梗阻性脑积水侧脑室及室周脑组织生物力学响应的有限元分析

目的运用有限元方法对梗阻性脑积水进行计算机模拟,研究分析侧脑室及室周脑组织的生物力学响应及其所产生的病理生理影响。方法依据正常国人颅脑MRI轴位T2加权图像获取解剖信息,在有限元软件ANSYS中生成包含侧脑室前、后角和体部的半侧脑层面的二维有限元模型。模拟脑组织为固、液两相物质组成的线性多孔弹性材料,设定生物力学特性参数及边界条件和初始条件,施加载荷,运用有限元软件ABAQUS进行计算求解,以云图形式输出结果。结果有限元模型动态模拟了梗阻性脑积水侧脑室各部的扩张过程,直观显示出各个时间步室周脑组织内的应力类型及分布、各部的应变和位移。结论膨胀性应力集中引起角部脑水肿;梗阻性脑积水早期侧脑室角部形态变化最明显;体部附近脑组织结构容易受压移位。这些生物力学响应是室内压增高的结果,也与侧脑室的解剖形态密切相关。     

Ischemic and hemorrhagic cerebral lesions of the newborn

Neonatal pathology comprises a large array of cerebral lesions due to ischemic and/or hemorrhagic mechanisms. Pathogenesis, neuropathology, clinical settings in the acute stages as well as short and long-term outcome are discussed.     

Long-term potentiation in the optic tectum of rainbow trout

We examined synaptic plasticity in the optic tectum of rainbow trout by extracellular recordings. We found that the field-excitatory postsynaptic potential in the retinotectal synapses was potentiated by repetitive stimuli of 1.0 Hz for 20 s to the retinotectal afferents. The long-term potentiation (LTP) developed slowly, and was maintained for at least 2 h. Applications of an antagonist for N-methyl-D-aspartic acid (NMDA) receptors or Mg²⁺-free saline showed that activation of NMDA receptors was required to form the LTP beyond the induction period. The present findings indicate that presynaptic stimulation in the retinotectal synapses causes LTP mediated by NMDA receptors in the optic tectum of rainbow trout.     

胎儿脑灰质异位合并FLNA基因突变病例报告

报告1例产前超声联合胎儿颅脑磁共振成像（magnetic resonance imaging,MRI）诊断胎儿脑灰质异位合并细丝蛋白A（filamin A,FLNA）基因突变的病例。患者超声检测结果显示侧脑室外壁凹凸不平,颅后窝池宽,透明隔间腔略窄,小脑延髓池轻度增宽。MRI诊断结果为胎儿脑灰质异位合并大枕大池。羊水穿刺获得脱落细胞,采用全外显子测序和基因拷贝数变异（copy number variations,CNV）分析,显示与脑灰质异位疾病相关的FLNA基因外显子出现缺失,其为可能导致脑灰质异位的致病基因。因此,超声结合胎儿颅脑MRI能有效提高脑灰质异位的诊断率,其中染色体检查可筛查出部分致病原因,并对下次妊娠提供帮助。该病例可丰富临床医生对胎儿大脑灰质异位的产前超声检查、合并畸形、临床表现等的认识。     

Periventricular- intraventricular hemorrhage in the premature infant- A historical perspective

The objective of this chapter is to trace the evolution of intraventricular hemorrhage in the premature infant highlighting the importance of the germinal matrix, a critical role for cerebral blood flow changes in the genesis of hemorrhage, clinical factors that increase the bleeding risk, and potential preventative strategies. In 1976, neuropathological studies demonstrated capillary rupture within the germinal matrix as the precursor of hemorrhage. In 1980, introduction of cranial ultrasound facilitated diagnosis of intraventricular hemorrhage. In 1979, loss of cerebral autoregulation in sick newborn infants was demonstrated. In the 1980’s, studies demonstrated the importance of intravascular factors in provoking hemorrhage. In 1983, the association of cerebral blood flow velocity fluctuations and subsequent hemorrhage was demonstrated. In 1994, antenatal steroids use to accelerate lung development was recommended. This was associated with an unanticipated reduction in hemorrhage. In the mid 1990’s early indomethacin administration was associated with a reduction of severe hemorrhage.     

Factors influencing the development of periventricular lucencies in patients with raised intracranial pressure

Summary Sixty patients with raised intracranial pressure and lowered attenuation areas around the lateral ventricles (periventricular lucency, PVL) on CT scanning were reviewed, and compared with a control group of 90 similar patients who did not have PVL. It was confirmed that PVL tends to occur in patients with acute or subacute obstructive hydrocephalus due to a tumour, and is more common in the presence of papilloedema and/or a decreased level of consciousness. Patients with very dilated lateral ventricles did not in general have PVL, but it was frequently seen in association with diastasis of the sutures. Twelve patients with PVL had no other clinical or radiological indication of raised intracranial pressure. Comparison with the control cases did not reveal any reason as to why some patients should develop PVL while others did not.     

Treatment of drug-resistant epilepsy in patients with periventricular nodular heterotopia using RNS® System: Efficacy and description of chronic electrophysiological recordings

ObjectivesDescribe changes in clinical seizure frequency and electrophysiological data recorded in patients with medically-intractable seizures and periventricular nodular heterotopias (PVNH) treated with the RNS® System (NeuroPace, Inc., Mountain View, CA).MethodsClinical seizures from eight patients (mean follow-up of 10.1 years) were analyzed pre- and post-treatment. Chronic ambulatory electrocorticograms (ECoGs) recorded from PVNHs, hippocampus and neocortex were evaluated to identify the earliest electrographic seizure onset type, pattern of spread, and interictal characteristics.ResultsMean reduction in disabling seizures was 85.7 % (n = 8); seven patients had >50% seizure reduction and two were seizure-free in the final year of analysis. Seizure rate showed a progressive reduction over the course of the study with the highest rate of improvement in the first two to three years after implantation. Four of seven patients with one PVNH lead and a second lead in the hippocampus or neocortex had some electrographic seizures first recorded at either lead location, suggesting two foci or seizure propagation patterns. Low voltage fast type activity was the prominent seizure onset pattern. Interictal ECoG power was lower in PVNH than hippocampus.ConclusionsRNS® System treatment substantially reduced clinical seizure frequency in patients with PVNH. Analysis of ictal ECoG records suggests PVNH may be involved in seizure generation.SignificanceChronic ECoG recordings suggest PVNH tissue can actively participate in epileptogenic networks. Direct brain-responsive neurostimulation is a safe and effective treatment option in such patients, progressively reducing seizure rate over a period of years.     

颅脑超声诊断新生儿脑损伤的临床价值

目的探讨颅脑超声诊断新生儿脑损伤的临床价值。方法应用颅脑超声对1 387例住院新生儿进行早期检查及随访,分析声像图表现。结果颅脑超声检查1 387例,其中正常声像图594例,异常声像图793例。结论颅脑超声对新生儿脑损伤诊断率高,并能连续监测新生儿病情变化,故可成为新生儿脑损伤早期诊断、判断其严重程度及随访的有效手段。     

Automated morphometric magnetic resonance imaging analysis for the detection of periventricular nodular heterotopia

Purpose: To describe a novel magnetic resonance imaging (MRI) postprocessing technique for the detection of periventricular nodular heterotopia (PNH) and to evaluate its diagnostic value. The method is a further development of voxel‐based morphometric analysis with focus on a region of interest around the lateral ventricles to increase the sensitivity and specificity for automated detection of abnormally located gray matter in this area. Methods: T₁‐weighted MRI volume data sets were normalized and segmented in statistical parametric mapping (SPM 5 software), and the distribution of gray matter was compared to a normal database. As a new approach, individual masks derived from segmentation of the lateral ventricles were used to restrict the search for ectopic gray matter to the periventricular area. PNH were automatically detected by localizing the maximum deviation from the normal database in this area, provided that the z‐score exceeded a certain threshold. The optimal z‐score threshold for maximum sensitivity and specificity was determined by a receiver operating characteristic (ROC) curve analysis. The method was applied in 40 patients with PNH and 400 controls. Key Findings: PNH were detected in 37 of 40 patients, and false positives were found in 34 of 400 controls, amounting to 92.5% sensitivity and 91.5% specificity. In 17 of the patients in whom PNH could be identified, these lesions had been overlooked in the past, and in 8 patients even in the high‐resolution MRI subsequently used for postprocessing. Significance: The results suggest that automated morphometric MRI analysis with focus on ectopic gray matter in the periventricular areas facilitates the evaluation of MRI data and increases the sensitivity for the detection of PNH.     

Transient structural MRI patterns correlate with the motor functions in preterm infants

AimTo explore the relationships between transient structural brain patterns on MRI at preterm and at term-equivalent age (TEA) as a predictor of general movements (GMs) and motor development at 1-year corrected age (CA) in very preterm infants.MethodsIn this prospective study, 30 very preterm infants (median = 28wks; 16 males) had structural magnetic resonance imaging (MRI) at preterm (median = 31wks + 6d) and at TEA (median = 40wks) and neuromotor assessments. The quality of GMs was assessed by Prechtl’s general movements assessment and a detailed analysis of the motor repertoire was performed by calculating a motor optimality score (MOS), both at term age and at 3 months post-term. Motor development at 1-year CA was evaluated with the Infant Motor Profile (IMP). Associations between qualitative MRI findings and neuromotor scores were investigated.ResultsAbnormal GMs and low motor performance at 1-year CA were associated with the poor visibility of transient structural pattern, that is with sagittal strata.InterpretationTransient structural MRI pattern, sagittal strata, at preterm age is related to the quality of GMs and later motor development in preterm infants. This transient fetal brain compartment may be considered as a component of neurobiological basis for early neuromotor behavior, as expressed by GMs.