Brain ventricular wall movement assessed by a gated cine MR trueFISP sequence in patients treated with endoscopic third ventriculostomy

The purpose of this study was to investigate the value of brain ventricular wall movement assessment with a gated cine trueFISP MR sequence for the diagnosis of endoscopic third ventriculostomy (ETV) patency. Sixteen healthy volunteers and ten consecutive patients with noncommunicating hydrocephalus were explored with a MR scanner (Siemens, Avanto 1.5 T) before, 1 week and 3 months after ETV. TrueFISP was evaluated qualitatively (ventricular wall movement and CSF flow through ETV) and quantitatively [distance moved (DMLT) during a cardiac cycle by the lamina terminalis]. The third ventricle volume (TVV) was assessed. Statistical analysis was performed using nonparametric tests. There was no motion of the lamina terminalis (LT) detected on preoperative data. A pulsatile motion of the LT was found for patients with a patent ETV and for controls. DMLT and TVV were correlated (r = 0.79, P = 0.006). A transient dysfunction of ETV was successfully diagnosed on the trueFISP sequence with no motion of the LT or CSF flow observed. The trueFISP sequence appears reliable for the diagnosis of ETV patency and provides non-invasive assessment of the movement of the ventricular wall related to CSF pressure changes.     

Third ventriculostomy patency: comparison of findings at cine phase-contrast MR imaging and at direct exploration.

BACKGROUND AND PURPOSE: Two-dimensional phase-contrast (PC) MR imaging is a known method for evaluating CSF flow after third ventriculostomy. In this study, we attempted to confirm the accuracy of cine PC MR imaging for determining the patency of a third ventriculostomy as compared with direct reexploration of the floor of the third ventricle. METHODS: We examined 11 patients with third ventriculostomies who had a total of 13 reoperations for symptomatic obstructive hydrocephalus. In 12 of the 13 reexplorations, cine PC MR studies were obtained before repeat surgery, and the diagnoses suggested by imaging were compared with intraoperative findings. RESULTS: Four of five patients who had no flow on MR images had new membranes that covered the orifice; the fifth patient still had a small perforation visible at the time of operation. Three of four patients who had subtle flow on MR images were found to have occlusion with new membranes; the fourth had an incomplete new membrane. Finally, two of three who had a patent ventriculostomy had completely open perforations without membrane formation; the third patient had nonobstructive early membrane formation. At 3 months' follow-up, two flow studies were read as subtle without any clinical symptoms; however, these eventually progressed to become symptomatic, and occlusion with new membrane formation was confirmed during surgical reexploration. CONCLUSION: Cine PC MR imaging is a reliable technique for detecting the patency of a third ventriculostomy, but minor flow, as defined in this report, appears to be an early sign of closure.     

Evaluation of the patency of endoscopic third ventriculostomy using phase contrast MRI-CSF flowmetry as diagnostic approach

Purpose

The aim is to assess the usefulness of cine phase-contrast MRI for evaluation of patency of endoscopic third ventriculostomy operation and correlation with clinical state postoperatively.

Frequency analyses of CSF flow on cine MRI in normal pressure hydrocephalus

Our objective was to clarify intracranial cerebrospinal fluid (CSF) flow dynamics in normal-pressure hydrocephalus (NPH). Frequency analyses of CSF flow measured with phase-contrast cine MRI were performed. The CSF flow spectra in the aqueduct were determined in patients (n=51) with NPH, brain atrophy or asymptomatic ventricular dilation (VD), and in healthy volunteers (control group; n=25). The changes in CSF flow spectra were also analyzed after intravenous injection of acetazolamide. Moreover, a phase transfer function (PTF) calculated from the spectra of the driving vascular pulsation and CSF flow in the aqueduct were assessed. These values were compared with the pressure volume response (PVR). The amplitude in the NPH group was significantly larger than that in the VD or control group because of a decrease in compliance. The phase in the NPH group was significantly different from that in either the VD or the control group, but no difference was found between the VD and control groups. The amplitude increased in all groups after acetazolamide injection. The PTF in the NPH group was significantly larger than in the control group, and a positive correlation was noted between PTF and PVR. Frequency analyses of CSF flow measured by cine MRI make it possible to noninvasively obtain a more detailed picture of the pathophysiology of NPH. Electronic Publication     

颅内疾病对导水管脑脊液流量的影响

目的：探讨用磁共振相位对比电影(PC cine)对导水管脑脊液定量测量的临床应用价值。方法：将35例中枢神经系统不同疾病分三组，用PC cine方法进行导水管脑脊液流量测量。结果：在脑血管病组伴白质改变时导水管流量增加；梗阻性脑积水导水管流量减少，流动波形异常；交通性脑积水导水管流量增加，波形圆钝。结论：磁共振PC cine方法测量导水管脑脊液流量简单易行，可为临床提供更多的影像信息。     

Spontaneous ventriculostomy: report of three cases revealed by flow-sensitive phase-contrast cine MR imaging.

Spontaneous ventriculostomy is a rare condition that occurs with the spontaneous rupture of a ventricle, resulting in a communication between the ventricular system and the subarachnoid space. Three cases of spontaneous ventriculostomy through the floor of the third ventricle that occurred in cases of chronic obstructive hydrocephalus are presented. The communication was identified via flow-sensitive phase-contrast cine MR imaging. Spontaneous ventriculostomy is probably a result of a rupture of the normally thin membrane that forms the floor of the third ventricle and, with long-standing obstructive hydrocephalus, creates an internal drainage pathway that spontaneously compensates for the hydrocephalus.     

MR imaging of Liliequist's membrane

Liliequist's membrane is an arachnoid structure well-known to neurosurgeons. However, the importance of this membrane had been lost until the development of endoscopic third ventriculostomy (ETV). ETV is superior in its minimal invasiveness, but in some subgroups of hydrocephalus, the effectiveness of ETV may be reduced. Liliequist's membrane may block the cerebrospinal fluid (CSF) flow from the defect of the third ventricle floor, which may cause failure of ETV. Liliequist's membrane can be visualized on magnetic resonance (MR) imaging in normal healthy individuals, however, its visibility is different among individuals. CSF artifacts exist to varying degrees, but do not impede visualization of Liliequist's membrane in most subjects. Since Liliequist's membrane is a cisternal structure, the three-dimensional (3D) constructive interference in steady state (CISS) sequence is useful. The outcome of ETV could be predicted with MR imaging findings of Liliequist's membrane in a patient with obstructive hydrocephalus. High-field (≥3 Tesla) MR imaging of Liliequist's membrane also offers superior resolution and is expected to provide additional information about Liliequist's membrane.     

Changes in aqueductal CSF stroke volume and progression of symptoms in patients with unshunted idiopathic normal pressure hydrocephalus

BACKGROUND AND PURPOSE: Idiopathic normal pressure hydrocephalus (iNPH) represents a diagnostic challenge, given its variable presentation and progression. Stroke volume (SV), defined as the mean volume of CSF passing through the aqueduct during both systole and diastole, greater than or equal to 42 μL, serves as a selection criterion for patients with good probabilities of improvement after ventriculoperitoneal shunt surgery (VPS). In this study, we evaluated the changes in SV during the progression of clinical symptoms in patients with suspected NPH.MATERIALS AND METHODS: Nine patients who presented with clinical and radiologic evidence of NPH, but refused treatment with VPS, were evaluated every 6 months for up to 2 years for progression in their clinical symptoms and changes in their SV, as measured by phase-contrast cine MR imaging (PCCMR).RESULTS: SV seems to increase between the onset of the symptoms and the following 18 to 20 months, then seems to plateau, followed in the next 18 to 20 months by a slight decline, and finally to a more precipitous drop in the next 12 months. During this time, however, the patient''s clinical symptoms progressively worsen.CONCLUSION: Patients with a low SV have not necessarily had brain atrophy and can show, in the following months, a progressive increase in SV, which qualifies them as good candidates for VPS. The progressive reduction of the SV in untreated patients with worsening clinical symptoms may be a sign of a progressive cerebral ischemic injury, which renders the NPH irreversible.

The syndrome of progressive mental deterioration and neurologic disturbances including psychomotor retardation, gait unsteadiness, and incontinence of urine associated with hydrocephalus, in the setting of normal CSF pressure on lumbar puncture and the absence of papilledema, was coined normal pressure hydrocephalus (NPH) in 1965.¹ To this day, the exact cause of the idiopathic form of NPH (iNPH) remains unclear. However, it is generally agreed on that on the basis of NPH, there is an abnormal absorption of CSF with a consequent accumulation of CSF in the ventricular space. For at least the last 20 years, the mainstay of therapy for NPH has been diversion of CSF via a ventriculoperitoneal shunt (VPS).^2,3 iNPH typically manifests in elderly people, and its correct diagnosis is complicated by the variability of its clinical presentation and progression. iNPH can resemble, or occur in combination with, various disorders such as cerebrovascular disease, neurodegenerative disorders (eg, Alzheimer disease, Parkinson disease, Lewy body disease), primary urologic disorders, and spinal stenosis. Not all patients initially diagnosed with NPH improve after VPS, which may be because of misdiagnosis⁴ or because the disease has progressed to a stage of irreversible neurodegeneration. In clinical practice, a careful selection of patients for surgery is the main challenge of this syndrome.MR imaging has been proposed to quantify the flow of CSF in the aqueduct.^5,6 By phase-contrast cine MR imaging (PCCMR), the stroke volume (SV), defined as the mean volume passing through the aqueduct during both systole and diastole, can be calculated. A SV greater than or equal to 42 μL serves as a selection criterion for patients with good probabilities of improvement after VPS.⁷ The goal of this work is to analyze the changes in SV and the progression of symptoms in patients diagnosed with iNPH who refused treatment with VPS.     

磁共振相位对比电影对蛛网膜囊肿与蛛网膜下腔扩大的鉴别诊断

目的：应用磁共振相位对比法,揭示脑与脑脊液运动的相互关系,以评价此方法对鉴别蛛网膜囊肿与蛛网膜下腔扩大的诊断价值。材料与方法：运用磁共振相位对比电影和流动分析软件,对１０例健康人脑与脑脊液运动规律相关性进行研究和１０例影像学疑蛛网膜囊肿或蛛网膜下腔扩大患者的脑脊液运动进行最化分析,绘出一个心动周期不同时相脑脊液流量贡线和时间、信号强度曲线,并进行分析比较。结果：脑脊液流动是由脑运动驱动引起,而脑运     

PC-MRI技术在非梗阻性脑积水诊断中的应用

目的探讨相位对比MRI(PC-MRI)技术在诊断非梗阻性脑积水和脑小血管病中的应用价值。方法采用Phillips 3.0 T PC-MRI设备,测量11例交通性脑积水、6例正常压力性脑积水、9例脑小血管病病人及13例健康志愿者的中脑导水管脑脊液(CSF)动力学指标(峰值流速、搏出量),并分别对4组的各项指标采用SNK-q检验进行组间两两比较。结果 1正常对照组、非梗阻性脑积水组和脑小血管病组的中脑导水管水平CSF运动呈双向、"U"型曲线,非梗阻性脑积水组的峰值流速较高,且收缩期峰值流速高于舒张期。2交通性脑积水组与正常压力性脑积水组,以及正常压力性脑积水组与脑小血管病组间CSF收缩期峰值流速的差异具有统计学意义(P<0.05),而且此3组收缩期峰值流速均高于对照组。非梗阻性脑积水组舒张期峰值流速高于正常对照组和脑小血管病组。4组间搏出量两两比较其差异均有统计学意义(均P<0.05),且非梗阻性脑积水组搏出量呈反向,脑小血管病组搏出量较对照组明显减低。结论 PC-MRI可用来诊断非梗阻性脑积水,并对鉴别非梗阻性脑积水和脑小血管病有重要价值。     

MR ventriculography for the study of CSF flow

BACKGROUND AND PURPOSE: Various MR techniques have been used to assess CSF flow and to image the subarachnoid spaces and ventricles. Anecdotal reports describe the use of intrathecal and intraventricular gadolinium-based contrast agents in humans and animals. We sought to determine the clinical usefulness of gadolinium-enhanced MR ventriculography for assessing CSF flow in patients with various neurologic conditions. METHODS: Five patients (three female and two male patients aged 6 months to 65 years) were included in the study. After performing sagittal, coronal, and axial T1-weighted MR imaging of the brain, 0.02-0.04 mmol of gadodiamide was injected into the lateral ventricle. Sagittal, coronal, and axial T1-weighted imaging was repeated soon after the injection. We were specifically looking for the site of obstruction to CSF flow in those patients with hydrocephalus, communication between cysts and ventricles, elucidation of suspicious intraventricular lesions, and patency of third ventriculostomies. RESULTS: MR ventriculography showed good delineation of the ventricular system in all patients. In one patient with carcinomatosis and hydrocephalus, a block to contrast material flow was detected at the right foramen of Luschka. In another patient with hydrocephalus, partial block to the flow of contrast material was demonstrated at the right foramen of Monro. In a patient with hydrocephalus and a posterior fossa cyst, flow of contrast material was blocked between the third ventricle and the cyst, with a thin streak of contrast material in the aqueduct. As an assessment of the patency of a third ventriculostomy, MR ventriculography showed flow of contrast material into the suprasellar cisterns from the third ventricle in one patient and absence of flow in another. CONCLUSION: MR ventriculography is a safe technique for assessing CSF flow, with application in determining the site of obstruction in hydrocephalus, in assessing communication between cysts and the ventricle, and in determining the functioning status of endoscopic third ventriculostomies.     

Cerebrospinal fluid pulsation amplitude and its quantitative relationship to cerebral blood flow pulsations: a phase-contrast MR flow imaging study

Our purpose in this investigation was to explain the heterogeneity in the cerebrospinal fluid (CSF) flow pulsation amplitudes. To this end, we determined the contributions of the cerebral arterial and jugular venous flow pulsations to the amplitude of the CSF pulsation. We examined 21 healthy subjects by cine phase-contrast MRI at the C2–3 disc level to demonstrate the CSF and vascular flows as waveforms. Multiple regression analysis was performed to calculate the contributions of (a) the arterial and venous waveform amplitudes and (b) the delay between the maximum systolic slopes of the arterial and venous waveforms (AV delay), in order to predict the amplitude of the CSF waveform. The contribution of the arterial waveform amplitude was positive (r = 0.61; p = 0.003) to the CSF waveform amplitude and that of the venous waveform amplitude was negative (r = −0.50; p = 0.006). Both in combination accounted for 56 % of the variance in predicting the CSF waveform amplitude (p < 0.0006). The contribution of AV delay was not significant. The results show that the variance in the CSF flow pulsation amplitudes can be explained by concurrent evaluation of the CSF and vascular flows. Improvement in the techniques, and controlled experiments, may allow use of CSF flow pulsation amplitudes for clinical applications in the non-invasive assessment of intracranial dynamics by MRI. Received: 3 January 1996 Accepted: 5 June 1996     

Cerebrospinal fluid flow in patients with dilated ventricles studied with MR imaging

The purpose of this study was to measure the cerebrospinal fluid (CSF) velocity and flow in the aqueduct in patients with wide ventricles with or without signs of normal pressure hydrocephalus (NPH) before and after shunt surgery. We studied 18 patients with wide ventricles with MRI and measured the CSF velocity values in the aqueducts. Twelve patients with the clinical triad of NPH were examined. Six patients were studied only before shunt surgery and 6 patients were studied both before and after shunt surgery. Three patients with wide ventricles without clinical triad of NPH, and 3 patients with hydrocephalus following subarachnoid hemorrhage were also examined. Seven NPH patients with hyperdynamic CSF flow and three NPH patients with normal CSF velocity and flow values showed a positive clinical response to shunt surgery. Two of the three patients with hydrocephalus and hyperdynamic CSF flow values in the aqueduct secondary to subarachnoid bleeding responded to shunt surgery. One patient with same disease and low CSF velocity and flow values did not respond. No change was detected in the CSF flow values of the aqueduct when measurements before and after shunt surgery were compared. Ventriculoperitoneal shunting does not change the CSF dynamics in the aqueduct. Received: 8 March 1999; Revised: 30 November 1999; Accepted: 23 February 2000     

Spontaneous intracranial hypotension: morphological findings and CSF flow dynamics studied by MRI

We report on a case of spontaneous intracranial hypotension (SIH) presenting with classic MR findings, such as diffuse smooth thickening and intense contrast enhancement of the dura matter, increased size of the pituitary gland and downward displacement of the brain. In this case an engorgement of the cavernous sinuses is reported as an additional imaging finding of SIH. Moreover, phase-contrast MR study of the CSF flow dynamics revealed at the level of the aqueduct a decrease of the systolic and diastolic flow volume of CSF. A normalization of the flow volume was observed when SIH subsided.     

CSF flow imaging in the management of third ventriculostomy with a reversed fast imaging with steady-state precession sequence

The aim of this study was evaluation of a fast and slow-flow sensitive 2D steady-state free-precession sequence for its capability to prove the patency of endoscopic third ventriculostomy (TVS) in obstructive hydrocephalus, and to exclude communicating third ventricle prior to TVS. We compared gated and ungated variants of this sequence for this purpose. Twenty-three patients with obstructive hydrocephalus underwent 36 MR examinations with a 2D reversed fast imaging with steady-state precession (PSIF) sequence in a retrospectively cardiac gated (cine) and a faster but ungated version beside T1- and T2-weighted sequences in three planes. Thirteen patients were examined both before and after TVS, 4 patients solely before, and 6 patients solely after TVS. Imaging diagnoses were compared with intraoperative findings and clinical findings after TVS. Preoperative diagnosis of non-communicating third ventricle and cisterns was intraoperatively confirmed in 16 of 17 cases. Preoperative MRI was inconclusive in 1 case. Postoperative MRI revealed sufficient TVS in 16 of 19 cases and obstructed TVS in 3 of 19 cases due to several reasons. Findings at MRI were consistent in 19 of 19 cases with the clinical course and intraoperative results. The faster but ungated PSIF sequence was found to be diagnostically equivalent to the cardiac gated cine sequence. The CSF flow imaging with a 2D reversed fast imaging with steady-state precession sequence in conjunction with conventional T1- and T2-weighted images is a fast and reliable tool for pre- and postoperative functional evaluation in third ventriculostomy. Electronic Publication     

Stereotactic third ventriculostomy: assessment of patency with MR imaging

Ventricular CSF signal-intensity characteristics indicative of flowing CSF on MR images (CSF flow void) were analyzed in 20 patients who underwent a CT-based stereotactic third ventriculostomy for presumed internal obstructive hydrocephalus between October 1985 and June 1988. The status of all ventriculostomies was assessed postoperatively by radionuclide ventriculography. Postoperative MR and ventriculographic findings were correlated with the patients' subsequent clinical course. A CSF flow void in the anterior and inferior third ventricle, which seems to indicate vigorous pulsatile CSF flow through a functioning ventriculostomy, was present in all 19 patients who were clinically improved after ventriculostomy. In all 19 of these patients the radionuclide ventriculogram demonstrated normal CSF dynamics. One of the 20 patients did not improve postoperatively. The ventriculogram in this patient revealed delayed ventricular clearing and impaired CSF resorption, and the postoperative MR image did not demonstrate an anterior/inferior third ventricular CSF flow void. Eight of these patients were evaluated preoperatively by MR; one of these eight was the single nonimproved individual. None of the eight preoperative MR studies demonstrated a CSF flow void in the anterior/inferior third ventricle; however, this finding was present in seven of seven postoperative MR studies in clinically improved patients. We conclude that the presence of a CSF flow void in the anterior/inferior third ventricle on a postoperative MR examination is sufficient to document patency of a third ventriculostomy. The absence of this finding may be due to a nonpatent ventriculostomy or perhaps an extraventricular CSF obstruction. The more invasive ventriculogram may be reserved for this situation to distinguish between these latter two possibilities.     

Intracranial CSF flow in pediatric hydrocephalus: evaluation with cine-MR imaging.

PURPOSE: 1) To describe the pattern of normal intracranial CSF flow in children and 2) to demonstrate altered CSF flow patterns in pediatric hydrocephalus and ventriculomegaly with flow-sensitized cine-MR examinations. METHOD: Cardiac gated, multiframe, gradient echo sequences on a 1.5-T system were displayed on a closed loop cine format and compared to standard MR images. Areas of normal flow and areas of diminished flow were determined. RESULTS: 1) In normal children, the CSF flow follows a consistent pattern with a to-and-fro movement of flow in the aqueduct, foramen of Magendie, and in the dorsal and ventral subarachnoid space at the cervicomedullary junction. 2) In patients with ventricular enlargement, the flow studies showed regional abnormalities of the CSF flow patterns: specifically, lack of flow and hyperdynamic flow. CONCLUSION: Cine-MR for CSF flow evaluation is a useful adjunct to routine MR in the evaluation of pediatric hydrocephalus because it can assist in determining the probable level of CSF obstruction.     

SPAMM, cine phase contrast imaging and fast spin-echo T2-weighted imaging in the study of intracranial cerebrospinal fluid (CSF) flow

AIM: To compare the qualitative assessment of cerebrospinal fluid (CSF) flow using a SPAMM (spatial modulation of magnetization) technique with cine phase contrast images (cine PC) and fast spin echo (FSE) T2-weighted images. MATERIALS AND METHODS: SPAMM, PC and T2-weighted sequences were performed on 22 occasions in 19 patients. Eleven of the studies were performed following a neuroendoscopic third ventriculostomy (NTV), and in these cases, the success of the NTV was determined by clinical follow-up. Two observers used consensus to grade the presence of CSF flow at nine different sites for each study. RESULTS: At 14 of the 178 matched sites, which could be assessed by both SPAMM and cine PC, SPAMM CSF flow grade was higher than that of cine PC. At a further 14/178 matched sites, the cine PC grade was higher than that of SPAMM. There was definite CSF flow at 113/182 (62%) of all the cine PC sites assessed, and 110/181 (61%) of all SPAMM sites assessed whilst 108/198 (54%) of FSE T2-weighted image sites demonstrated flow voids. Cine PC grades were higher than SPAMM at the cerebral aqueduct (P < 0.05, Wilcoxon sign rank test). Definite CSF flow within the anterior third ventricle was present in 4/5 (SPAMM) and 3/5 (cine PC) successful NTVs, 0/2 (SPAMM and cine PC) unsuccessful NTVs and 1/10 (SPAMM and cine PC) patients without NTV. CONCLUSION: SPAMM provides a comparable assessment of intracranial CSF flow to that of cine phase contrast imaging at all CSF sites except the cerebral aqueduct.     

Cerebrospinal fluid flow in children with normal and dilated ventricles studied by MR imaging

Purpose: To quantify the cerebrospinal fluid (CSF) dynamics in the aqueduct of children with normal and dilated ventricles using MR phase-contrast technique.Material and Methods: Eighteen patients (6 months to 17 years of age) with various neurological symptoms underwent routine brain MR imaging and CSF flow measurement in the aqueduct. Nine patients had normal ventricles, 5 had dilated ventricles and 4 had a ventriculoperitoneal shunt.Results: The CSF velocity and flow rates in the aqueduct in patients with normal and dilated ventricles showed marked inter-individual variation and clear overlap. In a patient with tight aqueductal stenosis and increased ventricular pressure, pronounced CSF flow in the aqueduct was measured. Absence of flow in another patient with aqueductal stenosis was detected. Measurable although low flow in the aqueduct in 4 patients with a ventriculoperitoneal shunt was found.Conclusion: Quantitative phase MR flow measurement in the aqueduct demonstrated aqueductal stenosis; these patients had either pronounced flow or no flow in the aqueduct.