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.

"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.

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.

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.

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.

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.

CT Fluoroscopy for Image-Guided Procedures: Physician Radiation Dose During Full-Rotation and Partial-Angle CT Scanning.

PURPOSE: To determine physician radiation exposure when using partial-angle computed tomography (CT) fluoroscopy (PACT) vs conventional full-rotation CT and whether there is an optimal tube/detector position at which physician dose is minimized. MATERIALS AND METHODS: Physician radiation dose (entrance air kerma) was measured for full-rotation CT (360°) and PACT (240°) at all tube/detector positions using a human-mimicking phantom placed in a 64-channel multidetector CT. Parameters included 120 kV, 20- and 40-mm collimation, and 100 mA. The mean, standard deviation, and increase/decrease in physician dose compared with a full-rotation scan were reported. RESULTS: Physician radiation exposure during CT fluoroscopy with PACT was highly dependent on the position of the tube/detector during scanning. The lowest PACT physician dose was when the physician was on the detector side (center view angle 116°; -35% decreased dose vs full-angle CT). The highest PACT physician dose was with the physician on the tube side (center view angle 298°; +34% increased dose vs full-angle CT), all doses P <.05 vs full-rotation CT. CONCLUSIONS: Partial-angle CT has the potential to both significantly increase or decrease physician radiation dose during CT fluoroscopy-guided procedures. The detector/tube position has a profound effect on physician dose. The lowest dose during PACT was achieved when the physician was located on the detector side (ie, distant from the tube). This data could be used to optimize CT fluoroscopy parameters to reduce physician radiation exposure for PACT-capable scanners.

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.

A Multiinstitutional Study on Wasted CT Scans for Over 60,000 Patients.

OBJECTIVE. Repeated imaging is an unnecessary source of patient radiation exposure, a detriment to patient satisfaction, and a waste of time and money. Although analysis of rates of repeated and rejected images is mandated in mammography and recommended in radiography, the available data on these rates for CT are limited. MATERIALS AND METHODS. In this retrospective study, an automated repeat-reject rate analysis algorithm was used to quantify repeat rates from 61,102 patient examinations obtained between 2015 and 2018. The algorithm used DICOM metadata to identify repeat acquisitions. We quantified rates for one academic site and one rural site. The method allows scanner-, technologist-, protocol-, and indication-specific rates to be determined. Positive predictive values and sensitivity were estimated for correctly identifying and classifying repeat acquisitions. Repeat rates were compared between sites to identify areas for targeted technologist training. RESULTS. Of 61,102 examinations, 4676 instances of repeat scanning contributed excess radiation dose to patients. Estimated helical overlap repeat rates were 1.4% (95% CI, 1.2-1.6%) for the rural site and 1.1% (95% CI, 1.0-1.2%) for the academic site. Significant differences in rates of repeat imaging required because of bolus tracking (11.6% vs 4.3%; p < 0.001) and helical extension (3.3% vs 1.8%; p < 0.001) were observed between sites. Positive predictive values ranged from 91% to 99% depending on the reason for repeat imaging and site location. Sensitivity of the algorithm was 92% (95% CI, 87-96%). Rates tended to be highest for emergent imaging procedures and exceeded 9% for certain protocols. CONCLUSION. Our multiinstitutional automated quantification of repeat rates for CT provided a useful metric for unnecessary radiation exposure and identification of technologists in need of training.

Head Impact Burden and Change in Neurocognitive Function During a Season of Youth Football.

OBJECTIVE: To determine the association of repetitive subconcussive head impacts with functional outcomes in primary and high school tackle football players. SETTING: Youth football fields and an outpatient sports neurology clinic. PARTICIPANTS: A total of 112 primary school (n = 55, age 9-12 years) and high school (n = 57, age 15-18 years) football players. DESIGN: A prospective cohort study. MAIN MEASURES: Helmet-based sensors were used to record head impacts during practices and games during the 2016 football season. Impact g-forces were summed to yield a measure of cumulative impact. History of self-reported premorbid medical diagnoses was obtained preseason. Players completed assessments of a variety of outcomes both pre- and postseason: neuropsychological test performance, symptoms, vestibular and ocular-motor screening, balance, parent-completed attention-deficit hyperactivity disorder (ADHD) symptoms, and self-reported behavioral adjustment. RESULTS: Average cumulative impact was 3700 (standard deviation = 2700) g-forces for the season and did not differ between age groups (P = .594). Cumulative impact did not predict pre- to postseason change scores on any outcome measures (all P > .05). Instead, younger age group and reported history of premorbid ADHD predicted change scores on several cognitive testing measures and parent-reported ADHD symptoms, while reported history of premorbid anxiety and depression predicted change scores on symptom reporting. CONCLUSIONS: In youth tackle football, subconcussive head impacts sustained over the course of a single season may not be associated with neurocognitive functional outcomes. The absence of a significant association may reflect the relatively short follow-up interval, and signals the need for studies across multiple seasons.

Utilization of conventional neuroimaging following youth concussion.

BACKGROUND/OBJECTIVE: Conventional neuroimaging is not recommended for the routine diagnosis of concussion, but some patients with concussion undergo computed tomography (CT) or magnetic resonance imaging (MRI). The objective of this study was to explore the clinical factors that predict neuroimaging utilization in concussion. METHODS: Concussion-related CT and MRI data were analysed from 1953 patients, aged 10-19 years, who presented to a sports concussion clinic within 30 days of injury. RESULTS: The majority of CT scans (n = 193) were obtained during the acute concussion period (mean = 2.7 days post-concussion), whereas MRI scans (n = 134) were ordered later during recovery (mean = 39.4 days post-concussion). Predictors of CT utilization included loss of consciousness, amnesia and vomiting (all p < 0.001). Prior concussion (p = 0.002) and continued participation in activity after injury (p = 0.03) predicted greater MRI utilization. Neuroimaging with either CT (p = 0.024, hazard ratio = 1.2) or MRI (p < 0.001, hazard ratio = 2.75) was associated with prolonged symptoms. Only 3.1% of CTs and 1.5% of MRIs demonstrated signs of traumatic brain injury. CONCLUSION: Several clinical factors predict neuroimaging utilization in patients with concussion. CT is generally used acutely, while MRI is used in the sub-acute and chronic post-concussion periods. In a sports concussion clinic, delayed neuroimaging has limited clinical yield.

Specific Factors Influence Postconcussion Symptom Duration among Youth Referred to a Sports Concussion Clinic.

OBJECTIVE: To identify the clinical factors that influence the duration of postconcussion symptoms among youth referred to a sports concussion clinic. STUDY DESIGN: A retrospective cohort study was conducted to evaluate several potential predictors of symptom duration via a Cox proportional hazards analyses. The individual postconcussion symptom scores were highly correlated, so these symptoms were analyzed in the statistical model as coefficients derived from principal component analyses. RESULTS: Among 1953 youth with concussion, 1755 (89.9%) had dates of reported symptom resolution. The remainder (10.1%) were lost to follow-up and censored. The median time to recovery was 18 days (range 1-353 days). By 30 days, 72.6% had recovered; by 60 days, 91.4% had recovered; and by 90 days, 96.8% had recovered. Several variables in a multivariate Cox model predicted postconcussion symptom duration: female sex (P < .001, hazard ratio [HR] = 1.28), continued activity participation (P = .02, HR = 1.13), loss of consciousness (P = .03, HR = 1.18), anterograde amnesia (P = .04, HR = 1.15), premorbid headaches (P = .03, HR = 1.15), symptom components from the day of concussion (emotion, P = .03, HR = 1.08), and the day of clinic evaluation (cognitive-fatigue, P < .001, HR = 1.22; cephalalgic, P < .001, HR = 1.27; emotional, P = .05, HR = 1.08; arousal-stimulation, P = .003, HR = 1.1). In univariate analyses, greater symptom scores generally predicted longer symptom durations. Worsening of symptoms from the day of concussion to the day of clinic evaluation also predicted longer recovery (P < .001, HR = 1.59). CONCLUSIONS: Several factors help to predict protracted postconcussion symptom durations among youth referred to a sports concussion clinic.

Post-traumatic headaches correlate with migraine symptoms in youth with concussion.

OBJECTIVE: The term "post-traumatic migraine" (PTM) has been used to describe post-traumatic headaches (PTHs) that have associated migraine features, but studies of this relationship are lacking. The objective of the present study was to determine whether PTH correlates strongly with migraine symptoms among youth with concussion. METHODS: Twenty-three symptoms were analyzed from a retrospective cohort of 1953 pediatric patients with concussion. A principal component analysis (PCA) with oblique Promax rotation was conducted to explore underlying symptom relationships in the full cohort and in subcohorts stratified by the presence (n = 414) or absence (n = 1526) of premorbid headache. RESULTS: The mean patient age was 14.1 years; 63% were male. Headache was the most common postconcussion symptom, acknowledged by 69.4% of patients. When considering the full cohort, the PCA demonstrated clustering of headache with photophobia, phonophobia, nausea, dizziness, and neck pain. Similar clustering was present among patients without premorbid headaches. Repeating the analysis in the patients with preconcussion headaches led to elimination of neck pain from the cluster. CONCLUSIONS: PTH correlates strongly with other migraine symptoms among youth with concussion, regardless of premorbid headaches. This clustering of migraine symptoms supports the existence of PTM as a distinct clinical entity in some patients.

Nucleosomes accelerate transcription factor dissociation.

Transcription factors (TF) bind DNA-target sites within promoters to activate gene expression. TFs target their DNA-recognition sequences with high specificity by binding with resident times of up to hours in vitro. However, in vivo TFs can exchange on the order of seconds. The factors that regulate TF dynamics in vivo and increase dissociation rates by orders of magnitude are not known. We investigated TF binding and dissociation dynamics at their recognition sequence within duplex DNA, single nucleosomes and short nucleosome arrays with single molecule total internal reflection fluorescence (smTIRF) microscopy. We find that the rate of TF dissociation from its site within either nucleosomes or nucleosome arrays is increased by 1000-fold relative to duplex DNA. Our results suggest that TF binding within chromatin could be responsible for the dramatic increase in TF exchange in vivo. Furthermore, these studies demonstrate that nucleosomes regulate DNA-protein interactions not only by preventing DNA-protein binding but by dramatically increasing the dissociation rate of protein complexes from their DNA-binding sites.

High school principals' resources, knowledge, and practices regarding the returning student with concussion.

OBJECTIVE: To determine high school principals' self-reported resources, knowledge, and practices regarding the management of students returning to school following concussion. STUDY DESIGN: A cross-sectional survey of public high school principals in the state of Ohio assessed respondent and school demographics, respondent concussion training, school resources, and monitoring and accommodation practices for students with concussion. RESULTS: Of the 695 eligible high school principals, 465 (66.9%) completed the survey. Over one-third of principals (37.2%) had some form of concussion training in the past year. Those with training were more likely to promote training of other school faculty (57.4% vs 30.6%, P < .001). Principals were asked to identify school personnel who are designated as case managers for students with concussion. Schools without a designated case manager were less likely to have an athletic trainer (P < .001) and had fewer students (median 424.5 vs 599) than schools with a case manager. Principals could list at least 1 faculty designee who communicates with health professionals more often for student-athletes than for nonathletes (P < .001). Most principals were willing to provide students with short-term academic accommodations, but 30.1% required a health professional's note prior to making any academic changes. Only 32% of principals reported providing families with a written academic plan following concussion. CONCLUSIONS: Schools differ in their resources and management strategies for students returning to school after concussion. Understanding these differences can help health professionals to overcome potential barriers in managing their school-aged patients with concussion.

How long is too long? The lack of consensus regarding the post-concussion syndrome diagnosis.

BACKGROUND/AIM: A standard definition of Post-concussion Syndrome (PCS) does not exist. The objective was to determine consensus regarding the definition of PCS among physician members of the American College of Sports Medicine (ACSM). METHODS: Physician members of the ACSM were sent an electronic survey to determine opinions regarding the PCS diagnosis. RESULTS: Five hundred and ninety-seven physicians completed the survey. When asked the minimum duration of symptoms required to diagnose PCS, respondents answered: <2 weeks (26.6%), 2 weeks to 1 month (20.4%), 1-3 months (33%) and >3 months (11.1%). Physicians who see ≥10% concussion patients in their practise, as well as physicians whose concussion population consists of >50% paediatric patients, were more likely to require >1 month of symptoms (p < 0.001). When asked the minimum number of symptoms required to diagnose PCS, responses varied: one symptom (55.9%), two symptoms (17.6%), three symptoms (14.6%) and four or more symptoms (3.2%). Respondents from the US were more likely than non-US respondents to require only one symptom for the PCS diagnosis (p = 0.01). CONCLUSIONS: There is a lack of consensus regarding the definition of PCS among physician members of the ACSM. A standard definition would improve consistency in concussion research and in clinical practise.

Comparing patient and parent recall of 90-day and 30-day migraine disability using elements of the PedMIDAS and an Internet headache diary.

AIM: The aim of this article is to compare 90-day and 30-day recall of Pediatric Migraine Disability Assessment (PedMIDAS) elements and headache frequency against daily entries from an Internet headache diary among pediatric patients and their parents. METHODS: In a prospective cohort study, patients aged 10-18 years with episodic migraine or probable migraine completed a 90-day Internet-based headache diary that incorporated PedMIDAS questions. Following the 90-day diary period, patients and parents completed modified PedMIDAS instruments to assess 90-day and 30-day recall. Intraclass correlation coefficients (ICC) were calculated to measure recall reliability. The Kruskal-Wallis and Jonckheere-Terpstra tests were used to explore recall accuracy as it relates to each participant's self-reported confidence in recall and to patient age. RESULTS: Fifty-two subjects completed 90 consecutive diary entries. Comparing 30-day to 90-day recall of PedMIDAS elements, ICC scores improved by 26.2% (patients) and 17.5% (parents). Patients had better recall than their parents for all study measures. Self-reported confidence in recall and patient age had limited and inconsistent effects on recall accuracy. CONCLUSION: The optimal recall interval to assess migraine disability must balance recall accuracy with generalizability across a range of headache frequencies. When compared to daily diary entries, recall accuracy of PedMIDAS elements and headache frequency improves at 30 days compared to 90 days. Parent report of migraine disability should not be used as a replacement for patient report.

PedMIDAS-based scoring underestimates migraine disability on non-school days.

OBJECTIVE: The aim of this study is to compare daily Pediatric Migraine Disability Assessment (PedMIDAS)-based scores for headaches occurring on school days vs non-school days and during the school year vs the summer holiday. BACKGROUND: The PedMIDAS is the only instrument validated to assess migraine disability among school-aged children. However, the PedMIDAS may underestimate disability during prolonged school holidays. METHODS: In a prospective cohort study, migraine patients aged 10-18 years completed a 90-day Internet-based headache diary. For each headache day, they answered PedMIDAS-based questions and rated their headache intensity (scale 1-10). PedMIDAS-based scores, headache intensity ratings, and relative headache frequencies were compared for school days vs non-school days and for the school year vs the summer holiday. RESULTS: Fifty-two patients completed 4680 diary entries comprising 984 headache days. The headache frequencies and intensity ratings did not differ between time periods. However, the mean headache disability scores (as measured from PedMIDAS-based questions) were significantly different for school days (0.85) compared to non-school days (0.45), P < .001, and for the school year (0.73) compared to the summer holiday (0.46), P < .016. CONCLUSION: Given similar headache intensities and frequencies, daily PedMIDAS-based scores significantly underestimate headache disability on non-school days. Accordingly, PedMIDAS scoring during the school year may not be comparable to assessments done during the summer holiday. These potential differences must be considered when using the instrument as an outcome measure for clinical trials.

Regulation of the nucleosome unwrapping rate controls DNA accessibility.

Eukaryotic genomes are repetitively wrapped into nucleosomes that then regulate access of transcription and DNA repair complexes to DNA. The mechanisms that regulate extrinsic protein interactions within nucleosomes are unresolved. We demonstrate that modulation of the nucleosome unwrapping rate regulates protein binding within nucleosomes. Histone H3 acetyl-lysine 56 [H3(K56ac)] and DNA sequence within the nucleosome entry-exit region additively influence nucleosomal DNA accessibility by increasing the unwrapping rate without impacting rewrapping. These combined epigenetic and genetic factors influence transcription factor (TF) occupancy within the nucleosome by at least one order of magnitude and enhance nucleosome disassembly by the DNA mismatch repair complex, hMSH2-hMSH6. Our results combined with the observation that ∼30% of Saccharomyces cerevisiae TF-binding sites reside in the nucleosome entry-exit region suggest that modulation of nucleosome unwrapping is a mechanism for regulating transcription and DNA repair.