After the production of the gradient coil of the magnetic resonance imaging system, electromagnetic field testing is required to verify whether the assembly accuracy meets the electromagnetic field requirements. Since the passive magnetic field B _z satisfies the Laplace ^,s equation and is a harmonic function, and according to the extreme value principle of harmonic function, the maximum or minimum values of B _z can only appear on the boundaries, so the observation points of the magnetic field are generally selected on the surface of the spherical imaging area. For superconducting magnets used for human body magnetic resonance imaging, a spherical area with a center diameter of 40~50 cm is generally selected as the shimming target area. Only the field value of the target area needs to be measured, and the spherical harmonic coefficients obtained after data processing are used to determine the magnetic field performance of the gradient coil. There are many testing principles and methods for electromagnetic fields, so there is no unified way and method in the field of commercial applications. This article is based on the Gauss-Legendre numerical integration, measures and analyzes the magnetic field performance of gradient coils by building a data acquisition system, and this article applies numerical analysis methods to calculate the spherical harmonic coefficients of the magnetic field using discrete test data, providing a feasible method for the production and testing of gradient coils.
Magnetic Resonance Imaging/methods* ; Magnetic Fields ; Electromagnetic Fields ; Equipment Design

Tuberculous meningitis is a central nervous system infectious disease caused by Mycobacterium tuberculosis. Its clinical manifestations are nonspecific, and effective pathogenic diagnostic methods are lacking, which often lead to delayed diagnosis and treatment, impacting the prognosis of patients. Therefore, early and rapid etiological diagnosis is crucial for the diagnosis and treatment of tuberculous meningitis. This article provides a review of novel detection technologies developed in recent years that can be used for the diagnosis of tuberculous meningitis, covering nucleic acid detection methods, metabolomics, and proteomics, and offering prospects for future development.

Currently， there are many difficulties in formulating recommendations of traditional Chinese medicine （TCM） clinical practice guidelines. This paper analyzed and summarized the unique or prominent difficult issues in the formulation of recommendations faced by TCM guidelines， such as experts' professional background and experience bringing about the preferance from the academic emotion， inconsistency between different academic schools making it difficult to reach consensus， lack of guiding principles of the decision weight of different dimensions for recommendations. Therefore， methodological suggestions have been put forward， including organizing parallel TCM and western medicine consensus group， improving the method of combining TCM and western medicine paradigm， attaching great importance to the evidence-based governance of academic schools， and promoting the research on different dimensions for recommendation formulation， which may provide a methodological reference for the guideline development.

The Ehlers-Danlos syndrome(EDS)is a rare inherent connective tissue disorder.The prev-alence of EDS in the population is estimated at one out of ten thousand to one out of a hundred thousand.The vascular EDS(vEDS)are rare among the subtypes but are the worst in prognosis.The article reports a case of vEDS admitted to the hospital.The patient was a young man complaining of a sudden onset of aphasia in right hemiparalysis and severe left abdominal pain for unknown reasons.The diagnosis was made after the genetic testing.The patient suffered from vEDS.Then,the multi-disciplinary team(MDT)made a treatment plan tailored to this young patient.The complexity in classification and delusive presentations of the EDS make the correct diagnosis very challenging.This article hopes to report this case and to share the experiences to the bet-ter understanding of this disease.

Objective:To analyze the influential factors of blurred vision after general anesthesia.Methods:The clinical data of 997 patients who underwent elective general anesthesia at The No. 1 People's Hospital of Pinghu from September 2022 to May 2023 were retrospectively analyzed. The data collected included age, sex, body mass index, American Society of Anesthesiologists classification, history of hypertension, history of diabetes, operation duration (specifically whether it exceeded 3 hours), surgical position (whether the patient was in the supine position), operating room temperature, use of penehyclidine hydrochloride, use of muscle relaxant antagonists, use of atropine, blood pressure (specifically whether it was ≥ 30% of the baseline value), fluid input, blood loss, and use of pneumoperitoneum. Collinearity diagnosis and univariate logistic regression analysis were conducted to select factors with statistical significance. Subsequently, multivariate logistic regression analysis was performed.Results:Univariate and multivariate logistic regression analyses showed that age > 65 years ( OR = 1.47, 95% CI: 1.01-2.15, P = 0.043), surgical position (non-supine position) ( OR = 1.54, 95% CI: 1.06-2.25, P = 0.025), operation time exceeding 3 hours ( OR = 1.76, 95% CI: 1.05-2.94, P = 0.031), and the use of penehyclidine hydrochloride ( OR = 4.91, 95% CI: 3.35-7.21, P < 0.001) were identified as factors contributing to postoperative blurred vision in patients undergoing general anesthesia. Conclusion:Factors contributing to postoperative blurred vision in patients undergoing general anesthesia include age > 65 years, the use of penehyclidine hydrochloride during surgery, operation time exceeding 3 hours, and non-supine surgical position. Clinically, it is essential to implement early and effective preoperative education, enhance intraoperative nursing quality, and optimize preoperative medication for general anesthesia to reduce the incidence of blurred vision after surgery.

Objective:To explore the impact of intradialytic hypotension (IDH) on brain component volume, as well as its relationship with depression and cognitive function changes in maintenance hemodialysis patients.Method:It was a cross-sectional observational study. Clinical data of 119 patients under maintenance hemodialysis in Peking Union Medical College Hospital from July 2013 to July 2014 were collected, retrospectively. Patients were divided into IDH group and non-IDH group. 3.0T Magnetic resonance imaging examination of the head for all patients was completed and the results of volume analysis of each component of the brain were extracted. Cognitive function was assessed by the Chinese version of the simplified mental state examination scale (C-MMSE) and the Chinese version of the Montreal cognitive assessment scale (C-MoCA). Depressive status was assessed by the Hamilton depression scale 17 (HAMD_17) and living ability was assessed by the Alzheimer's disease collaborative study-daily living ability assessment questionnaire. In addition, the Philadelphia word learning test was used to measure memory, the Boston naming test to measure language, the connection test A and B to measure executive ability, and the Stroup test C to measure attention. The differences in brain component volume, cognitive function, emotion, and life ability between two groups of patients were compared, and the correlation between IDH and brain component volume was explored by regression analysis.Result:A total of 119 patients were included in this study, of whom 22 (18.5%) had hypotension during dialysis. The volumes of amygdala, cuneiform lobe, and posterior cingulate gyrus in IDH group were significantly smaller than those in the non-hypotension group [ (1.6±0.2) mm 3vs. (1.7±0.2) mm 3, t=2.674, P=0.009; (6.9±0.8) mm 3vs. (7.4±1.0) mm 3, t=2.187, P=0.031; (6.9±0.8) mm 3vs. (7.4±0.9) mm 3, t=2.252, P=0.024]. The differences of gray matter, white matter volume between the two groups showed a similar trend but did not reach statistical significance. And lacunar infarction and cerebral microbleeds were more common in IDH group. The daily living ability scores of the two groups were similar (65.51±11.52 vs. 65.71±11.53, Z=-0.456, P=0.648). The proportion of patients with cognitive abnormalities was higher in the IDH group, without statistical significance. The proportion of depression was similar. Univariate linear regression analysis showed that IDH was significantly negatively correlated with the volume of amygdala, cuneiform cortex, and posterior cingulate gyrus, which control emotions in the brain ( B=-0.117, 95% CI -0.203--0.030, P=0.009; B=-0.484, 95% CI -0.923--0.046, P=0.031; B=-0.485, 95% CI -0.911--0.058, P=0.026). After multivariate adjustment, decreased amygdala volume was still correlated with IDH ( B=-0.111, 95% CI -0.198--0.025, P=0.026). Conclusion:Recurrent IDH may lead to atrophy of various brain components, which may be one of the reasons for cognitive and emotional changes in maintenance hemodialysis patients.

Syndrome differentiation and treatment is a unique mode of diagnosis in traditional Chinese medicine （TCM）. The establishment of scientific and standardized syndrome diagnosis standards is an important link to evaluate the clinical efficacy of TCM objectively and systematically， and also a prerequisite for the promotion and development of TCM to obtain international recognition. This article reviewed the basic modes and existed problems of the current syndrome diagnosis criteria， and proposed to construct a multidimensional core information set integrating the minimized core symptoms， the artificial intelligence signs， the multi-modal laboratory indicators， and multi-omics specific markers， so as to present syndrome characteristics from multiple perspectives systematically. This paper also described the basic mode， constructure， as well as the process and methodology to be adopted in the establishment of the standardized diagnostic research method. The core information set of diagnostic symptoms not only took into account the specificity of the disease， but also improved the inconsistency due to the complexity and subjectivity of the syndrome differentiation， thereby providing a methodological basis for the standardization of TCM syndrome differentiation in clinical research.

  Objective  To summarize the clinical characteristics and RNF216 gene mutation of a patient with Gordon Holmes syndrome (GHS), and to improve the understanding of the genetic and clinica characteristics of this disease through literature review.  Methods  We collected the clinical data of the patient with GHS, extracted the DNA from 2 mL peripheral venous blood of the patient and his parents for whole exome gene detection, and then we analyzed the clinical and genetic characteristics of all previously reported patients with RNF216 gene mutation.  Results  The young male patient was short in stature at sixyearsold and was diagnosed growth hormone deficiency.He had no secondary sexual characteristics by the age of 15 and was diagnosed hypogonadal hypogonadism.After the age of 22, he gradually developed abnormal gait and had progressive decline in speech, motor, and cognitive functions.Whole exome sequencing revealed a homozygous, nonsense mutation c.1549C>T (p.R517*) in the RNF216 gene.His parents were consanguineous and were heterozygous carriers of the mutations with phenotypic normality.Combined with literature review and this case report results showed that a total of 21 patients of the disease in the world and among them 15 had pathogenic variants of RNF216 gene mutation.7 of the 15 had truncated mutations, 5 had missense mutations, and 1 synonym mutation, 1 splice mutation, and 1 deletion mutation respectively.RNF216 gene mutation can be seen in neurodegenerative diseases with multiple overlapping symptoms of GHS, Huntington-like disease, and 4H syndrome.The main clinical manifestations are hypogonadotropic hypogonadism and early-onset progressive neurological dysfunction in adolescence or early adulthood.The median age of onset of neurological symptoms is 28 years old, featuring cerebellar ataxia, dysarthria, and cognitive impairment, as well as imaging manifestations of extensive white matter lesions and cerebellar atrophy.  Conclusions  The mutation of RNF216 gene can cause GHS.Genetic testing is helpful to the diagnosis and treatment of rare diseases.

  Objective  To evaluate the clinical and paraclinical features of Chinese patients with anti- LGI1 encephalitis.  Methods  Patients with memory deficits, psychiatric symptoms, seizures or altered level of consciousness, suspicious of encephalitis, at presentation to Peking Union Medical College Hospital were recruited between July 2013 and January 2018, and tested for anti-LGI1 antibodies in their serum and/or cerebrospinal fluid(CSF) samples. Patients with anti-LGI1 antibodies were enrolled. The demographic characteristics, clinical manifestations, laboratory examination results, neuroimaging features, immunotherapy, follow-up practices and outcomes for included patients were registered and analyzed.  Results  The study enrolled 120 patients, of whom 66.7% were male. The median age was 61 years (interquartile range [IQR]: 49-66 years). Seizures(65.0%) were the most common initial symptoms. Most patients developed seizures (95.0%), including faciobrachial dystonic seizures (54.2%), memory deficits (92.5%), and psychiatric symptoms (69.1%). Brain MRI and ¹⁸F-FDG PET / CT showed that the lesions were mainly located in unilateral or bilateral medial temporal lobes, and (or) basal ganglia. Of the patients, 95.0% received intravenous immunoglobulin (IVIg) or corticosteroids, 47.5% received mycophenolate mofetil as long-term immunotherapy, and no one received second-line immunotherapy. The median follow-up was 34.2 months(IQR: 22.0-45.6 months). 91.2% had a good outcome (modified Rankin Scale score≤2 points). Residual mild memory deficits were present in 47.8% of the patients. Nine deaths were documented. Relapses occurred in 24.8% of the patients in the first year. In total, 24 (20%)cases were young patients(onset age ≤45 years).There were fewer males among the younger patients(37.5% vs. 74.0%, P < 0.01). Besides, there were fewer younger patients with psychiatric symptoms(50.0% vs. 74.0%, P=0.02), hyponatremia(33.3% vs. 68.8%, P < 0.01), and abnormalities on brain ¹⁸F-FDG PET/CT(20.8% vs. 47.9%, P=0.02). The relapse-free survival rate was significantly higher in the young patients.  Conclusions  Elderly males were predominant in patients with anti-LGI1 encephalitis. Most patients developed symptoms of limbic encephalitis and/or FDBS during the disease course. Several patients were young adults and lacked typical symptoms. Neuroimaging features were consistent with the involvement of limbic system or basal ganglia. Patients with anti-LGI1 encephalitis respond well to immunotherapy, irrespective of the age.

We presented an adolescent with recurrent intracranial hemorrhage and skin lesion. The diagnosis was unclear and the treatment was difficult. Through a multidisciplinary effort type Ⅰ interferon disease was suspected and later, an interferon-stimulated gene was further detected. Considering the high morbidity and fatality rate of recurrent intracranial hemorrhage, tofacitinib and hydroxychloroquine were administered. After treatment, the livedo reticularis was significantly regressed. Unfortunately, the intracranial hemorrhage recurred due to a pre-existing cerebral aneurysm, leading to death of the patient. The diagnosis and treatment of this case highlight the importance of multidisciplinary collaboration in the diagnosis and treatment of difficult and rare diseases.