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.     

神经内镜下导水管成形术治疗导水管梗阻性脑积水

目的 探讨软性神经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 2007年2月至2008年4月,应用电子软性神经内镜对16例导水管梗阻性脑积水在软性内镜下分别经额或枕下入路行导水管成形术.结果 16例患者导水管均成功再通,术后高颅压症状缓解,无意识障碍、动眼神经麻痹等导水管成形术相关并发症出现.12例术后6个月磁共振电影成像检查显示中脑导水管脑脊液最大流速较术前增加(2.18±0.34)cm/s,最大流量较术前增加(0.22±0.07)ml/s.结论 软性内镜下导水管成形术对治疗导水管狭窄或膜性梗阻导致的脑积水是一种安全有效的方法 ,但应严格掌握手术适应证.     

可调压分流管治疗颅内静脉异常回流所致高颅压性脑积水

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.

Abstract：

Objective To evaluate the application of phase-contrast cine magnetic resonance imaging (MRI) in endoscopic aqueductoplasty for patients with obstructive hydrocephalus. Methods The clinical diagnosis of hydrocephalus due to aqueduct obstruction in 23 patients was confirmed by phasecontrast cine MRI examination. The patients were treated with endoscopic aqueductoplasty. MRI was repeated during follow- up period. The cerebrospinal fluid (CSF) flow velocity in aqueduct was measured to determine whether the aqueduct was obstructed. Results The Results of phase -contrast cine MRI examinations indicated that there was no CSF flow in aqueduct in any patient. Aqueductoplasty was successfully performed in all patients. After one week, the Results of phase - contrast cine MRI examinations showed an average CSF flow velocity of (4.74 ± 1.77) cm/s. During follow - up period, intracranial hypertension recurred in two patients in whom CSF flow was not seen inside the aqueduct by phase - contrast cine MRI scan and the aqueduct re - occlusion was revealed by endoscopic exploration. Conclusions By measuring CSF flow velocity, phase - contrast cine MRI could accurately identify whether the aqueduct is obstructed. It should play an important role in the diagnosis of obstructive hydrocephalus and evaluation of theeffectiveness of aqueductoplasty, and it could be used for follow - up evaluation as well.     

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。     

磁共振电影成像与第三脑室底造瘘术后评估

目的 探讨相位对比磁共振电影成像法在对非交通性脑积水患者行第三脑室底造瘘术后瘘口开通状况的评估价值.方法 利用相位对比磁共振电影成像法对128例非交通性脑积水患者行神经内镜下第三脑室底造瘘术后进行瘘口的流速测定,并作为随访方法 .对部分术后临床症状缓解不佳、或在随访期内再次出现高颅压症状的患者进行二次内镜下探查,结合术中探查及二次手术前磁共振电影成像检查结果 来分析电影成像检查对判断造瘘口是否开通的准确性.结果 3例术后临床症状缓解不佳,电影成像检查显示脑脊液流过瘘口良好,二次手术探查中亦证实造瘘口处于开通状况;16例患者术后再次出现高颅压的患者,磁共振电影成像检查显示造瘘口脑脊液流速明显减小,二次内镜下手术探查显示造瘘口闭塞或明显狭窄,重新造瘘后临床症状改善.电影成像检查结果 和手术探查显示的结果 符合率为100%.结论 磁共振电影成像可以精确反映第三脑室底造瘘术后造瘘口开通情况,可以作为评估造瘘后造瘘口开通状况的金标准及重要的随访手段.     

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；大脑半球占生病变组为低动力学，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。     

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。     

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。     

置管扩张中脑导水管治疗梗阻性脑积水

脑积水是神经外科常见病，根据积水的原因不同，其治疗方法亦不相同。梗阻性脑积水的手术方法虽多，但都是通过分流来解决梗阻问题，并未恢复脑脊液的正常循环途径。中脑导水管扩张置管引流治疗梗阻性脑积水的方法，符合脑脊液循环的生理性需要，且疗效良好，现报道3例于下。     

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.     

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.     

Endoscopic aqueductoplasty in the treatment of aqueductal stenosis

OBJECTIVE: Endoscopic aqueductoplasty is an option in the treatment of obstructive hydrocephalus caused by aqueductal stenoses. We report on our experience with this endoscopic technique, focussing on indications, operative technique, and results. METHODS: A series of 39 endoscopic aqueductoplasties was performed in 33 patients harbouring a hydrocephalus caused by aqueductal stenosis. In 13 patients, a third ventriculostomy was simultaneously performed. There was no endoscopy-related mortality. One aqueductoplasty had to be abandoned. In 7 patients, reclosure of the restored aqueduct required an endoscopic revision. In 25 patients (76%), the hydrocephalus-related symptoms resolved or improved. The condition was unchanged in 8 patients. Four patients needed to be shunted. The ventricles decreased in size in 22 patients (67%), were larger in 2, and unchanged in the remaining 9 patients. CONCLUSION: Endoscopic aqueductoplasty is a treatment option in patients with hydrocephalus caused by membranous aqueductal stenosis. Unfortunately, the reclosure rate is higher than initially expected. More experience and longer follow-up are necessary to determine the value of endoscopic aqueductoplasty in the treatment of hydrocephalus caused by aqueductal stenosis.     

Samoistna wentrykulostomia komory trzeciej w przebiegu wodogłowia o złożonej etiologii: opis przypadku

Third ventriculostomy (TV) is the most common neuroendoscopic procedure for restoration of near physiological circulation of cerebrospinal fluid in obstructive hydrocephalus. Among 70 adults operated on using this technique, the authors encountered one case of spontaneous TV. Only a few case reports of spontaneous ventriculostomy revealed by ventriculography, flow-sensitive phase-contrast cine magnetic resonance imaging (MRI) or at autopsy have been published.A 43-year-old woman with symptoms of hydrocephalus and signs of chronic obstructive hydrocephalus secondary to aqueductal stenosis on MRI was qualified for TV. Enlarged infundibulo-mammillary triangle with perforation was noted intraoperatively. During the postoperative course, the condition of the patient partially improved although radiological appearance remained unchanged. Three weeks later symptoms of hydrocephalus recurred and the patient underwent an infusion test which revealed increased cerebrospinal fluid outflow resistance. Implantation of a ventriculo-peritoneal shunt yielded stable improvement. Spontaneous TV should be taken into consideration during selection of patients for TV, especially in cases with chronic obstructive hydrocephalus.     

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.     

Endoscopic aqueductoplasty in the treatment of aqueductal stenosis

Objective Endoscopic aqueductoplasty is an option of treatment of obstructive hydrocephalus caused by aqueductal stenosis. We report on our experience with this endoscopic technique. Materials and methods Eighteen patients with primary or secondary aqueductal stenosis underwent endoscopic aqueductoplasty (EA) with or without stenting between July 2004 and January 2007. EA, EA with a stent, EA with endoscopic third ventriculostomy (ETV), and EA with stenting in addition to ETV were performed in eight, five, three, and two patients, respectively. A repeat endoscopic procedure was done in one patient. EA with a stent was performed in case 1, 8 months after first endoscopic procedure. In four cases, aqueductoplasty with stent was performed through a suboccipital approach. Results There were no deaths due to the neuroendoscopic procedures. All of the patients showed improvement or resolution of their preoperative symptoms, although in case 1 a new endoscopic procedure was performed: EA with a stent. Conclusion Cerebral aqueductoplasty is an effective and successful treatment for membranous and/or short-segment stenosis of the sylvian aqueduct. Endoscopic aqueductoplasty candidates must be selected very carefully but longer follow-up periods are necessary to evaluate long-term aqueductal patency after aqueductoplasty.     

Phase-contrast cine MRI revealing en valve mechanism in spontaneous third ventriculostomy: Report of a case and literature review

A 50-year-old epileptic woman affected by hydrocephalus due to aqueductal stenosis was admitted to the hospital because of headache, dysarthria, and mild lateral pulsion. Cranial computed tomography (CT) revealed left cerebellar hemorrhage. Subsequent magnetic resonance imaging (MRI) of the brain demonstrated an enlarged ventricular system unchanged from prior studies. Flow-sensitive phase-contrast (PC) cine magnetic resonance imaging showed flow absence through the aqueduct and flow pulsations through the third ventricle floor in systole and diastole, consistent with spontaneous third ventricle patency. On stationary tissue images, the third ventricle floor and the mamillary body were displaced downward at systole and upward at diastole. Stenosis of the cerebral aqueduct of Sylvius was also shown. Retrospective evaluation of the sagittal T2-weighted images disclosed flow void at the level of the third ventricle floor. On–off movements of the third ventricle floor could account for chronic hydrocephalus persistence by an en valve mechanism. Spontaneous third ventriculostomy (STV) was diagnosed on the basis of these findings.     

Tectal plate gliomas: a review

Introduction

Tectal plate gliomas are generally benign neoplastic lesions arising in the brainstem which can, with local extension, obstruct the aqueduct of Sylvius and lead to hydrocephalus.

Anatomy

Diagnosis is based on initial suspicion fostered by the presentation of an obstructive hydrocephalus followed by physical exam which may potentially reveal indications of pyramidal tract dysfunction or cranial nerve palsies.

Discussion

MRI studies reveal a characteristic well-circumscribed, isodense or hypodense mass on T1-weighted images, with hyperdensity on T2 imaging. Yet current radiological methods insufficiently distinguish tectal plate gliomas from brainstem tumors or gliomas in the neighboring structures, and a definitive diagnosis requires biopsy and histopathological analysis. Management is planned according to the degree of associated signs and symptoms, and may range from diligent observation and periodic screening for advancing tumor development, to cerebrospinal fluid shunting in an effort to resolve obstructive hydrocephalus, to radio- and chemotherapy. A wide range of minimally invasive approaches using endoscopy is available for the neurosurgeon, including endoscopic third ventriculostomy and endoscopic aqueductoplasty.