Bedside detection of intracranial midline shift using portable magnetic resonance imaging

Neuroimaging is crucial for assessing mass effect in brain-injured patients. Transport to an imaging suite, however, is challenging for critically ill patients. We evaluated the use of a low magnetic field, portable MRI (pMRI) for assessing midline shift (MLS). In this observational study, 0.064 T pMRI exams were performed on stroke patients admitted to the neuroscience intensive care unit at Yale New Haven Hospital. Dichotomous (present or absent) and continuous MLS measurements were obtained on pMRI exams and locally available and accessible standard-of-care imaging exams (CT or MRI). We evaluated the agreement between pMRI and standard-of-care measurements. Additionally, we assessed the relationship between pMRI-based MLS and functional outcome (modified Rankin Scale). A total of 102 patients were included in the final study (48 ischemic stroke; 54 intracranial hemorrhage). There was significant concordance between pMRI and standard-of-care measurements (dichotomous, κ = 0.87; continuous, ICC = 0.94). Low-field pMRI identified MLS with a sensitivity of 0.93 and specificity of 0.96. Moreover, pMRI MLS assessments predicted poor clinical outcome at discharge (dichotomous: adjusted OR 7.98, 95% CI 2.07–40.04, p = 0.005; continuous: adjusted OR 1.59, 95% CI 1.11–2.49, p = 0.021). Low-field pMRI may serve as a valuable bedside tool for detecting mass effect.

Residential MRI: Development of A Mobile Anywhere-Everywhere MRI Lab

Magnetic resonance imaging (MRI) enables unprecedented visualization of brain and central nervous system anatomy, microstructure, function, and physiology. However, unlike electroencephalography (EEG) or functional near infrared spectroscopy (fNIRS), which can be used within a doctor’s office, research laboratory, or at a participant’s home, MRI remains a hospital or center-based modality. The need for patients or research participants to travel to the scanner limits overall healthcare access and potentially biases research study populations. The recent introduction of low magnetic field strength, lightweight, and portable MRI systems offer the potential to extend beyond these traditional hospital and imaging center boundaries. Here we describe the development and deployment of a mobile imaging lab in a modified cargo van that incorporates a removable low field permanent magnet MRI system. The mobile lab allows, for the first time, rapid and routine ‘residential’ MRI that can be performed at home, community center, school, etc. Breaking traditional barriers of access, this mobile approach will enable imaging of patients and participants who have mobility challenges, live long distances from imaging centers, or are otherwise unable to travel to an imaging center or hospital.

Low magnetic-field induced high temperature dynamic magnetoelectric coupling performances in Z-type Sr3Co2Fe24O41

Magnetic-field induced dynamic magnetoelectric coupling effects and polarization performance of Z-type Sr3Co2Fe24O41 (SCFO) ceramic has been investigated. Results found that SCFO’s transverse tapered magnetic structure can induce electric polarization, and its electric polarization direction will not change under external magnetic effects. First-order dynamic magnetoelectric coupling coefficient (α) and second-order dynamic magnetoelectric coupling coefficient (β) of SCFO exhibited strong response main in magnetic structural phase transition region. The magnetoelectric structural phase transition position appeared in low magnetic field, and the magnetic moment vector and its corresponding electric polarization vector of SCFO exhibited the most unstable state near its equilibrium position, which is beneficial for inducing strong dynamic magnetoelectric coupling response. When the applied magnetic fields to SCFO increased, the magnetic moment stability near the equilibrium position increased, and the dynamic magnetoelectric coupling response decreased. Results showed that the dynamic magnetoelectric coupling response of SCFO can bear T1 = 370 K high temperature. The dynamic magnetoelectric coupling response induced by low magnetic fields in SCFO contributes to its actual application in next generation magnetoelectric information storage devices.

Effect of Low Magnetic Field on Biomimetic Deposition of Hydroxyapatite on Titanium and BIOLINE Stainless Steel

In this work, we evaluated the effect of a low magnetic field on the deposition of hydroxyapatite (HAp) on different metallic substrates. The substrates studied were titanium and BIOLINE stainless steel SS316LVM with and without Ta and TaN/Ta coatings. Before deposition, the uncoated Ti and SS316LVM substrates were treated with alkali to improve the adhesion of the films prompted to be formed. Next, all substrates (coated and uncoated) were immersed in stimulated body fluid (SBF) at physiological conditions of 37 °C, pH = 7.4, in the presence of magnetic fields from 0.15 T and 0.22 T for 7, 10, and 14 days. The formed films were characterized using SEM, FTIR, and the contact angle. Ti and SS316LVM substrates presented Ca/P relations closer to the stoichiometric HAp. It was demonstrated that in both coatings, Ta and Ta/N, an increase of the bioactivity was obtained. Additionally, our results showed that the application of magnetic fields has a significant effect on the increment in the mass:area ratio of HAp. Finally, the contact angle values were lower than 90°, showing an increase in hydrophilicity with respect to the metallic substrates.

Suppression of relaxation of higher polarization moments of alkali atoms in superfrequent spin-exchange collisions

Consideration of nonlinear spin-exchange equations showed that, in addition to the well-known suppression of the relaxation of the transverse orientation of atoms in a low magnetic field, relaxation of higher polarization moments (alignment, octupole, hexadecapole, etc) are also suppressed. Such suppression of relaxation is caused by the conservation of the transverse angular momentum of atoms in collisions.