RF coil design strategies for improving SNR at the ultrahigh magnetic field of 10.5 Tesla.

Purpose: To develop multichannel transmit and receive arrays towards capturing the ultimate-intrinsic-SNR (uiSNR) at 10.5 Tesla (T) and to demonstrate the feasibility and potential of whole-brain, high-resolution human brain imaging at this high field strength. Methods: A dual row 16-channel self-decoupled transmit (Tx) array was converted to a 16Tx/Rx transceiver using custom transmit/receive switches. A 64-channel receive-only (64Rx) array was built to fit into the 16Tx/Rx array. Electromagnetic modeling and experiments were employed to define safe operation limits of the resulting 16Tx/80Rx array and obtain FDA approval for human use. Results: The 64Rx array alone captured approximately 50% of the central uiSNR at 10.5T while the identical 7T 64Rx array captured ∼76% of uiSNR at this lower field strength. The 16Tx/80Rx configuration brought the fraction of uiSNR captured at 10.5T to levels comparable to the performance of the 64Rx array at 7T. SNR data obtained at the two field strengths with these arrays displayed dependent increases over a large central region. Whole-brain high resolution T 2 * and T 1 weighted anatomical and gradient-recalled echo EPI BOLD fMRI images were obtained at 10.5T for the first time with such an advanced array, illustrating the promise of >10T fields in studying the human brain. Conclusion: We demonstrated the ability to approach the uiSNR at 10.5T over the human brain with a novel, high channel count array, achieving large SNR gains over 7T, currently the most commonly employed ultrahigh field platform, and demonstrate high resolution and high contrast anatomical and functional imaging at 10.5T.

Faster bi-stable visual switching in psychosis.

Bi-stable stimuli evoke two distinct perceptual interpretations that alternate and compete for dominance. Bi-stable perception is thought to be driven at least in part by mutual suppression between distinct neural populations that represent each percept. Abnormal visual perception has been observed among people with psychotic psychopathology (PwPP), and there is evidence to suggest that these visual deficits may depend on impaired neural suppression in the visual cortex. However, it is not yet clear whether bi-stable visual perception is abnormal among PwPP. Here, we examined bi-stable perception in a visual structure-from-motion task using a rotating cylinder illusion in a group of 65 PwPP, 44 first-degree biological relatives, and 43 healthy controls. Data from a 'real switch' task, in which physical depth cues signaled real switches in rotation direction were used to exclude individuals who did not show adequate task performance. In addition, we measured concentrations of neurochemicals, including glutamate, glutamine, and γ-amino butyric acid (GABA), involved in excitatory and inhibitory neurotransmission. These neurochemicals were measured non-invasively in the visual cortex using 7 tesla MR spectroscopy. We found that PwPP and their relatives showed faster bi-stable switch rates than healthy controls. Faster switch rates also correlated with significantly higher psychiatric symptom levels, specifically disorganization, across all participants. However, we did not observe any significant relationships across individuals between neurochemical concentrations and SFM switch rates. Our results are consistent with a reduction in suppressive neural processes during structure-from-motion perception in PwPP, and suggest that genetic liability for psychosis is associated with disrupted bi-stable perception.

Performance of receive head arrays versus ultimate intrinsic SNR at 7 T and 10.5 T.

PURPOSE: We examined magnetic field dependent SNR gains and ability to capture them with multichannel receive arrays for human head imaging in going from 7 T, the most commonly used ultrahigh magnetic field (UHF) platform at the present, to 10.5 T, which represents the emerging new frontier of >10 T in UHFs. METHODS: Electromagnetic (EM) models of 31-channel and 63-channel multichannel arrays built for 10.5 T were developed for 10.5 T and 7 T simulations. A 7 T version of the 63-channel array with an identical coil layout was also built. Array performance was evaluated in the EM model using a phantom mimicking the size and electrical properties of the human head and a digital human head model. Experimental data was obtained at 7 T and 10.5 T with the 63-channel array. Ultimate intrinsic SNR (uiSNR) was calculated for the two field strengths using a voxelized cloud of dipoles enclosing the phantom or the digital human head model as a reference to assess the performance of the two arrays and field depended SNR gains. RESULTS: uiSNR calculations in both the phantom and the digital human head model demonstrated SNR gains at 10.5 T relative to 7 T of 2.6 centrally, ˜2 at the location corresponding to the edge of the brain, ˜1.4 at the periphery. The EM models demonstrated that, centrally, both arrays captured ˜90% of the uiSNR at 7 T, but only ˜65% at 10.5 T, leading only to ˜2-fold gain in array SNR in going from 7 to 10.5 T. This trend was also observed experimentally with the 63-channel array capturing a larger fraction of the uiSNR at 7 T compared to 10.5 T, although the percentage of uiSNR captured were slightly lower at both field strengths compared to EM simulation results. CONCLUSIONS: Major uiSNR gains are predicted for human head imaging in going from 7 T to 10.5 T, ranging from ˜2-fold at locations corresponding to the edge of the brain to 2.6-fold at the center, corresponding to approximately quadratic increase with the magnetic field. Realistic 31- and 63-channel receive arrays, however, approach the central uiSNR at 7 T, but fail to do so at 10.5 T, suggesting that more coils and/or different type of coils will be needed at 10.5 T and higher magnetic fields.

Discrimination Predicts Suboptimal Adherence to CPAP Treatment and Mediates Black-White Differences in Use.

BACKGROUND: Although racial and ethnic differences in CPAP adherence for OSA are widely established, no studies have examined the influence of perceived racial discrimination on CPAP usage, to our knowledge. RESEARCH QUESTION: (1) Do Black adults with OSA report experiencing greater amounts of discrimination than non-Hispanic White adults? (2) Is discrimination associated with poorer CPAP adherence over time, independent of self-identified race? (3) Does discrimination mediate the relationship between self-identified Black race and CPAP usage? STUDY DESIGN AND METHODS: In this prospective study, Black and non-Hispanic White adults with OSA initiating CPAP were enrolled from two sleep centers and completed questionnaires including sociodemographics, perceived discrimination, daytime sleepiness, insomnia symptoms, and depressive symptoms. Perceived discrimination was measured using the Everyday Discrimination Scale (EDS). Black and White group comparisons for baseline sociodemographic variables, sleep symptoms, and perceived discrimination were performed with Student t test or χ2/Fisher exact test, as appropriate. A linear regression model was completed with self-identified Black race and EDS total score as the primary independent variables of interest and mean daily CPAP usage at 30 and 90 days serving as the dependent outcomes. This regression modeling was repeated after adjusting for psychosocial variables known to be associated with CPAP usage. EDS total score was explored as a potential mediator of the association between self-identified Black race and mean daily CPAP adherence at 30 and 90 days. RESULTS: The sample for this analysis consisted of 78 participants (31% female, 38% Black) with a mean age of 57 ± 14 years. Sixty percent of the Black adults reported they experienced racial discrimination at least a few times each year. Relative to White adults, Black adults were also more likely to indicate more than one reason for discrimination (27% vs 4%, P = .003). Adjusting for discrimination, self-identified Black race was associated with 1.4 (95% CI, -2.3 to -0.4 h; P = .006) and 1.6 (95% CI, -2.6 to -0.6 h; P = .003) fewer hours of mean daily CPAP usage at 30 and 90 days, respectively. In the fully adjusted model, a 1-unit change in the total discrimination score (more discrimination) was associated with a 0.08-h (95% CI, 0.01-0.15 h; P = .029) and 0.08-h (95% CI, 0.01-0.16 h; P = .045) change in mean daily CPAP usage at 30 and 90 days, respectively. INTERPRETATION: Adults with OSA who encountered racial discrimination experienced greater decrement in CPAP usage than those who did not experience racial discrimination.

The effects of social support and support types on continuous positive airway pressure use after 1month of therapy among adults with obstructive sleep apnea.

BACKGROUND: The relationship between perceived social support and continuous positive airway pressure remains understudied among individuals with obstructive sleep apnea. The aim of this prospective cohort study was to determine if baseline perceived social support and subtypes predict regular continuous positive airway pressure use after 1month of therapy. METHODS: Adults with obstructive sleep apnea initiating continuous positive airway pressure therapy were recruited from sleep clinics in New York City. Demographics, medical history, and comorbidities were obtained from patient interview and review of medical records. Objective continuous positive airway pressure adherence data was collected at the first clinical follow-up. RESULTS: Seventy-five participants (32% female; non-Hispanic Black 41%; mean age of 56 ± 14years) provided data. In adjusted analyses, poorer levels of overall social support, and subtypes including informational/emotional support, and positive social interactions were associated with lower continuous positive airway pressure use at 1month. Relative to patients reporting higher levels of support, participants endorsing lower levels of overall social support, positive social interaction and emotional/informational support had 1.6 hours (95% CI: 0.5,2.7, hours; p = .007), 1.3 hours (95% CI: 0.2,2.4; p = .026), and 1.2 hours (95% CI: 0.05,2.4; p = .041) lower mean daily continuous positive airway pressure use at 1month, respectively. CONCLUSION: Focusing on social support overall and positive social interaction particularly, could be an effective approach to improve continuous positive airway pressure adherence in patients at risk of suboptimal adherence.

Skin sensory alteration and kneeling ability following cruciate retaining total knee arthroplasty are not affected by the incision position: A randomised controlled trial of simultaneous bilateral surgery.

PURPOSE: The purpose of this randomised controlled trial was to assess the impact of skin incision location on the patients' ability to kneel. METHODS: A total of 29 patients undergoing bilateral total knee arthroplasty (58 knees) were randomised to receive a lateral or midline incision, with the contralateral limb receiving the alternative option. Cruciate retaining implants were used in all cases by three experienced arthroplasty surgeons. The primary outcome measures assessed functional ability to kneel using an innovative five-point kneeling scale, preferred knee to kneel on and the area of cutaneous sensory loss around the incision at 6 weeks, 6 months and 12 months. Secondary outcome measures were the OKS, KOOS JR, FJS and EQ5D patient reported outcome measures (PROMS), length of surgical scar, overall knee preference and range of motion (ROM). RESULTS: There were no significant differences between the two groups for any primary or secondary outcome measures. Flexion range however, had a significant positive correlation with kneeling score (r = 0.335, p = 0.010). The kneeling score increased at each time point after surgery and was significantly greater at 12 months than preoperatively (2.7 v 3.5, p = 0.015). The area of sensory loss lateral to the incision was significantly less at 6 and 12 months than at 6 weeks (43.6cm2 and 40.1cm2 v 84.1cm2, p < 0.0001). CONCLUSION: The ability to kneel following cruciate retaining total knee arthroplasty is not affected by the incision position but by time and flexion range. TKA improves the ability to kneel by 12 months post-surgery. Sensory loss lateral to the incision reduces with time. LEVEL OF EVIDENCE: Therapeutic Level 2.

Patients with knee osteoarthritis have altered gait and gaze patterns compared to age-matched controls: A pilot study.

PURPOSE: Although knee Osteoarthritis (KOA) sufferers are at an increased risk of falls, possibly due to impaired gait function, the associated gaze behaviour in patients with KOA are largely unknown. Thus, we compared gait and gaze behaviours characteristics between KOA patients and asymptomatic age-matched controls. RESULTS: For Timed Up and Go (TUG) and stair climb tasks, the KOA group demonstrated longer periods of gaze fixations with less frequency of fixations compared to the control group. Conversely, for the Timed up and Go Agility (TUGA) test shorter fixation and frequency patterns were observed. The KOA group presented a shorter final stride length prior to the initiation of the first step in the Stair climb assessment. In addition, for the 30m walk and dual task assessments, the average step length was significantly shorter in the KOA group compared to controls. CONCLUSION: Overall, we found altered gait and gaze behaviours are evident in KOA patients which could relate to their increased falls risk.

Emerging advances in biosecurity to underpin human, animal, plant, and ecosystem health.

One Biosecurity is an interdisciplinary approach to policy and research that builds on the interconnections between human, animal, plant, and ecosystem health to effectively prevent and mitigate the impacts of invasive alien species. To support this approach requires that key cross-sectoral research innovations be identified and prioritized. Following an interdisciplinary horizon scan for emerging research that underpins One Biosecurity, four major interlinked advances were identified: implementation of new surveillance technologies adopting state-of-the-art sensors connected to the Internet of Things, deployable handheld molecular and genomic tracing tools, the incorporation of wellbeing and diverse human values into biosecurity decision-making, and sophisticated socio-environmental models and data capture. The relevance and applicability of these innovations to address threats from pathogens, pests, and weeds in both terrestrial and aquatic ecosystems emphasize the opportunity to build critical mass around interdisciplinary teams at a global scale that can rapidly advance science solutions targeting biosecurity threats.

Image-derived instrumentation vs. conventional instrumentation with 3D planning for glenoid component placement in reverse total shoulder replacements: a randomized controlled trial.

Hypothesis: Glenoid baseplate positioning for reverse total shoulder arthroplasty (rTSA) is important for stability and longevity, with techniques such as image-derived instrumentation (IDI) developed for improving implant placement accuracy. We performed a single-blinded randomized controlled trial comparing glenoid baseplate insertion accuracy with 3D preoperative planning and IDI jigs vs. 3D preoperative planning and conventional instrumentation. Methods: All patients had a preoperative 3D computed tomography to create an IDI; then underwent rTSA according to their randomized method. Repeat computed tomography scans performed at six weeks postoperatively were compared to the preoperative plan to assess for accuracy of implantation. Patient-reported outcome measures and plain radiographs were collected with 2-year follow-up. Results: Forty-seven rTSA patients were included (IDI n = 24, conventional instrumentation n = 23). The IDI group was more likely to have a guidewire placement within 2mm of the preoperative plan in the superior/inferior plane (P = .01); and exhibited a smaller degree of error when the native glenoid retroversion was >10° (P = .047). There was no difference in patient-reported outcome measures or other radiographic parameters between the two groups. Conclusion: IDI is an accurate method for glenoid guidewire and component placement in rTSA, particularly in the superior/inferior plane and in glenoids with native retroversion >10°, when compared to conventional instrumentation.

Use of a Commercial 7-T MRI Scanner for Clinical Brain Imaging: Indications, Protocols, Challenges, and Solutions-A Single-Center Experience.

The first commercially available 7-T MRI scanner (Magnetom Terra) was approved by the FDA in 2017 for clinical imaging of the brain and knee. After initial protocol development and sequence optimization efforts in volunteers, the 7-T system, in combination with an FDA-approved 1-channel transmit/32-channel receive array head coil, can now be routinely used for clinical brain MRI examinations. The ultrahigh field strength of 7-T MRI has the advantages of improved spatial resolution, increased SNR, and increased CNR but also introduces an array of new technical challenges. The purpose of this article is to describe an institutional experience with the use of the commercially available 7-T MRI scanner for routine clinical brain imaging. Specific clinical indications for which 7-T MRI may be useful for brain imaging include brain tumor evaluation with possible perfusion imaging and/or spectroscopy, radiotherapy planning; evaluation of multiple sclerosis and other demyelinating diseases, evaluation of Parkinson disease and guidance of deep brain stimulator placement, high-detail intracranial MRA and vessel wall imaging, evaluation of pituitary pathology, and evaluation of epilepsy. Detailed protocols, including sequence parameters, for these various indications are presented, and implementation challenges (including artifacts, safety, and side effects) and potential solutions are explored.

Efficacy of surgeon-directed suprascapular and axillary nerve blocks in shoulder arthroscopy: a 3-arm prospective randomized controlled trial.

Background: The use of regional anesthesia in shoulder arthroscopy improves perioperative pain control, thereby reducing the need for opioids and their recognized side effects. Occasionally one type of block is not suitable for a patient's anatomy or comorbidities or requires a specially trained anesthetist to safely perform. The primary aim of this study is to compare the efficacy of 3 different nerve blocks for pain management in patients undergoing shoulder arthroscopy. Methods: A 3-arm, blinded, randomized controlled trial in patients undergoing elective, unilateral shoulder arthroscopic procedures between August 2018 and November 2020 was conducted at a single center. One hundred and thirty participants were randomized into 1 of 3 regional anesthesia techniques. The first group received an ultrasound-guided interscalene block performed by an anesthetist (US + ISB). The second group received an ultrasound-guided suprascapular nerve block and an axillary nerve block by an anesthetist (US + SSANB). The final group received a suprascapular nerve block without ultrasound and an axillary nerve block under arthroscopic guidance by an orthopedic surgeon (A + SSANB). Intraoperative pain response, analgesia requirements, and side effects were recorded. Visual analogue pain scores and opioid doses were recorded in the Post Anaesthesia Care Unit (PACU) and daily for 8 days following the procedure. Results: Twelve patients withdrew from the study after randomization, leaving 39 participants in US + ISB, 40 in US + SSANB, and 39 in A + SSANB. The US + ISB group required significantly lower intraoperative opioid doses than US + SSANB and A + SSANB (P < .001) and postoperatively in PACU (P < .001). After discharge from hospital, there were no differences between all groups in daily analgesia requirements (P = .063). There was significantly more nerve complications with 6 patient-reported complications in the US + ISB group (P = .02). There were no reported differences in satisfaction rates between groups (P = .41); however, the A + SSANB group was more likely to report a wish to not have a regional anesthetic again (P = .04). Conclusion: The US + ISB group required lower opioid doses perioperatively; however, there was no difference between groups after discharge from PACU. The analgesia requirements between the US + SSANB and A + SSANB were similar intraoperatively and postoperatively. A surgeon-administered SSANB may be a viable alternative when an experienced regional anesthetist is not available.

The psychosis human connectome project: Design and rationale for studies of visual neurophysiology.

Visual perception is abnormal in psychotic disorders such as schizophrenia. In addition to hallucinations, laboratory tests show differences in fundamental visual processes including contrast sensitivity, center-surround interactions, and perceptual organization. A number of hypotheses have been proposed to explain visual dysfunction in psychotic disorders, including an imbalance between excitation and inhibition. However, the precise neural basis of abnormal visual perception in people with psychotic psychopathology (PwPP) remains unknown. Here, we describe the behavioral and 7 tesla MRI methods we used to interrogate visual neurophysiology in PwPP as part of the Psychosis Human Connectome Project (HCP). In addition to PwPP (n = 66) and healthy controls (n = 43), we also recruited first-degree biological relatives (n = 44) in order to examine the role of genetic liability for psychosis in visual perception. Our visual tasks were designed to assess fundamental visual processes in PwPP, whereas MR spectroscopy enabled us to examine neurochemistry, including excitatory and inhibitory markers. We show that it is feasible to collect high-quality data across multiple psychophysical, functional MRI, and MR spectroscopy experiments with a sizable number of participants at a single research site. These data, in addition to those from our previously described 3 tesla experiments, will be made publicly available in order to facilitate further investigations by other research groups. By combining visual neuroscience techniques and HCP brain imaging methods, our experiments offer new opportunities to investigate the neural basis of abnormal visual perception in PwPP.

Faster bi-stable visual switching in psychosis.

Bi-stable stimuli evoke two distinct perceptual interpretations that alternate and compete for dominance. Bi-stable perception is thought to be driven at least in part by mutual suppression between distinct neural populations that represent each percept. Abnormal visual perception is observed among people with psychotic psychopathology (PwPP), and there is evidence to suggest that these visual deficits may depend on impaired neural suppression in visual cortex. However, it is not yet clear whether bi-stable visual perception is abnormal among PwPP. Here, we examined bi-stable perception in a visual structure-from-motion task using a rotating cylinder illusion in a group of 65 PwPP, 44 first-degree biological relatives, and 43 healthy controls. Data from a 'real switch' task, in which physical depth cues signaled real switches in rotation direction were used to exclude individuals who did not show adequate task performance. In addition, we measured concentrations of neurochemicals, including glutamate, glutamine, and γ-amino butyric acid (GABA), involved in excitatory and inhibitory neurotransmission. These neurochemicals were measured non-invasively in visual cortex using 7 tesla MR spectroscopy. We found that PwPP and their relatives showed faster bi-stable switch rates than healthy controls. Faster switch rates also correlated with significantly higher psychiatric symptom levels across all participants. However, we did not observe any significant relationships across individuals between neurochemical concentrations and SFM switch rates. Our results are consistent with a reduction in suppressive neural processes during structure-from-motion perception in PwPP, and suggest that genetic liability for psychosis is associated with disrupted bi-stable perception.

Patient-reported outcome measures for patellofemoral disorders: a systematic review.

INTRODUCTION: Patellofemoral conditions include, but are not limited to, anterior knee pain syndrome and patellar instability. Patients and surgeons may find it difficult to identify the specific source of the symptoms and clinical scenarios, so patient-reported outcome measures (PROMs) may be a useful diagnostic aid. There are a number of available PROMs for patellofemoral conditions, which are often used indistinctly. This systematic review explores the available PROMs for patellofemoral conditions, their use and methodological quality. METHODS: A systematic review was conducted, searching for scientific articles relating to PROMs in patellofemoral conditions, from inception to July 2022. Scoring systems including physician-directed or imagining assessment were not included. All types of conditions in the patellofemoral joint were considered. RESULTS: Twenty-two relevant PROMs were encountered, divided into four categories: eight PROMs for anterior knee pain syndrome, five for patellar instability, four for other patellofemoral conditions and five for non-specific PROMs. CONCLUSIONS: While many PROMs have been found used in patellofemoral research, only few of them have showed sufficient methodological quality. In addition, PROMs employed in PF literature are often inaccurately chosen. This review may help authors to better understand the characteristics of specific patellofemoral PROMs, in order to select the more appropriate and recommended ones. LEVEL OF EVIDENCE: Level II.

Magnetic field strength dependent SNR gain at the center of a spherical phantom and up to 11.7T.

PURPOSE: The SNR at the center of a spherical phantom of known electrical properties was measured in quasi-identical experimental conditions as a function of magnetic field strength between 3 T and 11.7 T. METHODS: The SNR was measured at the center of a spherical water saline phantom with a gradient-recalled echo sequence. Measurements were performed at NeuroSpin at 3, 7, and 11.7 T. The phantom was then shipped to Maastricht University and then to the University of Minnesota for additional data points at 7, 9.4, and 10.5 T. Experiments were carried out with the exact same type of birdcage volume coil (except at 3 T, where a similar coil was used) to attempt at isolating the evolution of SNR with field strength alone. Phantom electrical properties were characterized over the corresponding frequency range. RESULTS: Electrical properties were found to barely vary over the frequency range. Removing the influence of the flip-angle excitation inhomogeneity was crucial, as expected. After such correction, measurements revealed a gain of SNR growing as B0 1.94 ± 0.16 compared with B0 2.13 according to ultimate intrinsic SNR theory. CONCLUSIONS: By using quasi-identical experimental setups (RF volume coil, phantom, electrical properties, and protocol), this work reports experimental data between 3 T and 11.7 T, enabling the comparison with SNR theories in which conductivity and permittivity can be assumed to be constant with respect to field strength. According to ultimate SNR theory, these results can be reasonably extrapolated to the performance of receive arrays with greater than about 32 elements for central SNR in the same spherical phantom.

The efficacy of topical preparations in reducing the incidence of Cutibacterium acnes at the start and conclusion of total shoulder arthroplasty: a randomized controlled trial.

BACKGROUND: Preoperative skin preparations for total shoulder arthroplasty (TSA) are not standardized for Cutibacterium acnes eradication. Topical benzyl peroxide (BPO) and benzyl peroxide with clindamycin (BPO-C) have been shown to reduce the bacterial load of C acnes on the skin. Our aim was to investigate whether preoperative application of these topical antimicrobials reduced superficial colonization and deep tissue inoculation of C acnes in patients undergoing TSA. METHODS: In a prospective, single-blinded randomized controlled trial, 101 patients undergoing primary TSA were randomized to receive either topical pHisoHex (hexachlorophene [1% triclosan; sodium benzoate, 5 mg/mL; and benzyl alcohol, 5 mg/mL]) (n = 35), 5% BPO (n = 33), or 5% BPO with 1% clindamycin (n = 33). Skin swabs obtained prior to topical application and after topical application before surgery, as well as 3 intraoperative swabs (dermis after incision, on joint capsule entry, and dermis at wound closure), were cultured. The primary outcome was positive culture findings and successful decolonization. RESULTS: All 3 topical preparations were effective in decreasing the rate of C acnes. The application of pHisoHex reduced skin colonization by 50%, BPO reduced skin colonization by 73.7%, and BPO-C reduced skin colonization by 81.5%. The topical preparation of BPO-C was more effective in decreasing the rate of C acnes at the preoperative and intraoperative swab time points compared with pHisoHex and BPO (P = .003). Failure to eradicate C acnes with topical preparations consistently resulted in deep tissue inoculation. There was an increase in the C acnes contamination rate on the skin during closure (33%) compared with skin cultures taken at surgery commencement (22%). CONCLUSION: Topical application of BPO and BPO-C preoperatively is more effective than pHisoHex in reducing colonization and contamination of the surgical field with C acnes in patients undergoing TSA.

Intraosseous Regional Prophylactic Antibiotics Decrease the Risk of Prosthetic Joint Infection in Primary TKA: A Multicenter Study.

BACKGROUND: Recent studies have demonstrated that the administration of regional prophylactic antibiotics by intraosseous (IO) injection achieves tissue concentrations around the knee that are 10- to 15-fold higher than intravenous (IV) delivery of prophylactic antibiotics. It is currently unknown whether the use of regional prophylactic antibiotics for primary TKA would result in a lower risk of prosthetic joint infection (PJI). QUESTIONS/PURPOSES: (1) Is IO injection of prophylactic antibiotics associated with a decreased risk of early (< 12 months) deep PJI compared with traditional IV prophylactic antibiotics? (2) What other patient factors are associated with an increased risk of early PJI after TKA, and do regional prophylactic antibiotics influence these risk factors? (3) Can IO antibiotics be administered to all patients, and what complications occurred from the delivery of IO prophylactic antibiotics? METHODS: A retrospective comparative study of all primary TKAs (1909 TKAs) over a 5-year period (January 2013 to December 2017) was performed to determine the risk of early PJI. Three primary TKAs did not meet the study inclusion criteria and were excluded from the study, leaving a total of 1906 TKAs (725 IO, 1181 IV) for analysis at a minimum of 12 months after index procedure. Both cohorts exhibited similar ages, BMI, and American Society of Anesthesiologists (ASA) grades; however, a greater proportion of patients in the IO cohort were smokers (p = 0.01), while a greater proportion of patients were diabetic in the IV cohort (p = 0.006). The PJI risk between IO and IV delivery techniques was compared while adjusting for patient demographics and medical comorbidities. Complications related to IO delivery-inability to administer via IO technique, compartment syndrome, fat embolism, and red man syndrome with vancomycin use-were recorded. RESULTS: The delivery of regional prophylactic antibiotics by the IO technique resulted in a lower PJI risk than IV prophylactic antibiotics (0.1% [1 of 725] compared with 1.4% [16 of 1181]; relative risk 0.10 [95% CI 0.01 to 0.77]; p = 0.03). BMI (ß = -0.17; standard error = 0.08; p = 0.02), diabetes (ß = -1.80; standard error = 0.75; p = 0.02), and renal failure (ß = -2.37; standard error = 0.84; p = 0.01) were factors associated with of PJI, while smoking, sex, and ASA score were not contributing factors (p > 0.05). Although BMI, diabetes, and renal failure were identified as infection risk factors, the use of IO antibiotics in these patients did not result in a lower PJI risk compared with IV antibiotics (p > 0.05). IO antibiotics were able to be successfully administered to all patients in this cohort, and there were no complications related to the delivery of IO antibiotics. CONCLUSION: Surgeons should consider administering regional prophylactic antibiotics in primary TKA to reduce the risk of early PJI. Future randomized prospective clinical trials are needed to validate the efficacy of regional prophylactic antibiotics in reducing the PJI risk in primary TKA. LEVEL OF EVIDENCE: Level III, therapeutic study.

A self-decoupled 32-channel receive array for human-brain MRI at 10.5 T.

PURPOSE: Receive array layout, noise mitigation, and B0 field strength are crucial contributors to SNR and parallel-imaging performance. Here, we investigate SNR and parallel-imaging gains at 10.5 T compared with 7 T using 32-channel receive arrays at both fields. METHODS: A self-decoupled 32-channel receive array for human brain imaging at 10.5 T (10.5T-32Rx), consisting of 31 loops and one cloverleaf element, was co-designed and built in tandem with a 16-channel dual-row loop transmitter. Novel receive array design and self-decoupling techniques were implemented. Parallel imaging performance, in terms of SNR and noise amplification (g-factor), of the 10.5T-32Rx was compared with the performance of an industry-standard 32-channel receiver at 7 T (7T-32Rx) through experimental phantom measurements. RESULTS: Compared with the 7T-32Rx, the 10.5T-32Rx provided 1.46 times the central SNR and 2.08 times the peripheral SNR. Minimum inverse g-factor value of the 10.5T-32Rx (min[1/g] = 0.56) was 51% higher than that of the 7T-32Rx (min[1/g] = 0.37) with R = 4 × 4 2D acceleration, resulting in significantly enhanced parallel-imaging performance at 10.5 T compared with 7 T. The g-factor values of 10.5 T-32 Rx were on par with those of a 64-channel receiver at 7 T (eg, 1.8 vs 1.9, respectively, with R = 4 × 4 axial acceleration). CONCLUSION: Experimental measurements demonstrated effective self-decoupling of the receive array as well as substantial gains in SNR and parallel-imaging performance at 10.5 T compared with 7 T.

Orthopaedic patients underestimate their body weight too: a cross-sectional study.

INTRODUCTION: The relation between a large body mass and comorbidity, certain types of cancers and musculoskeletal disorders has been extensively documented. However, a high proportion of overweight patients appears unaware of the medical risks of their condition and frequently underestimates their body weight. This observation is prevalent across numerous medical specialties and settings. METHODS: This study analysed the misperception of obesity status in a cohort of 1137 patients attending an orthopaedic clinic by means of self-completed questionnaires and objective biometrics. RESULTS: Patients displayed a poor estimation of the self-body mass index (34.6%), especially among larger individuals, with 45.15% of pre-obese and 21.17% of obese patients previously attempting weight-loss. A direct association between low educational achievement and obesity rates was observed in orthopaedic patients. DISCUSSION: Obesity is a well-known contributor to many conditions, including musculoskeletal diseases. Despite this association, many obese patients consider their body mass as normal. Misperception of self-body weight has been documented in many medical specialities, and this study confirms the same scenario in orthopaedic patients. CONCLUSION: The association between self-image distortion and obesity observed in this study may assist in the evaluation and management of obesity cases in orthopaedic clinics.