Search

Multifrequency resonances in the pulsed-optically detected magnetic resonance (ODMR) spectra of electron spins in ensemble nitrogen-vacancy (NV) centers in diamonds are investigated under strong radio frequency (RF) driving at a MHz frequency range and weak microwave driving at a GHz frequency range in a bias static magnetic field for quantum sensing applications. First, we demonstrate that the coherent destruction of tunneling, which leads to the disappearance of the main resonance peaks, can be utilized for precise calibration of the RF amplitude. Next, we clarify the condition for enhancing the sensitivity of a DC magnetic field under strong RF driving at the RF frequency that matches the split frequency due to the hyperfine interaction between 15 N nuclear spins and the NV electron spins. Our findings indicate that strong RF driving increases the sensitivity of the DC magnetic field by enhancing the ODMR contrast and reducing the linewidth. The above results contribute to certifying the quantitative accuracy of RF imaging and enhancing the sensitivity of the DC magnetic field imaging using ensemble NV centers in diamonds. [ABSTRACT FROM AUTHOR]

Motivated by the booming development of spintronics based on quantum dot systems, we employed the standard nonequilibrium Green's function theory to derive the transport formula and the heat generation formula of a quantum dot coupled to a substrate and study the relation between spin current and its accompanying heating or cooling. Our results demonstrate that (i) a thermal bias combined with Zeeman splitting can generate steady spin current in a limited dot level range, while a rotating magnetic field can generate time-average spin current in a global range and pure spin current can induce more heat generation than non-pure spin current; (ii) magnetic resonance of spin current can also effectively enhance heat generation; (iii) appropriate environmental temperature in conjunction with a thermal bias makes cooling, while increasing the frequency of the rotating magnetic can easily give rise to the transition from cooling to heating; and (iv) enhancing the coupling between quantum dots and substrates can effectively reduce heat generation while maintaining the fundamental properties of pure spin current. [ABSTRACT FROM AUTHOR]

We report device-level damping measurements using spin-torque driven ferromagnetic resonance on perpendicular magnetic random-access memory cells. It is shown that thermal agitation enhances the apparent damping for cells smaller than about 55 nm. The effect is fundamental and does not reflect a true damping increase. In addition to the thermal effect, it is still found that device-level damping is higher than film-level damping and increases with decreasing cell size. This is attributed to edge damage caused by device patterning. [ABSTRACT FROM AUTHOR]

We implanted Fe+ ions in nanodiamond (ND) powder containing negatively charged nitrogen-vacancy (NV−) centers and studied their Raman spectra and optically detected magnetic resonance (ODMR) in various applied magnetic fields with green light (532 nm) excitation. In Raman spectra, we observed a blue shift of the NV− peak associated with the conversion of the electronic sp3 configuration to the disordered sp2 one typical for the carbon/graphite structure. In the ODMR spectra, we observed a red shift of the resonance position caused by local heating by an absorptive environment that recovers after annealing. To reveal the red shift mechanism in ODMR, we created a controlled absorptive environment around ND by adding iron-based Fe2O3 and graphitic sp2 powders to the ND suspension. This admixture caused a substantial increase in the observed shift proportional to the applied laser power, corresponding to an increase in the local temperature by 150–180 K. This surprisingly large shift is absent in non-irradiated NV-ND powders, is associated only with the modification of the local temperature by the absorptive environment of NV-NDs, and can be studied using ODMR signals of NV−. [ABSTRACT FROM AUTHOR]

Electron spin resonance pulsed dipolar spectroscopy (PDS) has become popular in protein 3D structure analysis. PDS studies yield distance distributions between a pair or multiple pairs of spin probes attached to protein molecules, which can be used directly in structural studies or as constraints in theoretical predictions. Double-quantum coherence (DQC) is a highly sensitive and accurate PDS technique to study protein structures in the solid state and under physiologically relevant conditions. In this work, we have derived analytical expressions for the DQC signal for a system with N-dipolar coupled spin-1/2 particles in the solid state. The expressions are integrated over the relevant spatial parameters to obtain closed form DQC signal expressions. These expressions contain the concentration-dependent "instantaneous diffusion" and the background signal. For micromolar and lower concentrations, these effects are negligible. An approximate analysis is provided for cases of finite pulses. The expressions obtained in this work should improve the analysis of DQC experimental data significantly, and the analytical approach could be extended easily to a wide range of magnetic resonance phenomena. [ABSTRACT FROM AUTHOR]

The study and modeling of water exchange in complex media using different applications of diffusion and relaxation magnetic resonance (MR) have been of interest in recent years. Most models attempt to describe this process using a first order kinetics expression, which is appropriate to describe chemical exchange; however, it may not be suitable to describe diffusion-driven exchange since it has no direct relationship to diffusion dynamics of water molecules. In this paper, these limitations are addressed through a more general exchange expression that does consider such important properties. This exchange fraction expression features a multi-exponential recovery at short times and a mono-exponential decay at long times, both of which are not captured by the first order kinetics expression. Furthermore, simplified exchange expressions containing partial information of the analyzed system's diffusion and relaxation processes and geometry are proposed, which can potentially be employed in already established estimation protocols. Finally, exchange fractions estimated from simulated MR data and derived here were compared, showing qualitative similarities but quantitative differences, suggesting that the features of the derived exchange fraction in this paper can be partially recovered by employing an existing estimation framework. [ABSTRACT FROM AUTHOR]

We combine micromagnetic simulations and nitrogen-vacancy (NV) defect center spin relaxometry measurements to study magnon modes in inhomogeneous spin textures. A thin, micrometer-scale ferromagnetic disk is magnetized in a vortex state in which the magnetization curls around a central core. Micromagnetic simulations show that at zero applied field, the magnetization dynamics of the disk consist of a low frequency gyrotropic mode and higher frequency azimuthal magnon modes, all far detuned from the NV spin transition frequencies. An in-plane static magnetic field breaks the azimuthal symmetry of the vortex state, resulting in the magnon modes transforming in frequency and spatial profile as the field increases. Experimentally, we probe the dynamics of vortex magnetization as a function of applied in-plane static field and ac driving frequency by optically monitoring a nearby NV defect center spin. At certain values of the applied magnetic field, we observe enhanced spin relaxation when driving at twice the frequency of the NV ground state spin transition in optically detected magnetic resonance measurements. We attribute this effect to parallel pumping of a magnon mode in the disk producing magnons at half the excitation frequency. Micromagnetic simulations support this finding, showing spatial and spectral overlap of a confined magnon mode and an NV spin transition, with sufficient interaction strength to explain the observed signal. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy (NV) center is a promising candidate to realize practical quantum sensors with high sensitivity and high spatial resolution at room temperature and atmospheric pressure. In conventional high-frequency AC magnetometry with NV centers, the setup requires a pulse sequence with an appropriate time synchronization and strong microwave power. To avoid these practical difficulties, AC magnetometry using continuous-wave optically detected magnetic resonance (CW-ODMR) was recently demonstrated. That previous study utilized radio frequency (RF)-dressed states generated by the coherent interaction between the electron spin of the NV center and the RF wave. However, the drawback of this method is that the detectable frequency of the AC magnetic fields is fixed. Here, we propose and demonstrate frequency-tunable magnetic field sensing based on CW-ODMR. In the new sensing scheme, we obtain RF double-dressed states by irradiation with RF fields at two different frequencies. One creates the RF-dressed states and changes the frequency of the target AC field. The other is a target AC field that induces a change in the CW-ODMR spectrum by generating the RF double-dressed states through coherent interaction with the RF-dressed states. The sensitivity of our method is estimated to be comparable to or even higher than that of the conventional method based on the RF field with a single frequency. The estimated bandwidth is 7.5 MHz, higher than that of the conventional method using the RF-dressed states. Our frequency-tunable magnetic field sensor based on CW-ODMR paves the way for new applications in diamond devices. [ABSTRACT FROM AUTHOR]

Optical metamaterials, sensing, nonlinear optics, and surface-enhanced spectroscopies have witnessed the remarkable potential of the anapole mode. While dielectric particles with a high refractive index have garnered significant attention in recent years, the exploration of plasmonic anapole modes with intense localized electric field enhancements in the visible frequency range remains limited. In this study, we present a theoretical investigation on the relationship between the strongest near-field response and magnetic anapole modes, along with their substantial enhancement of Raman signals from probing molecules. These captivating findings arise from the design of a practical metallic oblate spheroid–film plasmonic system that generates magnetic anapole resonances at frequencies within the visible–near-infrared range. This research not only sheds light on the underlying mechanisms in a wide range of plasmon-enhanced spectroscopies but also paves the way for innovative nano-device designs. [ABSTRACT FROM AUTHOR]

Owing to magnetoelastic coupling, surface acoustic waves (SAWs) may be scattered resonantly by magnetic elements, such as nickel stripes. The scattering may be further enhanced via the Borrmann effect when the elements are organized into an array that matches the acoustic wavelength. We use finite-element modeling to consider single- and double-layer stripes patterned on top of a lithium niobate surface that carries Love surface waves. We do observe enhancement in the coupling for single-layer stripes, but only for Gilbert damping below its realistic value. For double-layered stripes, a weak yet clear and distinct signature of Bragg reflection is identified far away from the acoustic band edge, even for a realistic damping value. Double-layered stripes also offer better magnetic tunability when their magnetic period is different from the periodicity of elastic properties of the structure because of staggered magnetization patterns. The results pave the way for the design of magnetoacoustic metamaterials with an enhanced coupling between propagating SAWs and local magnetic resonances and for the development of reconfigurable SAW-based circuitry. [ABSTRACT FROM AUTHOR]

We demonstrate a real-time, single-shot vector magnetic measurement technique using synchronous coherent population trapping (SCPT) in an apparatus consisting of a small rubidium vapor cell. Vector modality of our magnetometer is enabled by designing a feedback system based on performing a peak-lock on a particularly strong 2 Ω L magnetic resonance produced in the SCPT spectrum and compensating the external magnetic field via a three-axis field coil. With its current design, this magnetometer exhibits high sensitivities of approximately 155 , 129 , and 57 pT / Hz in measuring the magnetic field vector components along the (x,y,z) axes. Sensitivities closer to the shot-noise limit can be achieved in the future by reducing the technical noise of our equipment and by employing a differential detection and polarization rotation measurement scheme in our system. [ABSTRACT FROM AUTHOR]

Peripheral nerve disorders refer to any condition that damages the peripheral nervous system with variable presentations and numerous causes. The diagnosis is usually suspected clinically and then confirmed using electrophysiology. Yet electrodiagnostic studies lack precise anatomical delineation and often cannot determine the underlying cause of the peripheral neuropathy. However, thanks to recent technological advances, high-resolution ultrasound (HRUS) and magnetic resonance (MR) imaging have emerged as exceptional modalities to identify the exact site of pathology and demonstrate the underlying etiology. These developments have led to a multimodality approach to peripheral nerve disorders. Imaging provides anatomical and morphological information while functional evaluation remains derived from electrodiagnostic study. This article reviews the HRUS features of common as well as less frequent peripheral nerve disorders: entrapment neuropathies, traumatic injuries, neuralgic amyotrophy, polyneuropathies, and nerve tumors. [ABSTRACT FROM AUTHOR]

Purpose: Smell ability is associated with nasopharyngeal obstruction. Herein, we evaluated the effect of nasopharyngeal obstruction by adenoid hypertrophy on the olfactory bulb (OB) volume and olfactory sulcus (OS) depth in children. Methods: A total of 135 children who were candidates for brain magnetic resonance imagining scanning were enrolled in the study. The olfactory disorder-negative statements questionnaire was utilized to assess the patient-reported olfactory status. A validated sleep questionnaire was used to assess sleeping status. According to the adenoidal/nasopharyngeal (A/N) ratio, the children were divided into two groups: those with an A/N ratio ≤ 0.5 (n = 70) and those with an A/N ratio > 0.5 (n = 65). OB volume and OS depth measurements were performed on coronal T2-weighted images using planimetric manual contouring. The mean OB volumes and OS depths on the right and left sides were used for the evaluation. Results: The mean OB volume of the group with an A/N ratio > 0.5 was significantly lower than that of the group with an A/N ratio ≤ 0.5 (P = 0.003), while there was no difference in the mean OS depth between groups (P = 0.061). In those with an A/N ratio > 0.5, the mean OB volume in older children (aged 9–12 years) was significantly lower than that in younger children (aged 5–8 years) (P = 0.012). In terms of laterality, the OS depth on the right side was significantly larger than that on the left side in both groups (P = 0.039 and P = 0.001). In the group with an A/N ratio ≤ 0.5, the OB volume on the right side was also significantly larger than that on the left side (P = 0.040); however, no such difference was observed in the group with an A/N ratio > 0.5 (P = 0.630). No sex-based differences were evident for any variable. Conclusions: Children with nasopharyngeal obstruction greater than 50% have a significantly smaller OB volume. Our results suggest that morphological alterations in OB may contribute to the pathogenic mechanism of olfactory dysfunction related to nasopharyngeal obstruction. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective cohort study. Objective: To evaluate the mid-term effect of intervertebral disc degeneration (DD) in patients with adolescent idiopathic scoliosis (AIS) who underwent pedicle screw instrumentation (PSI) and rod derotation (RD) with direct vertebral rotation (DVR). Summary of Background Data: Posterior spinal fusion is a mainstay of surgical treatment in AIS, and DVR is considered a main corrective maneuver for vertebral rotation. However, the mid-term effect of intervertebral DD after DVR is still unknown in AIS. Methods: A total of 336 vertebrae for 48 patients with AIS who underwent PSI and RD with DVR were retrospectively assessed for intervertebral DD. They were divided into two groups based upon intervertebral DD, defined as Pfirmann grade more than IV. The Pfirrmann grade and modic change were evaluated at the disc above the uppermost instrumented vertebra (UIV), the disc below the lowest instrumented vertebra (LIV), and the lumbar disc levels. Results: With the 11.6 years of mean follow-up, 41.7% (20/48) of patients exhibited DD, while modic changes were observed in 4.2% (2/48) of the included patients. The discs below the LIV, L4-5, and L5-S1 were significantly shown to have an increasing trend of Pfirmann grade. The preoperative thoracic kyphosis was significantly lower in the DD group (22.0°) than in the non-DD group (31.4°) (P = 0.025) and negatively correlated with DD (r = -0.482, P = 0.018). The Pfirrmann grade of L5-S1 showed a high level of correlation with DD (r = 0.604, P < 0.001). Conclusions: The degenerative change at the disc below the LIV, L4-5, and L5-S1 levels was observed following PSI and RD with DVR. Thoracic hypokyphosis may negatively influence intervertebral discs in patients with AIS required for deformity correction. Therefore, the restoration of thoracic kyphosis is important to prevent long-term DD in AIS. [ABSTRACT FROM AUTHOR]

Cranial ultrasound reliably diagnoses many neonatal brain disorders. Adding Doppler imaging expands the spectrum by providing information on the status of the vasculature and haemodynamics that may guide further diagnostic and clinical management. Doppler imaging may identify neonates with congenital or acquired vascular abnormalities such as perinatal stroke, sinuvenous thrombosis, vein of Galen malformation, dural sinus malformation, sinus pericranii, and developmental venous anomaly. These entities may need further investigation with complementary imaging modalities such as magnetic resonance imaging and magnetic resonance angiography, or conventional angiography. This review aims to help clinicians to improve their Doppler sonography knowledge and skills in order to use this helpful tool in neonates with neurological symptoms or suspected cerebral vascular abnormalities admitted to the neonatal intensive care unit. [ABSTRACT FROM AUTHOR]

Increased myocardial T1 values on cardiovascular MRI (CMRI) have been shown to be a surrogate marker for myocardial fibrosis. The use of CMRI in patients on hemodialysis (HD) remains limited. This research aimed to explore the characteristics of native T1 values in HD patients and identify factors related to T1 values. A total of thirty-two patients on HD and fourteen healthy controls were included in this study. All participants underwent CMRI. Using modified Look-Locker inversion recovery (MOLLI) sequence, native T1 mapping was achieved. Native CMRI T1 values were compared between the two groups. In order to analyze the relationship between T1 values and clinical parameters, correlation analysis was performed in patients on HD. Patients on HD exhibited elevated global native T1 values compared to control subjects. In the HD group, the global native T1 value correlated positively with intact parathyroid hormone (iPTH) (r = 0.418, p = 0.017) and negatively with triglycerides (r= −0.366, p = 0.039). Moreover, the global native T1 value exhibited a positive correlation with the left ventricular end-diastolic volume indexed to body surface area (BSA; r = 0.528, p = 0.014), left ventricular end-systolic volume indexed to BSA (r = 0.506, p = 0.019), and left ventricular mass indexed to BSA (r = 0.600, p = 0.005). A negative correlation was observed between the global native T1 value and ejection fraction (r = 0.-0.551, p = 0.010). The global native T1 value was prolonged in HD patients compared with controls. In the HD group, the global T1 value correlated strongly with iPTH, triglycerides, and cardiac structural and functional parameters. [ABSTRACT FROM AUTHOR]

Background: Different MR elastography (MRE) systems may produce different stiffness measurements, making direct comparison difficult in multi‐center investigations. Purpose: To assess the repeatability and reproducibility of liver stiffness measured by three typical MRE systems. Study Type: Prospective. Population/Phantoms: Thirty volunteers without liver disease history (20 males, aged 21–28)/5 gel phantoms. Field Strength/Sequence: 3.0 T United Imaging Healthcare (UIH), 1.5 T Siemens Healthcare, 3.0 T General Electric Healthcare (GE)/Echo planar imaging‐based MRE sequence. Assessment: Wave images of volunteers and phantoms were acquired by three MRE systems. Tissue stiffness was evaluated by two observers, while phantom stiffness was assessed automatically by code. The reproducibility across three MRE systems was quantified based on the mean stiffness of each volunteer and phantom. Statistical Tests: Intraclass correlation coefficients (ICC), coefficients of variation (CV), and Bland–Altman analyses were used to assess the interobserver reproducibility, the interscan repeatability, and the intersystem reproducibility. Paired t‐tests were performed to assess the interobserver and interscan variation. Friedman tests with Dunn's multiple comparison correction were performed to assess the intersystem variation. P values less than 0.05 indicated significant difference. Results: The reproducibility of stiffness measured by the two observers demonstrated consistency with ICC > 0.92, CV < 4.32%, Mean bias < 2.23%, and P > 0.06. The repeatability of measurements obtained using the electromagnetic system for the liver revealed ICC > 0.96, CV < 3.86%, Mean bias < 0.19%, P > 0.90. When considering the range of reproducibility across the three systems for liver evaluations, results ranged with ICCs from 0.70 to 0.87, CVs from 6.46% to 10.99%, and Mean biases between 1.89% and 6.30%. Phantom studies showed similar results. The values of measured stiffness differed across all three systems significantly. Data Conclusion: Liver stiffness values measured from different MRE systems can be different, but the measurements across the three MRE systems produced consistent results with excellent reproducibility. Evidence Level: 1 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) was applied to determine the sex of polar cod (Boreogadus saida Lepechin, 1774) (Actinopterygii: Gadidae) and to follow the gonadal development in individual animals over time. Individual unanaesthetised fish were transferred to a measurement chamber inside a preclinical 9.4 T MRI scanner and continuously perfused with aerated seawater. A screening procedure at an average of 3.5 h, consisting of a set of MRI scans of different orientations, was repeated every 4 weeks on the same set of reproducing B. saida (n = 10) with a body length of about 20 cm. Adapted multi‐slice flow‐compensated fast low‐angle shot (FcFLASH) and rapid acquisition with relaxation enhancement (RARE) protocols with an in‐plane resolution of 313 μm and an acquisition time of 2.5 min were used to visualise the morphology of various organs, including the gonads within the field of view (FOV). The MR images provided high resolution, enabling specific sex determination, calculation of gonad volumes, and determination of oocyte sizes. Gonad maturation was followed over 4 months from November 2021 until shortly before spawning in February 2022. The gonad volume increased by 2.3–25.5% for males and by 11.5–760.7% for females during the observation period. From October to February, the oocyte diameter increased from 427 μm (n = 1) to 1346 ± 27 μm (n = 4). Interestingly, individual oocytes showed changes in MR contrast over time that can be attributed to the morphological development of the oocytes. The results fit well with previous literature data from classical invasive studies. The presented approach has great potential for various ecophysiological applications such as monitoring natural or delayed development of internal organs or sex determination under different environmental conditions. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most common primary malignancies of the liver and a leading cause for cancer-related deaths worldwide. HCC surveillance aims at early detection. The recommended strategy for screening HCC is biannual ultrasound with or without alpha-fetoprotein. However, this strategy is associated with sub-optimal sensitivity. Abbreviated magnetic resonance imaging (AMRI) is a promising alternative to ultrasound (US) for surveillance of HCC. The data regarding the role of AMRI in HCC screening is evolving. There are different AMRI protocols, each having its merits and disadvantages. In this review, we discuss the need for AMRI, protocols of AMRI and hindrances to widespread adoption of AMRI. [ABSTRACT FROM AUTHOR]

Brain disorders are impacting billions of individuals worldwide. Magnetic Resonance (MR) Imaging is the most widely used imaging modality to examine brain abnormalities. However, MR images may be corrupted by the presence of noise primarily Rician noise, artifacts, and distortions that affect the accuracy in the detection of abnormalities. To overcome these issues, a novel Fuzzy Type-II driven modified Anisotropic Diffusion filter (FDAD) framework is proposed, where the edge threshold constraint of the diffusion coefficient has been automated by calculation of ultra-fuzziness in an image instead of manual calculation. Ultra-fuzziness keeps edges and boundaries better with an appropriate threshold value and also prevents over-smoothing and restores fine details of abnormalities in MR images. After this, the Extended Contrast Limited Adaptive Histogram Equalization (ECLAHE) is applied to sharpen the details of abnormalities. Center for Biomedical Research Excellence (COBRE) functional MR (fMR) image datasets are used to demonstrate the proficiency of the proposed work. To gauge the effectiveness of the proposed methodology, a qualitative analysis has been carried out on a subset of fMR datasets, each characterized by different noise variations. The assessment encompassed both qualitative and quantitative metrics to compare the proposed method with the prevailing state of the art. A parametric quantitative analysis of the proposed method is performed and plotted using full reference image interpretation, human visual system, and no reference image interpretation. Finally, these results collectively illustrate the proficiency of the method to enhance and preserve the edges and sharpen details of abnormalities with removal of Rician noise. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lifelong PE patients show altered resting-state brain network in the left precuneus. • Right supplementary motor area (SMA) also exhibits significant network changes. • DC values correlated with IELT and CIPE in left precuneus, right SMA regions. The aim of this study was to investigate alterations in the resting-state brain functional network characteristics of lifelong premature ejaculation (PE) patients using surface-based degree centrality (DC), and to analyze the correlation between these alterations and clinical symptoms in PE patients. The study included individuals with lifelong PE (patient group, n = 36) and a control group matched by age and education level (control group, n = 22). Resting-state functional magnetic resonance imaging (fMRI) scans were performed on all participants. Surface-based degree centrality analysis was conducted and the differences between the two groups were compared using t-tests. Further, the DC values of brain regions showing significant differences were correlated with clinical symptoms. Compared to the control group, the patient group exhibited significantly reduced degree centrality (DC) values in the left precuneus and significantly increased DC values in the right supplementary motor area (SMA). Furthermore, intravaginal ejaculatory latency time (IELT) and Chinese Index of Premature Ejaculation (CIPE) values were positively correlated with left precuneus DC values and negatively correlated with right SMA DC values. Patients with primary lifelong ejaculation demonstrate abnormalities in key brain network nodes and their connections with relevant brain regions, which are strongly associate with clinical symptoms. These findings enhance our understanding of the neuronal pathological changes in PE patients. [ABSTRACT FROM AUTHOR]

ABATRACTTwo new compounds, namely, isorhamnenin-3-O-neohesperidin-6′′-linoleic acid ester (1) and isorhamnenin-3-O-neohesperidin-6′′-palmitate (2), along with 17 known compounds, were isolated from Pollen Typhae Carbonisatus (PTC). Their structures were elucidated on the basis of one-dimensional (1D)-, two-dimensional (2D)-nuclear magnetic resonance (NMR), and high-resolution electrospray ionization mass spectrometry (HRESIMS) spectroscopic data analyses. The two new compounds (1 and 2) exhibited a protective effect in a dose-dependent manner and promoted tube generation in the oxygen-glucose deprivation/reoxygenation (OGD/R)-induced human brain microvascular endothelial cells (HBMECs). [ABSTRACT FROM AUTHOR]

Summary Mandibular advancement devices are an effective treatment option for obstructive sleep apnea. While their efficacy depends on the degree of mandibular protrusion, other contributing factors influencing the optimal outcome are not fully understood. This magnetic resonance imaging‐based pilot study aimed at investigating whether there are promising planimetric parameters that may be related to the optimal therapeutic position. A second aim was to assess possible sex‐specific differences. Planimetric data from magnetic resonance imaging taken in the habitual position and four protrusion grades were collected from 11 female and 14 male patients with obstructive sleep apnea (age 45 ± 13.3 years; body mass index 27.6 ± 4.5 kg m−2). Data were correlated with outcome as substantiated by polygraphic data obtained at the habitual position and at each of two protrusion positions considered to reveal the highest treatment effect. Protrusion degree and lateral widening of the retropalatal region correlated most strongly (R = 0.56, p < 0.001). Relationships between planimetric data and treatment success were most pronounced at the level of the smallest cross‐section, expressed, for example, by a correlation between oxygen desaturation index and lateral diameter (R = −0.4, p = 0.012). Female participants appeared to show improved polygraphic values at a lower protrusion degree than males. Data from magnetic resonance imaging allow for a comprehensive analysis combining insights from planimetric velopharyngeal measurements at different individual protrusion grades and correlation with outcome. The results of this pilot work encourage further evaluation in large‐scale studies. These should focus on the velopharyngeal region and investigate the influence of sex more closely. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aims Methods Results Conclusions Predose trough concentrations (Ctrough) of intravenous infliximab (IV‐IFX) during maintenance therapy are associated with therapeutic outcomes in patients with Crohn's disease (CD). A subcutaneous formulation of infliximab (SC‐IFX) has shown high Ctrough values due to its favourable pharmacokinetics.To evaluate the association of Ctrough of SC‐IFX with therapeutic outcomes and the threshold of SC‐IFX Ctrough for achieving mucosal healing (MH) and transmural healing (TH) in patients with CD.We performed this cross‐sectional study in patients with CD who had received SC‐IFX maintenance therapy for ≥ 6 months. We measured SC‐IFX Ctrough immediately before SC‐IFX injection. We performed ileocolonoscopy/single‐balloon enteroscopy and/or magnetic resonance enterography within 3 months of SC‐IFX Ctrough measurement. MH was defined as SES‐CD–ulcerated surface subscore of 0. TH was defined as simplified MaRIA score of 0.We enrolled 124 patients with MH in 77.9% (74/95) and TH in 36.3% (37/102). SC‐IFX Ctrough was significantly higher in patients with MH (24.1 vs.16.9 μg/mL; p = 0.001) and TH (26.0 vs. 20.5 μg/mL; p = 0.007) than in those without. ROC analysis identified that the threshold of SC‐IFX Ctrough for MH and TH were 17.5 and 30.3 μg/mL, respectively. Multivariate logistic regression showed that SC‐IFX Ctrough was significantly associated with MH (OR 1.16; 95% CI 1.05–1.27; p = 0.002) and TH (OR 1.08; 95% CI 1.02–1.14; p = 0.005).SC‐IFX Ctrough was positively associated with MH (≥ 18 μg/mL) and TH (≥ 30 μg/mL) in patients with CD, which may guide treatment decisions to optimise therapeutic response in the era of treat‐to‐target. [ABSTRACT FROM AUTHOR]

Magnetic resonance image-guided brachytherapy is essential in the management of locally advanced cervical cancer. This study compares disease and toxicity outcomes in cervical cancer patients treated with 24 Gy/3 fractions (Fr) versus the conventional 28 Gy/4 Fr. This retrospective study included 241 consecutive patients with International Federation of Gynecology and Obstetrics 2018 stage IB to IVA cervical cancer treated with definitive chemoradiation between April 2014 and March 2021. Disease-free survival (DFS) was estimated using the Kaplan-Meier method and compared using the log-rank test. Cumulative incidence of local failure (LF), distant failure (DF), and G2+ gastrointestinal (GI), urinary and vaginal toxicity were estimated using the cumulative incidence function with death as a competing risk and compared using Gray's test. Of the 241 patients, 42% received 24 Gy/3 Fr and 58% received 28 Gy/4 Fr. With a median follow-up of 3.2 (range, 0.2-9.2) years, there were 14 local, 41 regional nodal, and 51 distant failures in 63 (26%) patients. No significant differences were found between the 24 Gy/3 Fr and 28 Gy/4 Fr groups in 3-year DFS (77% vs 68%, P =.21), the 3-year cumulative incidence of LF (5% vs 7%, P =.57), DF (22% vs 25%, P =.86), G2+ GI toxicity (11% vs 20%, P =.13), or G2+ vaginal toxicity (14% vs 17%, P =.48), respectively. The 3-year cumulative G2+ urinary toxicity rate was lower in the 24 Gy/3 Fr group (9% vs 23%, P =.03). Patients with cervical cancer treated with 24 Gy/3 Fr had similar DFS, LF, DF, GI, and vaginal toxicity rates and a trend toward a lower G2+ urinary toxicity rate compared with those treated with 28 Gy/4 Fr. A less resource-intensive brachytherapy fractionation schedule of 24 Gy/3 Fr is a safe alternative to 28 Gy/4 Fr for definitive treatment of cervical cancer. [ABSTRACT FROM AUTHOR]

As a method based on the deformable surface evolution, brain extraction tools (BET) is widely used for brain extraction on cranial 3D magnetic resonance (MR) images. BET iteratively applies an evolution model depending on local parameters to the deformable surface until it reaches the brain border. In this paper, we propose a modified BET based on the fast model introducing a global parameter, the global mean inter-vertex distance of deformable surface. The surface evolution consists of two steps driven by two models: pre-processing step by the fast model and major step by the original model. We demonstrated our method in the experiments with T1-weighted and diffusion weighted MR images of 19 normal subjects. The modified BET converged within 300 iterations less than half of about 1000 iterations in the original BET, while reducing substantially the false negative regions and self-intersections. The proposed method may be efficient for high resolution images and large-scale studies. [ABSTRACT FROM AUTHOR]

We sought to assess cardiac magnetic resonance derived left ventricular hemodynamic forces (HDF) in athletes compared to patients with hypertension. Sixty athletes and 48 hypertensive patients were studied. HDF were measured during the entire cardiac cycle, the systolic phase, suction, early LV filling, and atrial thrust. Statistical comparisons were made between athletes and hypertensive patients, and between endurance and strength athletes. The slope of the systolic ejection was higher in athletes compared to hypertensive patients (541.5 vs. 435 1/sec; p = 0.033). Athletes showed higher HDF during the first phase of systole (4.53 vs. 3.86; p = 0.047) and the systolic impulse (11.26 vs. 8.76; p = 0.045). Compared to hypertensive patients, the AUC of the elastic rebound in athletes was lower (-0.31 vs. -0.44; p = 0.011). Moreover, hypertensive patients had an abnormal suction as revealed by a divergent direction (apex-to-base) of the HDF. The atrial thrust was higher in hypertensive patients than in athletes (-0.31 vs. -0.05; p < 0.001). Compared to endurance athletes, strength athletes had a shorter duration of the systolic impulse (250 vs. 280 ms; p = 0.019) and higher AUC during the early LV filling (1.65 vs. 0.97; p = 0.016). We conclude that HDF allows distinction between the hemodynamic patterns of athletes and patients with hypertension. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) is a major cause of morbidity and mortality, impacting healthcare systems and economies. Early identification of poor outcomes is crucial for effective treatment. This systematic review assesses the prognostic value of computed tomography (CT) and magnetic resonance imaging (MRI) findings in predicting poor neurological outcomes and mortality in the acute phase of TBI. A comprehensive search of Scopus, MEDLINE, and Web of science databases was performed to identify studies examining CT and MR-based imaging findings and their association with poor outcomes as assessed by Glasgow outcome score as well as mortality within the early acute phase of TBI following injury/admission. Qualitative evaluation of included studies revealed several imaging sequences that modify the outcome of the patients, including extra-axial and intra-axial hemorrhage, swirl sign, contrast extravasation, midline shift, closed and open cranial cisterns, signs of edema, presence of cranial fractures, intracranial hemorrhage, cerebral microbleeds, diffuse axonal injury, apparent diffusion coefficient and fractional anisotropy in diffusion tensor imaging, as well as, concentrations of brain metabolites(N-acetyl aspartate, Creatinine, Choline, Myo-inositol, glutamate, and glutamine) in magnetic resonance spectroscopy. Among these markers, subarachnoid hemorrhage (SAH) and subdural hematoma (SDH) emerged as the most predictive of poor outcomes based on meta-analysis findings. SAH was significantly associated with an increased risk of mortality (OR: 3.35, 95% CI: 2.41–4.65, I²=51.3%) and poor outcomes (OR: 2.69, 95% CI: 2.44–2.96, I²=0%). Similarly, SDH correlated with higher mortality risk (OR: 2.44, 95% CI: 2.14–2.78, I²=0%) and worse outcomes (OR: 2.00, 95% CI: 1.12–3.59, I²=60.9%). In contrast, epidural hematoma (EDH) was linked to better outcomes (OR: 0.60, 95% CI: 0.52–0.68, I²=0%) but not significantly associated with mortality (OR: 0.38, 95% CI: 0.09–1.65, I²=73.7%). The results of this systematic review and meta-analysis provide an overview of clinically feasible imaging markers of prognostic value and may inform clinical decision-making in the future. [ABSTRACT FROM AUTHOR]

Background and Aims Intravenous iron therapies contain iron–carbohydrate complexes, designed to ensure iron becomes bioavailable via the intermediary of spleen and liver reticuloendothelial macrophages. How other tissues obtain and handle this iron remains unknown. This study addresses this question in the context of the heart. Methods A prospective observational study was conducted in 12 patients receiving ferric carboxymaltose (FCM) for iron deficiency. Myocardial, spleen, and liver magnetic resonance relaxation times and plasma iron markers were collected longitudinally. To examine the handling of iron taken up by the myocardium, intracellular labile iron pool (LIP) was imaged in FCM-treated mice and cells. Results In patients, myocardial relaxation time T1 dropped maximally 3 h post-FCM, remaining low 42 days later, while splenic T1 dropped maximally at 14 days, recovering by 42 days. In plasma, non-transferrin-bound iron (NTBI) peaked at 3 h, while ferritin peaked at 14 days. Changes in liver T1 diverged among patients. In mice, myocardial LIP rose 1 h and remained elevated 42 days after FCM. In cardiomyocytes, FCM exposure raised LIP rapidly. This was prevented by inhibitors of NTBI transporters T-type and L-type calcium channels and divalent metal transporter 1. Conclusions Intravenous iron therapy with FCM delivers iron to the myocardium rapidly through NTBI transporters, independently of reticuloendothelial macrophages. This iron remains labile for weeks, reflecting the myocardium's limited iron storage capacity. These findings challenge current notions of how the heart obtains iron from these therapies and highlight the potential for long-term dosing to cause cumulative iron build-up in the heart. [ABSTRACT FROM AUTHOR]

High dose-rate brachytherapy presents a promising therapeutic avenue for prostate cancer management, involving the temporary implantation of catheters which deliver radioactive sources to the cancerous site. However, as catheters puncture and penetrate the prostate, tissue deformation is evident which may affect the accuracy and efficiency of the treatment. In this work, a data-driven in silico modelling procedure is proposed to simulate brachytherapy while accounting for prostate biomechanics. Comprehensive magnetic resonance and transrectal ultrasound images acquired prior, during and post brachytherapy are employed for model personalisation, while the therapeutic procedure is simulated via sequential insertion of multiple catheters in the prostate gland. The medical imaging data are also employed for model evaluation, thus, demonstrating the potential of the proposed in silico procedure to be utilised pre- and intra-operatively in the clinical setting. [ABSTRACT FROM AUTHOR]

The objective of our study is to measure perirenal fat thickness using MRI in individuals with steatotic liver disease and investigate the relationship between perirenal fat thickness and metabolic syndrome. This retrospective study included consecutive patients with steatotic liver disease who underwent magnetic resonance imaging-proton density fat fraction from October 2018 to February 2020. Among them, patients with crossed fused kidneys or who underwent nephrectomy were excluded. The metabolic abnormalities were reviewed; presence of hypertension, type 2 diabetes, abdominal circumference, triglyceride, and high-density lipoprotein. Perirenal fat was measured in four directions in both kidneys and the total sum of them was calculated. A total of 250 patients (140 males and 110 females) were included. Perirenal fat thickness showed a moderate correlation with waist circumference, creatinine, and hepatic fat fraction (all p < 0.001). Perirenal fat thickness was significantly higher in patients with metabolic syndrome than in patients without (76.8 mm vs. 65.1 mm, p = 0.004). In multivariable regression analysis, the group with high perirenal fat thickness had as significantly higher odd ratio of 2.71 compared to the low group. The perirenal fat thickness is independently associated with metabolic syndrome in patients with steatotic liver disease. [ABSTRACT FROM AUTHOR]

Obstructive hypertrophic cardiomyopathy (oHCM) is characterized by left ventricular (LV) hypertrophy, LV outflow tract obstruction, and left atrial dilation, which can be associated with progressive heart failure, atrial fibrillation, and stroke. Aficamten is a next-in-class cardiac myosin inhibitor that reduces outflow tract obstruction by modulating cardiac contractility, with the potential to reverse pathological remodeling and, in turn, reduce cardiovascular events. This study sought to investigate the effect of aficamten on cardiac remodeling compared with placebo using cardiovascular magnetic resonance (CMR) and its association with key clinical endpoints in the SEQUOIA-HCM (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM) CMR substudy. SEQUOIA-HCM was a phase 3 double-blind, placebo-controlled trial for adults with symptomatic oHCM who were randomized 1:1 to 24 weeks of aficamten (dose range: 5-20 mg) or placebo. Eligible participants were offered enrollment in the CMR substudy with studies performed at baseline and week 24. Image analysis was performed in a blinded fashion by a core laboratory. Of the 282 randomized patients, 57 (20%) participated in the substudy, and of those, 50 (88%) completed both baseline and week 24 CMR. Baseline characteristics of the CMR cohort were similar to the overall study population. Of these 50 patients, 21 received aficamten and 29 received placebo. Relative to placebo, patients receiving aficamten demonstrated significant reductions (Δ least-squares mean) in LV mass index (−15 g/m2; 95% CI: −25 to −6 g/m2; P = 0.001), maximal LV wall thickness (−2.1 mm; 95% CI: −3.1 to −1.1 mm; P < 0.001), left atrial volume index (−13 mL/m2; 95% CI: −19 to −7 mL/m2; P < 0.001), native T1 relaxation time (−37 ms; 95% CI: −69 to −5 ms; P = 0.026), indexed extracellular volume fraction (−3.9 g/m2; 95% CI: −7.0 to −0.9 g/m2; P = 0.014), and indexed myocyte mass (−14 g/m2; 95% CI: −23 to −4 g/m2; P = 0.004), while there were no significant changes in LV chamber volumes, LV replacement fibrosis (late gadolinium enhancement mass −0.7 g; 95% CI: −2.9 to 1.6 g; P = 0.54), or extracellular volume (0.7%; 95% CI: −2.2% to 3.6%; P = 0.61). The CMR substudy of SEQUOIA-HCM demonstrated that treatment with aficamten relative to placebo for 24 weeks resulted in favorable cardiac remodeling. These changes, particularly with regard to LV mass, wall thickness, and left atrial size, could potentially lead to reduced cardiovascular events including heart failure and atrial fibrillation with longer follow-up. (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM [SEQUOIA-HCM]; NCT05186818) [ABSTRACT FROM AUTHOR]

Among magnetic materials, spinel ferrite is regarded as a potentially excellent low-frequency electromagnetic wave (2–8 GHz) absorber with low magnetic resonance frequency. However, spinel ferrite manufactured by conventional methods tends to be shape-isotropic, making the magnetic loss of the absorber quite weak under the Snoek Limit. Accordingly, our work prepares a highly shape-anisotropic Ni 0.5 Mn 0.5 Nd 0.04 Fe 1.96 O 4 ferrite (H-NMNF) with multiple crystal structures (mainly decahedral) via a novel sol-gel method. Compared with the uniformly laminated Ni 0.5 Mn 0.5 Nd 0.04 Fe 1.96 O 4 ferrite prepared by the conventional sol-gel method (C-NMNF), the natural resonance loss of H-NMNF is dramatically improved owing to the enhanced shape-anisotropic effect resulting in the Snoek Limit being breached. The results show that H-NMNF achieves the maximum effective absorption bandwidth (EAB max) of 6.64 GHz (2.96–9.6 GHz) at a thinner matching thickness of 5.1 mm, covering approximately the entire low-frequency band. This study provides methodological guidance for manufacturing magnetic loss materials with high shape-anisotropy and a new strategy for fabricating ultra-broadband, low-frequency magnetic electromagnetic wave absorbers. [ABSTRACT FROM AUTHOR]

Background: Anal fistula (AF) is an abnormal tunnel under the skin connecting the anal canal in the colon to the skin of buttocks. Fat-suppressed (FS) proton density-weighted (PDW) imaging is mainly used for the diagnosis of diseases involving bones and joints. Until now, its value in the diagnosis of anal fistula has been rarely reported. Purpose: To compare three magnetic resonance imaging (MRI) sequences – diffusion-weighted imaging (DWI), FS-PDW), and contrast-enhanced (CE) T1-weighted (T1W) imaging – for the diagnostic value of the internal opening of AF. Material and Methods: MRI scans of 132 patients suspected of having AF between December 2021 and April 2023 were retrospectively analyzed. In total, 65 patients who underwent preoperative MRI and were treated surgically were included. The lesion conspicuity and accuracy for featuring AF were calculated by evaluating the three imaging datasets DWI, FS-PDW, and CE-T1W imaging, with surgical findings serving as the reference standard for the presence of fistulas. The statistical analysis included the application of the chi-square test and Kruskal–Wallis test. Results: In 65 patients with AF, 87 internal openings of AF were confirmed. In terms of the diagnostic accuracy of the internal openings, both FS-PDW and CE-T1W imaging sequences were significantly better than DWI sequences, and the difference was statistically significant (P < 0.05). Conclusion: The FS-PDW imaging sequence showed comparable diagnostic performance of the internal opening of AF to CE-T1W imaging, which can provide an important diagnostic basis for clinical procedures. [ABSTRACT FROM AUTHOR]

Background/Objectives: Huntington's disease (HD) is a fully penetrant neurodegenerative disease with a profound effect on quality of life. In recent years, there has been rapid growth in the description of its pathogenesis and diagnosis. Magnetic resonance spectroscopy (MRS) measurements can aid in the discrimination between premanifest Huntington's disease (Pre-HD) and healthy control (HC) subjects to establish early supportive and symptomatic management. Our objective was to evaluate metabolic changes using MRS to shed light on its potential as a biomarker through a systematic review. Methods: We followed the PRISMA guidelines, extracting articles from PubMed, Scopus, and the Virtual Health Library. We included patients with pre-HD, HD, and HC subjected to MRS, reporting the concentration of metabolites in at least one brain region. Results: In the putamen, N-acetyl Aspartate (NAA) was significantly decreased in 77.9% and total NAA (tNAA) was decreased in 72.4% of cases; no significant difference was found in 27.5% (n = 19) of cases. Furthermore, when looking into HD vs. pre-HD in the putamen, tNAA and NAA were decreased in 100% of participants. In the caudate nucleus, NAA and creatine were significantly decreased in 100% of HD in comparison to pre-HD participants, whereas tNAA showed a significant decrease in only 50%. Conclusions: MRS can be a relevant tool for the early diagnosis of HD; potential objective biomarkers related to its onset and pathogenesis exist and show differences between controls, pre-HD and HD patients. However, an effort should be made to standardize MRS methodology and reporting in subsequent studies. [ABSTRACT FROM AUTHOR]

Aortic stenosis (AS) is associated with the development of replacement myocardial fibrosis/scar. Given the dose-dependent relationship between scar and clinical outcomes after aortic valve replacement (AVR) surgery, scar quantity may serve as an important risk-stratification tool to aid decision-making on the optimal timing of AVR. Scar is non-invasively assessed and quantified by cardiovascular magnetic resonance (CMR) imaging. Several quantification techniques exist, and consensus on the optimal technique is lacking. These techniques range from a visual manual method to fully automated ones. This review describes the different scar quantification techniques used and highlights their strengths and shortfalls within the context of AS. The two most commonly used techniques in AS include the semi-automated signal threshold versus reference mean (STRM) and full-width half-maximum (FWHM) techniques. The accuracy and reproducibility of these techniques may be hindered in AS by the coexistence of diffuse interstitial fibrosis and the presence of relatively small, non-bright scars. The validation of these techniques against histology, which is the current gold standard for scar quantification in AS, is limited. Based on the best current evidence, the STRM method using a threshold of three standard deviations above the mean signal intensity of remote myocardium is recommended. The high reproducibility of the FWHM technique in non-AS cohorts has been shown and merits further evaluation within the context of AS. Future directions include the use of quantitative T1 mapping for the detection and quantification of scar, as well as the development of serum biomarkers that reflect the fibrotic status of the myocardium in AS. [ABSTRACT FROM AUTHOR]

Background/Objectives: To review the findings of a multiparametric MRI (the "liver triple screen") solution for the non-invasive assessment of liver fat, iron, and fibrosis in patients with chronic liver disease (CLD). Methods: A retrospective evaluation of all consecutive triple screen MRI cases was performed at our institution over the last 32 months. Relevant clinical, laboratory, and radiologic data were analyzed using descriptive statistics. Results: There were 268 patients, including 162 (60.4%) males and 106 (39.6%) females. The mean age was 54 ± 15.2 years (range 16 to 71 years). The most common cause of CLD was metabolic dysfunction-associated steatotic liver disease (MASLD) at 45.5%. The most common referring physician group was Gastroenterology at 62.7%. In 23.9% of cases, the reason for ordering the MRI was a pre-existing failed or unreliable US elastography. There were 17 cases (6.3%) of MRI technical failure. Our analysis revealed liver fibrosis in 66% of patients, steatosis in 68.3%, and iron overload in 22.1%. Combined fibrosis and steatosis were seen in 28.7%, steatosis and iron overload in 16.8%, fibrosis and iron overload in 6%, and combined fibrosis, steatosis, and iron overload in 4.1%. A positive MEFIB index, a predictor of liver-related outcomes, was found in 57 (27.5%) of 207 patients. Incidental findings were found in 14.9% of all MRIs. Conclusions: The liver triple screen MRI is an effective tool for evaluating liver fat, iron, and fibrosis in patients with CLD. It provides essential clinical information and can help identify MASLD patients at risk for liver-related outcomes. [ABSTRACT FROM AUTHOR]

Allophane and ferrihydrite are the main hosts of phosphate in allophanic Andosols, which are vital soil resources that support high human population densities. However, the sorption mechanism of phosphate on allophane has not been elucidated, unlike that of ferrihydrite. In particular, the effects of residence time on phosphate sorbed on allophane remain unclear. Therefore, the objectives of this study were to (1) understand the effect of residence time on the stability of phosphate sorbed on allophanic Andosol and allophane by desorption experiments using arsenate and (2) elucidate the sorption mechanism of phosphate on allophane using solid‐state 31P nuclear magnetic resonance (NMR). Consequently, the slow sorption of phosphate onto allophanic Andosol, allophane, and ferrihydrite continued for approximately 150 days. The ratio of total desorbable phosphate to phosphate sorbed onto the allophanic Andosol and allophane decreased with increasing residence time. In other words, phosphate sorption on allophanic Andosol and allophane was more irreversible with increasing residence time. The NMR spectra and X‐ray diffraction patterns showed that the molecular environment of phosphate sorbed onto allophane and ferrihydrite did not change at any residence time. Therefore, the slow sorption and irreversibility of phosphate were caused not by surface precipitation but by internal diffusion. In addition, the NMR spectra showed that most of the phosphate sorbed on allophane was present as inner‐sphere complexes. Core Ideas: We explored residence time's effects on phosphate sorbed on allophanic Andosol and allophane.Phosphate sorption on Andosol and allophane continued for approximately 150 days.Nuclear magnetic resonance (NMR) spectra did not notably change during long‐term phosphate sorption to allophane.Irreversibility of sorbed phosphate increased with residence time.Internal diffusion by soil in the phosphate sorption process is very important. [ABSTRACT FROM AUTHOR]

Objective: To assess the efficacy and safety of iguratimod in adult patients with active axial spondyloarthritis (axSpA). Method: This randomized, double-blind, placebo-controlled clinical trial lasted for 28 weeks. Patients with axSpA were randomized 1:1 to receive iguratimod 25 mg twice daily or a placebo. All patients also took celecoxib 200 mg twice daily for the first 4 weeks and on demand from 4 to 28 weeks. The primary endpoints were ASAS20 at 4 weeks and the non-steroidal anti-inflammatory drug (NSAID) index at 28 weeks. Other assessment variables included ASAS40, ASAS5/6 response rates, Spondyloarthritis Research Consortium of Canada (SPARCC) scores, and adverse events. Results: In total, 35 patients completed the study and were included for analyses. The median (interquartile range) NSAID index was 43.8 (34.9–51.8) in the iguratimod group, which is significantly lower than 68.9 (42.5–86.4) in the placebo group (p = 0.025). ASAS response rates and changes in disease activity scores were similar between the iguratimod and placebo groups. Patients in the iguratimod group had more improvement in median (interquartile range) SPARCC scores for sacroiliac joints than did those in the placebo group [71% (54–100%) vs 40% (0–52%), p = 0.006]. Iguratimod combined with celecoxib was not associated with a greater risk of adverse effects than was monotherapy with celecoxib. No severe adverse events occurred. Conclusions: In the treatment of active axSpA, iguratimod has a potential NSAID-sparing effect, and may also reduce magnetic resonance imaging-assessed bone marrow oedema in sacroiliac joints. Iguratimod provides an additional treatment option for patients with active axSpA.Clinical trial registration numberChiCTR2000029112, Chinese Clinical Trial Registry () [ABSTRACT FROM AUTHOR]

We established an efficient method using high-speed countercurrent chromatography (HSCCC) combined with preparative high-performance liquid chromatography (prep-HPLC) for isolating and purifying Gelsemium elegans (G. elegans) alkaloids. First, the two-phase solvent system composed of 1% triethylamine aqueous solution/n-hexane/ethyl acetate/ethanol (volume ratio 4:2:3:2) was employed to separate the crude extract (350 mg) using HSCCC. Subsequently, the mixture that resulted from HSCCC was further separated by Prep-HPLC, resulting in seven pure compounds including: 14-hydroxygelsenicine (1, 12.1 mg), sempervirine (2, 20.8 mg), 19-(R)-hydroxydihydrogelelsevirine (3, 10.1 mg), koumine (4, 50.5 mg), gelsemine (5, 32.2 mg), gelselvirine (6, 50.5 mg), and 11-hydroxyhumanmantenine (7, 12.5 mg). The purity of these seven compounds were 97.4, 98.9, 98.5, 99, 99.5, 96.8, and 85.5%, as determined by HPLC. The chemical structures of the seven compounds were analyzed and confirmed by electrospray ionization mass spectrometry (ESI-MS), 1H-nuclear magnetic resonance (1H NMR), and 13 C-nuclear magnetic resonance (13 C NMR) spectra. The results indicate that the HSCCC-prep-HPLC method can effectively separate the major alkaloids from the purified G. elegans, holding promising prospects for potential applications in the separation and identification of other traditional Chinese medicines. [ABSTRACT FROM AUTHOR]

Background: Magnetic resonance (MR) imaging devices have been integrated with medical linear accelerators (linac) in radiation therapy. Both perpendicular linac‐MR (LMR‐B⊥) and parallel (LMR‐B∥) systems exist, where due to the MR's magnetic field dose can be perturbed in the patient. Dose perturbations from the electron return effect (ERE) and electron streaming effects (ESEs) are present in LMR‐B⊥ systems, where a dose collimating effect has been observed in LMR‐B∥ systems. Purpose: To report on an asymmetric dose perturbation which is present at the interface between two different materials during treatment in parallel linac‐MR (LMR‐B∥) systems. To the best of our knowledge, these asymmetric dose effects, "Lateral Scattered Electron Return Effect" (LS‐ERE) have not been previously reported. Methods: BEAMnrc and EGSnrc Monte Carlo (MC) radiation transport codes were used with the EEMF macro to emulate a 6 FFF beam from the 0.5‐T Alberta linac‐MR (LMR). Simulations were performed at 0.5 and 1.5 T in several different phantom material–interface combinations and field sizes including from modulated MLC‐like fields. MC simulations quantified LS‐ERE in patient CT datasets for the head, breast, and lung. LS‐ERE cancellation techniques were investigated. LS‐ERE asymmetries were quantified by subtracting an antiparallel dose from the parallel dose, dividing by two and normalizing to the global 0‐T maximum dose. GafChromic film measurements were made in the 0.5‐T Alberta LMR‐B∥ system using solid water at the water–air interface to validate MC simulations. ERE was simulated for an emulated LMR‐B⊥ system and compared to LMR‐B∥ dose perturbations. Results: LS‐ERE is mostly independent of field size for fields >1 × 1 cm2. For 5 × 5‐cm2 fields at 0.5T/1.5T, LS‐ERE asymmetries are ≤±6.9%/6.9% at bone–air and ≤±9.0%/7.0% at tissue–air for nonair doses, and ≤±4.1%/5.5% at tissue–lung interfaces. LS‐ERE increases as the density gradient increases, where the magnitude and extent of LS‐ERE are reduced as field strength increases. For a single 5 × 5‐cm2 field at 0.5T/1.5T, the LS‐ERE asymmetry is ≤±10.2%/8.5% at the tissue–air sinus interface for head, ≤±4.2%/5.3% at the spine–lung interface for the lung, and ≤±5.7%/4.9% at the skin–air interface for a breast tangent plan at 0.5T/1.5T. POP fields mostly remove LS‐ERE asymmetries, with magnetic field reversal during treatment being the most effective method. Skin dose was investigated and compared to 0‐T treatments for 0.5T/1.5T LMR‐B∥ single field breast and head treatments. Including all dosimetric magnetic field perturbations, a 21%/24% and 22%/22% increase in skin dose to head and breast, respectively, was observed, of which LS‐ERE is responsible for approximately 30% of the total. Measured LS‐ERE asymmetries and dose enhancements at the water–air interface using GafChromic film were in excellent agreement with MC simulations. ERE in 1.5‐T LMR‐B⊥ systems are on average 5.5 times larger than total dose perturbations at 0.5 T in LMR‐B∥ systems. Conclusion: LS‐ERE is present at the interface between materials and awareness of LS‐ERE is crucial for proper TPS evaluation for LMR‐B∥ treatments, especially in areas where large tissue density gradients exist. [ABSTRACT FROM AUTHOR]

Background: Precise glioma segmentation from multi‐parametric magnetic resonance (MR) images is essential for brain glioma diagnosis. However, due to the indistinct boundaries between tumor sub‐regions and the heterogeneous appearances of gliomas in volumetric MR scans, designing a reliable and automated glioma segmentation method is still challenging. Although existing 3D Transformer‐based or convolution‐based segmentation networks have obtained promising results via multi‐modal feature fusion strategies or contextual learning methods, they widely lack the capability of hierarchical interactions between different modalities and cannot effectively learn comprehensive feature representations related to all glioma sub‐regions. Purpose: To overcome these problems, in this paper, we propose a 3D hierarchical cross‐modality interaction network (HCMINet) using Transformers and convolutions for accurate multi‐modal glioma segmentation, which leverages an effective hierarchical cross‐modality interaction strategy to sufficiently learn modality‐specific and modality‐shared knowledge correlated to glioma sub‐region segmentation from multi‐parametric MR images. Methods: In the HCMINet, we first design a hierarchical cross‐modality interaction Transformer (HCMITrans) encoder to hierarchically encode and fuse heterogeneous multi‐modal features by Transformer‐based intra‐modal embeddings and inter‐modal interactions in multiple encoding stages, which effectively captures complex cross‐modality correlations while modeling global contexts. Then, we collaborate an HCMITrans encoder with a modality‐shared convolutional encoder to construct the dual‐encoder architecture in the encoding stage, which can learn the abundant contextual information from global and local perspectives. Finally, in the decoding stage, we present a progressive hybrid context fusion (PHCF) decoder to progressively fuse local and global features extracted by the dual‐encoder architecture, which utilizes the local‐global context fusion (LGCF) module to efficiently alleviate the contextual discrepancy among the decoding features. Results: Extensive experiments are conducted on two public and competitive glioma benchmark datasets, including the BraTS2020 dataset with 494 patients and the BraTS2021 dataset with 1251 patients. Results show that our proposed method outperforms existing Transformer‐based and CNN‐based methods using other multi‐modal fusion strategies in our experiments. Specifically, the proposed HCMINet achieves state‐of‐the‐art mean DSC values of 85.33% and 91.09% on the BraTS2020 online validation dataset and the BraTS2021 local testing dataset, respectively. Conclusions: Our proposed method can accurately and automatically segment glioma regions from multi‐parametric MR images, which is beneficial for the quantitative analysis of brain gliomas and helpful for reducing the annotation burden of neuroradiologists. [ABSTRACT FROM AUTHOR]

Aims: We aimed to explore the extent to which individuals previously diagnosed with nonalcoholic fatty liver disease (NAFLD) meet the criteria fulfilled with the new nomenclature, metabolic dysfunction‐associated steatotic liver disease (MASLD), within an Asian primary clinic cohort. Additionally, we assessed the reliability of the diagnostic performance of FIB‐4 and NAFLD fibrosis score (NFS) for MASLD within the primary clinic cohort. Methods: This retrospective cross‐sectional study included participants who underwent magnetic resonance elastography and abdominal ultrasonography during their health checkups at nationwide health promotion centers (n = 6740). Results: The prevalence rates of NAFLD and MASLD diagnosed based on ultrasonography results were 36.7% and 38.0%, respectively. Notably, 96.8% of patients in the NAFLD cohort fulfilled the new criteria for MASLD. A small proportion of patients with NAFLD (n = 80, 3.2%) did not meet the MASLD criteria. Additionally, 168 patients (6.6%) were newly added to the MASLD group. The areas under the receiver operating characteristic curves for diagnosing advanced hepatic fibrosis for FIB‐4 (0.824 in NAFLD vs. 0.818 in MASLD, p = 0.891) and NFS (0.803 in NAFLD vs. 0.781 in MASLD, p = 0.618) were comparable between the MASLD and NAFLD groups. Furthermore, the sensitivity, specificity, positive predictive value, and negative predictive value of FIB‐4 and NFS for advanced fibrosis in MASLD were also comparable to those in NAFLD. Conclusions: Most patients (96.8%) previously diagnosed with NAFLD fulfilled the new criteria for MASLD in an Asian primary clinic cohort. Diagnostic performance of FIB‐4 in the MASLD cohort demonstrated satisfactory results. [ABSTRACT FROM AUTHOR]

Objective: In nonalcoholic fatty liver disease (NAFLD), liver fibrosis is the strongest predictor of adverse outcomes. We sought to investigate the relationship between liver fibrosis and cardiac remodeling in participants from the general population using magnetic resonance imaging (MRI), as well as explore potential mechanistic pathways by analyzing circulating cardiovascular biomarkers. Methods: In this cross-sectional study, we prospectively included participants with type 2 diabetes and individually matched controls from the SCAPIS (Swedish CArdioPulmonary bioImage Study) cohort in Linköping, Sweden. Between November 2017 and July 2018, participants underwent MRI at 1.5 Tesla for quantification of liver proton density fat fraction (spectroscopy), liver fibrosis (stiffness from elastography), left ventricular (LV) structure and function, as well as myocardial native T1 mapping. We analyzed 278 circulating cardiovascular biomarkers using a Bayesian statistical approach. Results: In total, 92 participants were enrolled (mean age 59.5 ± 4.6 years, 32 women). The mean liver stiffness was 2.1 ± 0.4 kPa. 53 participants displayed hepatic steatosis. LV concentricity increased across quartiles of liver stiffness. Neither liver fat nor liver stiffness displayed any relationships to myocardial tissue characteristics (native T1). In a regression analysis, liver stiffness was related to increased LV concentricity. This association was independent of diabetes and liver fat (Beta = 0.26, p = 0.0053), but was attenuated (Beta = 0.17, p = 0.077) when also adjusting for circulating levels of interleukin-1 receptor type 2. Conclusion: MRI reveals that liver fibrosis is associated to structural LV remodeling, in terms of increased concentricity, in participants from the general population. This relationship could involve the interleukin-1 signaling. Clinical relevance statement: Liver fibrosis may be considered a cardiovascular risk factor in patients without cirrhosis. Further research on the mechanisms that link liver fibrosis to left ventricular concentricity may reveal potential therapeutic targets in patients with non-alcoholic fatty liver disease (NAFLD). Key Points: Previously, studies on liver fibrosis and cardiac remodeling have focused on advanced stages of liver fibrosis. Liver fibrosis is associated with left ventricular (LV) concentricity and may relate to interleukin-1 receptor type 2. Interleukin-1 signaling is a potential mechanistic interlink between early liver fibrosis and LV remodeling. [ABSTRACT FROM AUTHOR]

Objective: To comprehensively assess the impact of aging, cigarette smoking, and chronic obstructive pulmonary disease (COPD) on pulmonary physiology using 129Xe MR. Methods: A total of 90 subjects were categorized into four groups, including healthy young (HY, n = 20), age-matched control (AMC, n = 20), asymptomatic smokers (AS, n = 28), and COPD patients (n = 22). 129Xe MR was utilized to obtain pulmonary physiological parameters, including ventilation defect percent (VDP), alveolar sleeve depth (h), apparent diffusion coefficient (ADC), total septal wall thickness (d), and ratio of xenon signal from red blood cells and interstitial tissue/plasma (RBC/TP). Results: Significant differences were found in the measured VDP (p = 0.035), h (p = 0.003), and RBC/TP (p = 0.003) between the HY and AMC groups. Compared with the AMC group, higher VDP (p = 0.020) and d (p = 0.048) were found in the AS group; higher VDP (p < 0.001), d (p < 0.001) and ADC (p < 0.001), and lower h (p < 0.001) and RBC/TP (p < 0.001) were found in the COPD group. Moreover, significant differences were also found in the measured VDP (p < 0.001), h (p < 0.001), ADC (p < 0.001), d (p = 0.008), and RBC/TP (p = 0.032) between the AS and COPD groups. Conclusion: Our findings indicate that pulmonary structure and functional changes caused by aging, cigarette smoking, and COPD are various, and show a progressive deterioration with the accumulation of these risk factors, including cigarette smoking and COPD. Clinical relevance statement: Pathophysiological changes can be difficult to comprehensively understand due to limitations in common techniques and multifactorial etiologies. 129Xe MRI can demonstrate structural and functional changes caused by several common factors and can be used to better understand patients' underlying pathology. Key Points: Standard techniques for assessing pathophysiological lung function changes, spirometry, and chest CT come with limitations. 129Xe MR demonstrated progressive deterioration with accumulation of the investigated risk factors, without these limitations. 129Xe MR can assess lung changes related to these risk factors to stage and evaluate the etiology of the disease. [ABSTRACT FROM AUTHOR]

Objectives: To compare the repeatability and interrelation of various late gadolinium enhancement (LGE) assessment techniques for monitoring fibrotic changes in myocarditis follow-up. Materials and methods: LGE extent change between baseline and 3-month cardiovascular magnetic resonance (CMR) was compared in patients with acute myocarditis using the full width at half maximum (FWHM), gray-scale thresholds at 5 and 6 standard deviations (SD5 and SD6), visual assessment with threshold (VAT) and full manual (FM) techniques. In addition, visual presence score (VPS), visual transmurality score (VTS), and a simplified visual change score (VCS) were assessed. Intraclass-correlation (ICC) was used to evaluate repeatability, and methods were compared using Spearman's correlation. Results: Forty-seven patients (38 male, median age: 27 [IQR: 21; 38] years) were included. LGE extent change differed among quantitative techniques (p < 0.01), with variability in the proportion of patients showing LGE change during follow-up (FWHM: 62%, SD5: 74%, SD6: 66%, VAT: 43%, FM: 60%, VPS: 53%, VTS: 77%, VCS: 89%). Repeatability was highest with FWHM (ICC: 0.97) and lowest with SD5 (ICC: 0.89). Semiquantitative scoring had slightly lower values (VPS ICC: 0.81; VTS ICC: 0.71). VCS repeatability was excellent (ICC: 0.93). VPS and VTS correlated with quantitative techniques, while VCS was positively associated with VPS, VTS, VAT, and FM, but not with FWHM, SD5, and SD6. Conclusion: FWHM offers the least observer-dependent LGE follow-up after myocarditis. VPS, VTS, and VCS are practical alternatives, showing reliable correlations with quantitative methods. Classification of patients exhibiting either stable or changing LGE relies on the assessment technique. Clinical relevance statement: This study shows that LGE monitoring in myocarditis is technique-dependent; the FWHM method yields the most consistent fibrotic tracking results, with scoring-based techniques as reliable alternatives. Key Points: Recognition of fibrotic changes during myocarditis follow-up is significantly influenced by the choice of the quantification technique employed. The FWHM technique ensures highly repeatable tracking of myocarditis-related LGE changes. Segment-based visual scoring and the simplified visual change score offer practical, reproducible alternatives in resource-limited settings. [ABSTRACT FROM AUTHOR]

Objectives: To analyze the ability of magnetic resonance (MR) to identify cystic biliary atresia (CBA) and choledochal cyst (CC). Methods: Infants (≤ 1 year old) who were diagnosed with CBA or CC type I/IV from January 2010 to July 2023 were retrospectively reviewed. Imaging characteristics on MR were compared between the CBA and CC groups. Binary logistic regression and the area under the receiver operating characteristic curve (AUC) were analyzed for the identification of CBA. Results: Sixty-three patients with CBA (median age, 30 days) and 172 patients with CC (median age, 60 days) were included. Gallbladder (GB) wall thickness (cutoff, 1.2 mm) showed 98.4% sensitivity and 100% specificity (AUC, 0.998). MR-triangular cord thickness (MR-TCT) (cutoff, 4.1 mm) showed 100% sensitivity and 95.9% specificity (AUC, 0.986). The bile duct loop visualization showed 96.8% sensitivity and 100% specificity (AUC, 0.984). Proximal bile duct (PBD) diameter (cutoff, 1.3 mm) showed 92.1% sensitivity and 95.3% specificity (AUC, 0.977). Cyst wall thickness (cutoff, 1 mm) showed 77.8% sensitivity and 95.3% specificity (AUC, 0.942). The combination of GB wall thickness > 1.2 mm and MR-TCT > 4.1 mm, GB wall thickness > 1.2 mm and loop visualization, GB wall thickness > 1.2 mm, and cyst wall thickness > 1 mm showed 100% sensitivity and 100% specificity (AUC, 1.000). Conclusions: Imaging characteristics on MR might be used to identify CBA and CC, and the combination of GB wall thickness and MR-TCT, or loop visualization, or cyst wall thickness, has a perfect diagnostic value. Clinical relevance statement: Early and accurate differentiation of CBA and CC is essential, but current methods rely on inherently subjective ultrasound. Biliary features on MRI allow for an objective, accurate diagnosis. Key Points: Cystic biliary atresia and choledochal cysts have similar clinical presentations, but require different treatments at different ages. Examined MR features eliminate ultrasound related subjectivity and diagnose cystic biliary atresia with nearly perfect accuracy. Early and accurate differentiation between these entities allows for timely life-saving intervention. [ABSTRACT FROM AUTHOR]

Objectives: To investigate associations between tissue diffusion, stiffness, and different tumor microenvironment features in resected hepatocellular carcinoma (HCC). Methods: Seventy-two patients were prospectively included for preoperative magnetic resonance (MR) diffusion-weighted imaging and MR elastography examination. The mean apparent diffusion coefficient (ADC) and stiffness value were measured on the central three slices of the tumor and peri-tumor area. Cell density, tumor-stroma ratio (TSR), lymphocyte-rich HCC (LR-HCC), and CD8 + T cell infiltration were estimated in resected tumors. The interobserver agreement of MRI measurements and subjective pathological evaluation was assessed. Variables influencing ADC and stiffness were screened with univariate analyses, and then identified with multivariable linear regression. The potential relationship between explored imaging biomarkers and histopathological features was assessed with linear regression after adjustment for other influencing factors. Results: Seventy-two patients (male/female: 59/13, mean age: 56 ± 10.2 years) were included for analysis. Inter-reader agreement was good or excellent regarding MRI measurements and histopathological evaluation. No correlation between tumor ADC and tumor stiffness was found. Multivariable linear regression confirmed that cell density was the only factor associated with tumor ADC (Estimate = −0.03, p = 0.006), and tumor-stroma ratio was the only factor associated with tumor stiffness (Estimate = −0.18, p = 0.03). After adjustment for fibrosis stage (Estimate = 0.43, p < 0.001) and age (Estimate = 0.04, p < 0.001) in the multivariate linear regression, intra-tumoral CD8 + T cell infiltration remained a significant factor associated with peri-tumor stiffness (Estimate = 0.63, p = 0.02). Conclusions: Tumor ADC surpasses tumor stiffness as a biomarker of cellularity. Tumor stiffness is associated with tumor-stroma ratio and peri-tumor stiffness might be an imaging biomarker of intra-tumoral immune microenvironment. Clinical relevance statement: Tissue stiffness could potentially serve as an imaging biomarker of the intra-tumoral immune microenvironment of hepatocellular carcinoma and aid in patient selection for immunotherapy. Key Points: Apparent diffusion coefficient reflects cellularity of hepatocellular carcinoma. Tumor stiffness reflects tumor-stroma ratio of hepatocellular carcinoma and is associated with tumor-infiltrating lymphocytes. Tumor and peri-tumor stiffness might serve as imaging biomarkers of intra-tumoral immune microenvironment. [ABSTRACT FROM AUTHOR]

Metabolic syndrome (MetS) has become a major public health challenge in recent years. Nuclear magnetic resonance, as a nondestructive measurement, has been widely used in medical diagnosis and screening. Compared to conventional magnetic resonance imaging and nuclear magnetic spectroscopy, low-field nuclear magnetic resonance is superior in portability, simplicity, and low-cost. In this study, a novel approach based on low-field magnetic resonance analysis is proposed to detect metabolic syndrome. T1–T2 correlation relaxometry is employed to measure human serum. Combining with a classification model based on partial least squares discriminant analysis (PLS-DA), the detection of metabolic syndrome is realized. The classification models based on both T1–T2 relaxation correlation data and spectrum are compared. Additionally, classification model based on convolutional neural networks (CNNs) is also evaluated for comparison. The experimental results indicate that the PLS-DA model based on the T1–T2 spectrum achieves a better performance. Specifically, the area under curve, accuracy, F1 score, recall and precision of the classification model evaluated on testing group are 0.784, 70.91%, 75.00%, 77.42%, and 72.73%, respectively. On the other hand, the testing results of CNN model trained using T1–T2 spectrum are 0.774, 65.45%, 61.22%, 48.39%, and 83.33% for AUC, accuracy, F1 score, recall, and precision. The experimental results reveal the limitation of CNN models on small datasets. In this study, T1–T2 correlation relaxometry is employed for the analysis of MetS for the first time, and the feasibility of proposed method has been demonstrated. [ABSTRACT FROM AUTHOR]