镜像破裂与未破裂后交通动脉瘤血流动力学的数值模拟分析

目的 探讨镜像破裂与未破裂动脉瘤的血流动力学特征差异.方法 1例镜像破裂与未破裂后交通动脉瘤的三维血管造影资料,采用数学建模的方法,利用流体力学软件分析两者的血流动力学参数及流场特征.结果 双侧动脉瘤的血流方式一致,但破裂动脉瘤射入流更宽且冲击域分布不一致;最大流速高于未破裂动脉瘤;破裂动脉瘤壁面切应力(wall shear stress,WSS)分布不均,低WSS区域较大.结论 血流动力学在镜像的破裂与未破裂动脉瘤中存在差异,高流速与低壁面切应力可能与动脉瘤破裂出血相关.     

破裂与未破裂镜像后交通动脉瘤形态与血流动力学分析

目的探讨破裂与未破裂颅内动脉瘤的血流动力学与形态学差异,分析动脉瘤破裂的危险因素。方法回顾性分析8例镜像后交通动脉瘤病人（均为一侧破裂,一侧未破裂）的临床资料,均行3D—DSA检查,建立数值模型。将16个动脉瘤按是否破裂分组,分析破裂组与未破裂组之间的形态学与血流动力学参数特征。结果破裂组动脉瘤平均擘面切应力（WSS）明显低于未破裂组（P〈0．05）;而低壁面切应力面积（LSA）比率和体颈比值明显高于未破裂组（P〈0．05）。剪切震荡指数（OSI）、动脉瘤直径、大小比率、血管角度和动脉瘤倾角组间差异无统计学意义（P〉0．05）。结论镜像后交通动脉瘤可能是研究动脉瘤破裂风险的理想模型,血流动力学与形态学在判断动脉瘤破裂风险方面同等重要。     

颅内破裂动脉瘤的血流动力学特征:基于流固耦合技术的计算流体力学模拟分析

目的 探讨颅内破裂动脉瘤破裂点和瘤囊处血流动力学特征。方法 选择2018年1月至2019年6月收治的颅内破裂动脉瘤21例，根据术前CTA、DSA数据三维重建动脉瘤模型，采用ANSYS软件计算动脉瘤破裂点和瘤囊处血流动力相关参数[壁剪切应力（WSS）、切应力震荡指数（OSI）]。结果 动脉瘤破裂点WSS[（0.215±0.047）Pa]明显低于瘤囊WSS[（0.464±0.148）Pa；P<0.001]。动脉瘤破裂点OSI[（0.035±0.024）]与瘤囊OSI[（0.030±0.016）]无统计学差异（P>0.05）。在一个心动周期中，随着血流动力学的变化，动脉瘤形态出现规律的变化，载瘤动脉及动脉瘤的形态变化存在明显差异，即动脉瘤两侧壁的形态变化相对较小，动脉瘤破裂点处形态变化明显。结论 颅内动脉瘤破裂点较动脉瘤囊WSS更低而形态变化更大，颅内动脉瘤破裂与WSS呈负相关，而与形态变化呈正相关。     

壁面切应力与颅内动脉瘤的研究进展

壁面切应力(WSS)是血流对血管壁的切向摩擦力,平行作用于血管壁.WSS被认为是与颅内动脉瘤发生、生长和破裂关系最密切的血流动力学参数.由于缺乏统一标准,WSS这一参数如何影响动脉瘤仍存在争议.本文结合文献,对WSS在颅内动脉瘤中的作用研究进展作一综述.     

颈内动脉后交通动脉小动脉瘤破裂危险因素分析

目的 探讨颈内动脉后交通动脉小动脉瘤（直径≤5 mm）破裂出血的危险因素。方法 回顾性分析83例颈内动脉后交通动脉小动脉瘤（破裂动脉瘤47例,未破裂动脉瘤36例）的临床资料、3D-DSA影像参数和血流动力学参数,采用多元Logistic回归分析检验危险因素。结果 动脉瘤呈分叉型（OR=3.368;95% CI为1.124~10.094;P=0.030）和不规则形（OR=5.706;95% CI为1.415~23.011;P=0.014）是颈内动脉后交通动脉小动脉瘤破裂的独立危险因素;而壁面切应力与动脉瘤破裂呈负相关（OR=0.053;95% CI为0.005~0.520;P=0.012）。结论 分叉型形状、不规则型形状和低壁面切应力是颈内动脉后交通动脉小动脉瘤破裂的独立危险因子。     

壁面切应力和颅内动脉瘤复杂的相互关系

颅内动脉瘤是动脉壁的病理性突出。以影像学为基础的计算机流体力学(computational fluid dynamics,CFD)已经预示着血液动力学和颅内动脉瘤破裂的关系。高壁面切应力(wall shear stress,WSS)导致颅内动脉瘤的产生。高或者低WSS都能导致动脉瘤的生长和破裂。低WSS会启动炎症细胞介质通路,导致大的、厚壁动脉瘤的生长以及破裂,而高WSS以及正壁面切应力梯度会触发壁细胞介质通路,导致小的薄壁透明型动脉瘤的生长和破裂。     

两种常见形态颅内动脉瘤的血流动力学研究

目的 对颅内动脉瘤进行三维数值模拟并分类.分析其血流动力学特性.方法 联合应用Matlab、Ansys、Fluent等软件及自写程序对39例颅内动脉瘤进行数值模拟.结果 两类动脉瘤模型流人道的血流速度、动压及壁面切应力最高,流出道次之,瘤顶部最低;且A类(长宽比>1.8)动脉瘤破裂率明显高于B类(长宽比≤1.8).A类动脉瘤流人道侧壁和瘤顶部壁而切应力比值(WSS'sratio)明显大于B类动脉瘤;且与其长宽比成正相关.结论 颅内动脉瘤顶部的血流速度、动压及壁面切应力均最低,是其破裂的主要原因和部位.流人道和瘤顶部壁面切应力比值及动脉瘤的长宽比反映动脉瘤的破裂风险,其比值越大,破裂风险越高.     

基于影像数据的三维颅内动脉瘤血流动力学数值：手术前后壁面切模拟对比

背景：颅内动脉瘤是由于动脉血管壁病理性局限性扩张产生的脑血管瘤样突起。血流动力学因素被认为是颅内动脉瘤形成、生长、破裂过程中的一个重要因素，因此基于计算流体力学的计算机数值模拟技术得到了广泛的应用。 目的：通过对颅内动脉瘤术前术后进行血流动力学分析计算，探讨颅内动脉瘤术后壁面切应力的变化对动脉瘤是否复发的影响。 方法：对1例复发病例和1例未复发病例术前、术后的动脉瘤进行建模，实行血流动力学计算。 结果与结论：复发病例术后动脉瘤残颈处的切应力局部剧增；未复发病例术后动脉瘤残颈处切应力普遍减小。术后动脉瘤残颈处壁面切应力与术前相比，若普遍减小，能够降低动脉瘤复发的风险；反之，则增大了动脉瘤复发的风险，动脉瘤易复发。     

颅内镜面动脉瘤破裂的危险因素及预测研究

目的 探讨颅内镜面动脉瘤破裂的危险因素及预测指标。方法 回顾性纳入2016年1月-2021年12月于本院诊治颅内镜面动脉瘤患者共62例124个,根据动脉瘤是否破裂分为破裂组(60个)和未破裂组(64个);比较2组一般资料、电子计算机断层扫描(Computed tomography, CT)表现及血流动力学指标,采用Logistic回归模型分析颅内镜面动脉瘤破裂的独立危险因素,描绘受试者工作特征(Receiver operating characteristic, ROC)曲线评价上述独立危险因素的临床预测效能。结果 破裂组CT扫描动脉瘤最大径、颈宽、尺寸比、壁切应力变异系数、平均壁切应力均值变异系数、平均壁切应力绝对值变异系数、壁切应力梯度变异系数及平均壁切应力梯度变异系数均显著多于未破裂组(P<0.05);破裂组压力变异系数显著少于未破裂组(P<0.05);将单因素分析有统计学意义指标纳入Logistic回归模型行多因素分析显示,壁切应力变异系数和壁切应力梯度变异系数均是颅内镜面动脉瘤破裂的独立危险因素(P<0.05);ROC曲线分析显示,壁切应力变异系数联合壁切应...     

微血管多普勒超声在颈内动脉瘤手术中的应用

目的 探讨微血管多普勒超声(MVD)在颈内动脉瘤手术中的应用.方法 采用探头频率20MHz、直径1.5 mm,对32例颈内动脉瘤患者(共计36个动脉瘤)进行动脉瘤夹闭前后血流动力学监测.术后血管造影进行评估.结果 所有患者均能在动脉瘤顶或瘤体部监测到涡流样或毛刺样血流信号、闻及杂音.动脉瘤夹闭术后即刻监测,发现载瘤动脉狭窄8例,闭塞1例;动脉瘤夹闭不全2例,均经调整瘤夹位置,显示载瘤动脉远段的血流频谱形态和音频信号正常,术后经DSA/CTA证实.以上情况的发生与动脉瘤大小及载瘤动脉有粥样硬化斑块有关.结论 MVD可作为颅内动脉瘤手术的常规检测方法,尤其对瘤颈粗、甚至无明显瘤颈的巨大型动脉瘤手术具有指导意义.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.