Flexible and floating choroid plexus cyst of the third ventricle: an ultrasonographic video documentation

Introduction Choroid plexus cysts can lead to isolation of the lateral ventricles and distension of the third ventricle. We present an ultrasonographic video documentation of an infant with variably shaped and localized choroid plexus cyst of the third ventricle. Case report An infant had periods of increased intracranial pressure with changing dilatation of the first to third ventricle. Cerebral ultrasonography of the not crying boy demonstrated a choroid plexus cyst limply hanging down from the roof of the third ventricle to the beginning of the aqueduct of Sylvius. During crying, the cyst prolapsed from the third into left lateral ventricle and was strangled by the foramen of Monro. Endoscopic cyst fenestration and third ventriculostomy continuously solved the problem of intermittent hydrocephalus occlusus. Conclusion Depending not only on localization and size but also on cyst form and cerebrospinal fluid pressure, a single choroid plexus cyst can cause various obstructions of cerebrospinal fluid pathways.     

正常中脑导水管脑脊液流动磁共振定量研究

目的 :运用磁共振相位对比电影法非侵袭性测量中脑导水管脑脊液流动方向、流速及流量改变情况。方法 :测量 15例正常志愿者 (年龄 2 1～ 4 7岁 ,平均 31 4岁 )中脑导水管脑脊液流动情况 ,在正中矢状位T1WI图像上选择垂直于导水管层面 ,编码速率 2 0cm/s。测量相应层面导水管截面积 ,计算相应导水管区脑脊液流量 ,并研究在一个心动周期内CSF流动改变情况。结果 :正常中脑导水管脑脊液流动在一个心动周期内表现为双向流动 ,即收缩期向下流动和舒张期向上流动 ,收缩期平均向下峰流速和舒张期平均向上峰流速分别为 12 6 7± 3 5 8mm/s和 11 5 8± 3 96mm/s,平均向下及向上流量分别为 1 311± 0 74 0ml/min(0 0 18± 0 0 12ml/心动周期 )和 1 0 6 8± 0 5 6 8ml/min(0 0 14± 0 0 0 9ml/心动周期 ) ,平均净流量为 0 2 6 0± 0 2 4 9ml/min(0 0 0 4± 0 0 0 4ml/心动周期 ) ;脑脊液向下流动平均最大峰速发生在一个心动周期的R波后平均 18%时间点 (心动周期的 5 7ms,平均心动周期 85 7ms) ,向上最大峰流速出现在心动周期的 87%时间点 (心动周期的6 86ms,平均心动周期 85 7ms) ,而逆向流动发生在R波后平均 4 4 %～ 5 8%时间点 (心动周期的 343～ 4 5 7ms,平均心动周期85 7ms)。结论 :磁共振相位对比     

Hydrocephalus induced by immunological blockage of the subcommissural organ–Reissner's fiber (RF) complex by maternal transfer of anti-RF antibodies

Stenosis of the cerebral aqueduct seems to be a key event for the development of congenital hydrocephalus. The causes of such a stenosis are not well known. Overholser et al. in 1954 (Anat Rec 120:917-933) proposed the hypothesis that a dysfunction of the subcommissural organ (SCO) leads to aqueductal stenosis and congenital hydrocephalus. The SCO is a brain gland, located at the entrance of the cerebral aqueduct, that secretes glycoproteins into the cerebrospinal fluid that, upon release, assemble into a fibrous structure known as Reissner's fiber (RF). By the permanent addition of new molecules to its rostral end, RF grows and extends along the aqueduct, fourth ventricle, and central canal of the spinal cord. The immunological blockage of the SCO-RF complex has been used to test Overholser's hypothesis. The following was the sequence of events occurring in pregnant rats that had been immunized with RF glycoproteins: the mother produced anti-RF antibodies and transferred them to the fetus through the placenta and to the pup through the milk, and the antibodies reached the brain of the fetus and pup and blocked the SCO-RF complex. This resulted in a permanent absence of RF that was followed by stenosis of the cerebral aqueduct, and then by the appearance of hydrocephalus. The latter was patent until the end of the 6-month observation period. The chronic hydrocephalic state appeared, in turn, to induce new alterations of the SCO. It is concluded that a selective immunological knock out of the SCO-RF complex leads to hydrocephalus.     

Aqueductal lesions in 6-aminonicotinamide-treated suckling mice

Summary Suckling mice which received a single intraperitoneal injection of 6-aminonicotinamide on the 5th postnatal day, consistently developed hydrocephalus. During the early stages of hydrocephalus (7–9 days after injection), aqueductal lesions were characterized by edematous ependymal and subependymal cells, and spongy changes in the periaqueductal area, which resulted in aqueduct stenosis. Later stages (after 20 days post-injection) showed that these edematous changes totally subsided, leaving an obliterated aqueduct which was similar to that of human congenital hydrocephalus. At the completely obliterated area, ultrastructural investigation disclosed a normal-looking neuropil but no aqueductal lumen. In the remaining ependymal cell, increased intermediate filaments and lipid droplets occurred. These data suggest that acute ependymal cell degeneration during the perinatal period may result in the profile of aqueduct agenesis in human congenital hydrocephalus.Supported in part by research grants NS-03356, NS-10803 from NINCDS, USPHS     

MRI in aqueduct compression and obstructive hydrocephalus due to an ectatic basilar artery

We describe a patient with an ectatic basilar artery in whom MRI showed marked indentation of the floor of the third ventricle and backward displacement of the midbrain, probably causing aqueduct stenosis. It appeared likely that the associated hydrocephalus was due not only to any water-hammer effect, but also to occlusion of the aqueduct.     

Unpredictable Hearing Loss after Intratympanic Gentamicin Treatment for Vertigo. A New Theory

A new hypothesis is advanced suggesting that unpredictable cases of profound hearing loss after intratympanic gentamicin treatment (IGT) may be caused by decreased patency of the communication routes between the inner ear and the cerebrospinal fluid, primarily of the cochlear aqueduct. A tympanic displacement analyzer, which can indirectly analyze inner ear and intracranial pressure changes and can also evaluate the efficiency of communication between these two compartments, was used. Two cases are presented: in the first, a patient who became deaf after IGT showed signs of decreased patency of the communication routes with the tympanic membrane displacement (TMD) test; in the second, a patient without hearing damage after IGT had efficient communication evaluated by the TMD test. These preliminary findings are in accordance with the proposed pathophysiology. If future clinical studies confirm the present theory and findings, it may prove possible to predict and prevent deafness after IGT and possibly also after systemic aminoglycoside treatment.     

Diagnosis and treatment for pure aqueductal tumor

Pure aqueductal tumor (PAT) typically originates from pure aqueductal region and is extremely rare. It is radiographically similar to tectal glioma. We examined two patients with PATs who were diagnosed with pilocytic astrocytoma and rosette-forming glioneuronal tumor. Both cases showed a progressive clinical course. It is important to distinguish between PAT and tectal glioma by radiographic imaging because the treatment strategy is different. While observation is common for tectal gliomas, a biopsy is recommended at the same time of endoscopic third ventriculostomy for PAT with hydrocephalus. Low-grade PATs show an aggressive clinical course in some cases. Our two cases also showed aggressive course in spite of no genetic aggressive mutations. Sagittal view by constructive interference in steady state (CISS) imaging was helpful to make an accurate diagnosis of PAT. Close observation is needed if PAT is diagnosed as low-grade tumor.     

大前庭水管综合征患者鼓膜吸收率特征初探

目的探讨大前庭水管综合征(Large Vestibular Aqueduct Syndrome,LVAS)患者宽频声导抗(Wideband Acoustic Immittance,WAI)测试中的声导抗峰压值的鼓膜吸收率特征。方法选取40例经CT确诊大前庭水管综合征患者,进行声导抗峰压值的鼓膜吸收率测试,并收集相同数量同龄正常组进行对比。计算鼓室图峰压值对应的各频率鼓膜吸收率数值,计算吸收率相对面积。使用独立t检验对两组鼓室峰压值吸收率面积、吸收率峰值进行比较。结果在226~1000Hz,LVAS组吸收率面积大于正常儿童的吸收率面积,差异有显著统计学意义;在1000~8000Hz,LVAS组吸收率面积与正常儿童的吸收率面积间的差异无统计学意义;LVAS组和正常儿童吸收率峰值无统计学差异。结论在低频(226~1000Hz)时LVAS组与正常组声导抗峰压值的鼓膜吸收率相对面积差异显著。     

大前庭水管综合征的基因诊断和SLC26A4基因突变分析

目的应用变性高效液相色谱分析和序列分析方法进行大前庭水管综合征患者的SLC26A4（PDS）基因全序列扫描,分析大前庭水管综合征的SLC26A4基因型变化和遗传特征.方法来自35个家庭的38例患者多患中重度感音性耳聋,所有患者颞骨CT均显示前庭水管明显扩大.以高效液相色谱分析结合序列分析进行SLC26A4基因分析.结果共发现32个先证者携带有SLC26A4基因突变,其中纯合突变11例,复合突变9例,单一杂合突变12例,3个先证者未发现突变,在所有受检患者中突变发现率91.4%（32/35）.共发现8种突变类型58个突变,其中IVS7-2 A＞G突变为中国人最常见的SLC26A4突变,共发现其纯合型10例,杂合突变13例,即有71.9%的患者（23/32）携带此种突变,2168A＞G为第二常见突变,共有8名患者携带此杂合突变,另发现1229C＞T,IVS15＋5G＞A,1226 G＞A,1199-1200insT,946 G＞T,916-917 ins G突变形式,后三种突变为国内外尚未报道的新突变.四种复发性突变IVS7-2 A＞G、2168A＞G、1229C＞T、IVS15＋5G＞A在此组病例的30例患者均有出现.三个多发家庭的同胞患者均具有一样的SLC26A4突变.结论大前庭水管综合征是典型的常染色体隐性遗传疾病,SLC26A4基因突变是其明确的致病因素,SLC26A4基因检测是诊断大前庭水管综合征的重要方法之一.     

正常中脑导水管脑脊液流动与年龄相关性研究

目的对正常女性中脑导水管层面脑脊液(cerebralspinal fluid,CSF)的流动情况进行磁共振(magnetic resonance imaging,MRI)定量研究并将其与年龄进行回归分析。方法筛选38例正常女性志愿者,测量其中脑导水管CSF流动情况,以年龄作为因变量,流速(收缩期向下最大流速V1,舒张期向上最大流速V2、平均向下流速V3、平均向上流速V4及平均流速V5)、流量(收缩期向下最大流量Q1、舒张期向上最大流量Q2、平均向下流量Q3、平均向上流量Q4、平均流量Q5、平均净流量Q6)及心动周期(收缩期向下最大流速对应心动周期T1、舒张期向上最大流速对应心动周期T2、平均心动周期T3)作为自变量进行线性回归分析。结果一般回归方程分别为age=38.146+0.825V1+0.705V2-0.738V3-0.298V4-0.887V5,age=46.899-117.944Q1+21.319Q2-191.968Q3+62.774Q4-84.361Q5-227.401Q6,age=36.047+0.063T1+0.016T2+0.010T3。各项指标P均>0.05,无显著性差异。结论自变量流速、流量及心动周期3者对因变量年龄无显著性影响。在应用MR定量分析CSF流速、流量及心动周期时无需考虑年龄因素。