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Phased array (PA) receive coils are built such that coil elements approximate independent antenna behavior. One method of achieving this goal is to use an available decoupling method to decouple adjacent coil elements. The purpose of this work was to compare the relative performance of two decoupling methods as a function of variation in sample load. Two PA receive coils with 5 channels (5-ch) each, equal outer dimensions, and formed on 12 cm diameter cylindrical phantoms of conductivities 0.3, 0.6, and 0.9 S/m were evaluated for relative signal-to-noise ratio (SNR) and parallel imaging performance. They were only tuned and matched to the 0.6 S/m phantom. Simulated and measured axial, sagittal, and coronal 5-ch PA coil SNR ratios were compared by dividing the overlap by the capacitive decoupled coil SNR results. Issues related to the selection of capacitor values for the two decoupling methods were evaluated by taking the ratio of the match and tune capacitors for large and small 2 channel (2-ch) PA coils. The SNR ratios showed that the SNR of the two decoupling methods were very similar. The inverse geometry-factor maps showed similar but better overall parallel imaging performance for the capacitive decoupled method. The quotients for the 2-ch PA coils’ maximum and minimum capacitor value ratios are 3.28 and 1.38 for the large and 3.28 and 2.22 for the small PA. The results of this paper demonstrate that as the sample load varies, the capacitive and overlap decoupling methods are very similar in relative SNR and this similarity continues for parallel imaging performance. Although, for the 5-ch coils studied, the capacitive decoupling method has a slight SNR and parallel imaging advantage and it was noted that the capacitive decoupled coil is more likely to encounter unbuildable PA coil configurations.

Purpose. Although full-wave simulations could be used to aid in RF coil design, the algorithms may be too slow for an iterative optimization algorithm. If quasistatic simulations are accurate within the design tolerance, then their use could reduce simulation time by orders of magnitude compared to full-wave simulations. This paper examines the accuracy of quasistatic and full-wave simulations at 3 Tesla. Methods. Three sets of eight coils ranging from 3–10 cm (24 total) were used to measure SNR on three phantoms with conductivities of 0.3, 0.6, and 0.9 S/m. The phantom conductivities were chosen to represent those typically found in human tissues. The range of coil element sizes represents the sizes of coil elements seen in typical coil designs. SNR was determined using the magnetic and electric fields calculated by quasistatic and full-wave simulations. Each simulated SNR dataset was scaled to minimize the root mean squared error (RMSE) when compared against measured SNR data. In addition, the noise values calculated by each simulation were compared against benchtop measured noise values. Results. The RMSE was 0.285 and 0.087 for the quasistatic and full-wave simulations, respectively. The maximum and minimum quotient values, when taking the ratio of simulated to measured SNR values, were 1.69 and 0.20 for the quasistatic simulations and 1.29 and 0.75 for the full-wave simulations, respectively. The ratio ranges, for the calculated quasistatic and full-wave total noise values compared to benchtop measured noise values, were 0.83–1.06 and 0.27–3.02, respectively. Conclusions. Full-wave simulations were on average 3x more accurate than the quasistatic simulations. Full-wave simulations were more accurate in characterizing the wave effects within the sample, though they were not able to fully account for the skin effect when calculating coil noise.

Background and Objectives: Burnout is prevalent among clinicians and entails negative personal, professional, and organizational consequences. Assessments of burnout are typically anonymous to facilitate psychological safety. This limits the capacity of leadership to help struggling providers and reduces the level of demographic detail. Nonanonymous, confidential assessments may facilitate outreach to individuals or targeted interventions for at-risk populations. Methods: We administered the Maslach Burnout Inventory to physician faculty and advanced practice providers in an academic department of family medicine. We identified a wellness officer within the department who served as an honest broker to keep nonanonymous survey responses confidential. Respondents had the option of taking the survey anonymously or confidentially. Anonymous respondents were allowed to withhold demographic information to ensure anonymity. Results: Sixty-seven of 109 providers responded (61% response rate), with 46 (69%) doing so confidentially. Burnout rates were similar between groups: 48% among confidential respondents, and 43% among anonymous respondents (P=.71). Subscales of the MBI also showed no significant differences. Because a large proportion of anonymous respondents withheld demographic data, no demographic trends could be identified among them. Younger confidential respondents were more likely to exhibit depersonalization (P=.01). Conclusions: Most participants chose to respond confidentially. There was no significant difference in the level of burnout between confidential and anonymous respondents. Our findings refute the conventional wisdom that clinicians require anonymity to respond to burnout surveys. This finding has the potential to open a new line of inquiry regarding burnout, its drivers and potential solutions.

Purpose To demonstrate the interchangeable neck shape-specific (NSS) coil concept that supplements standard commercial spine and head/neck coils to provide simultaneous high-resolution (hi-res) head/neck imaging with high signal-to-noise ratio (SNR). Methods Two NSS coils were constructed on formers designed to fit two different neck shapes. A 7-channel (7ch) ladder array was constructed on a medium neck former, and a 9-channel (9ch) ladder array was constructed on large neck former. Both coils were interchangeable with the same preamp housing. Results The 7ch and 9ch coils demonstrate SNR gains of approximately 4 times and 3 times over the Siemens 20-channel head/neck coil in the carotid arteries of our volunteers, respectively. Coupling between the Siemens 32-channel spine coil, Siemens 20-channel head/neck coil, and the NSS coils was negligible, allowing for simultaneous hi-res head/neck imaging with high SNR. Conclusions This study demonstrates that supplementing existing commercial spine and head/neck coils with an NSS coil allows uniform simultaneous hi-res imaging with high SNR in the anterior neck, while maintaining SNR of the commercial coil in the head and posterior neck. Magn Reson Med 78:2460-2468, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

PURPOSE To develop a method for rapid prediction of the geometric focus location in MR coordinates of a focused ultrasound (US) transducer with arbitrary position and orientation without sonicating. METHODS Three small tracker coil circuits were designed, constructed, attached to the transducer housing of a breast-specific MR-guided focused US (MRgFUS) system with 5 degrees of freedom, and connected to receiver channel inputs of an MRI scanner. A one-dimensional sequence applied in three orthogonal directions determined the position of each tracker, which was then corrected for gradient nonlinearity. In a calibration step, low-level heating located the US focus in one transducer position orientation where the tracker positions were also known. Subsequent US focus locations were determined from the isometric transformation of the trackers. The accuracy of this method was verified by comparing the tracking coil predictions to thermal center of mass calculated using MR thermometry data acquired at 16 different transducer positions for MRgFUS sonications in a homogeneous gelatin phantom. RESULTS The tracker coil predicted focus was an average distance of 2.1 ± 1.1 mm from the thermal center of mass. The one-dimensional locator sequence and prediction calculations took less than 1 s to perform. CONCLUSION This technique accurately predicts the geometric focus for a transducer with arbitrary position and orientation without sonicating. Magn Reson Med 77:2424-2430, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Purpose The purpose of this work was to develop and evaluate a system consisting of an insertable gradient, RF coils, and animal positioning hardware to enable imaging of the internal structure of the cochlea and other inner ear structures of a guinea pig model at 3T. Methods Transmit and receive RF coils, and an animal positioning system, were developed and integrated with an insertable gradient and animal monitoring system for improved guinea pig cochlea imaging when compared to a standard clinical 3T MRI system. A resolution phantom with 120 μm line separations was used to assess the contrast improvements with the insertable gradient. A homogeneous phantom was used to assess the SNR and homogeneity of the RF coils. FLASH imaging was used to observe the temporal passage of gadolinium contrast through the guinea pig cochlea. Results The insertable gradient enabled increased resolution imaging with nearly twice the contrast-to-noise ratio. The small animal array had better SNR for imaging the guinea pig cochlea (about 14 mm deep) than the commercial Siemens wrist coil (2.2×) and the small birdcage coil (1.6×). The positioning device kept the animal secure and stationary. Injected gadolinium contrast allowed visualization of the internal cochlear structures with FLASH image acquisition, which achieved 100 μm isotropic resolution images in 33 min. Conclusion The specialized RF coils and animal holding equipment designed to operate within the composite gradient enabled higher resolution images than could be obtained from the available RF coils operating in the conventional gradients on the clinical MRI system. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 44B: 89–101, 2015

Background : Venous thromboembolism (VTE) prophylaxis is underutilized in hospitalized medical patients. Underutilization might occur as a result of resident practice variation incurred by using a complex risk assessment tool. Objective : To examine what impact repetitive exposure to an electronic point-based VTE risk assessment tool has on resident inter-rater reliability and protocol adherence. Design : Pre and post intervention cross-sectional cohort study. Setting : Single academic center. Patients : Convenience samples of Internal Medicine residents. Interventions : Residents completed clinical vignettes before and after any exposure to an electronic risk assessment tool and reminder alert. They were asked to make three determinations using a point-based VTE risk assessment tool: risk stratification, identify contraindications, and VTE prevention strategy. Measurements : Inter-rater reliability for risk assessment, contraindications, and VTE prophylaxis strategy and protocol adherence. Results : Kappa scores for VTE risk assessment did not change, but improved for VTE plan increasing from 0.28 to 0.37. Protocol adherence improved from 71% in 2008 to 79% (P = 0.06). There was a significant decrease in under-prophylaxis (22% to 6%, P 0.0001) but a significant increase in over-prophylaxis (7% to 16%, P = 0.001). Conclusions : Using clinical vignettes, we determined that daily exposure to an electronic risk assessment tool did not improve the inter-rater reliability of a point-based risk assessment tool when used by medical residents. This might be due to inexperienced providers using a complex point-based tool. Overall, adherence improved, and under-prophylaxis decreased, but over-prophylaxis increased. Clinical vignettes are a generalizable method to monitor resident prophylaxis practices and way to identify educational and process improvement opportunities. doi:10.4021/jocmr766w

Background Pennsylvania is home to Amish and Mennonite communities with an estimated combined population of over 90,000 people. Under-immunization is common with vaccine preventable diseases, including tetanus, periodically presenting among children from these communities. Nearly 20% of nationally reported pediatric tetanus cases in the past 10 years were treated at our institution, the tertiary care center which serves these unique populations. We characterize demographics and costs of treating this rare, but largely preventable infection. Methods Chart review based on ICD-9 codes for tetanus infection in patients aged 0–17 years treated for clinically diagnosed tetanus infection between January 2006 and December 2015. Cost data were extracted from Horizon Business Insight software and analyzed in Microsoft Excel. Cases were mapped using UDS Mapper. Results Four cases of pediatric tetanus infection were identified with 100% occurring in unimmunized patients and 3 of 4 (75%) in Amish individuals. Treatment costs amounted to $121,170 with estimated payment of $80,664 resulting in a net loss to the hospital of $40,506 over the course of 10 years. Each case treated resulted in a median loss of $4,402 to the hospital. Conclusion The costs of treating this vaccine preventable disease for both hospitals and under-immunized Amish and Mennonite communities, who tend to pay out-of-pocket, should be emphasized in targeted outreach and education programs at the population level. Disclosures All authors: No reported disclosures.

Computer-based tools to assess venous thromboembolism (VTE) risk have been shown to increase VTE pharmacoprophylaxis rates and decrease VTE incidence in high-risk hospitalized patients. However, VTE risk may be underestimated using computer-based tools alone. We tested the effect of a provider-enhanced clinical decision support (CDS) tool on VTE pharmacoprophylaxis and VTE incidence in patients who would have been deemed "low risk" using a computer-based risk-assessment tool alone.The study sample was adult patients hospitalized during a 13-month period who were determined to be at low risk for VTE with a computer-based risk-assessment tool. The provider-enhanced CDS tool was implemented 4 months into the study period and required providers to stratify patients as being at high, moderate, or low risk for VTE. We compared rates of VTE pharmacoprophylaxis and VTE incidence before and after implementation of the provider-enhanced CDS tool.There were 1322 patients in the 4-month pre-implementation period and 3347 patients in the 9-month post-implementation period who were determined to be at low risk for VTE based on a computer-based risk-assessment tool. Using the provider-enhanced CDS tool, providers stratified 31% of these computer-assigned low-risk patients as being at moderate risk for VTE and 7% as being at high risk for VTE. The rate of VTE pharmacoprophylaxis increased from 27% to 34% (P0.01). The venous thromboprophylaxis rate decreased from 0.98% to 0.42% after implementation of the provider-enhanced CDS tool (P0.02).Patients identified as being at low risk for VTE solely by computer-based algorithms may include patients whom providers determine to be at risk for VTE. Provider-enhanced CDS tools may outperform computer-based VTE risk-stratification algorithms.

BACKGROUND: Venous thromboembolic events (VTE) are a significant cause of mortality in hospitalized medical and surgical patients. Despite recommendations and guidelines, current evidence demonstrates that VTE prophylaxis remains underutilized in at-risk patients. The process of providing VTE prophylaxis begins with assessing each patient's VTE risk. Using an individualized, point-based protocol in the assessment process is a complex task, and might contribute to variability in VTE prescribing behavior. There are no published data on how reliably residents can perform risk assessment and prophylaxis using a point-based VTE risk assessment tool. OBJECTIVE: Our aim was to determine inter-rater reliability of a point-based risk assessment tool by residents early in the academic year. DESIGN: The design was a cross-sectional-cohort observational study. SETTING: The site was an academic medical center. PATIENTS: Case-based clinical vignettes were used. INTERVENTIONS: Verbal instructions were given to medical residents about how to apply our hospital's point-based VTE risk assessment tool. MEASUREMENTS: Interobserver agreement was measured of: 1) risk score, 2) risk-stratification, 3) identification of contraindications, 4) VTE prophylaxis plan, and 5) resident adherence to the protocol. RESULTS: The intra-class correlation (ICC) for the total risk score was 0.66 and the kappa coefficient for risk stratification was 0.51. The kappa scores for absolute and relative contraindications were 0.29 and 0.23, respectively. The kappa score for the VTE plan was 0.28. CONCLUSIONS: We determined that, following brief instructions early in the academic year, a point-based VTE risk assessment tool has only fair to moderate inter-rater reliability, with suboptimal adherence to the protocol. Both might lead to underutilization of VTE prevention strategies. Journal of Hospital Medicine 2011. © 2011 Society of Hospital Medicine.

Asexually-reproducing gametophytes of the four tropical fern genera Hymenophyllum, Trichomanes, Grammitis, and Vittaria occur in the uplands of the southeastern United States (Farrar, 1967). The most common and abundant of these is the Appalachian Vittaria gametophyte, which Farrar (1978) has described in detail. Dr. A. J. Sharp of the University of Tennessee was the first to find and collect the Appalachian Vittaria gametophyte in the area of the Mountain Lake Biological Station in Virginia. Since that time, Dr. W. H. Wagner, Jr. of the University of Michigan collected it in the same area and catalogued it into a pteridophyte flora (Wagner, 1963). Other pteridologists have collected it in the area of the Highlands Biological Station in North Carolina (Wagner et al., 1970; Pittillo et al., 1975) and in Tennessee (Wofford & Evans, 1979). Other collections have located these gametophytes in several eastern states in and around the southern Appalachians (Farrar, 1978; Gastony, 1977). Appalachian Vittaria gametophytes are long-lived and produce extensive colonies in deep, protected crevices of non-calcareous rock. Although antheridia and archegonia are produced on the gametophytes, reduced, juvenile sporophytes have been found only once in the field by Farrar (1978). They were recognizable as Vittaria, but lacked sufficient characters for identification to species. Since most taxonomic characters for determining fern species are based on sporophyte morphology, the origin and affinities of these gametophytes are uncertain. They were first assigned to the genus Vittaria by Wagner and Sharp (1963) based on finding similar morphological characters between the gametophytes of the Appalachian Vittaria and those of Vittaria lineata (L.) J. E. Smith from Florida. The chromosome counts reported by Gastony (1977) have provided further evidence of their relationship. The experimental production of sporophytes might provide additional taxonomic characters for comparison with the Vittaria species. Farrar (1978) reported that Appalachian Vittaria gametophytes were difficult to maintain in axenic culture and ceased to grow on defined media. We report here successful axenic culture of the Appalachian Vittaria gametophyte and the spontaneous formation of callus and sporophytes.