Frontiers in Operations: Valuing Nursing Productivity in Emergency Departments.

Problem definition: We quantify the increase in productivity in emergency departments (ED) from increasing nurse staff. We then estimate the associated revenue gains for the hospital and the associated welfare gains for society. Academic/practical relevance: The United States is over a decade into the worst nursing shortage crisis in history, fueled by chronic under-investment. To demonstrate to hospital managers and policymakers the benefits of investing in nursing, we clarify the positive downstream effects of doing so in the ED setting. Methodology: We use a high-resolution data set of patient visits to the ED of a major U.S. academic hospital. Time-dependent hazard estimation methods (nonparametric and parametric) are used to study how the realtime service speed of a patient varies with the state of the ED, including the time-varying workloads of the assigned nurse. A counterfactual simulation is used to estimate the gains from increasing nurse staff in the ED. Results: We find that lightening a nurse's workload by one patient is associated with a 14% service speedup for every patient under the nurse's care. Simulation studies suggest that adding one more nurse to the busiest 12-hour shift of each day can shorten stays and avert $160,000 in lost patient wages per 10,000 visits. The reduction in service times also frees up capacity for treating more patients and generate $470,000 in additional net revenues for the hospital per 10,000 visits. Extensive sensitivity analyses suggest that our key message-investing in nursing will more than pay for itself-is likely to hold across a wide range of EDs. Managerial implications: In determining whether to invest in more nursing resources, hospital managers need to look beyond whether payer reimbursements alone are sufficient to cover the upfront costs, to also account for the resulting downstream benefits.

A Rare Prolactin-secreting Pituitary Carcinoma With Epidural and Thecal Metastases.

Pituitary carcinomas are rare but associated with significant morbidity and mortality. They remain challenging to diagnose and manage. In this case, we describe a 56-year-old man who presented with erectile dysfunction and binocular vertical diplopia. He had central hypogonadism, secondary adrenal insufficiency, and central hypothyroidism on biochemical testing. His serum prolactin was 1517 mcg/L (1517 ng/mL; reference range 4-15 mcg/L), and his sellar magnetic resonance imaging showed a 2.0 × 2.2 × 3.1 cm pituitary tumor. Pathology revealed a prolactin-secreting carcinoma. Despite treatment with a high-dose dopaminergic, 2 transsphenoidal resections, and 1 course of radiation, prolactin levels continued to rise. He developed metastases to the epidural space and thecal sac from the thoracic to sacral spine, for which he received 12 cycles of temozolomide chemotherapy with initial clinical and biochemical response. This was followed by disease escape and progression. We discuss the clinical and imaging features that warrant a high index of suspicion for pituitary carcinoma and review contemporary treatment.

Perinatal Azithromycin Provides Limited Neuroprotection in an Ovine Model of Neonatal Hypoxic-Ischemic Encephalopathy.

BACKGROUND: Hypoxic-ischemic brain injury/encephalopathy affects about 1.15 million neonates per year, 96% of whom are born in low- and middle-income countries. Therapeutic hypothermia is not effective in this setting, possibly because injury occurs significantly before birth. Here, we studied the pharmacokinetics, safety, and efficacy of perinatal azithromycin administration in near-term lambs following global ischemic injury to support earlier treatment approaches. METHODS: Ewes and their lambs of both sexes (n=34, 141-143 days) were randomly assigned to receive azithromycin or placebo before delivery as well as postnatally. Lambs were subjected to severe global hypoxia-ischemia utilizing an acute umbilical cord occlusion model. Outcomes were assessed over a 6-day period. RESULTS: While maternal azithromycin exhibited relatively low placental transfer, azithromycin-treated lambs recovered spontaneous circulation faster following the initiation of cardiopulmonary resuscitation and were extubated sooner. Additionally, peri- and postnatal azithromycin administration was well tolerated, demonstrating a 77-hour plasma elimination half-life, as well as significant accumulation in the brain and other tissues. Azithromycin administration resulted in a systemic immunomodulatory effect, demonstrated by reductions in proinflammatory IL-6 (interleukin-6) levels. Treated lambs exhibited a trend toward improved neurodevelopmental outcomes while histological analysis revealed that azithromycin supported white matter preservation and attenuated inflammation in the cingulate and parasagittal cortex. CONCLUSIONS: Perinatal azithromycin administration enhances neonatal resuscitation, attenuates neuroinflammation, and supports limited improvement of select histological outcomes in an ovine model of hypoxic-ischemic brain injury/encephalopathy.

The importance of measuring prolactin prior to surgical management of a pituitary lesion: An illustrative case.

The characterization of sellar and suprasellar lesions is reliant on patient presentation, medical imaging, and hormone profiling. Prolactinomas are the most common type of functional pituitary adenomas, accounting for up to 57%. Importantly, prolactinomas can present without clear symptoms and with doubtful or even normal imaging. A 41-year-old male patient was referred to neurosurgery for consideration for resection of a sellar lesion, as initial CT imaging suggested a large meningioma. Subsequent MRI of the sella favored macroadenoma, meningioma, and craniopharyngioma as the top differential considerations. These conditions all indicate a diagnosis that would require surgical management. Clinical evaluation of this patient did not elicit any obvious clinical features suggestive of hyperprolactinemia. Fortunately, we obtained a full hormone panel which revealed a significantly elevated prolactin level of 17,390 µg/L. Based on this elevated prolactin level, we diagnosed a pituitary giant prolactinoma. Treatment with a dopamine agonist therapy was initiated and the response confirmed this diagnosis. This case demonstrates the importance of obtaining a prolactin level prior to surgical management of a sellar lesion. Had a prolactin level not been obtained, this patient would have undergone surgical resection based on both the imaging and clinical judgment.

Toward the use of MRI measurements of bound and pore water in fracture risk assessment.

The current clinical assessment of fracture risk lacks information about the inherent quality of a person's bone tissue. Working toward an imaging-based approach to quantify both a bone tissue quality marker (tissue hydration as water bound to the matrix) and a bone microstructure marker (porosity as water in pores), we hypothesized that the concentrations of bound water (Cbw) are lower and concentrations of pore water (Cpw) are higher in patients with osteoporosis (OP) than in age- and sex-matched adults without the disease. Using recent developments in ultrashort echo time (UTE) magnetic resonance imaging (MRI), maps of Cbw and Cpw were acquired from the uninjured distal third radius (Study 1) of 20 patients who experienced a fragility fracture of the distal radius (Fx) and 20 healthy controls (Non-Fx) and from the tibia mid-diaphysis (Study 2) of 30 women with clinical OP (low T-scores) and 15 women without OP (normal T-scores). In Study 1, Cbw was significantly lower (p = 0.0018) and Cpw was higher (p = 0.0022) in the Fx than in the Non-Fx group. In forward stepwise, logistic regression models using Bayesian Information Criterion for selecting the best set of predictors (from imaging parameters, age, BMI, and DXA scanner type), the area-under-the-receiver operator characteristics-curve (AUC with 95 % confidence intervals) was 0.73 (0.56, 0.86) for hip aBMD (best predictors without MRI) and 0.86 (0.70, 0.95) for the combination of Cbw and Cpw (best predictors overall). In Study 2, Cbw was significantly lower (p = 0.0005) in women with OP (23.8 ± 4.3 1H mol/L) than in women without OP (29.9 ± 6.4 1H mol/L); Cpw was significantly higher by estimate of 2.9 1H mol/L (p = 0.0298) with clinical OP, but only when accounting for the type of UTE-MRI scan with 3D providing higher values than 2D (p < 0.0001). Lastly, Cbw, but not Cpw, was sensitive to bone forming osteoporosis medications over 12-months. UTE-MRI-derived measurements of bound and pore water concentrations are potential, aBMD-independent predictors of fracture risk.

Grit: what is it and why does it matter in medicine?

Grit refers to the combination of passion and perseverance for long-term goals. Grit has emerged as a recent topic of interest within the medical community. With ever-increasing rates of burnout and psychological distress, increasing attention has been directed towards modulatory or protective factors for these deleterious outcomes. Grit has been studied in regard to a variety of outcomes and variables in medicine. This article reviews the current literature on grit in medicine and summarises the current research on grit and performance metrics, personality characteristics, longitudinal progression, psychological well-being, diversity, equity and inclusion, burnout and residency attrition. While there is inconclusive evidence on the influence of grit on performance metrics in medicine, research consistently demonstrates a positive correlation between grit and psychological well-being and a negative correlation between grit and burnout. After discussing some of the inherent limitations of this type of research, this article suggests some possible implications and future areas for research and their potential role in cultivating psychologically healthy physicians and promoting successful careers in medicine.

Retired Orthopedic Surgeons' Reflections on Their Lives and Careers: A Cross-Sectional Study.

Background: Retired surgeons often have limited opportunities to disseminate their wisdom and expertise in a structured manner to their younger colleagues. In addition, when asked to reflect on their personal and professional lives, many physicians say they wish they had done something differently. The extent to which this is true of retired orthopedic surgeons is not known. Purpose: We sought to determine the percentage of retired orthopedic surgeons who say that they would like to have changed something in their life/career and delineate the most commonly desired changes. Methods: We conducted a cross-sectional study of retired orthopedic surgeons, by emailing a Qualtrics survey to 5864 emeritus members of the American Academy of Orthopaedic Surgeons (AAOS), with 1 initial email invitation in April 2021 followed by 2 reminders in May 2021. The survey employed a branching logic, with up to 16 questions designed to determine whether they would have done anything differently in their life/career. Results: The survey was completed by 1165 of 5864 emeritus AAOS members, for a response rate of nearly 20%. The 3 most represented surgical subspecialties were general orthopedics, adult reconstruction, and hand and upper extremity surgery. Respondents' average age was 74.9 years and age at retirement was 67.8 years; nearly half worked part-time before retiring. More than 80% of the participants said that they had retired at the appropriate time, and 28.5% said they wished they had done something differently. The wished-for changes most often noted were spending more time with family, spending more time on personal wellness, and selecting better practice partners. Conclusion: The results of our survey of retired orthopedic surgeons show that while most were satisfied with their lives and careers, some had regrets. These findings suggest that there may be factors in the work lives of current surgeons that could be altered to reduce regret. Further study is warranted.

Grit: what is it and why does it matter in medicine?

Grit refers to the combination of passion and perseverance for long-term goals. Grit has emerged as a recent topic of interest within the medical community. With ever-increasing rates of burnout and psychological distress, increasing attention has been directed towards modulatory or protective factors for these deleterious outcomes. Grit has been studied in regard to a variety of outcomes and variables in medicine. This article reviews the current literature on grit in medicine and summarises the current research on grit and performance metrics, personality characteristics, longitudinal progression, psychological well-being, diversity, equity and inclusion, burnout and residency attrition. While there is inconclusive evidence on the influence of grit on performance metrics in medicine, research consistently demonstrates a positive correlation between grit and psychological well-being and a negative correlation between grit and burnout. After discussing some of the inherent limitations of this type of research, this article suggests some possible implications and future areas for research and their potential role in cultivating psychologically healthy physicians and promoting successful careers in medicine.

The Relationships Between Grit, Burnout, and Demographic Characteristics in Medical Students.

Grit, a positive psychological trait comprised of perseverance and passion, has been correlated with physician burnout but has not been extensively studied among medical students. Identification of the relationship between grit and burnout as well as between burnout and other demographics could help to identify students at risk of burnout, while informing educational strategies to increase grit in the medical occupation. For this cross-sectional study, an online, email-based survey including demographic questions, the Maslach Burnout Inventory-Human Services (Medical Personnel) Survey, and the Short Grit Scale was distributed to an entire student body of allopathic medical students via a schoolwide listserv in 2019. The response rate was 39.6% (177/444). Negative correlations were displayed between grit and emotional exhaustion, depersonalization, and overall burnout. Positive correlation was demonstrated between grit and personal accomplishment. Male participants had higher depersonalization than female participants and fourth year medical students had higher depersonalization than other years of training. Fourth year medical students had higher personal accomplishment than other years of training and married students had higher personal accomplishment than those who had never been married. These findings are important not only for potential identification of students at risk of burnout, but also for development of strategies to bolster grit and mitigate distressing experiences in the medical occupation. Future studies are necessary to gauge how this relationship may evolve throughout a medical career.

Pearls & Oy-sters: Salt and Pepper Sign, PLNTY for Drug-Resistant Epilepsy.

Drug-resistant epilepsy, defined as the failure of 2 or more antiseizure medications to achieve seizure freedom, is responsible for 2/3 of epilepsy cases. Tumors are responsible for up to 15% of all adult onset and up to 6% of childhood onset epilepsies. Among these tumors, commonly known subtypes DNET, ganglioglioma, and low-grade astrocytoma are often suspected. New advances in tumor classification have been made, with genetics playing a key role in tumor classification. Polymorphic low-grade neuroepithelial tumor of the young (PLNTY) is a highly epileptogenic subtype of tumors that may mimic low-grade gliomas but offer pathologic and genetic clues: oligodendroglioma-like cellular components and infiltration patterns and strong CD34-immunopositive stain. In addition, a key finding is radiologic: a unifocal abnormality best seen on MRI brain in FLAIR sequence as the "salt and pepper sign" and calcifications appreciated on CT head.

Modified Brunelli Reconstruction for Scapholunate Ligament Dissociation.

Background: The present video article describes the steps, alternatives, and outcomes of the modified Brunelli reconstruction, also known as 3-ligament tenodesis, for the treatment of irreparable scapholunate dissociations. Description: The presently described technique is generally utilized in cases in which there is an irreparable disruption of the scapholunate ligament and widening of the scapholunate junction with no carpal arthritis. Alternatives: Other treatment options for irreparable scapholunate dissociation include various forms of capsulotenodesis, bone-ligament-bone reconstruction, tendon-based reconstructions, partial wrist arthrodesis, and proximal row carpectomy. Rationale: The modified Brunelli reconstruction is indicated for a nonrepairable complete scapholunate ligament injury with a reducible rotatory subluxation of the scaphoid, without cartilage degeneration. The dorsal scapholunate ligament is reconstructed and the distal palmar scaphoid rotation is corrected with use of a distally based flexor carpi radialis tendon. The reconstruction is achieved by placing the flexor carpi radialis tendon through a transosseous scaphoid tunnel and weaving the tendon through the dorsal ulnar capsule or radiotriquetral ligament. Expected Outcomes: The modified Brunelli technique has been shown to restore wrist motion to 70% to 80% of that of the contralateral wrist and grip strength to 65% to 75% of that of the contralateral wrist, as well as to provide good pain relief in approximately 70% to 80% of patients. Important Tips: With use of simple instrumentation, C-arm fluoroscopy, and proper surgical technique, this operative procedure is fairly reproducible. Acronyms and Abbreviations: FCR = flexor carpi radialisK-wire = Kirschner wire.

Feasibility of deconvolution-based multiphase CT angiography perfusion maps in acute ischemic stroke: Simulation and concordance with CT perfusion.

OBJECTIVES: Integration of CT perfusion (CTP) with requisite non-contrast CT and CT angiography (CTA) stroke imaging may allow efficient stroke lesion volume measurement. Using surrogate images from CTP, we simulated the feasibility of using multiphase CTA (mCTA) to generate perfusion maps and assess target mismatch profiles. MATERIALS AND METHODS: Patients with acute ischemic stroke who received admission CTP were included in this study. Four CTP images (surrogate mCTA, one pre-contrast and three post-contrast, starting at the arterial peak then at 8 s intervals) were selected according to the CTP arterial time-density curve to simulate non-contrast CT and mCTA images. Cerebral blood flow (CBF) and Tmax maps were calculated using the same model-based deconvolution algorithm for the standard CTP and surrogate mCTA studies. Infarct and penumbra were delineated with CBF < 20% and Tmax > 6 s threshold, respectively. Classification accuracy of surrogate mCTA target mismatch (infarct <70 ml; penumbra ≥15 ml; mismatch ratio ≥1.8) with respect to standard CTP was assessed. Agreement between infarct and penumbra volumes from standard CTP and surrogate mCTA maps were evaluated by Bland-Altman analysis. RESULTS: Of 34 included patients, 28 had target mismatch and 6 did not by standard CTP. Accuracy of classifying target mismatch profiles with surrogate mCTA was 79% with respect to that from standard CTP. Mean  ±  standard deviation of differences (standard CTP minus surrogate mCTA) of infarct and penumbra volumes were 9.8 ± 14.8 ml and 20.1 ± 45.4 ml, respectively. CONCLUSIONS: Surrogate mCTA ischemic lesion volumes agreed with those from standard CTP and may be an efficient alternative when CTP is not practical.

Coordination and Pilot Implementation of a Standardized Data Collection for Touching Hands.

PURPOSE: Touching Hands is an American Society for Surgery of the Hand program that provides hand surgeries to the world's underserved communities. The purpose of this study was to develop and implement a systematic data collection method for Touching Hands to assess patient outcomes, volunteer impact, alleviated disease burden, and cost-effectiveness. METHODS: Research electronic data capture (REDCap) was used as the secure software platform to facilitate data collection. The Quick Disabilities of the Arm, Shoulder and Hand questionnaire was used to assess pre-and postoperative patient-reported outcomes. The Maslach Burnout Inventory-Human Services (Medical Personnel) survey was administered to volunteers before and after the mission to measure impact on volunteers. Case information was collected to calculate disability-adjusted life years and cost-effectiveness. RESULTS: The data collection system was implemented in some capacity in 4 domestic and 3 international mission sites during 2020 and 2021. CONCLUSIONS: Substantial limitations exist for the implementation of a systematic data collection framework for Touching Hands and warrant further modification and optimization. CLINICAL RELEVANCE: A REDCap database can be used for standardized and centralized patient and volunteer data collection for Touching Hands missions.

Sterility of Miniature C-arm Fluoroscopy in Hand and Upper Extremity Surgery.

Previous studies have demonstrated that sterile equipment is frequently contaminated intraoperatively, yet the incidence of miniature c-arm (MCA) contamination in hand and upper extremity surgery is unclear. To examine this incidence, a prospective study of MCA sterility in hand and upper extremity cases was performed in a hospital main operating room (MOR) ( n = 13) or an ambulatory surgery center operating room (AOR) ( n = 16) at a single tertiary care center. Case length, MCA usage parameters, and sterility of the MCA through the case were examined. We found that MOR surgical times trended toward significance ( p = 0.055) and that MOR MCAs had significantly more contamination prior to draping than AOR MCAs ( p < 0.001). In MORs and AORs, 46.2 and 37.5% of MCAs respectively were contaminated intraoperatively. In MORs and AORs, 85.7 and 80% of noncontaminated cases, respectively, used the above hand- table technique, while 50 and 83.3% of contaminated MOR and AOR cases, respectively, used a below hand-table technique. Similar CPT codes were noted in both settings. Thus, a high-rate of MCA intraoperative contamination occurs in both settings. MCA placement below the hand-table may impact intraoperative contamination, even to distant MCA areas. Regular sterilization of equipment and awareness of these possible risk factors could lower bacterial burden.

Intraoperative use of impact microindentation to assess distal radius bone quality.

Impact microindentation is a new technique that measures the resistance of a patient's bone to micro-indentation but has not yet been implemented in an intraoperative setting. To assess the technique's safety and utility, we acquired microindentation measurements of bone material strength index (BMSi) using the OsteoProbe prior to distal radius fixation with a volar locking plate. Subsequently, the patients received a dual-energy x-ray absorptiometry scan to measure the areal bone mineral density of the proximal femur, lumbar spine, and contralateral distal radius. By assigning the patients to low-energy, fragility fracture (n = 17) and high-energy fracture (n = 11) groups based on clinical history, we investigated whether intraoperative BMSi was sensitive to osteoporosis. Impact microindentation added a maximum of 10 min of operative time and did not result in any intraoperative or postoperative complications. There were, however, no significant differences in BMSi at the radius between these two groups. This study demonstrates the feasibility of performing intraoperative impact microindentation to directly assess a patient's bone quality, but additional research is necessary to establish whether intraoperative microindentation can identify patients with inferior bone matrix quality.

The Complex Relationship Between Cooling Parameters and Neuroprotection in a Model of Selective Hypothermia.

Background: Hypothermia remains the best studied neuroprotectant. Despite extensive positive large and small animal data, side effects continue to limit human applications. Selective hypothermia is an efficient way of applying neuroprotection to the brain without the systemic complications of global hypothermia. However, optimal depth and duration of therapeutic hypothermia are still unknown. We analyzed a large animal cohort study of selective hypothermia for statistical relationships between depth or duration of hypothermia and the final stroke volume. Methods: A cohort of 30 swine stroke subjects provided the dataset for normothermic and selective hypothermic animals. Hypothermic parameters including duration, temperature nadir, and an Area Under the Curve measurement for 34 and 30°C were correlated with the final infarct volumes measured by MRI and histology. Results: Between group comparisons continue to demonstrate a reduction in infarct volume with selective hypothermia. Histologically-derived infarct volumes were 1.2 mm3 smaller in hypothermia-treated pigs (P = 0.04) and showed a similar, but non-significant reduction in MRI (P = 0.15). However, within the selective hypothermia group, more intense cooling, as measured through increased AUC 34 and decreased temperature nadir was associated with larger infarct proportions by MRI [Pearson's r = 0.48 (p = 0.05) and r = -0.59 (p = 0.01), respectively]. Reevaluation of the entire cohort with quadratic regression demonstrated a U-shaped pattern, wherein the average infarct proportion was minimized at 515 degree-minutes (AUC34) of cooling, and increased thereafter. In a single case of direct brain tissue oxygen monitoring during selective hypothermia, brain tissue oxygen strongly correlated with brain temperature reduction over the course of selective hypothermia to 23°C. Conclusions: In a large animal model of selective hypothermia applied to focal ischemia, there is a non-monotone relationship between duration and depth of hypothermia and stroke volume reduction. This suggests a limit to depth or duration of selective hypothermia for optimal neuroprotection. Further research is required to delineate more precise depth and duration limits for selective hypothermia.

Low-dose CT Perfusion with Sparse-view Filtered Back Projection in Acute Ischemic Stroke.

RATIONALE AND OBJECTIVES: Radiation dose associated with computed tomography (CT) perfusion (CTP) may discourage its use despite its added diagnostic benefit in quantifying ischemic lesion volume. Sparse-view CT reduces scan dose by acquiring fewer X-ray projections per gantry rotation but is contaminated by streaking artifacts using filtered back projection (FBP). We investigated the achievable dose reduction by sparse-view CTP with FBP without affecting CTP lesion volume estimations. MATERIALS AND METHODS: Thirty-eight consecutive patients with acute ischemic stroke and CTP were included in this simulation study. CTP projection data was simulated by forward projecting original reconstructions with 984 views and adding Gaussian noise. Full-view (984 views) and sparse-view (492, 328, 246, and 164 views) CTP studies were simulated by FBP of simulated projection data. Cerebral blood flow (CBF) and time-to-maximum of the impulse residue function (Tmax) maps were generated by deconvolution for each simulated CTP study. Ischemic volumes were measured by CBF<30% relative to the contralateral hemisphere and Tmax > 6 s. Volume accuracy was evaluated with respect to the full-view CTP study by the Friedman test with post hoc multiplicity-adjusted pairwise tests and Bland-Altman analysis. RESULTS: Friedman and multiplicity-adjusted pairwise tests indicated that 164-view CBF < 30%, 246- and 164-view Tmax > 6 s volumes were significantly different to full-view volumes (p < 0.001). Mean difference ± standard deviation (sparse minus full-view lesion volume) ranged from -1.0 ± 2.8 ml to -4.1 ± 11.7 ml for CBF < 30% and -2.9 ± 3.8 ml to -12.5 ± 19.9 ml for Tmax > 6 s from 492 to 164 views, respectively. CONCLUSION: By ischemic volume accuracy, our study indicates that sparse-view CTP may allow dose reduction by up to a factor of 3.

Ultra-High Field 7-Tesla Magnetic Resonance Imaging and Electroencephalography Findings in Epilepsy.

PURPOSE: Assessment of patients for temporal lobe epilepsy (TLE) surgery requires multimodality input, including EEG recordings to ensure optimal surgical planning. Often EEG demonstrates abnormal foci not detected on 1.5T MRI. Ultra-high field MRI at 7T provides improved resolution of the brain. We investigated the utility of 7T MRI to detect potential anatomical abnormalities associated with EEG changes. METHODS: Ultra-high field data were acquired on a 7T MRI scanner for 13 patients with history of drug resistant TLE who had had EEG telemetry recordings. Qualitative evaluation of 7T imaging for presence of focal abnormalities detected on EEG was performed. Correlation of 7T MRI findings with EEG recordings of focal slowing or interictal epileptic spikes (IEDs), and seizures was performed. RESULTS: Assessment of 7T MRI demonstrated concordance with TLE as determined by the multidisciplinary team in 61.5% of cases (n = 8). Among these, 3 patients exhibited supportive abnormal 7T MRI abnormalities not detected by 1.5T MRI. In patients who underwent surgery, 72.7% had concordant histopathology findings with 7T MRI findings (n = 8). However, qualitative assessment of 7T images revealed focal anatomical abnormalities to account for EEG findings in only 15.4% of patients (n = 2). Other regions that were found to have localized IEDs in addition to the lesional temporal lobe, included the contralateral temporal lobe (n = 5), frontal lobe (n = 3), and parieto-occipital lobe (n = 2). CONCLUSION: Ultra-high field 7T MRI findings show concordance with clinical data. However, 7T MRI did not reveal anatomical findings to account for abnormalities detected by EEG.

Investigating the Association between Aortic Arch Variants and Intracranial Aneurysms.

BACKGROUND: There is an association between anterior cerebral artery vessel asymmetry and anterior communicating artery aneurysm, presumably based on flow dynamics. The purpose of this study is to investigate the potential relationship between aortic arch branching patterns and incidence of intracranial aneurysm. METHODS: This study included patients scanned over 1 year at our tertiary care center who underwent high-resolution imaging (computed tomography angiography or digital subtracted angiogram) of the head and neck arteries, aortic arch, and superior mediastinum. Exclusion criteria included patients with suboptimal images. Patient age, gender, aortic arch branching pattern, and the presence, location, and number of aneurysms were documented. RESULTS: Among the 1082 patients analyzed, 250 (23%) patients had a variant aortic arch branching pattern, 22 (8.8%) of whom had aneurysms. There were 104 patients with 126 aneurysms, with majority of patients with normal aortic arch branching pattern (n = 82, 79%). The most common variant was a common origin of the left common carotid artery and brachiocephalic trunk with or without direct origin of the left vertebral artery. Twenty-two patients with aneurysms had an aberrant aortic arch (21%), compared to 232 patients without an aneurysm (24%). Fischer exact test showed no statistically significant difference between the incidence of aneurysm with different aortic arch variant groups (two-tailed p-value = 0.715). CONCLUSION: To our knowledge, this is the first study to examine the association between aortic arch branching patterns and incidence of intracranial aneurysm. No significant association was found between aortic arch branching pattern and the incidence of intracranial aneurysm.

Dynamic PET-facilitated modeling and high-dose rifampin regimens for Staphylococcus aureus orthopedic implant-associated infections.

Staphylococcus aureus is a major human pathogen causing serious implant­associated infections. Combination treatment with rifampin (10 to 15 mg/kg per day), which has dose-dependent activity, is recommended to treat S. aureus orthopedic implant­associated infections. Rifampin, however, has limited bone penetration. Here, dynamic 11C-rifampin positron emission tomography (PET) performed in prospectively enrolled patients with confirmed S. aureus bone infection (n = 3) or without orthopedic infection (n = 12) demonstrated bone/plasma area under the concentration-time curve ratio of 0.14 (interquartile range, 0.09 to 0.19), exposures lower than previously thought. PET-based pharmacokinetic modeling predicted rifampin concentration-time profiles in bone and facilitated studies in a mouse model of S. aureus orthopedic implant infection. Administration of high-dose rifampin (human equipotent to 35 mg/kg per day) substantially increased bone concentrations (2 mg/liter versus <0.2 mg/liter with standard dosing) in mice and achieved higher bacterial killing and biofilm disruption. Treatment for 4 weeks with high-dose rifampin and vancomycin was noninferior to the recommended 6-week treatment of standard-dose rifampin with vancomycin in mice (risk difference, −6.7% favoring high-dose rifampin regimen). High-dose rifampin treatment ameliorated antimicrobial resistance (0% versus 38%; P = 0.04) and mitigated adverse bone remodeling (P < 0.01). Last, whole-genome sequencing demonstrated that administration of high-dose rifampin in mice reduced selection of bacterial mutations conferring rifampin resistance (rpoB) and mutations in genes potentially linked to persistence. These data suggest that administration of high-dose rifampin is necessary to achieve optimal bone concentrations, which could shorten and improve treatments for S. aureus orthopedic implant infections.