RF shimming in the cervical spinal cord at 7T

ABSTRACT: Purpose : Advancing the development of 7 T MRI for spinal cord imaging is crucial for the enhanced diagnosis and monitoring of various neurodegenerative diseases and traumas. However, a significant challenge at this field strength is the transmit field inhomogeneity. Such inhomogeneity is particularly problematic for imaging the small, deep anatomical structures of the cervical spinal cord, as it can cause uneven signal intensity and elevate the local specific absorption ratio, compromising image quality. This multisite study explores several RF shimming techniques in the cervical spinal cord. Methods Data were collected from 5 participants between two 7 T sites with a custom 8Tx/20Rx parallel transmission coil. We explored two radiofrequency (RF) shimming approaches from an MRI vendor and four from an open-source toolbox, showcasing their ability to enhance transmit field and signal homogeneity along the cervical spinal cord. Results The circularly polarized (CP), coefficient of variation (CoV), and specific absorption rate (SAR) efficiency shim modes showed the highest B₁⁺ efficiency, and the vendor-based “patient” and “volume” modes showed the lowest B₁⁺ efficiency. The coefficient of variation method produced the highest CSF/spinal cord contrast on T₂*-weighted scans (ratio of 1.27 ± 0.03), and the lowest variation of that contrast along the superior–inferior axis. Conclusion The study's findings highlight the potential of RF shimming to advance 7 T MRI's clinical utility for central nervous system imaging by enabling more homogenous and efficient spinal cord imaging. Additionally, the research incorporates a reproducible Jupyter Notebook, enhancing the study's transparency and facilitating peer verification

Tax-Preferred Savings Vehicles: Can Financial Education Improve Asset Location Decisions?

Abstract In this study, we conduct a stated-choice experiment to analyze the decision to contribute to either a front- or back-loaded tax-preferred retirement savings account. Our experimental design includes a randomized financial education intervention that provides information on the tax implications of both types of account. Respondents who were exposed to the intervention have greater knowledge of these accounts and make contribution choices that increase their after-tax income. Using a well-defined benchmark, we show that on average, respondents who experienced the intervention increase their discounted welfare by about 4% of their contribution amount.</jats:p

Some characteristics and observations of long diffuse discharges produced by the focussing of a TEA-CO₂ pulse with an axicon

A theoretical and an experimental study of long diffuse laser produced plasmas with axicon lenses is presented. It is shown that the heating of a helium plasma is strongly dependent on the nitrogen tail of the TEA-CO2 laser pulse when the initial electronic density (produced by photopreionization) is sufficiently high, but still below the breakdown threshold. Furthermore, a theoretical model is used to evaluate the radial expansion of the plasma in order to determine the effective volume of the plasma when dealing with rapidly evolving processes. </jats:p

Constituents of effective support for homecare workers providing care to people with dementia at end of life

Objective: The aim of this study was to enhance understanding about homecare workers providing care to people with dementia at end of life by exploring homecare workers’ perceptions of challenges and the support they needed and sometimes received. Methods: Qualitative semi-structured interviews were conducted with 29 homecare workers and 13 homecare managers in England. Framework analysis was used to analyse the data.Findings: Four overarching challenges were identified: working with clients with dementia, including clients’ sometimes unpredictable responses, communication difficulties, and mood changes; caring for the dying; conflict with family members; and working alone, which often left homecare workers at risk of exhaustion, fatigue, and a sense of isolation. When their work entailed high levels of emotion, such as a client’s death or getting embroiled in a client’s family conflict, they felt emotionally drained, under-prepared and overwhelmed. Supportive elements include receiving encouragement and learning from experienced peers and their feelings being acknowledged by managers at their employing homecare agency. Some workers were offered time off or encouraged to attend the client’s funeral as a means of supporting the process of bereavement.Conclusions: Peer and manager support are essential and effective in coping with work pressures. There is a need to develop models of effective support to alleviate staff’s practical, emotional and interpersonal pressures. However, due to the isolating nature of homecare work, managers may not recognise early signs of their staff finding stress unmanageable and miss the opportunity to mitigate these negative effects<br/

Implication of the phosphatidylinositol-3 kinase/protein kinase b signaling pathway in the neuroprotective effect of estradiol in the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mice

The present experiments sought to determine the implication of estrogen receptors (ERα and ERβ) and their interaction with insulin-like growth factor receptor (IGF-IR) signaling pathways in neuroprotection by estradiol against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity. C57BL/6 male mice were pretreated for 5 days with 17β-estradiol, an estrogen receptor α(ERα) agonist, 4,4′,4″-(4-propyl-[1H] -pyrazole-1,3,5-triyl)tris-phenol (PPT), or an estrogen receptor β (ERβ) agonist, 5-androsten-3β, 17β-diol (Δ5-diol). On day 5, mice received MPTP (9 mg/kg) or saline injections, and estrogenic treatments were continued for 5 more days. MPTP decreased striatal dopamine, measured by high-performance liquid chromatography, to 59% of control values; 17β-estradiol and PPT but not δ5-diol protected against this depletion. MPTP increased IGF-IR measured by Western blot, which was prevented by PPT. The phosphorylation of protein kinase B (Akt) (at serine 473), an essential mediator of IGF-I neuroprotective actions, increased after 17β-estradiol and tended to increase with PPT but not with δ5-diol treatments in MPTP mice. Glycogen synthase kinase 3β (GSK3β) phosphorylation (at serine 9) was greatly reduced in MPTP mice; this was completely prevented by PPT, whereas 17β-estradiol and Δ5-diol treatments were less effective. The ratio between the levels of striatal Bcl-2 and BAD proteins, two apoptotic regulators, decreased after MPTP treatment. This effect was effectively prevented only in the animals treated with PPT. In nonlesioned mice, 17β-estradiol and PPT increased phosphorylation of striatal Akt and GSK3β, whereas the other markers measured remained unchanged. Δ5-Diol increased GSK3β phosphorylation less than the PPT treatment. These results suggest that a pretreatment with estradiol promoted dopamine neuron survival by activating ERα and increasing Akt and GSK3β phosphorylation. Copyright © 2006 The American Society for Pharmacology and Experimental Therapeutics.Peer Reviewe

MP46: Clinically significant traumatic intracranial haemorrhage following minor head trauma in older adults: a retrospective cohort study

Introduction: The primary objective of this study was to determine the incidence of clinically significant traumatic intracranial haemorrhage (T-ICH) following minor head trauma in older adults. Secondary objective was to investigate the impact of anticoagulant and antiplatelet therapies on T-ICH incidence. Methods: This retrospective cohort study extracted data from electronic patient records. The cohort consisted of patients presenting after a fall and/or head injury and presented to one of five ED between 1st March 2010 and 31st July 2017. Inclusion criteria were age ≥ 65 years old and a minor head trauma defined as an impact to the head without fulfilling criteria for traumatic brain injury. Results: From the 1,000 electronic medical records evaluated, 311 cases were included. The mean age was 80.1 (SD 7.9) years. One hundred and eighty-nine (189) patients (60.8%) were on an anticoagulant (n = 69), antiplatelet (n = 130) or both (n = 16). Twenty patients (6.4%) developed a clinically significant T-ICH. Anticoagulation and/or antiplatelets therapies were not associated with an increased risk of clinically significant T-ICH in this cohort (Odds ratio (OR) 2.7, 95% CI 0.9-8.3). Conclusion: In this cohort of older adults presenting to the ED following minor head trauma, the incidence of clinically significant T-ICH was 6.4%.</jats:p