Aqueduct In Patients Research Articles

Comparison of radiological abnormalities between the jugular bulb and the vestibular aqueduct in patients with Ménière's disease.

Anatomical variations of the inner ear may contribute to the development of Ménière's disease (MD), which is a complex inner ear disorder histopathologically characterized by idiopathic endolymphatic hydrops (ELH). Abnormalities of the vestibular aqueduct (VA) and the jugular bulb (JB) have been suggested as predisposing factors. Yet, few studies have investigated the correlation between JB abnormalities and VA variations as well as its clinical relevance in these patients. In this retrospective study, we investigated the differences in the incidence of radiological abnormalities of the VA and JB in patients with definite MD. Anatomical variations of JB and VA were evaluated based on high-resolution CT (HRCT) in a series of 103 patients with MD (93 unilateral cases and 10 bilateral cases). JB-related indices included JB anteroposterior and mediolateral diameter, JB height, JB type regarding to Manjila classification system, and incidences of JB diverticulum (JBD), JB related inner ear dehiscence (JBID), and inner ear adjacent JB (IAJB). VA-related indices included CT-VA visibility, CT-VA morphology (funnel, tubular, filiform, hollow, and obliterated-shaped type), and peri-VA pneumatization. Radiological indices were compared between MD ears and control ears. Radiological JB abnormalities were comparable between MD ears and control ears. As for VA-related indices, the CT-VA visibility was lower in MD ears than in control ears (p = 0.004). The distribution of CT-VA morphology was significantly different between MD and control ears (p = 0.013), with a higher proportion of obliterated-shaped type in MD ears (22.1%) than in control ears (6.6%). Compared with JB abnormalities, the anatomical variations of VA are more likely to be an anatomically predisposing factor for MD.

A subject-specific assessment of measurement errors and their correction in cerebrospinal fluid velocity maps using 4D flow MRI.

Phase-contrast MRI (PC-MRI) of cerebrospinal fluid (CSF) velocity is used to evaluate the characteristics of intracranial diseases, such as normal-pressure hydrocephalus (NPH). Nevertheless, PC-MRI has several potential error sources, with eddy-current-based phase offset error being non-negligible in CSF measurement. In this study, we assess the measurement error of CSF velocity maps obtained using 4D flow MRI and evaluate correction methods. CSF velocity maps of 10 patients with NPH were acquired using 4D flow MRI (velocity-encoding = 5 cm/s). Distributed phase offset error was estimated for a whole 3D background field by polynomial fitting using robust regression analysis. This estimated phase offset error was then used to correct the CSF velocity maps. The estimated error profiles were compared with those obtained using an existing 2D correction approach involving local background information near the region of interest. The residual standard error of the polynomial fitting against the phase offset error extracted from the measured velocities was within 0.2 cm/s. The spatial dependencies of the phase offset errors showed similar tendencies in all cases, but sufficient differences in these values were found to indicate requirement of velocity correction. Differences of the estimated errors among other correction approaches were in the order of 10-2 cm/s, and the estimated errors were in good agreement with those obtained using existing approaches. Our method is capable of estimating the measurement error of CSF velocity maps obtained from 4D flow MRI and provides quantitatively reasonable characteristics for the main CSF profile in the cerebral aqueduct in patients with NPH.

Nonsurgical treatment of obstructive hydrocephalus by face-down positioning: Report of four cases

BackgroundTransient obstructive hydrocephalus is a rare condition. Previous case reports have described spontaneous resolution of obstructive hydrocephalus, although the entire mechanism has not yet been clarified. Case descriptionWe report four cases of transient obstructive hydrocephalus after subarachnoid hemorrhage (2 cases) and intra-cerebral hemorrhage (2 cases) caused by obstruction of the aqueduct in patients who presented with altered consciousness that resolved soon after changing their posture from the supine to semi-prone (face-down) position. ConclusionsFace-down positioning might be beneficial for patients with delayed obstructive hydrocephalus, especially that due to a mobile hematoma in the third ventricle.

Change in average peak cerebrospinal fluid velocity at the cerebral aqueduct, before and after lumbar CSF tapping by the use of phase contrast MRI, and its effect on gait improvement in patients with normal pressure hydrocephalus.

To compare the change in peak cerebrospinal (CSF) flow velocity at the cerebral aqueduct in patients with normal pressure hydrocephalus (NPH) before and after CSF tapping with clinical outcome of the patients, i.e., gait improvement. Forty patients with NPH were evaluated before and after CSF tapping on 3 consecutive days at our institution. Gait improvement was compared with the average peak velocity at the cerebral aqueduct. The average peak velocity was also compared before and after lumbar CSF tapping using phase contrast magnetic resonance imaging (PC-MRI). The different flow parameters were compared using paired t-test. The average peak velocity before and after lumbar CSF tapping was 5.8196 ± 1.420 cm/s and 4.1411 ± 1.0638 cm/s, respectively. The peak positive, negative, and average velocity decreased in the post-tap group. In our study, 70% of the patients showed gait improvement, and a comparison of the gait improvement with the change in average peak velocity was statistically significant (P = 0.001). Comparison of the change in peak positive and negative velocity with gait improvement was also statistically significant, with a P value of 0.004 and <0.001, respectively. Rest of the CSF flow parameters were statistically insignificant. PC-MRI is a sensitive method to support the diagnosis of NPH. Different flow parameters were comparable before and after CSF tapping. The parameters which might be useful for assessing clinical improvement include a change in the peak average, as well as positive, and negative velocity.

Position of the Internal Aperture of Vestibular Aqueduct in Patients With Enlarged Vestibular Aqueduct.

To investigate the position of the internal aperture of vestibular aqueduct and its relationship to hearing level in patients with enlarged vestibular aqueduct (EVA). The size of the common crus and the position of the internal aperture of vestibular aqueduct were compared among control subjects, EVA patients with and without other inner ear malformations. Auditory steady-state response thresholds were compared between EVA patients with different positions of internal apertures. The common crus in EVA patients was shorter than in control subjects (p < 0.05). The internal aperture of the vestibular aqueduct opened solely into the common crus in control subjects, simultaneously into the common crus and vestibule in almost 45% of EVA patients, solely into the common crus, and the vestibule in almost 30 and 25% of EVA patients, respectively. Auditory steady-state response thresholds at 2000 and 4000 Hz were higher in EVA patients whose internal apertures of vestibular aqueducts opened simultaneously into the common crus and vestibule than in those whose internal apertures opened solely into the common crus. The common crus is shorter in EVA patients than in control subjects. The internal aperture of the vestibular aqueduct opens solely into the common crus in control subjects. It opens simultaneously into the common crus and vestibule in almost half of the EVA patients. The EVA patients whose internal apertures of vestibular aqueducts open solely into the common crus may have better hearing than those whose internal apertures open simultaneously into the common crus and vestibule.

Morphometric Study of the Vestibular Aqueduct in Patients With Enlarged Vestibular Aqueduct.

To test whether there are significant differences in the morphologic features of the enlarged vestibular aqueduct (EVA) and its anatomic relationships with adjacent structures between EVA patients with and without other inner ear malformations. The morphology of vestibular aqueduct, volume of vestibule, and anatomic location of facial nerve (FN) were compared among 3 groups. Group A, 18 control subjects; group B, 32 EVA patients without other inner ear malformations; group C, 14 EVA patients with other inner ear malformations. The isthmus of the aqueduct and vestibular volume in group C were larger than those in group B (P < 0.05). Positive correlations were identified between the length of the aqueduct and the vestibular volume in groups B and C. The vertical FN segment in group C located more anteriorly than that in groups A and B (P < 0.05). Compared with EVA patients without other inner ear malformations, the aqueduct, and vestibule in EVA patients with other inner ear malformations are larger, the vertical FN segment locates more anteriorly.

Radiological findings of the cochlear aqueduct in patients with Meniere's disease using high-resolution CT and high-resolution MRI.

The objective of the present study was to evaluate the cochlear aqueduct (CA) in Meniere's disease (MD) and to disclose radiological differences of CA between MD and non-MD patients by means of high-resolution computed tomography (HRCT) and high-resolution magnetic resonance imaging (HRMRI). Radiological data of 86 ears of MD patients which were separated into 52 ears of diseased side group (MD-D group) and 34 ears of contralateral non-affected side group of unilateral MD (MD-ND group), 27 ears of patients with sensorineural hearing loss (SNHL group) and 56 ears of patients with somatoform dizziness and normal hearing (control group) were analyzed retrospectively. The bony type of CA, the bony length of CA, and the bony width of CA medial orifice was measured in HRCT. The visibility of CA in HRMRI was scored. Fluid length in CA and fluid width in medial orifice were measured in HRMRI. Data were compared between MD-D, MD-ND, SNHL, and control group. There were no significant differences in the bony type of CA, bony length of CA, bony width of CA medial orifice, and fluid width of CA medial orifice between MD-D, MD-ND, SNHL and control group (p > 0.05). However, CA fluid length of MD-D (5.13 ± 1.88 mm) and of MD-ND group (5.44 ± 1.81 mm) was significantly shorter than fluid length of SNHL (6.90 ± 1.55 mm) (p < 0.001, p = 0.001) and of control group (7.43 ± 1.24 mm) (p < 0.001, p < 0.001). The ratio between CA fluid length and CA bony length was the smallest in MD-D group (0.403; p = 0.009). CA bony dimensions of affected ears of MD are normal, but CA fluid length is decreased.

Vestibular aqueduct in sudden sensorineural hearing loss

To evaluate the vestibular aqueduct in patients with sudden sensorineural hearing loss. We evaluated 19 patients (12 men and seven women; age range, 22-79 years) with unilateral sudden sensorineural hearing loss, using computed tomography and magnetic resonance imaging. All these patients had unilateral sudden sensorineural hearing loss. We also evaluated 47 control subjects (22 men and 25 women; age range, 22-79 years). In sensorineural hearing loss affected ears, the width of the vestibular aqueduct at the midpoint and at the operculum was significantly greater than that in contralateral ears or in control ears. The width of the vestibular aqueduct at the midpoint and the operculum did not correlate with the audiometric threshold or the audiogram configuration. Contrast enhancement of the ipsilateral endolymphatic sac was observed in 17 of 19 patients with sudden sensorineural hearing loss (89 per cent). Eleven of these 17 patients also showed enhancement on the contralateral side, but no patient showed enhancement only on the contralateral side. In sensorineural hearing loss affected ears, the width of the vestibular aqueduct did not differ significantly between those patients with and without enhancement. The vestibular aqueducts of sudden sensorineural hearing loss affected ears are wider than those of controls. Precise imaging and evaluation of the inner ear is essential when investigating the pathological conditions responsible for sudden sensorineural hearing loss.

CEREBROSPINAL FLUID FLOW IN CHILDREN WITH NORMAL AND DILATED VENTRICLES STUDIED BY MR IMAGING

. To quantify the cerebrospinal fluid (CSF) dynamics in the aqueduct of children with normal and dilated ventricles using MR phase-contrast technique. 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. 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. Quantitative phase MR flow measurement in the aqueduct demonstrated aqueductal stenosis; these patients had either pronounced flow or no flow in the aqueduct.

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.

External aperture of the vestibular aqueduct in Meniere's disease.

To study the relationship of the length of the external aperture of the vestibular aqueduct and the ratio of the summating potential and action potential (SP:AP) in patients with Meniere's disease. Retrospective case study. Neurotology referral center. Fifty-four patients with Meniere's disease and nine control subjects without Meniere's disease. The external aperture of the vestibular aqueduct was measured from a three-dimensional surface reconstruction computed tomography scan. Transtympanic electrocochleography was performed on patients with Meniere's disease. The length of the external aperture of the vestibular aqueduct in the Meniere's disease ears was related to the SP:AP ratio in the Meniere's disease ears and compared with controls. The average length of the external aperture was 3.79 +/- 2.92 mm in Meniere's disease ears and 5.35 +/- 1.73 mm in the control ears (p < 0.05). An enlarged SP:AP ratio was found in 95% of ears in the group with nonvisible external apertures of the vestibular aqueduct, 91% of ears in the <5 mm group, 58% of ears in the 5-7 mm group, and 29% of ears in the >7 mm group (chi-square = 24.814; p = 0.000). The length of the external aperture of the vestibular aqueduct in patients with Meniere's disease is significantly shorter than in those without Meniere's disease. Endolymphatic hydrops, evidenced by an enlarged SP:AP ratio, was related to the length of the external aperture of the vestibular aqueduct. The shorter the external aperture, the more often the SP:AP ratio was enlarged. A short or nonvisible external aperture of the vestibular aqueduct is a predisposing factor to the development of Meniere's disease.

Measurement of the patency of the cochlear aqueduct in patients with Meniere's disease and in normal hearing subjects

Objective. The hydrostatic pressure of the inner ear is affected by cerebrospinal fluid pressure through the cochlear aqueduct. Hydrostatic pressure is proposed to affect inner ear physiology. In this study the patency of the cochlear aqueduct in patients with Menière’s disease was compared with normal hearing control ears. Materials and methods. Changes of perilymphatic pressure following rapid change of body position were measured non-invasively using the MMS-10 Tympanic Displacement Analyser in patients with Menière’s disease and in normal hearing subjects. Results. Following a rapid change of body position, the perilymphatic pressure changed within the first minute in affected, non-affected and control ears. However, in control ears a slightly delayed change of perilymphatic pressure after change of body position could be detected. Possibly, ears in controls are protected against rapid and large pressure changes of the cerebrospinal fluid compartment than patients with Menière’s disease. Conclusion. Pressure changes of the cerebrospinal fluid affect inner ear pressure immediately. Possibly, the patency of the cochlear aqueduct influences the pathogenesis of Menière’s disease. The influence of the cochlear aqueduct on the physiology and pathophysiology of the inner ear is unclear until now and might be subject for further investigation.

Quantitative analysis of CSF flow dynamics using MRI in normal pressure hydrocephalus.

In order to clarify the flow dynamics of cerebrospinal fluid (CSF) in normal pressure hydrocephalus (NPH), a phase-contrast cine magnetic resonance (MR) imaging technique with retrospective cardiac gating was used to measure the quantitative flow velocity of CSF in the aqueduct in patients with NPH after subarachnoid hemorrhage (SAH-NPH group, n = 17), idiopathic NPH (1-NPH group, n = 2), asymptomatic ventricular dilatation or brain atrophy (VD group, n = 7) and healthy volunteers (control group, n = 19). Intracranial pressure (ICP) and pressure volume response (PVR) were also measured during the shunt operation in six of the SAH- NPH group. The maximum CSF flow velocity (Vmax) in the aqueduct was significantly larger in the SAH-NPH group (9.21 +/- 4.12 cm/sec, mean +/- SD) than in the control group (5.27 +/- 1.77, p < 0.001) and the VD group (4.06 +/- 1.81, p < 0.005). Vmax was not different between the control and VD groups. There was a positive correlation between the PVR and the peak CSF flow velocity in the SAH-NPH group. These findings suggest that the changes of CSF flow velocity in the SAH-NPH group might be caused by a moderate decrease of intracranial compliance. The CSF flow study using MRI is useful to differentiate NPH from brain atrophy or asymptomatic ventricular dilatation and also to estimate the intracranial compliance.

Tomography of the Vestibular Aqueduct in Meniere's Disease—Use of Computed Readiography (CR)—

In order to evaluate usefullness of computed radiography (CR) in tomography of the vestibular aqueduct, visualization of the vestibular aqueduct in patients with Meniere's disease was compared between tomograms of computed and conventional radiography. Of 20 ears, 12 vestibular aqueducts (60%) were visualized in conventional tomography. On the other hand, all vestibular aqueducts were identified in tomography of computed radiography. Computed radiography seems to be superior to conventional radiography for tomography of the vestibular aqueduct.

Polytomography of the vestibular aqueduct in patients with Menière's disease.

Les patients ayant une maladie de Meniere tendent a avoir une pneumatisation mal developpee des cellules aeriennes periaqueducales, et tombent essentiellement dans les types 3 et 2 de Wilbrand

Stereotaxic reconstruction of the aqueduct of Sylvius.

A stereotaxic technique has been developed to cannulate the cerebral aqueduct in patients with hydrocephalus resulting from occlusion of the aqueduct of Sylvius. Precise placement of a 15- to 20-mm long radiopaque prosthesis between the third and fourth ventricles can reestablish the normal cerebrospinal fluid (CSF) pathway. Since 1974, seven patients have undergone aqueductal reconstruction. The surgical goal in this series was to manage the hydrocephalus by creating and maintaining a patent aqueductal channel. The follow-up period ranged from 1.5 to 6.5 years. In four cases, aqueductal reconstruction alone resulted in control of the hydrocephalus, although two patients underwent revisions of their prosthesis. Three patients ultimately required shunts, despite initial symptomatic improvement after reconstruction. In these seven cases (13 stereotaxic procedures), no mortality and no significant operative morbidity were encountered. Although the technique is relatively simple to perform, technical difficulties remain. At present, no clinical or radiographic test adequately discerns the ideal candidate for stereotaxic aqueductal reconstruction. Four patients required stereotaxic revision because of malposition or malfunction of the prosthesis. This approach should be reserved for patients with a short aqueductal occlusion, and normal distal CSF pathways and dynamics. The rationale, technique, problems, and results of stereotaxic reconstruction are presented.

Tomographic and clinical investigations on the vestibular aqueduct in patients with Meniere's disease

Tomographic and clinical investigations on the vestibular aqueduct in patients with Meniere's disease

The vestibular aqueduct in patients with Menière's disease. A tomographic and clinical investigation.

The vestibular aqueduct was identified on tomograms in all healthy subjects. In patients with severe Meniere's disease the visibility was affected. The aqueduct was visible in 65% of the non-diseased ears and in 59% of the diseased ears of patients with unilateral Meniere's disease, whereas the corresponding figure for bilaterally diseased ears was only 53%. Longstanding disease can impair the visibility, while it does not seem to be affected by advanced age per se No obvious relationship was found between the visibility on tomograms and the results of hearing tests and caloric tests. The vestibular aqueduct is shorter in patients with Meniere's disease than in healthy subjects. The pneumatization of the pyramid, which varies in normal individuals as well as in patients with Meniere's disease, influences the length of the aqueduct. The longest aqueducts in healthy subjects were found in those with large cell pneumatization in the vicinity of the aqueduct. Most patients with Meniere's disease lacked pneuma...