脑脊液相位对比动力学MRI研究

目的 相位对比动力学MRI无损伤性探测中脑导水管脑脊液动力学。方法 应用相位对比动力学MRI探测了170例中脑导水管脑脊液动力学，其中正常人群组79例，高血压人群组30例，颅内疾病人群组61例（本组分为交通性脑积水，梗阻性脑积水和大脑半球占位性病变3组）。所选择的参数为最大流速（Vmax），最大流量（Fmax），到头端峰值时间（Time to Vr）及脑脊液流动图。结果 79例正常人群组中脑导水管脑脊液动力学为等动力学，高血压人群组为高动力学；交通性脑积水为超高动力学；梗阻性脑积水为不规则动力学；大脑半球占位性病变组为低动力学。结论 相位对比动力学MRI对于多种疾病具有重要的临床意义。     

中脑导水管脑脊液动力学MRI研究

目的　无损伤性探测中脑导水管脑脊液动力学在临床实践中的意义。方法　应用 Ｃｉｎｅ Ｍ Ｒ Ｉ,测定了５３ 例患者中脑导水管脑脊液动力学指标（ 峰值流速、峰值流量、到头端峰值时间及 Ｃ Ｓ Ｆ 流动图） 。依据临床诊断,５３ 例分为五组： Ａ 对照组, Ｂ 交通性脑积水组, Ｃ 梗阻性脑积水组, Ｄ 颅内大脑半球占位性病变组, Ｅ 脑萎缩组。结果　 Ａ 组呈等动力学, Ｂ 组呈高动力学, Ｃ 组表现为高、等、低动力学, Ｄ组和 Ｅ 组为低动力学。结论　中脑导水管脑脊液流动的峰值流速、峰值流量、到头端峰值的时间以及脑脊液流动图对颅内某些疾患的诊断、鉴别诊断是有用的。同时,可以探讨脑积水分流指征及分流的有效性。     

Shunt surgery effects on cerebrospinal fluid flow across the aqueduct of Sylvius in patients with communicating hydrocephalus

We aimed to visualize and quantify the flow of cerebrospinal fluid (CSF) across the aqueduct of Sylvius in patients with communicating hydrocephalus using phase contrast MRI, and to evaluate the effect of ventriculoperitoneal (VP) shunt surgery on flow. We investigated aqueductal CSF flow using cine cardiac-gated phase contrast MRI in 10 normal volunteers and 10 patients with communicating hydrocephalus (who underwent VP shunt surgery). For qualitative evaluation, we used an in-plane phase contrast sequence in the midsagittal plane. Quantitative through-plane measurements were performed in the axial plane perpendicular to the aqueduct. The aqueduct area ranged from 0.02 cm² to 0.27 cm² in the shunt group; and from 0.01 cm² to 0.04 cm² in the control group (p < 0.05). Aqueductal stroke volume (mean, standard deviation SD) ranged from 1.9 μL to 33.17 μL (17.41 μL, 10.1132) in the control group; and from 5.63 μL to 256 μL (87.20 μL, 79.0383) in the study group. Post-operatively the aqueductal stroke volume reduced significantly, ranging from 0.60 μL to 48.77 μL (13.19 μL, 18.08) (p < 0.05). Peak systolic velocity (PSV) values in the patients before shunt surgery ranged from ?1.05 cm/s to ?8.10 cm/s (?4.39cm/s, 2.7619) and peak diastolic velocities (PDV) ranged from 0.62 cm/s to 5.16 cm/s (3.33 cm/s, 1.4451). Post- shunt; PSV values ranged from ?0.37 cm/s to ?3.90 cm/s (1.78 cm/s, 1.5143) and PDV range was 0.32 cm/s to 4.43 cm/s (1.78 cm/s, 1.6782). The post-operative reduction in velocity was significant (p < 0.05). Thus, the aqueductal CSF flow after VP shunt was similar to flow in healthy volunteers.     

Serial lumbar CSF pressure measurements and cranial computed tomographic findings in childhood tuberculous meningitis

Intracranial pressure (ICP) was monitored in 218 consecutive children with hydrocephalus secondary to tuberculous meningitis (TBM). All children underwent cranial computerized tomographic (CT) scanning and continuous lumbar cerebrospinal (CSF) pressure monitoring on admission. Noncommunicating hydrocephalus (37 children), as determined by air encephalography, was treated by ventriculoperitoneal (VP) shunting and communicating hydrocephalus (181 children), by means of daily acetazolamide and frusemide. Response of ICP to treatment in the group with communicating hydrocephalus was assessed by means of repeated CSF pressure monitoring and CT scanning. One hundred and eighty-five of the 218 patients survived the 1st month of treatment. The aim of this study was the retrospective determination of (1) the relationship between ICP measurements and CT findings on admission and (2) the characteristics of the ICP recording which correlated best with the CT criteria of compensated hydrocephalus after the 1st month of treatment. No relationship was found between the level of baseline CSF pressure and the degree of hydrocephalus, as demonstrated by CT scanning, on admission. Seventy-five per cent of the patients with communicating hydrocephalus that survived the 1st month of treatment complied with the CT criteria for compensated hydrocephalus. All these patients had a baseline CSF pressure below 15 mmHg and absence of high-amplitude B waves on the pressure recording done at the end of the 1st month. In this study repeated lumbar CSF pressure monitoring proved to be an effective instrument to assess the response of communicating tuberculous hydrocephalus to medical treatment and also accurately predicted the timing of compensation of the hydrocephalus. Received: 19 January 1999 Revised: 20 March 1999     

Quantitative assessment of cerebrospinal fluid hydrodynamics using a phase-contrast cine MR image in hydrocephalus

This investigation was undertaken to characterize CSF flow at the level of the aqueduct of Sylvius with a phase-contrast cine MR pulse sequence in 28 healthy volunteers. Sixteen patients with obstructive hydrocephalus and 11 patients with normal pressure hydrocephalus (NPH) were investigated with the same sequence before and after CSF diversion. The peak CSF flow velocity and stroke volume in the aqueduct increased significantly in the NPH group and decreased significantly in the obstructive hydrocephalus group. After lumboperitoneal shunting in the NPH group, the retrograde flow of CSF was anterogradely converted and the peak flow velocities decreased somewhat. The clinical diagnosis of NPH was well correlated with the results of cine MRI. After endoscopic III ventriculostomy in the obstructive hydrocephalus group we noted increased CSF flow velocity with markedly increased stroke volume at the prepontine cistern. Phase-contrast cine MR is useful in evaluating CSF dynamics in patients with hyperdynamic aqueductal CSF or aqueductal obstruction.     

磁共振相位电影对比法在内镜下导水管成形术中的应用

目的 探讨磁共振相位电影对比成像法在内镜下导水管成形术治疗导水管梗阻性脑积水的应用价值.方法 对23例诊断为导水管梗阻性脑积水的患者,术前常规采用磁共振相位电影对比法进一步确诊;手术采用电子软性神经内镜下导水管成形术,术中对导水管阻塞程度进行评估.术后1周及随访均采用磁共振相位电影对比法复查来测量导水管脑脊液流速流量以确定导水管是否开通.结果 23例术前磁共振相位电影对比法未见导水管脑脊液流动患者,术中见导水管完全闭塞或直径小于1 mm2;23例患者成形术均获成功,导水管扩张平均在4 mm左右,术后1周电影成像检查导水管平均流速为(4.74±1.77)cm/s,在随访期间,2例再次出现颅高压症状的患者,电影成像显示导水管未见脑脊液流动,二次内镜下探查见导水管重新闭塞.结论 磁共振相位电影对比法通过测量导水管内脑脊液流速流量来精确判断导水管开通情况,可以作为导水管梗阻性脑积水术前诊断及导水管成形术后疗效判断及随访的重要工具.     

Paradigm shift in hydrocephalus research in legacy of Dandy’s pioneering work: rationale for third ventriculostomy in communicating hydrocephalus

Objective This study aims to question the generally accepted cerebrospinal fluid (CSF) bulk flow theory suggesting that the CSF is exclusively absorbed by the arachnoid villi and that the cause of hydrocephalus is a CSF absorption deficit. In addition, this study aims to briefly describe the new hydrodynamic concept of hydrocephalus and the rationale for endoscopic third ventriculostomy (ETV) in communicating hydrocephalus. Critique The bulk flow theory has proven incapable of explaining the pivotal mechanisms behind communicating hydrocephalus. Thus, the theory is unable to explain why the ventricles enlarge, why the CSF pressure remains normal and why some patients improve after ETV. Hydrodynamic concept of hydrocephalus Communicating hydrocephalus is caused by decreased intracranial compliance increasing the systolic pressure transmission into the brain parenchyma. The increased systolic pressure in the brain distends the brain towards the skull and simultaneously compresses the periventricular region of the brain against the ventricles. The final result is the predominant enlargement of the ventricles and narrowing of the subarachnoid space. The ETV reduces the increased systolic pressure in the brain simply by venting ventricular CSF through the stoma. The patent aqueduct in communicating hydrocephalus is too narrow to vent the CSF sufficiently.     

Observation of CSF pulsatile flow in MRI--the signal void phenomenon

In a comparative study of MR images of 289 neurosurgical patients, loss of the signal intensity (signal void phenomenon) of CSF in the aqueduct was observed in 77 patients. This signal void phenomenon was seen most frequently in infants with chronic subdural hematoma (12 of 18) and patients of all age groups suffering from communicating hydrocephalus (10 of 14). It is known that CSF in the cranial cavity flows toward the spinal CSF space in to and fro manner responding to brain parenchyma pulsations. The velocity of this flow is to be faster in the narrower parts through the ventricular systems such as the aqueduct, Monro's foramen and the 4th ventricles. We think that in T2 weighted images signal void phenomenon reflects "high velocity signal loss" due to CSF flow. When the subarachnoid adhesions secondary to subarachnoid hemorrhage stagnate CSF flow in the subarachnoid space, the intraventricular CSF flow forms the main buffer for changes of the brain volume. This causes an increase in the amplitude of the pulsatile flow in the ventricular systems. Therefore the signal void phenomenon in the aqueductal CSF becomes more pronounced. It may be possible to differentiate normal circulation of CSF from abnormal with the bigger amplitude of CSF pulsatile flow, to understand the mechanisms of the normal pressure hydrocephalus or to diagnose a shunt malfunction. Therefore more insight in the CSF flow as imaged by MRI is needed, quantification of CSF flow will be the subjects of our further research.     

脑脊液循环动力学的初步计算机建模分析

目的 应用磁共振相位对比法和计算流体力学软件对脑脊液循环系统进行数值模拟,分析脑脊液循环的动力学特性,并与临床实际相比较.方法 用磁共振相位对比法测定2例正常人的中脑导水管脑脊液流速,并利用临床磁共振扫描图像建市脑脊液循环系统的数值模型,用Matlab软件及Enguage软件提取脑脊液循环系统的轮廓并进行网格划分,然后应用COMSOL Muhiphysics软件进行脑脊液循环系统数值模拟及脑脊液动力学分析.结果 通过模拟软件能模拟脑脊液循环存在的与心动周期相关的有规律的双向流动,表现为心脏收缩期向足侧流动,舒张期向头侧流动,各时相期计算出的速度与我们用磁共振相位对比法测定的在体速度相一致.同时脑脊液循环系统的数值模型能够计算得到颅内压力梯度、脑和脊髓组织固体应力等.结论 脑脊液循环系统的计算机建模分析能无创性得到脑脊液循环的各项动力学量化指标,计算所得与临床实际相符合.本模型为进一步研究一些中枢系统疾病如交通性脑积水、Chiari畸形、脊髓空洞症等的脑脊液动力学机制奠定了基础.     

Evaluating the effect of hydrocephalus cause on the manner of changes in the effective parameters and clinical symptoms of the disease

In the present study, the heads of 11 normal subjects and 21 patients affected by hydrocephalus due to three different causes were simulated using fluid–structure interaction (FSI). To validate the results, the calculated diagram of CSF velocity in aqueduct of Sylvius (AS) was compared with the similar velocity diagram measured using Cine PC-MRI for the same subject. After ensuring the agreement of results, other outputs such as CSF pressure were calculated non-invasively using FSI. The intracranial pressure and CSF pressure in AS and behind the optic nerve sheath were in patients 5–5.3 times the value in normal subjects and the ventricular system volume in patients was 10.2–11.1 times the value in normal subjects. However, the difference between the coefficient of variation and the maximum value of pressure and volume in different types of hydrocephalus was small. Furthermore, the difference between CSF stroke volumes in various types of hydrocephalus patients was less than 4.4%. Results showed that the intensity of clinical symptoms was similar in patients with similar CSF pressure and the cause of the hydrocephalus disease didn’t have any significant effect on the intensity of patients’ clinical symptoms and the manner of changes in effective parameters on disease. It was also found that the relation of CSF pressure and volume was 16.7% greater in patients with non-communicating hydrocephalus than in patients with communicating hydrocephalus. These results enhance the insight into hydrocephalus bio-mechanism and can help to choose the proper treatment method for hydrocephalus patients.     

导水管狭窄导致正常压力脑积水的第三脑室底造瘘术

目的 探讨神经内镜下第三脑室底造瘘术治疗导水管狭窄所致正常压力脑积水(normal pressure hydrocephalus，NPH)的有效性。方法对23例年龄12～71岁的自发性脑积水患者通过术前核磁电影成像法检查及腰穿测压评估，在确诊为导水管狭窄所致的正常压力脑积水后采用神经内镜下第三脑室底造瘘术，术后进行腰穿测压评估及疗效随访。结果19例患者术后腰穿压力较术前下降大于30mmH2O；显效17例，有效1例，暂时性有效1例，无效4例。结论神经内镜下的第三脑室底造瘘术治疗导水管狭窄导致的正常压力脑积水是一种安全、有效的手术方法，术前正确评估脑积水状况是手术成功的关键；核磁电影成像对确定导水管狭窄导致的NPH具有明显诊断价值。     

Slight elevation of baseline intracranial pressure after fluid infusion into CSF space in patients with hydrocephalus

OBJECTIVE: To investigate the elevation of resting cerebrospinal fluid (CSF) pressure recorded after a CSF infusion test in patients with hydrocephalus. MATERIAL AND METHODS: Fifty patients (30 men and 20 women, mean age 68 +/- 13 years) with ventriculomegaly and clinical symptoms of normal pressure hydrocephalus have been studied. Lumbar (56%) or intraventricular (44%) computerized infusion studies were performed to investigate the hydrodynamics of CSF. After infusion, the fall in ICP was recorded until a steady-state level was achieved and the difference between pre- and post-infusion resting ICP was calculated (DeltaICP). RESULTS: A positive difference (>2 mm Hg) between post- and pre-infusion resting ICP was identified in 31 infusion tests (62%). The mean value of the difference was 6.7 with an SD of 3.5 mm Hg. The patients who demonstrated this phenomenon had a greater elastance coefficient (p>0.05); DeltaICP was positively correlated with age (R=0.27; p=0.03), with the size of the brain's ventricles (R=0.63, p=0.03) and inversely with the severity of clinical impairment (Stein-Langfitt score R=-0.61, p=0.02; normal pressure hydrocephalus score: R=0.54; p<0.05). DeltaICP was independent of the site of infusion (lumbar or ventricular). CONCLUSION: In patients with a 'stiffer' brain, ICP returns to the resting level after the infusion test at a slightly higher level than before the test. The magnitude of this increase is greater when ventricles are more dilated and clinical symptoms are less severe.     

Measurement of peak CSF flow velocity at cerebral aqueduct, before and after lumbar CSF drainage, by use of phase-contrast MRI: utility in the management of idiopathic normal pressure hydrocephalus

OBJECTIVE: Since it was first described, normal pressure hydrocephalus (NPH) and its treatment by means of cerebrospinal fluid (CSF) shunting have been the focus of much investigation. Whatever be the cause of NPH, it has been hypothesized that in this disease there occurs decreased arterial expansion and an increased brain expansion leading to increased transmantle pressure. We cannot measure the latter, but fortunately the effect of these changes (increased peak flow velocity through the aqueduct) can be quantified with cine phase-contrast magnetic resonance imaging (MRI). This investigation was thus undertaken to characterize and measure CSF peak flow velocity at the level of the aqueduct, before and after lumbar CSF drainage, by means of a phase-contrast cine MRI and determine its role in selecting cases for shunt surgery. PATIENTS AND METHODS: 37 patients with clinically suspected NPH were included in the study. Changes in the hyperdynamic peak CSF flow velocity with 50 ml lumbar CSF drainage (mimicking shunt) were evaluated in them for considering shunt surgery. RESULTS: 14 out of 15 patients who were recommended for shunt surgery, based on changes peak flow velocity after lumbar CSF drainage, improved after shunt surgery. None of the cases which were not recommended for shunt surgery, based on changes in CSF peak flow velocity after lumbar CSF drainage, improved after shunt surgery (2 out of 22 cases). CONCLUSION: The study concluded that the phase-contrast MR imaging, done before and after CSF drainage, is a sensitive method to support the clinical diagnosis of normal pressure hydrocephalus, selecting patients of NPH who are likely to benefit from shunt surgery, and to select patients of NPH who are not likely to benefit from shunt surgery.     

CSF pressure assessed by lumbar puncture agrees with intracranial pressure

The accuracy of estimating intracranial pressure in brain tissue (ICP(BT)) via lumbar space was investigated using preset pressure levels in the interval 0 to 600 mm H(2)O in patients with communicating hydrocephalus. Lumbar space ICP correlated excellently to ICP(BT), demonstrated by a measured mean difference of 10 mm H(2)O (0.75 mm Hg) and a regression coefficient of 0.98. The concurrence supports the lumbar puncture as an accurate technique to determine ICP in patients with communicating CSF systems.     

Efficacy of endoscopic third ventriculostomy in old aged patients with normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a chronic disorder caused by interrupted CSF absorption or flow. Generally, shunt placement is first option for NPH treatment. Due to complications of ventriculo-peritoneal (VP) shunt placement, endoscopic third ventriculostomy (ETV) can be considered as an alternative treatment option. Here we report the efficacy of ETV especially in old aged patients with normal pressure hydrocephalus.Total 21 old aged patients with communicating hydrocephalus with opening pressure, measured via lumbar puncture, less than 20 cm H₂O underwent ETV. 15 patients had primary/idiopathic NPH and 6 patients had secondary NPH. All patients were studied with a MRI to observe the flow void at aqueduct and the fourth ventricle outflow. And all of them underwent ETV. In a group with peak velocity was higher than 5 cm/s, nine patients (75%) were evaluated was ‘favorable’ and three of them (25%) was scored ‘poor’. In another group with peak velocity less than 5 cm/s, three of them were scored ‘poor’ and two of them were scored ‘stable’. None of them was evaluated as ‘favorable’. We also evaluated the outcomes according to etiology: 12 patients (80% of the patients with primary NPH) were evaluated with ‘favorable’ after ETV treatment. Two patients (13.3%) were as ‘stable’. And one patient was as ‘poor’ evaluated. Five patients (83.3%) among patients with secondary NPH were as ‘poor’ evaluated and one of them was stable and no patient was as ‘favorable’ evaluated. 4 patients, which was as ‘poor’ evaluated in the group with the secondary NPH, underwent additional VP shunt implantation. Overall, the outcomes of the group with the idiopathic NPH after ETV treatment were more favorable than of the group with the secondary NPH.Our study suggest that ETV can be effective for selected elderly patients with primary/idiopathic NPH, when they satisfy criteria including positive aqueduct flow void on T2 Sagittal MRI and the aqueductal peak velocity, which is greater than 5 cm/s on cine MRI.     

PC-MRI在Ⅰ型Chiari畸形枕大池成形术后疗效评估中的应用

目的探讨磁共振相位对比电影成像(PC-MRI)技术在Ⅰ型Chiari畸形枕大池成形术后疗效评估中的应用价值。方法2018年6月至2020年12月前瞻性收集Ⅰ型Chiari畸形21例,均行枕大池成形术治疗,术前及术后6个月行PC-MRI检查,分析中脑导水管及脑桥腹侧脑脊液平均流量(MF)、头向峰值流速(Vumax)及足向峰值流速(Vdmax)。术后6个月,根据症状缓解与否,分为症状缓解组和无缓解组。结果术后6个月,15例术后症状消失或缓解(缓解组),6例症状无明显改善(无缓解组)。缓解组中脑导水管、脑桥腹侧Vdmax和Vumax较术前均明显降低(P<0.05),而MF则明显增加(P<0.05)。无缓解组手术前后中脑水管及脑桥腹侧脑脊液MF、Vdmax和Vumax均明显变化(P>0.05)。结论 PC-MRI可定量分析脑脊液流动情况,对Ⅰ型Chiari畸形术后疗效评估具有一定价值。     

梗阻性脑积水经第三脑室底造瘘术后颅内压变化规律

目的回顾性总结经内镜第三脑室底造瘘术(ETV)治疗梗阻性脑积水的手术技巧、疗效及术后颅内压(ICP)的变化规律及动态ICP监护的价值。方法经内镜行ETV治疗梗阻性脑积水共146例,病因包括导水管狭窄98例、颅内肿瘤48例(第三脑室及松果体区肿瘤)。术后行动态ICP监护53例(导水管狭窄36例、肿瘤17例),平均监护时长96 h。结果随访8个月至6年,术后脑积水明显缓解或消失138例(94.5%),8例脑积水缓解不明显或无效(5.5%),改行脑室腹腔分流术。ICP监护显示:术后6 h内平均ICP明显下降,低于10 mm Hg,此后缓慢轻度上升,96 h稳定于12 mm Hg;单纯导水管狭窄性脑积水平均ICP上升较缓慢、波动较小,最后达到10 mm Hg;而肿瘤性脑积水上升较快、波动较大,最后达到15 mm Hg。并发症28例(19.2%):术后发热22例,双额部硬膜外血肿1例、切口脑脊液漏2例、脑室少量积血2例、硬膜下积液1例。本组无死亡。结论 1第三脑室底造瘘治疗梗阻性脑积水(尤其是导水管狭窄脑积水)安全、有效,应作为其首选治疗手段;2术后行ICP动态监护,不仅可监测颅内压的变化,判断手术是否有效,同时可以观察有无脑室继发性出血等并发症及指导术后用药。     

天幕区硬脑膜动静脉瘘压迫导水管导致阻塞性脑积水

目的报道1例以阻塞性脑积水为首发表现的硬脑膜动静脉瘘(DAVF)。方法一男性52岁病人因行走不稳、尿失禁入院,CT和MR发现阻塞性脑积水,天幕附近存在异常血管影。脑血管造影诊断为天幕区DAVF,脑积水由扩张的引流静脉压迫中脑导水管所致。病人接受了血管内栓塞和脑室-腹腔分流手术。结果大部分闭塞了DAVF,脑积水症状消失。结论DAVF扩张的引流静脉压迫中脑导水管导致阻塞性脑积水极其罕见,这是文献中第2例有详细报道的此类病例;采用血管内方法闭塞病灶并行脑室-腹腔分流手术是合适的治疗方法。     

CSF dynamics following shunt operation, with special reference to the diurnal changes of CSF circulation

The purpose of this study is to study the pathophysiology of the cerebrospinal fluid (CSF) formation and circulation after a ventriculoperitoneal shunt operation. With the CSF flowmeter we developed, the CSF flow rate in the shunt tube has been measured non-traumatically over a 24-hour period in six patients. These include both communicating and noncommunicating hydrocephalus patients with ages ranging from 20 to 70. There were three cases of ruptured intracranial aneurysm, one cerebral contusion, one hypertensive brain stem hemorrhage and one occlusion of the aqueduct sylvius. Intraventricular pressure was continuously recorded for 24 hours prior to the shunt operation in each case, and the pressure changes were compared with the measured CSF flow rates in the shunt tube. The flow rate fluctuated between 0.05 ml/min and 1.2 ml/min with the supine position and high flow rates were detected in the early morning. Each case showed its own rhythm of CSF flow fluctuation during a 24-hour period, and the changes were compatible with the intraventricular pressure. It is suggested that there may be a relationship between these changes and an increased cerebral blood volume during the REM sleep stage.