Multi-target field control for matrix gradient coils.

OBJECTIVE: Conventional single-target field control for matrix gradient coils will add control complexity in MRI spatial encoding, such as designing specialized fields and sequences. This complexity can be reduced by multi-target field control, which is realized by optimizing the coil structure according to target fields. METHODS: Based on the principle of multi-target field control, the X, Y and Z gradient fields can be set as target fields, and all coil elements can then be divided into three groups to generate these fields. An improved simulated annealing algorithm is proposed to optimize the coil element distribution of each group to generate the corresponding target field. In the improved simulated annealing process, two swapping modes are presented, and randomly selected with certain probabilities that are set to 0.25, 0.5 and 0.75, respectively. The flexibility of the final designed structure is demonstrated by a spherical harmonic basis up to the full second order with single-target field control. An experimental platform is built to measure the gradient fields generated by the designed structure with multi-target target control. RESULTS: With three probabilities of swapping modes, three similar coil element distributions are optimized, and their maximum magnetic field errors for generating X, Y and Z gradients are all below 5%. The structure selected for the final design is the one with a probability of 0.75, considering the coil performance and structural symmetry. The maximum error for all target fields generated by single-target field control is also below 5%. The experimental results show that the measured gradient fields along the axes have enough strength and high linearity. CONCLUSIONS: With the proposed improved simulated annealing algorithm and swapping modes, multi-target field control for matrix gradient coils is verified and achieved in this study by optimizing the coil element distribution. Moreover, this study provides a solution to simplify the complexity of controlling the matrix gradient coil in spatial encoding.

Fast, high-quality, and unshielded 0.2 T low-field mobile MRI using minimal hardware resources.

OBJECTIVE: To propose a deep learning-based low-field mobile MRI strategy for fast, high-quality, unshielded imaging using minimal hardware resources. METHODS: Firstly, we analyze the correlation of EMI signals between the sensing coil and the MRI coil to preliminarily verify the feasibility of active EMI shielding using a single sensing coil. Then, a powerful deep learning EMI elimination model is proposed, which can accurately predict the EMI components in the MRI coil signals using EMI signals from at least one sensing coil. Further, deep learning models with different task objectives (super-resolution and denoising) are strategically stacked for multi-level post-processing to enable fast and high-quality low-field MRI. Finally, extensive phantom and brain experiments were conducted on a home-built 0.2 T mobile brain scanner for the evaluation of the proposed strategy. RESULTS: 20 healthy volunteers were recruited to participate in the experiment. The results show that the proposed strategy enables the 0.2 T scanner to generate images with sufficient anatomical information and diagnostic value under unshielded conditions using a single sensing coil. In particular, the EMI elimination outperforms the state-of-the-art deep learning methods and numerical computation methods. In addition, 2 × super-resolution (DDSRNet) and denoising (SwinIR) techniques enable further improvements in imaging speed and quality. DISCUSSION: The proposed strategy enables low-field mobile MRI scanners to achieve fast, high-quality imaging under unshielded conditions using minimal hardware resources, which has great significance for the widespread deployment of low-field mobile MRI scanners.

Optimization design of a permanent magnet used for a low field (0.2 T) movable MRI system.

OBJECTIVE: To design a lightweight permanent magnet for a lowfield movable head imaging MRI system. MATERIALS AND METHODS: To reduce the weight of the magnet, the pole pieces, anti-eddy current plates, and shimming rings were removed, and the distance between the two vertical yokes was shortened as much as possible. To compensate for the magnetic field deformation caused by the shortened distance between two vertical iron yokes, two side magnetic poles were added to the vertical yokes. The magnetic field distributions in magnetic poles, the iron yoke, and the spherical imaging region were simulated. Phantom and in vivo head imaging were conducted with a lowfield movable MRI prototype scanner equipped with the proposed permanent magnet. RESULTS: A permanent magnet with a center field of 0.19815 T, a homogeneity of 46 ppm over the 20 cm spherical imaging region, and a weight of 654 kg have been achieved. Acceptable images of a phantom and a human brain have been acquired with the prototype MRI scanner. DISCUSSION: The proposed permanent magnet design significantly reduces the magnet's weight compared with the conventional magnet structure and shows promise in promoting the development of lowfield compact MRI systems.

Analysis of coil element distribution and dimension for matrix gradient coils.

OBJECTIVE: The goal of this work is to analyze the influence of the distributions and dimensions of the coil elements and to present a method for improving the performance of the matrix gradient coil. METHODS: Three typical models (five structures in total) are presented, and a double-layer biplanar matrix gradient coil is used to install coil elements. Two metrics, namely, the role of coil elements and mutual inductance between coil elements, are proposed to assess the performance of coil systems. An optimization approach to design matrix gradient coils is introduced based on analyzing the distributions and dimensions of coil elements. The flexibility of the magnetic field generation of the designed coil structure is demonstrated by generating full third-order spherical harmonic fields and different oblique gradient fields. RESULTS: Matrix gradient coils with suitable distributions are capable of generating target magnetic fields. The role of coil elements quantitatively illustrates that the coil elements have different impacts on generating magnetic fields. Increasing the coil element dimension within a certain range can reduce the mutual inductance between coil elements and improve the performance of the coil system. The designed novel double-layer biplanar matrix gradient coil achieves an acceptable performance in generating different magnetic fields. CONCLUSIONS: The proposed metrics can provide theoretical support for designing matrix gradient coils and evaluating their performance. The role of coil elements contributes to analyzing the distributions of coil elements to decrease the number of coil elements and power amplifiers. The mutual inductance between coil elements can be a reference for designing the dimensions of coil elements.

Analysis on matrix gradient coil modeling.

OBJECTIVE: The current distribution of the matrix gradient coil can be optimized via matrix gradient coil modeling to reduce the Lorentz force on individual coil elements. Two different modeling approaches are adopted, and their respective characteristics are summarized. METHODS: The magnetic field at each coil element is calculated. Then, the Lorentz force, torque, and deformation of the energized coil element in the magnetic field are derived. Two modeling approaches for matrix gradient coil, namely, optimizing coil element current (OCEC) modeling and optimizing coil element Lorentz force (OCEF) modeling, are proposed to reduce the Lorentz force on individual coil elements. The characteristics of different modeling approaches are compared by analyzing the influence of the weighting factor on the performance of the coil system. The current, Lorentz force, torque, and deformation results calculated via different modeling approaches are also compared. RESULTS: Coil element magnetic fields are much weaker than the main magnetic field, and their effect can be ignored. Matrix gradient coil modeling with different regularization terms can help to decrease the current and Lorentz force of coil elements. The performance of the coil system calculated via different modeling approaches is similar when suitable weighting factors are adopted. The two modeling approaches, OCEC and OCEF, can better reduce the maximum current and Lorentz force on individual coil elements compared with the traditional modeling approach. CONCLUSIONS: Different modeling approaches can help to optimize the current distribution of coil elements and satisfy various requirements while maintaining the performance of the coil system.

Near-Null Magnetic Field Suppresses Fruit Growth in Arabidopsis.

We previously found that a near-null magnetic field affected reproductive growth in Arabidopsis under white light. To test whether the effect of a near-null magnetic field on fruit growth of Arabidopsis is related to cryptochrome, we grew wild-type Arabidopsis and cryptochrome double mutant, cry1/cry2, in a near-null magnetic field under blue light. We found that fruit growth of wild-type Arabidopsis instead of the cry1/cry2 mutant was suppressed by the near-null magnetic field. Furthermore, gibberellin (GA) levels of GA4 , GA9 , GA34 , and GA51 in fruits of wild-type plants in the near-null magnetic fields were significantly lower than local geomagnetic field controls. However, in cry1/cry2 mutants, levels of the four detected GAs in fruits in the near-null magnetic fields did not differ significantly from controls. Expressions of GA20-oxidase (GA20ox) genes (GA20ox1 and GA20ox2) and GA3-oxidase (GA3ox) genes (GA3ox1 and GA3ox3) in fruits of wild-type plants rather than cry1/cry2 mutants were downregulated by the near-null magnetic field. In contrast, expressions of GA2-oxidase (GA2ox) genes and GA signaling genes were not affected by the near-null magnetic field. These results indicate that suppression of fruit growth by the near-null magnetic field is mediated by cryptochrome and that GAs are involved in the regulation of fruit growth by the near-null magnetic field. © 2021 Bioelectromagnetics Society.

Suppression of Arabidopsis flowering by near-null magnetic field is mediated by auxin.

We previously found that flowering of Arabidopsis was suppressed by near-null magnetic field, which was related to cryptochrome. Auxin plays an important role in Arabidopsis flowering. To test whether auxin is involved in the suppression of Arabidopsis flowering by near-null magnetic field, we detected auxin level and expressions of auxin transport and signaling genes in wild-type Arabidopsis plants and cryptochrome double mutant, cry1/cry2, grown in near-null magnetic field. We found that indole-3-acetic acid (IAA) level in roots of wild-type plants in near-null magnetic field was significantly increased compared with the local geomagnetic field control, while IAA level in rosettes of 33-day-old wild-type plants in near-null magnetic field was significantly lower than the control. Expressions of three auxin transporter genes, PIN1, PIN3, and PIN7, in wild-type plants were upregulated by near-null magnetic field. Transcript levels of transcriptional repressor genes, IAA1, IAA5, IAA6, IAA16, and IAA19, were significantly higher in wild-type plants in near-null magnetic field than in control plants. However, IAA level and expressions of all the detected genes in cry1/cry2 mutants in near-null magnetic field were similar to controls. Our results suggest that near-null magnetic field affects the distribution of auxin in Arabidopsis by transcriptional upregulation of auxin transporter genes, and that change in distribution of auxin and increased expressions of transcriptional repressor genes result in delay of flowering in Arabidopsis in near-null magnetic field, which are mediated by cryptochrome. Bioelectromagnetics. 39:15-24, 2018. © 2017 Wiley Periodicals, Inc.

Gibberellins are involved in effect of near-null magnetic field on Arabidopsis flowering.

We previously found that flowering of Arabidopsis was suppressed by near-null magnetic field, which was related to the modification of cryptochrome. To disclose the physiological mechanism of this effect, we detected gibberellin (GA) levels and expressions of GA biosynthetic and signaling genes in wild type Arabidopsis plants and cryptochrome double mutant, cry1/cry2, grown in near-null magnetic field. We found that levels of GA4 , GA9 , GA34 , and GA51 in wild type plants in near-null magnetic field were significantly decreased compared with local geomagnetic field controls. However, GA levels in cry1/cry2 mutants in near-null magnetic field were similar to controls. Expressions of three GA20-oxidase (GA20ox) genes (GA20ox1, GA20ox2, and GA20ox3) and four GA3-oxidase (GA3ox) genes (GA3ox1, GA3ox2, GA3ox3, and GA3ox4) in wild type plants in near-null magnetic field were significantly reduced compared with controls, while expressions of GA20ox4, GA20ox5, GA2-oxidase (GA2ox) genes, and GA signaling-related genes in wild type plants in near-null magnetic field were not significantly different from controls. In contrast, expressions of all the detected GA biosynthetic and signaling genes in cry1/cry2 mutants were not affected by near-null magnetic field. Moreover, transcriptions of flowering-related genes, LFY and SOC1, in wild type plants were downregulated by near-null magnetic field, while they were not affected by near-null magnetic field in cry1/cry2 mutants. Our results suggest that the effect of near-null magnetic field on Arabidopsis flowering is GA-related, which is caused by cryptochrome-involved suppression of GA biosynthesis. Bioelectromagnetics. 38:1-10, 2017. © 2016 Wiley Periodicals, Inc.

Suppression of Arabidopsis flowering by near-null magnetic field is affected by light.

We previously reported that a near-null magnetic field suppressed Arabidopsis flowering in white light, which might be related to the function modification of cryptochrome (CRY). To further demonstrate that the effect of near-null magnetic field on Arabidopsis flowering is associated with CRY, Arabidopsis wild type and CRY mutant plants were grown in the near-null magnetic field under blue or red light with different light cycle and photosynthetic photon flux density. We found that Arabidopsis flowering was significantly suppressed by near-null magnetic field in blue light with lower intensity (10 µmol/m(2) /s) and shorter cycle (12 h period: 6 h light/6 h dark). However, flowering time of CRY1/CRY2 mutants did not show any difference between plants grown in near-null magnetic field and in local geomagnetic field under detected light conditions. In red light, no significant difference was shown in Arabidopsis flowering between plants in near-null magnetic field and local geomagnetic field under detected light cycles and intensities. These results suggest that changes of blue light cycle and intensity alter the effect of near-null magnetic field on Arabidopsis flowering, which is mediated by CRY.

Efficacy of Qingpeng ointment (a Tibetan medicine) for acute gouty arthritis: a multi-center, randomized, double-blind, placebo-controlled trial.

BACKGROUND: This study aims to assess the efficacy and safety of Qingpeng ointment (QPO), a Tibetan medicine for alleviating symptoms in individuals with acute gouty arthritis (AGA). METHODS: This study was a randomized, double-blind, placebo-controlled trial that involved individuals with AGA whose joint pain, as measured on a visual analog scale (VAS) from 0 to 10, was equal to or greater than 3. The participants were randomly assigned to either the QPO or the placebo group and received their respective treatments twice daily for seven consecutive days. In case of intolerable pain, the participants were allowed to use diclofenac sodium sustained-release tablets as a rescue medicine. The primary outcomes measured were joint pain and swelling, while the secondary outcomes included joint mobility, redness, serum uric acid levels, C-reactive protein levels, and the amount of remaining rescue medicine. Any adverse events that occurred during the trial were also recorded. RESULTS: A total of 203 cases were divided into two groups, with balanced baselines: 102 in the QPO group and 101 in the placebo group. For joint pain, differences between the groups were notable in the VAS scores [1.75 (0, 3.00) versus 2.00 (1.00, 3.50); P = 0.038], changes in VAS [5.00 (3.00, 6.00) versus 4.00 (2.00, 6.00); P = 0.036], and disappearance rate [26.47% compared to 15.84%; P = 0.046] after treatment. Concerning joint swelling, significant between-group differences were observed in the VAS scores [1.00 (0, 2.30) versus 2.00 (0.70, 3.00); P = 0.032] and disappearance rate [33.33% compared to 21.78%; P = 0.046] at treatment completion. The QPO group exhibited a statistically significant mobility improvement compared to the placebo group (P = 0.004). No significant differences were found in other secondary outcomes. Five patients, four from the QPO group and one from the other, encountered mild adverse events, primarily skin irritation. All of these cases were resolved after dosage reduction or discontinuation of the medication. CONCLUSIONS: Compared to the placebo, QPO exhibits positive effects on AGA by alleviating pain, reducing swelling, and enhancing joint mobility, without causing significant adverse effects. TRIAL REGISTRATION: ISRCTN34355813. Registered on 25/01/2021.

Removal of the local geomagnetic field affects reproductive growth in Arabidopsis.

The influence of the geomagnetic field-removed environment on Arabidopsis growth was investigated by cultivation of the plants in a near-null magnetic field and local geomagnetic field (45 µT) for the whole growth period under laboratory conditions. The biomass accumulation of plants in the near-null magnetic field was significantly suppressed at the time when plants were switching from vegetative growth to reproductive growth compared with that of plants grown in the local geomagnetic field, which was caused by a delay in the flowering of plants in the near-null magnetic field. At the early or later growth stage, no significant difference was shown in the biomass accumulation between the plants in the near-null magnetic field and local geomagnetic field. The average number of siliques and the production of seeds per plant in the near-null magnetic field was significantly lower by about 22% and 19%, respectively, than those of control plants. These resulted in a significant reduction of about 20% in the harvest index of plants in the near-null magnetic field compared with that of the controls. These results suggest that the removal of the local geomagnetic field negatively affects the reproductive growth of Arabidopsis, which thus affects the yield and harvest index.

Using imaging methods to assess severe calcinosis in juvenile dermatomyositis: A case report.

Calcinosis and lipodystrophy are severe complications of juvenile dermatomyositis (JDM). Up to 20% of patients have calcinosis, and the onset of calcinosis usually occurs 1 to 3 years after that of the illness. We report a case of JDM with severe complications of calcinosis and lipodystrophy, and we assess calcinosis using a variety of imaging methods. To evaluate the patient's inflammatory state, bone scintigraphy was performed, which demonstrated increased uptake in the right scapula, in addition, multiple calcifications are present subcutaneously on the shoulder and back, and inflammatory imaging features are also present in the right knee joint.

A Case of Neutrophilic Dermatoses-Sweet's Syndrome Coexisting with SAPHO Syndrome.

SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome is a rare disease characterized by osteoarticular and cutaneous manifestations. SAPHO syndrome mostly involves the skin, mainly presented as palmoplantar pustulosis and severe acne. Sweet's syndrome (SS) is a neutrophilic dermatosis of unknown cause, which may be caused by autoinflammation. So far, SAPHO syndrome complicated with SS has been rarely reported worldwide. Here, we present a rare case diagnosed in our hospital with detailed clinical information. This patient presented pain and swelling in her right leg. Later, she developed red papules on her right lower eyelid and a skin biopsy showed diffuse lymphocytic and neutrophilic infiltration in the superficial dermis. She was diagnosed with SAPHO syndrome and SS according to medical history and examination. These two diseases share parts of autoinflammatory signaling pathways and might be different variations of the spectrum of autoinflammatory diseases. Through this case, we aim to provide a new horizon for the regulation of neutrophils in SAPHO syndrome and skin lesions like SS.

Synovitis, acne, pustulosis, hyperostosis, osteitis syndrome with invisible organizing pneumonia: A case report.

We report the case of a 59-year-old female patient, presenting with pustular rash on both hands and pain in the lumbosacral part and left lower limb. A magnetic resonance imaging examination of the left leg was undertaken and the result showed that a malignant lesion with bone destruction of the left femoral shaft could not be excluded. Subsequently, bone tumor was excluded by pathological examination. Lung computed tomography scan showed patchy consolidation and cord shadow in the middle left lung. Subsequently, lung cancer was excluded by pathological examination, and the histopathological changes of lung were consistent with those of organized pneumonia. Blood tests revealed elevated C-reactive protein and erythrocyte sedimentation rate. Antinuclear antibody, rheumatoid factor, and human leukocyte antigen-B27 were unremarkable. Whole body bone scintigraphy via technetium 99m-methyl diphosphonate showed increased radionuclide uptake in the left middle femur. Based on her clinical manifestations, imaging results and bone scintigraphy, the patient was diagnosed as having synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome. Loxoprofen and Tripterygium wilfordii Hook F led to impressive clinical and radiologic improvement.

Family aggregation and prevalence of other autoimmune diseases in SAPHO syndrome.

Objective: SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis) syndrome is a heterogeneous disease that clinically manifests as chronic inflammatory osteoarticular and dermatological lesions. Few reports have described familial clustering of SAPHO syndrome cases. This research aimed to illustrate the family aggregation of SAPHO syndrome and investigate the prevalence of autoimmune disorders among SAPHO syndrome patients and first-degree relatives in a large cohort. Methods: We retrospectively reviewed the medical records of 233 SAPHO patients diagnosed at Peking Union Medical College Hospital. Direct phone calls were made to each first-degree relatives. All relatives of the patients who reported SAPHO syndrome were asked for a detailed outpatient evaluation. Results: A total of 233 patients and 1227 first-degree relatives were recruited. Six (2.6 %) patients had positive SAPHO family history, including four mother-daughter pairs and two sister pairs. Twenty-one (9.0 %) patients presented at least one kind of autoimmune disease, including 12 rheumatoid arthritis and 4 ulcerative colitis cases. Fifty-eight (24.9 %) SAPHO syndrome patients had 68 (5.5 %) first-degree relatives with at least one autoimmune disorder. The palmoplantar pustulosis, psoriasis vulgaris, and rheumatoid arthritis prevalence in our subjects were each higher than reference rates. Conclusion: This is the first evaluation of familial aggregation for SAPHO syndrome in a large cohort. SAPHO syndrome has a weak familial aggregation. There is a relatively high prevalence of coexisting autoimmune disease among patients with SAPHO syndrome and their first-degree relatives. These results would prompt physicians to screen SAPHO syndrome patients and their family members for concomitant autoimmune diseases. Keypoints: This study suggesting a potential genetic component in the pathogenesis of SAPHO syndrome. This study is the first to evaluate the family aggregation of SAPHO syndrome in a large cohort.

Coincidence of pachydermoperiostosis and synovitis, acne, pustulosis, hyperostosis, osteitis syndrome, a causal or casual association?

Pachydermoperiostosis (PDP) is a rare disorder characterized by skin thickening, acropachia, and periostosis. Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome is also an orphan disease featured by different dermatological and osteoarthritic manifestations. Herein, we report the first case of an adolescent male diagnosed with both PDP and SAPHO syndrome, presenting with digital clubbing, polyarthralgia, ostealgia, pachydermia and acne on his face, chest and back. Furthermore, we distinguish the characteristics of both diseases and explore the potential pathological mechanism for this coexistence in one patient. Further investigations are needed to establish the detailed pathophysiological association of these 2 diseases.

Work productivity and activity in patients with SAPHO syndrome: a cross-sectional observational study.

BACKGROUND: Our understanding of work productivity impairment among patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is limited. The purpose of this study was to provide an overview of work productivity loss in SAPHO syndrome patients through the use of the work productivity and activity impairment (WPAI) questionnaire, as well as to investigate the relationship between the WPAI and other disease-related indicators. METHODS: Patients for this cross-sectional study were recruited from Peking Union Medical College Hospital (Beijing, China). The questionnaires incorporating the WPAI were administered, along with the inclusion of demographic data, disease-specific measures, and general health variables. The construct validity of the WPAI was evaluated via the correlations between WPAI outcomes and other measures. Wilcoxon rank-sum tests and nonparametric Kruskal‒Wallis tests were used for the comparison of the WPAI outcomes between known groups. RESULTS: A total of 376 patients were included, and 201 patients (53.5%) were employed. The medians (interquartile range [IQR]) of absenteeism, presenteeism, work productivity loss, and activity impairment were 0% (0-13%), 20% (0-40%), 20% (0-52%), and 30% (0-50%), respectively. All of the WPAI outcomes showed moderate to strong correlations with other generic and disease-specific measures (|r| = 0.43-0.75), except for absenteeism. Increasing disease activity and worse health status were significantly associated with increased impairments of work productivity and activity. CONCLUSION: This study highlights the negative effects of SAPHO syndrome on the work productivity and activity of patients, thus indicating good construct validity and discriminative ability of the WPAI. To reduce the economic burden, it is important to improve the work productivity and daily activity of patients by ameliorating clinical care.