The gradient field, one of the core magnetic fields in magnetic resonance imaging (MRI) systems, is generated by gradient coils and plays a critical role in spatial encoding and the generation of echo signals. The uniformity or linearity of the gradient field directly impacts the quality and distortion level of MRI images. However, traditional point measurement methods lack accuracy in assessing the linearity of gradient fields, making it difficult to provide effective parameters for image distortion correction. This paper introduced a spherical measurement-based method that involved measuring the magnetic field distribution on a sphere, followed by detailed magnetic field calculations and linearity analysis. This study, applied to assess the nonlinearity of asymmetric head gradient coils, demonstrated more comprehensive and precise results compared to point measurement methods. This advancement not only strengthens the scientific basis for the design of gradient coils but also provides more reliable parameters and methods for the accurate correction of MRI image distortions.
Magnetic Resonance Imaging/instrumentation* ; Humans ; Image Processing, Computer-Assisted/methods* ; Nonlinear Dynamics ; Magnetic Fields ; Algorithms ; Phantoms, Imaging

Objective:To explore age-related variations in the angle of the cochlear basal turn using temporal bone CT, providing a reference for selecting the optimal Stenvers position radiographic projection angle in children and adults.Methods:The retrospective study included children and adults who underwent temporal bone CT scans at Beijing Tongren Hospital from November 2014 to April 2023. A total of 620 participants were included, including 368 males and 252 females. Patients were divided into 20 age-ralated groups: infants under one year old (3 to 11 months) were divided into monthly subgroups (9 groups); children and adolescents aged 1 to 18 years were grouped biennially (9 groups); adults were divided into two groups: 19 to 29 years and 30 to 40 years. Using multiplanar reconstruction (MPR) techniques, the CT images of the temporal bone were reformatted into oblique transverse sections to maximize the visibility of the cochlear basal turn.The cochlear basal turn angle was defined as the angle between the vertical axis of the cochlear basal turn and the mid-sagittal plane of the skull. Statistical analysis was performed to compare age-related differences in cochlear basal turn angles. Two additional patients were included to compare Stenvers position X-ray images with corresponding temporal bone CT scans, assessing the visibility of cochlear implant electrodes post-implantation.Results:Among infants aged 3 to 11 months, the cochlear basal turn angle was 29.4°±4.5°, with no significant differences observed between subgroups ( P>0.05). However, significant differences were found between infants (<1 year old) and the 1-2-year-old group compared to each age group from 3 to 40 years ( P<0.05). Additionally, the angles differed significantly between the 3-14-year-old groups and the 19-40-year-old groups ( P<0.05), whereas no significant differences were found among the remaining groups ( P>0.05). The visibility of the cochlear implant electrodes, appearing round in shape on standard Stenvers position X-ray images, closely resembled that observed in temporal bone CT scans. Conclusion:Age-related variations in the cochlear basal turn angle provide a valuable reference for optimizing Stenvers position radiography angles after cochlear implantation, improving the accuracy and quality of post-implantation imaging.

There exist risks of ionizing radiation in radiodiagnosis examinations. Implementing shielding protection following the optimization and as low as reasonably achievable (ALARA) principles represents a measure to reduce radiation doses to patients. The implementation of shielding protection in clinical practices should meet high requirements due to variations in the modalities and items in radiodiagnosis examinations, the characteristics and irradiation method of X-ray beams, the method of automatic selection of image quality and radiation dose-related parameters by imaging equipment, the radiation sensitivity of human tissues and organs. This review introduced the shielding products, methods and effects in various radiodiagnosis examinations, as well as the current status and challenges in their applications, aiming to provide a reference for future related research and clinical practices.

There exist risks of ionizing radiation in radiodiagnosis examinations. Implementing shielding protection following the optimization and as low as reasonably achievable (ALARA) principles represents a measure to reduce radiation doses to patients. The implementation of shielding protection in clinical practices should meet high requirements due to variations in the modalities and items in radiodiagnosis examinations, the characteristics and irradiation method of X-ray beams, the method of automatic selection of image quality and radiation dose-related parameters by imaging equipment, the radiation sensitivity of human tissues and organs. This review introduced the shielding products, methods and effects in various radiodiagnosis examinations, as well as the current status and challenges in their applications, aiming to provide a reference for future related research and clinical practices.

Objective:To explore age-related variations in the angle of the cochlear basal turn using temporal bone CT, providing a reference for selecting the optimal Stenvers position radiographic projection angle in children and adults.Methods:The retrospective study included children and adults who underwent temporal bone CT scans at Beijing Tongren Hospital from November 2014 to April 2023. A total of 620 participants were included, including 368 males and 252 females. Patients were divided into 20 age-ralated groups: infants under one year old (3 to 11 months) were divided into monthly subgroups (9 groups); children and adolescents aged 1 to 18 years were grouped biennially (9 groups); adults were divided into two groups: 19 to 29 years and 30 to 40 years. Using multiplanar reconstruction (MPR) techniques, the CT images of the temporal bone were reformatted into oblique transverse sections to maximize the visibility of the cochlear basal turn.The cochlear basal turn angle was defined as the angle between the vertical axis of the cochlear basal turn and the mid-sagittal plane of the skull. Statistical analysis was performed to compare age-related differences in cochlear basal turn angles. Two additional patients were included to compare Stenvers position X-ray images with corresponding temporal bone CT scans, assessing the visibility of cochlear implant electrodes post-implantation.Results:Among infants aged 3 to 11 months, the cochlear basal turn angle was 29.4°±4.5°, with no significant differences observed between subgroups ( P>0.05). However, significant differences were found between infants (<1 year old) and the 1-2-year-old group compared to each age group from 3 to 40 years ( P<0.05). Additionally, the angles differed significantly between the 3-14-year-old groups and the 19-40-year-old groups ( P<0.05), whereas no significant differences were found among the remaining groups ( P>0.05). The visibility of the cochlear implant electrodes, appearing round in shape on standard Stenvers position X-ray images, closely resembled that observed in temporal bone CT scans. Conclusion:Age-related variations in the cochlear basal turn angle provide a valuable reference for optimizing Stenvers position radiography angles after cochlear implantation, improving the accuracy and quality of post-implantation imaging.

Objective To visualize the research status and hotspots of women's common disease screening based on CiteSpace 6.1.R6,and to provide a reference for the in-depth research in this field thereafter.Methods The relevant articles were retrieved from the China National Knowledge Infrastructure with the time in-terval from January 1,1992 to December 13,2022.The analysis was conducted on the number of annual publica-tions,countries(regions),institutions,author collaboration networks,keyword co-occurrence,clustering,and bursts.Results A total of 900 papers that met the criteria were included,and the number of annual publications showed a trend of first increasing and then decreasing.The cross-institutional collaboration network was mature.The re-search hotspots mainly covered women's health,the prevalence of women's diseases,reproductive health,and breast diseases.The hotspots have evolved from an initial focus on reproductive health care to gynecological disease management,and eventually to reproductive health and holistic health care in women.Conclusions The attention should be kept on the screening of women's common diseases.It is advisable to synchronize the screening of women's common diseases with the screening of cervical and breast cancers to expand the screening coverage,promote early disease detection and treatment,and comprehensively safeguard women's health.

A 28-year-old woman was found to have coagulation factor Ⅷ activity (FⅧ∶C) <1% and von Willebrand factor antigen (VWF∶Ag) <1% during routine prenatal examinations. No pathogenic variation was found in the exon region of the VWF gene using next-generation sequencing. The clinical presentation of this patient does not match the clinical characteristics of type Ⅲ hemophilia [von Willebrand disease (VWD) ]; therefore, third-generation sequencing technology was used to perform whole-genome sequencing on the patient and her family members. Multiple members of the patient’s paternal family carried a heterozygous variant of VPS33B, c.869G>C. The family members carrying this variant all had varying degrees of reduced VWF levels (39% -56% ). Moreover, the proband was detected with the heterozygous variant c.1474dupA in GP1BA. The ACMG and Clinvar databases determined that this variation was associated with platelet-type pseudo VWD. The decrease in VWF levels caused by heterozygous variations in VPS33B in families is the first international report, and no previous studies have reported cases of severe decrease in plasma VWF levels caused by double heterozygous variations in VPS33B and GP1BA.

Objective To investigate the biomechanical effects of lingual metal-reinforced denture bases on edentulous implant-supported prostheses by three-dimensional finite element analysis,and provide references for the treatment of edentulous jaws.Methods Two implant-supported Locator-type overdenture models with lingual metal-reinforced and non-reinforced denture bases were constructed.A 150 N vertical load on the fovea of the posterior teeth,a 150 N oblique load on the fovea of the posterior teeth,and a 150 N vertical load on the anterior teeth were applied to simulate the centric occlusion,left and right lateral chewing,and anterior teeth cutting,and stresses on the tissues of two models were analyzed.Results When the posterior and anterior teeth were loaded vertically,the stress distribution on each organization was similar between the two denture base designs.The maximum stress difference was between 0 and 0.16 MPa.Under unilateral masticatory chewing,the range of stress concentration on denture base,implant and mucoperiosteum,and the maximum stress of the implant and peri-implant bone without metal reinforcement were significantly greater than those with metal reinforcement,and the maximum stress difference was between 0.59 MPa and 2.99 MPa.Conclusions Lingual metal-reinforced denture base can play a role in stress dispersion,or reduce the risk of bone resorption and denture base fracture to a certain extent.

Objective To investigate the mechanism of Sanguisorbae Radix(SR)in the treatment of ulcerative colitis(UC).Methods Using the GSE92415 dataset from the Gene Expression Omnibus database,we analyzed differentially expressed genes and carried out weighted gene correlation network analysis and FerrDb analysis.Core genes were identified through protein-protein interaction(PPI)network and correlation analysis.UC mouse model induced by dextran sulfate sodium(DSS)was constructed and treated with SR via intragastric administration for 9 days.Disease activity index(DAI)and colon length were recorded.Pathological changes in colon tissue were observed using the HE staining.Levels of inflammatory cytokines such as tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)were detected by enzyme linked immunosorbent assay(ELISA).Lipid peroxidantion factors such as malondialdehyde(MDA)and glutathione(GSH)were detected using biochemical test kits.Protein expression levels of zonula occludens protein-1(ZO-1)tight junction protein,peroxisome proliferator-activated receptor gamma(PPARG),solute carrier family 7 member 11(SCL7A11),and glutathione peroxidase 4(GPX4)were examined by Western blot or immunofluorescence labeling.Results Nine differentially expressed genes associated with ferroptosis were screened and PPARG was identified as a key gene.Correlation analysis showed a strong correlation between PPARG and ferroptosis.Subsequently,the potential mechanism of SR in improving UC in mice was discussed according to the bioinformatics screening results.The experimental results demonstrated that SR significantly reduced the DAI,prevented colon shortening and improved intestinal mucosal barrier function in the colon.SR decreased TNF-α and IL-6 levels,MDA content and GSH levels in colon tissues.SR also enhanced the expression of PPARG,SLC7A11 and GPX4,which reversed the effect of DSS in mice with colitis.Conclusions Ferroptosis is closely related to UC.SR can inhibit ferroptosis by regulating PPARG and SCL7A11/GPX4 expression,thereby improving colon epithelial injury and dysfunction in UC mice.This provides ideas and directions for UC treatment strategies.

Objective:To investigate the therapeutic effect of Baduanjin combined with resistance exercise and Baduanjin alone on elderly patients with type 2 diabetes mellitus(T2DM).Methods:The databases of CNKI,Wanfang,VIP,PubMed,and Web of Science were searched for randomized controlled trials(RCTs)on the effects of Baduanjin alone or combined with resistance exercise in elderly patients with T2DM.The search date was from the establishment of the database to Sep 21,2023.Review Manager 5.4 and Stata 16.0 softwares were used to conduct meta-analysis.Results were expressed as Random effect model standardized mean difference(SMD)and 95%confidence interval(CI).Results:A total of 14 RCTs involving 1 224 elderly patients with T2DM were included.The results of meta-analysis showed that Baduanjin alone or combined with resistance exercise in the treatment of elderly T2DM patients were better than the conventional treatment group in FPG,HbAlc,TC,TG,2hPG,HDL and LDL,and Baduanjin combined with resistance exercise were better than the Baduanjin alone group in FPG,HbAlc,TC,TG and LDL.Conclusion:Baduanjin alone or combined with resistance exercise has a significant therapeutic effect on elderly patients with T2DM,and the therapeutic effect of Baduanjin combined with resistance exercise is better.