, 81, and 20 HU for bone, respectively. CONCLUSION. For numerous materials, deep silicon PCD CT, in comparison with SE EID CT and DE EID CT, showed lower CT number variability as a function of size and CT numbers closer to ideal numbers. CLINICAL IMPACT. Greater reliability of CT numbers for PCD CT is important given the dependence of diagnostic pathways on CT numbers.

Using Billing Codes to Create a Pediatric Functional Status e-Score for Children Receiving Inpatient Rehabilitation.

OBJECTIVE: Provide proof-of-concept for development of a Pediatric Functional Status eScore (PFSeS). Demonstrate that expert clinicians rank billing codes as relevant to patient functional status and identify the domains that codes inform in a way that reliably matches analytical modeling. DESIGN: Retrospective chart review, modified Delphi, and nominal group techniques. SETTING: Large, urban, quaternary care children's hospital in the Midwestern United States. PARTICIPANTS: Data from 1955 unique patients and 2029 hospital admissions (2000-2020); 12 expert consultants representing the continuum of rehabilitation care reviewed 2893 codes (procedural, diagnostic, pharmaceutical, durable medical equipment). MAIN OUTCOME MEASURES: Consensus voting to determine whether codes were associated with functional status at discharge and, if so, what domains they informed (self-care, mobility, cognition/ communication). RESULTS: The top 250 and 500 codes identified by statistical modeling were mostly composed of codes selected by the consultant panel (78%-80% of the top 250 and 71%-78% of the top 500). The results provide evidence that clinical experts' selection of functionally meaningful codes corresponds with codes selected by statistical modeling as most strongly associated with WeeFIM domain scores. The top 5 codes most strongly related to functional independence ratings from a domain-specific assessment indicate clinically sensible relationships, further supporting the use of billing data in modeling to create a PFSeS. CONCLUSIONS: Development of a PFSeS that is predicated on billing data would improve researchers' ability to assess the functional status of children who receive inpatient rehabilitation care for a neurologic injury or illness. An expert clinician panel, representing the spectrum of medical and rehabilitative care, indicated that proposed statistical modeling identifies relevant codes mapped to 3 important domains: self-care, mobility, and cognition/communication.

Factors Contributing to Computed Tomography Trauma Scan Times at a Tertiary Center: Improving Emergency Department Trauma Imaging Workflow Through Targeted Interventions.

PURPOSES: The aims of the study are to identify factors contributing to computed tomography (CT) trauma scan turnaround time variation and to evaluate the effects of an automated intervention on time metrics. METHODS: Throughput metrics were captured via picture archiving and communication system from January 1, 2018, to December 16, 2019, and included 17,709 CT trauma scans from our institution. Initial data showed that imaging technologist variation played a significant role in trauma imaging turnaround time. In December 2019, we implemented a 2-pronged intervention: (1) educational intervention to techs and (2) modified trauma CT abdomen/pelvis to autogenerate and autosend reformats to picture archiving and communication system. A total of 13,169 trauma CT scans were evaluated from the postintervention period taking place from January 2020 to March 2021. Throughput metrics such as last image to first report interval and emergency department length of stay were captured and compared with performing technologist, time of day, and weekday versus weekend scans. RESULTS: Substantial variability among trauma CT scans was observed. For CT trauma abdomen/pelvis, the interval from last image to initial report decreased from 26.4 to 24.0 minutes ( P = 0.001) while the interval between first and last image time decreased from 11.4 to 4.2 minutes ( P < 0.001). Emergency department length of stay also decreased from 3.9 to 3.7 hours ( P < 0.0001) in the postintervention period. Variation among imaging technologist was statistically significant and became less significant after intervention ( P = 0.09, P = 0.54). CONCLUSIONS: Factors such as imaging technologist variability, time of day, and day of the week of trauma scans played a significant role in CT trauma turnaround time variability. Automation interventions can help with efficiency in image turnaround time.

Electrocardiographic Gating and Cerebral Perfusion Computed Tomography Option-Set Prevalence and Utilization Data From 62 Institutions in the United States.

OBJECTIVES: To provide the radiology community with data to address the question: "Compared with peer institutions, is my institution efficiently using its electrocardiographic (ECG) gating and cerebral perfusion-capable computed tomography (CT) scanners?" METHODS: In this retrospective study, we analyze 6 months of scanner utilization data from 62 institutions (299 locations, 507 scanners) to identify scanners capable of performing ECG gating and perfusion CT studies. We report the number of ECG gating/perfusion-capable scanners and locations as a function of the total number of locations and scanners in each institution. We additionally regress the number of ECG-gated and perfusion examinations on (1) the number of locations/scanners capable of performing these examinations and (2) the fraction of the institution's CT examination volume that requires ECG gating or perfusion. We provide look-up tables so an institution can compare its ECG-gated/perfusion examination volume to other institutions with similar ECG-gated/perfusion examination fractions and capable scanners. RESULTS: We detected an effect of both ECG-gating examination fraction and the number of ECG gating-capable scanners on ECG-gated examination volume ( χ21 = 77.5 [ P < 0.001] and χ21 = 64.2 [ P < 0.001], respectively). Similar results were obtained for perfusion examination fraction and perfusion-capable scanners as they relate to perfusion examination volume ( χ21 = 51.6 [ P < 0.001] and χ21 = 45.2 [ P < 0.001], respectively). The number of ECG gating/perfusion-capable scanners and locations within an institution were found to positively correlate with both the total number of locations and scanners within an institution ( P < 0.001 for all hypothesis tests). CONCLUSIONS: The study provides multi-institutional data on ECG gating and perfusion examination volumes that can be used to inform CT purchasing decisions.

Emergency department visits for mild traumatic brain injury in early childhood.

BACKGROUND: Brain injury during early childhood may disrupt key periods of neurodevelopment. Most research regarding mild traumatic brain injury (mTBI) has focused on school-age children. We sought to characterize the incidence and healthcare utilization for mTBI in young children presenting to U.S. emergency departments (ED). METHODS: The Nationwide Emergency Department Sample was queried for children age 0-6 years with mTBI from 2016 to 2019. Patients were excluded for focal or diffuse TBI, drowning or abuse mechanism, death in the ED or hospital, Injury Severity Score > 15, neurosurgical intervention, intubation, or blood product transfusion. RESULTS: National estimates included 1,372,291 patient visits: 63.5% were two years or younger, 57.5% were male, and 69.4% were injured in falls. The most common head injury diagnosis was "unspecified injury of head" (83%); this diagnosis decreased in frequency as age increased, in favor of a concussion diagnosis. Most patients were seen at low pediatric volume EDs (64.5%) and non-children's hospital EDs (86.2%), and 64.9% were seen at a non-teaching hospital. Over 98% were treated in the ED and discharged home. Computed tomography of the head and cervical spine were performed in 18.7% and 1.6% of patients, respectively, less often at children's hospitals (OR = 0.55, 95%CI = 0.41-0.76 for head and OR = 0.19, 95%CI = 0.11-0.34 for cervical spine). ED charges resulted in $540-681 million annually, and more than half of patients utilized Medicaid. CONCLUSIONS: Early childhood mTBI is prevalent and results in high financial burden in the U.S. There is wide variation in diagnostic coding and computed tomography scanning amongst EDs. More focused research is needed to identify optimal diagnostic tools and management strategies.

Estimated size of the clinical medical imaging physics workforce in the United States.

There is no current authoritative accounting of the number of clinical imaging physicists practicing in the United States. Information about the workforce is needed to inform future efforts to secure training pathways and opportunities. In this study, the AAPM Diagnostic Demand and Supply Projection Working Group collected lists of medical physicists from several state registration and licensure programs and the Conference of Radiation Control Program Directors (CRCPD) registry. By cross-referencing individuals among these lists, we were able to estimate the current imaging physics workforce in the United States by extrapolating based on population. The imaging physics workforce in the United States in 2019 consisted of approximately 1794 physicists supporting diagnostic X-ray (1073 board-certified) and 934 physicists supporting nuclear medicine (460 board-certified), with a number of individuals practicing in both subfields. There were an estimated 235 physicists supporting nuclear medicine exclusively (150 board-certified). The estimated total workforce, accounting for overlap, was 2029 medical physicists. These estimates are in approximate agreement with other published studies of segments of the workforce.

Predictors of Treatment Response to Multidisciplinary Care for Persistent Symptoms after Pediatric Concussion.

PURPOSE: To assess which pediatric patients experiencing persistent post-concussive symptoms (PCS) benefit most from multidisciplinary treatment including specialists in Neurology, Neuropsychology, Physical Therapy, and Athletic Training, and to explore the effectiveness of this approach. METHODS: A retrospective chart review of 56 adolescents 10-20 years old (M = 15.0 ± 2.1) receiving multidisciplinary care for PCS (>30 days) was conducted. RESULTS: Systolic blood pressure and Body Mass Index predicted time to concussion resolution (p < .05), such that higher values were associated with slower resolution. PCS scores significantly decreased between participants' initial and final clinic visits, p < .01, and among the 25 participants for whom pre-intervention PCS scores were available, symptom severity scores significantly declined following multidisciplinary intervention compared to pre-referral values (p < .01). CONCLUSIONS: Exploratory analyses reveal that multidisciplinary treatment is a promising approach for reducing symptoms among adolescents with PCS, and that those with greater levels of physical fitness may benefit most.

Exposure to Head Impacts and Cognitive and Behavioral Outcomes in Youth Tackle Football Players Across 4 Seasons.

Importance: Repetitive head impacts have been posited to contribute to neurocognitive and behavioral difficulties in contact sport athletes. Objective: To identify associations between cognitive and behavioral outcomes and head impacts measured in youth tackle football players over 4 seasons of play. Design, Setting, and Participants: This prospective cohort study was conducted from July 2016 through January 2020, spanning 4 football seasons. The setting was a youth tackle football program and outpatient medical clinic. Players were recruited from 4 football teams composed of fifth and sixth graders, and all interested players who volunteered to participate were enrolled. Data analysis was performed from March 2020 to June 2021. Exposures: Impacts were measured using helmet-based sensors during practices and games throughout 4 consecutive seasons of play. Impacts were summed to yield cumulative head impact gravitational force equivalents per season. Main Outcomes and Measures: Ten cognitive and behavioral measures were completed before and after each football season. Results: There were 70 male participants aged 9 to 12 years (mean [SD] age, 10.6 [0.64] years), with 18 completing all 4 years of the study. At the post-season 1 time point, higher cumulative impacts were associated with lower self-reported symptom burden (ß = -0.6; 95% CI, -1.0 to -0.2; P = .004). After correcting for multiple comparisons, no other associations were found between impacts and outcome measures. At multiple times throughout the study, premorbid attention-deficit/hyperactivity disorder, anxiety, and depression were associated with worse cognitive or behavioral scores, whereas a premorbid headache disorder or history of concussion was less often associated with outcomes. Conclusions and Relevance: In this cohort of youth tackle football players, premorbid conditions, including attention-deficit/hyperactivity disorder, anxiety, and depression, were associated with cognitive and behavioral outcomes more often than cumulative impact.

Treatment of Post-traumatic Headaches in Children: A Systematic Review.

Post-traumatic headache is a secondary headache disorder beginning within 7 days of head injury. We conducted a systematic review of the evidence for treatment of post-traumatic headache in children. Of 2169 unique articles screened, 12 were included. Most studies pertained to headaches after concussion. The authors of seven studies examined the effect of medications, 4 studied nonpharmacological therapies, and 1 studied the reduction of medication usage. Much of the evidence came from retrospective chart reviews, had low level of evidence, and had fair risk of bias. High-quality randomized controlled treatment trials are needed to guide the clinical management of this condition.

Sub pixel resolution using spectral-spatial encoding in x-ray imaging.

PURPOSE: Previous efforts at increasing spatial resolution have relied on decreasing focal spot and or detector element size. Many "super resolution" methods require physical movement of a component of the imaging system. This work describes a method for achieving spatial resolution on a scale smaller than the detector pixel without motion of the object or detector. METHODS: We introduce a weighting of the photon energy spectrum on a length scale smaller than a single pixel using a physical filter that can be placed between the focal spot and the object, between the object and the detector, or integrated into the x-ray source or detector. We refer to the method as sub pixel encoding (SPE). We show that if one acquires multiple measurements (i.e. x-ray projections), information can be synthesized at a spatial scale defined by the spectrum modulation, not the detector element size. Specifically, if one divides a detector pixel into n sub regions, and m photon-matter interactions are present, the number of x-ray measurements needed to solve for the detector response of each sub region is mxn. We discuss realizations of SPE using multiple x-ray spectra with an energy integrating detector, a single spectra with a photon counting detector, and the single photon-matter interaction case. We demonstrate the feasibility of the approach using a simulated energy integrating detector with a detector pitch of 2 mm for 80-140 kV medical and 200-600 kV industrial applications. Phantoms used for both example SPE realization had some features only a 1 mm detector could resolve. We calculate the covariance matrix of SPE output to characterize the and noise propagation and correlation of our test examples. RESULTS: The mathematical foundation of SPE is provided, with details worked out for several detector types and energy ranges. Two numerical simulations were provided to demonstrate feasibility. In both the medical and industrial simulations, some phantom features were only observable with the 1 mm and SPE synthesized 2 mm detector, while the 2 mm detector was not able to visualize them. Covariance matrix analysis demonstrated negative diagonal terms for both example cases. CONCLUSIONS: The concept of encoding object information at a length scale smaller than a single pixel element, and then retrieving that information was introduced. SPE simultaneously allows for an increase in spatial resolution and provides "dual energy" like information about the underlying photon-matter interactions.

A Metric for Quantification of Iodine Contrast Enhancement (Q-ICE) in Computed Tomography.

BACKGROUND: Poor contrast enhancement is related to issues with examination execution, contrast prescription, computed tomography (CT) protocols, and patient conditions. Currently, our community has no metric to monitor true enhancement on routine single-phase examinations because this requires knowledge of both pre- and postcontrast CT number. PURPOSE: We propose an automatable solution to quantifying contrast enhancement without requiring a dedicated noncontrast series. METHODS: The difference in CT number between a target region in an enhanced and unenhanced image defines the metric "quantification of iodine contrast enhancement" (Q-ICE). Quantification of iodine contrast enhancement uses the noncontrast bolus tracking baseline image from routine abdominal examinations, which mitigates the need for a dedicated noncontrast series. We applied this method retrospectively to 312 patient livers from 2 sites between 2017 and 2020. Each site used a weight-based contrast injection protocol for weights 60 to 113 kg and a constant volume less than 60 kg and greater than 113 kg. Hypothesis testing was performed to compare Q-ICE between sites and detect Q-ICE dependence on weight and kilovoltage (kV). RESULTS: Mean Q-ICE differed between sites (P = 0.004) by 4.96 Hounsfield unit with 95% confidence interval (1.63-8.28), albeit this difference was roughly 2 times smaller than the SD in Q-ICE across patients at a single site. For patients between 60 and 113 kg, we did not observe evidence of Q-ICE varying with patient weight (P = 0.920 and 0.064 for 120 and 140 kV, respectively). The Q-ICE did vary with patient weight for patients less than 60 kg (P = 0.003) and greater than 113 kg (P = 0.04). We observed a roughly 10 Hounsfield unit reduction in Q-ICE liver for patients scanned with 140 versus 120 kV. We observed several underenhancing examinations with an arterial phase appearance motivating our CT protocol optimization team to consider increasing the delay for slowly enhancing patients. CONCLUSIONS: A quality metric for quantifying CT contrast enhancement was developed and suggested tangible opportunities for quality improvement and potential financial savings.

Subconcussive Head Impacts and Neurocognitive Function Over 3 Seasons of Youth Football.

OBJECTIVE: To determine the association between repetitive subconcussive head impacts and neurobehavioral outcomes in youth tackle football players. METHODS: Using helmet-based sensors, we measured head impacts for 3 consecutive seasons of play in 29 male players age 9-11. Cumulative impact g's were calculated. Players completed a battery of outcome measures before and after each season, including neuropsychological testing, vestibular-ocular sensitivity, and self- and parent-reported measures of symptoms and attention-deficit hyperactivity disorder (ADHD). RESULTS: Average cumulative impact over 3 seasons was 13 900g. High-intensity hits predicted worse change for self-reported social adjustment (P = .001). Cumulative impact did not predict change in any of the outcome measures. History of ADHD, anxiety, and depression predicted worse change for self-reported symptoms and social adjustment, independent of head impacts. When players were stratified into 3 groups based on cumulative impact across all 3 seasons, differences in outcome measures existed prior to the start of the first season. These differences did not further increase over the course of the 3 seasons. CONCLUSION: Over 3 consecutive seasons of youth tackle football, we found no association between cumulative head impacts and neurobehavioral outcomes. Larger sample sizes and longer follow-up times would further assist in characterizing this relationship.

Applying a New CT Quality Metric in Radiology: How CT Pulmonary Angiography Repeat Rates Compare Across Institutions.

OBJECTIVES: To quantify overall CT repeat and reject rates at five institutions and investigate repeat and reject rates for CT pulmonary angiography (CTPA). METHODS: In this retrospective study, we apply an automated repeat rate analysis algorithm to 103,752 patient examinations performed at five institutions from July 2017 to August 2019. The algorithm identifies repeated scans for specific scanner and protocol combinations. For each institution, we compared repeat rates for CTPA to all other CT protocols. We used logistic regression and analysis of deviance to compare CTPA repeat rates across institutions and size-based protocols. RESULTS: Of 103,752 examinations, 1,447 contained repeated helical scans (1.4%). Overall repeat rates differed across institutions (P < .001) ranging from 0.8% to 1.8%. Large-patient CTPA repeat rates ranged from 3.0% to 11.2% with the odds (95% confidence intervals) of a repeat being 4.8 (3.5-6.6) times higher for large- relative to medium-patient CTPA protocols. CTPA repeat rates were elevated relative to all other CT protocols at four of five institutions, with strong evidence of an effect at two institutions (P < .001 for each; odds ratios: 2.0 [1.6-2.6] and 6.2 [4.4-8.9]) and somewhat weaker evidence at the others (P = .005 and P = 0.011; odds ratios: 2.2 [1.3-3.8] and 3.7 [1.5-9.1], respectively). Accounting for size-based protocols, CTPA repeat rates differed across institutions (P < .001). DISCUSSION: The results indicate low overall repeat rates (<2%) with CTPA rates elevated relative to other protocols. Large-patient CTPA rates were highest (eg, 11.2% at one institution). Differences in repeat rates across institutions suggest the potential for quality improvement.