Cerebrospinal Fluid Flow Parameters Research Articles

Possibilities of dynamic phase contrast MRI of cerebrospinal fluid for performing a tap test in a patient with idiopathic normotensive hydrocephalus

Idiopathic normotensive hydrocephalus (iNH) is a widespread disease in elderly patients. The effectiveness of iNG treatment and the subsequent quality of patients' lives directly depends on timely and early diagnosis. The criteria for diagnosing iNG that are used in neuroimaging can also be found in patients without clinical manifestations of this disease, and the widely used tap-test is an invasive technique with a rather low sensitivity. The need for early diagnosis and initiation of treatment before the development of irreversible damage to brain structures determines the relevance of the search for an accessible, minimally invasive, accurate and safe diagnostic method. The article presents a clinical observation of the use of phase-contrast MRI of cerebrospinal fluid (CSF) in a female patient with a positive response to the tap test with a quantitative analysis of changes in CSF flow parameters and ALVI and Evans indices depending on the time after CSF evacuation. Phase-contrast MRI of CSF with a quantitative assessment of CSF flow parameters in combination with an assessment of the ALVI index has the potential to increase the accuracy of diagnosing iNH and is of scientific interest for further research.

Analysis of blood and cerebrospinal fluid flows in preclinical AD. Preliminary results from ALFA+ cohort

AbstractBackgroundIntracranial cerebrospinal fluid (CSF) motion is driven by the wave pressure associated with arterial blood flow into the skull (Figure 1). Since one of the roles of CSF is the clearance of neural waste, it was investigated the relationship between blood and CSF flow parameters (as measured by magnetic resonance imaging [MRI]) and CSF Ab42/40 and ptau‐181 levels in the preclinical stages of Alzheimer’s disease (AD).MethodThree hundred sixty‐five subjects from the ALFA+ cohort underwent two MRI phase‐encoded velocity sequences (30 frames per cardiac cycle) to measure (1) blood flow in carotids below carotid bifurcation and (2) CSF flow through foramen magnum. The scanner’s Q‐flow tool was used to quantify stroke volume (volume per cardiac cycle), percent of vessel’s area increase and flow velocity increase, as a proxy for vessel elasticity and flow pulsatility, respectively. Associations between flow parameters and age, CSF Ab42/40 and ptau‐181 concentrations were sought, correcting for sex, age and time between lumbar puncture and MRI (P<0.05).ResultOne hundred thirty‐two subjects were excluded because the scanning session was not completed, showed missing or outlier values or did not pass quality control (artifacts or unbalanced outwards‐inwards CSF flow measures), resulting in a final sample size of 233 participants (mean age [SD]: 60.8±4.5 years; male: n = 73 [31.3%]). Figure 2 shows the plots with the most significant relationships between flow parameters, CSF biomarkers, CSF volume and age. It was observed that a higher stroke volume in CSF flow was associated with lower Ab42/40 and higher ptau‐181 concentrations in CSF.ConclusionThese results indicate that, despite the role of CSF in waste clearance, the accumulation of amyloid and tau in the brain might be neither caused nor enhanced by a global deficit in CSF circulation. We hypothesize that a higher volume of CSF associated with age and high ptau‐181 levels and/or the loss of parenchyma elasticity might reduce the global intracranial compressibility, resulting in an enhanced response to pressure increase due to blood flow into the skull, which could explain the observed increase in CSF flow associated with the early stages of AD.

Cerebrospinal Fluid Flow Parameters in Normal Subjects above 40 Years of Age

Abstract Background Cerebrospinal fluid (CSF) flow is altered in many conditions like normal pressure hydrocephalus (NPH), aqueduct stenosis, or Chiari malformation. It is very important to know the normal CSF flow parameters for properly diagnosing these conditions. No data on CSF flow parameters of the Indian population are available. Hence, this study was undertaken to generate normative CSF flow parameters in the Indian population. Aim Our aim was to estimate normal CSF flow parameters across the cerebral aqueduct in Indian subjects over 40 years of age. Settings and Design This observational study was done in the tertiary care institute on subjects undergoing magnetic resonance imaging (MRI) for indications like headache and having normal MRI. Methods Phase-contrast quantitative flow sequence was done in 100 subjects perpendicular to the cerebral aqueduct on 3.0T MRI (Discovery 750w with GEM suit, GE, Milwaukee, WI, United States) using a dedicated 32-channel head coil with 10 cm/s velocity encoding. The region of interest was kept at the cerebral aqueduct in cross-section. The inbuilt software calculated flow-time and velocity-time graphs and calculated peak systolic velocity (PSV), peak diastolic velocity (PDV), systolic flow (SF), and diastolic flow (DF). Stroke volume (SV) was calculated by averaging systolic and DFs. p-Value < 0.05 was considered significant. Results Mean age was 53.72 ± 10.53 (40–78) years with 41 males and 59 females. PSV, PDV, SF, DF, and SV all showed a significant linear correlation with age with p-values of 0.001, 0.004, 0.009, <0.001, and <0.001, respectively. Only PDV (p = 0.035) and DF (p = 0.045) varied significantly with sex, values being higher in males. Conclusion All five CSF flow parameters studied vary positively with age, and this variation is linear. Normal decadal median values calculated for these parameters can act as baseline values for the local population and help in defining conditions like NPH.

Callosal Angle Sub-Score of the Radscale in Patients with Idiopathic Normal Pressure Hydrocephalus Is Associated with Positive Tap Test Response.

The aim of the present study was the implementation of the composite imaging “Radscale” in patients with idiopathic normal pressure hydrocephalus (iNPH) and the evaluation of its score, as well as absolute stroke volume and peak flow velocity of cerebrospinal fluid (CSF) in aqueduct as indicators of a positive response following a tap test. Forty-five patients with iNPH were included. Clinical evaluation involved the 10 m timed walk test before and every 24 h for 3 consecutive days after evacuative lumbar puncture (LP). Neuropsychological evaluation comprised a mini mental state examination (MMSE), frontal assessment battery (FAB), 5-word test (5WT) and CLOX drawing test 1 and 2, which were carried out before and 48 h after LP. The tap test’s response was defined as a ≥20% improvement in gait and/or a ≥10% improvement in neuropsychological tests. All scores of neuropsychological and clinical variables, except for immediate 5WT and CLOX-1, differed significantly before and 48 h after LP. Improvement in time and steps of a 10 m timed walk test differed significantly between female and male patients. Out of 45 total patients, 19 were tap test responders and 26 non-responders. The total score of Radscale and CSF flow parameters did not differ between responders and non-responders. However, “Callosal angle” sub-score differed significantly between these two groups. A greater “callosal angle” sub-score, meaning more acute callosal angle, was associated with a positive tap test response, rendering it a useful measurement in the stratification of iNPH patients that will potentially respond to CSF shunting.

Cerebrospinal Fluid Flow Analysis in Tuberculous Meningitis Using Phase Contrast Technique on 3 Tesla MRI: A New Paradigm and Our Initial Experience.

Phase-contrast magnetic resonance imaging (PC-MRI) has been used for studying cerebrospinal fluid (CSF) dynamics in various CSF related disorders at aqueduct of Sylvius. To analyze the CSF flow dynamics qualitatively and quantitatively using PC-MRI across the aqueduct of Sylvius in diagnosed patients of tuberculous meningitis. Thirty patients, clinically diagnosed with tuberculous meningitis and mean age of 24 years (range: 12-60 years) were taken up to study the changes in CSF flow dynamics using PC-MRI with retrospective cardiac gating. Thirty age and sex matched healthy volunteers were also included for comparison and reference values. Flow quantification was done by through-plane scans acquired in the axial plane perpendicular to the aqueduct. For qualitative examination, in-plane phase contrast scans were acquired in the mid-sagittal plane. Encoding velocity was kept in craniocaudal direction. Calculated parameters were peak velocity (cm/s), average velocity (cm/s), average flow (mL/s), net forward volume (mL), and stroke volume (μL). Qualitatively, loss of normal sinusoidal waveform of CSF flow was noted in two cases of hydrocephalus with exaggerated flows. Quantitatively, CSF flow parameters showed marked numerical difference in tuberculous meningitis patients with hydrocephalus on comparison with healthy volunteers and with cases without hydrocephalus. PC-MRI is a sensitive technique to analyze altered CSF flow dynamics in tuberculous meningitis patients. This is a useful adjunct in imaging these patients to extract both the qualitative and quantitative information about CSF flow for comprehensive evaluation.

Cine phase-contrast magnetic resonance imaging evaluation of cerebrospinal fluid flow dynamics in healthy pediatric subjects.

ObjectiveTo evaluate cerebrospinal fluid dynamics, using cine phase-contrast magnetic resonance imaging (cine-PC MRI), in healthy pediatric subjects, determining the normal flow values in this population, as well as identifying differences related to age, sex, and body surface area.Materials and MethodsThis was a descriptive cross-sectional study involving 32 healthy children and adolescents, in whom the flow of cerebrospinal fluid through the cerebral aqueduct was evaluated quantitatively with cine-PC MRI. We used specialized software to analyze the images obtained with cine-PC MRI, drawing a region of interest on the aqueduct. A flow-time curve was obtained, as were automated measurements of the various parameters.ResultsThe following normal (mean) values were obtained: net flow, 1.10 ± 0.99 mL/m; stroke volume, 12.2 ± 10.1 µL/cycle; mean velocity, 0.72 ± 1.00 cm/s; peak systolic velocity, 5.28 ± 2.30 cm/s; peak diastolic velocity, 4.51 ± 1.77 cm/s. These values were not affected by age or sex. In addition, body surface area was not found to correlate significantly with mean velocity or stroke volume.ConclusionIn children and adolescents, the basic cerebrospinal fluid flow parameters, as determined by cine-PC MRI, appear to be independent of age and sex.

Using deep learning convolutional neural networks to automatically perform cerebral aqueduct CSF flow analysis

Since the development of phase-contrast magnetic resonance imaging (PC-MRI), quantification of cerebrospinal fluid (CSF) flow across the cerebral aqueduct has been utilized for diagnosis of conditions such as normal pressure hydrocephalus (NPH). This study aims to develop an automated method of aqueduct CSF flow analysis using convolution neural networks (CNNs), which can replace the current standard involving manual segmentation of aqueduct region of interest (ROI). Retrospective analysis was performed on 333 patients who underwent PC-MRI, totaling 353 imaging studies. Aqueduct flow measurements using manual ROI placement was performed independently by two radiologists. Two types of CNNs, MultiResUNet and UNet, were trained using ROI data from the senior radiologist, with PC-MRI studies being randomly divided into training (80%) and validation (20%) datasets. Segmentation performance was assessed using Dice similarity coefficient (DSC), and CSF flow parameters were calculated from both manual and CNN-derived ROIs. MultiResUNet, UNet and second radiologist (Rater 2) had DSCs of 0.933, 0.928, and 0.867, respectively, with p < 0.001 between CNNs and Rater 2. Comparison of CSF flow parameters showed excellent intraclass correlation coefficients (ICCs) for MultiResUNet, with lowest correlation being 0.67. For UNet, lower ICCs of −0.01 to 0.56 were observed. Only 3/353 (0.8%) studies failed to have appropriate ROIs placed by MultiResUNet, compared to 12/353 (3.4%) failed cases for UNet. In conclusion, CNNs were able to measure aqueductal CSF flow with similar performance to a senior neuroradiologist. MultiResUNet demonstrated fewer cases of segmentation failure and more consistent flow measurements compared to the widely adopted UNet.

Idiopathic Normal Pressure Hydrocephalus and Elderly Acquired Hydrocephalus: Evaluation With Cerebrospinal Fluid Flow and Ventricular Volume Parameters.

PurposeTo investigate differences in cerebrospinal fluid (CSF) flow through the aqueduct and to determine whether there is a relationship between CSF flow and ventricular volume parameters in idiopathic normal pressure hydrocephalus (iNPH) patients, elderly acquired hydrocephalus patients and age-matched healthy volunteers by phase-contrast MR (PC-MR).MethodsA total of 40 iNPH patients and 41 elderly acquired hydrocephalus patients and 26 age-matched healthy volunteers in the normal control (NC) group were included between November 2017 and October 2019 in this retrospective study. The following CSF flow parameters were measured with PC-MR: peak velocity, average velocity (AV), aqueductal stroke volume (ASV), net ASV, and net flow. The following ventricular volume parameters were measured: ventricular volume (VV), brain volume, total intracranial volume, and relative VV. Differences between the iNPH and acquired hydrocephalus groups were compared Mann–Whitney U test and correlations between CSF flow and ventricular volume parameters were assessed using the Spearman correlation coefficient.ResultsAqueductal stroke volume was significantly higher in the iNPH and acquired hydrocephalus groups than in the NC group, but did not differ significantly between the iNPH group and acquired hydrocephalus group. The AV, net ASV, and net flow in the iNPH and acquired hydrocephalus groups were significantly higher than those in the NC group (P < 0.0001), and those in the acquired hydrocephalus group were significantly higher than those in the iNPH group (P = 0.01, P = 0.007, P = 0.002, respectively). The direction of the AV and net ASV significantly differed among the three groups. There were no associations between the volume parameters and CSF flow according to PC-MR among the three groups.ConclusionCompared with iNPH, elderly acquired hydrocephalus demonstrated higher CSF hyperdynamic flow. Although increased CSF flow may contribute to further changes in ventricular morphology, there is no linear relationship between them. These findings might help increase our understanding of flow dynamics in iNPH and elderly acquired hydrocephalus.

Assessing test-retest reliability of phase contrast MRI for measuring cerebrospinal fluid and cerebral blood flow dynamics.

Pathological states occur when cerebrospinal fluid (CSF) and cerebral blood flow (CBF) dynamics become dysregulated in the brain. Phase-contrast MRI (PC-MRI) is a noninvasive imaging technique that enables quantitative measurements of CSF and CBF flow. While studies have validated PC-MRI as an imaging technique for flow, few studies have evaluated its reliability for CSF and CBF flow parameters commonly associated with neurological disease. The purpose of this study was to evaluate test-retest reliability at the cerebral aqueduct (CA) and C2-C3 area using PC-MRI to assess the feasibility of investigating CSF and CBF flow dynamics. This study was performed on 27 cognitively normal young adults (ages 20-35 years). Flow data was acquired on a 3T Siemens Prisma using a 2D cine-PC pulse sequence. Three consecutive flow measurements were acquired at the CA and C2-C3 area. Intraclass correlation coefficient (ICC) and coefficient of variance (CV) were used to evaluate intrarater, inter-rater, and test-retest reliability. Among the 26 flow parameters analyzed, 22 had excellent reliability (ICC > 0.80), including measurements of CSF stroke volume, flush peak, and fill peak, and 4 parameters had good reliability (ICC 0.60-0.79). 16 flow parameters had a mean CV ≤ 10%, 7 had a CV ≤ 15%, and 3 had a CV ≤ 30%. All CSF and CBF flow measurements had excellent inter-rater and intrarater reliability (ICC > 0.80). This study shows that CSF and CBF flow can be reliably measured at the CA and C2-C3 area using PC-MRI, making it a promising tool for studying flow dynamics in the central nervous system.

The oscillatory flow of the cerebrospinal fluid in the Sylvian aqueduct and the prepontine cistern measured with phase contrast MRI in children with hydrocephalus\u2014a preliminary report

IntroductionRecognizing patients with ventriculomegaly who are at risk of developing acute hydrocephalus presents a challenge for the clinician. The association between disturbed cerebrospinal fluid flow (CSF) and impaired brain compliance may play a role in the pathogenesis of hydrocephalus. Phase contrast MRI is a noninvasive technique which can be used to assess CSF parameters. The aim of the work is to evaluate the effectiveness of phase contrast MRI in recognizing patients at risk of acute hydrocephalus, based on measuring the pulsatile CSF flow parameters in the Sylvian aqueduct and prepontine cistern in children with ventriculomegaly.AimThe aim of the work is to characterize the parameters of cerebrospinal fluid (CSF) flow in the Sylvian aqueduct and prepontine cistern in children with ventriculomegaly with regard to patient age and symptoms. We hypothesize that the relationship between CSF flow parameters in these two regions will vary according to analyzed factors and it will allow to recognize children at risk of hydrocephalus.Materials and methodsA group of 26 children with ventriculomegaly (five girls and 21 boys) underwent phase contrast MRI examinations (Philips 3T Achieva with Q-flow integral application). Amplitudes of average and peak velocities of the CSF flow through the Sylvian aqueduct and prepontine cistern were used to calculate ratios of oscillation and peak velocities, respectively. The relationship between the oscillation coefficient, the peak velocity coefficient, and stroke volume was then assessed in accordance with age and clinical symptoms.ResultsThe peak velocity coefficient was significantly higher in patients with hyper-oscillating flow through the Sylvian aqueduct (3.04 ± 3.37 vs. 0.54 ± 0.28; p = 0.0094). Moreover, these patients tended to develop symptoms more often (p = 0.0612). No significant age-related changes were observed in CSF flow parameters.ConclusionPhase contrast MRI is a useful tool for noninvasive assessment of CSF flow parameters. The application of coefficients instead of direct values seems to better represent hemodynamic conditions in the ventricular system. However, further studies are required to evaluate their clinical significance and normal limits.

Quantitative Evaluation of Normal Aqueductal Cerebrospinal Fluid Flow Using Phase-Contrast Cine MRI According to Age and Sex.

The aim of this study was cerebrospinal fluid (CSF) flow quantification in the cerebral aqueduct using phase-contrast cine magnetic resonance ımaging (PCC-MRI) according to both sexes and three different age groups to obtain normative data. Seventy two volunteers with no cerebral pathology were included in this study. Subjects were divided into three age groups: 20-34 years, 35-49 years, and 50-65 years including equal gender groups. CSF flow's quantitatively evaluation was performed with images that were obtained by 1.5 T Magnetic Resonance (MR) unit from cerebral aqueduct level on the semi-axial plan. Between groups, peak velocity (cmsec-1 ), average velocity (cm/s), forward volume (mL), reverse volume (mL), net forward volume (mL), and average flow over range (ml/min) values of current flowing through aqueduct and average aqueductal areas were compared. There were no statistically significant differences in CSF flow parameters among different age groups and between sexes (P > 0.05). There was a statistically significant difference in average cerebral aqueduct area between the age group of 50-65 years and the other age groups (P = 0.002). The average aqueductal area was higher in the age group of 50-65 years. Normal aqueductal CSF flow parameters evaluated with PCC-MRI don't show a significant difference by age and sex. We have achieved the lower and upper values of these parameters would be useful in future clinical studies. The size of aqueductal area may also be explained by atrophy-dependent ventricular system dilatation in the elderly. Anat Rec, 300:549-555, 2017. © 2016 Wiley Periodicals, Inc.

Evaluation of aqueductal cerebrospinal fluid flow dynamics with phase-contrast cine magnetic resonance imaging in normal pediatric cases

PurposeThis study aimed to determine differences according to age groups and gender in the parameters of aqueductal cerebrospinal fluid (CSF) flow in childhood using phase-contrast cine magnetic resonance imaging (MRI) method. Materials and methodsThis prospective study included 47 boys and 36 girls for a total of 83 healthy children. The cases were divided into three groups depending on age as infants (1–12 months), children (12–120 months), and adolescents (120–204 months). To quantitatively evaluate CSF flow, images in the transverse plane were taken at the cerebral aqueduct level using the phase-contrast MR angiography technique in a 1.5-T MR unit. Peak and average velocity (cm/s), cranial direction, caudal direction and net volume (ml), and aqueduct area (mm2) were calculated. To assess differences between the groups, a one-way analysis of variance and least significant difference tests were used. ResultsA statistically significant difference was determined between children and adolescents in peak velocity and caudal direction volume (P=.012 and P=.039, respectively) and between infants and children in cranial direction volume (P=.036). Peak velocity, cranial direction, and net volume were higher in boys (P=.050, P=.016, and P=.029, respectively). There were no differences by age and gender in the aqueduct area. ConclusionIn conclusion, this study determined the normal values for the CSF flow parameters of velocity, volume, and aqueduct area using phase-contrast MRI in healthy children. Velocity and volume parameters varied according to age and sex and were not affected in the aqueductal area.

Interactions between Flow Oscillations and Biochemical Parameters in the Cerebrospinal Fluid.

The equilibrium between the ventricular and lumbar cerebrospinal fluid (CSF) compartments may be disturbed (in terms of flow and biochemistry) in patients with chronic hydrocephalus (CH). Using flow magnetic resonance imaging (MRI) and CSF assays, we sought to determine whether changes in CSF were associated with biochemical alterations. Nine elderly patients with CH underwent phase-contrast MRI. An index of CSF dynamics (Idyn) was defined as the product of the lumbar and ventricular CSF flows. During surgery, samples of CSF were collected from the lumbar and ventricular compartments and assayed for chloride, glucose and total protein. The lumbar/ventricular (L/V) ratio was calculated for each analyte. The ratio between measured and expected levels (Ibioch) was calculated for each analyte and compared with Idyn. Idyn varied from 0 to 100.103μl2.s2. In contrast to the L/V ratios for chloride and glucose, the L/V ratio for total protein varied markedly from one patient to another (mean ± standard deviation (SD): 2.63 ± 1.24). The Ibioch for total protein was strongly correlated with the corresponding Idyn (Spearman’s R: 0.98; p < 5 × 10−5).We observed correlated alterations in CSF flow and biochemical parameters in patients with CH. Our findings also highlight the value of dynamic flow analysis in the interpretation of data on CSF biochemistry.

Long-term neuropsychological sequelae in HIV-seronegative cryptococcal meningoencephalitis patients with and without ventriculoperitoneal shunts: a cine MRI study.

Background. Hydrocephalus in cryptococcal meningoencephalitis is most commonly managed with a ventriculoperitoneal shunt. This study applied cine magnetic resonance imaging (MRI) to evaluate initial disease severity on long-term cerebrospinal fluid (CSF) flow dynamics and associated neuropsychological sequelae in cryptococcal meningoencephalitis patients with and without ventriculoperitoneal shunts. Methods. Eighteen human immunodeficiency virus-seronegative cryptococcal meningoencephalitis patients (10 with shunts versus 8 without shunts) were compared with 32 age- and sex-matched healthy volunteers. All subjects underwent complete neurologic examination and neuropsychological testing. Cine MRI was conducted to evaluate CSF flow parameters. Initial CSF laboratory analysis and imaging findings were correlated with present CSF flow parameters and neuropsychological scores. Results. Patients without shunts had higher average flow than controls, suggesting chronic hydrocephalus. Initial Evans ratios and CSF glucose levels were associated with CSF peak velocity and flow. Worsening CSF flow parameters correlated with decreased neuropsychological performance. Conclusions. CSF flow parameter differences between the cryptococcal meningoencephalitis patients both with and without ventriculoperitoneal shunts could be detected by cine MRI and correlated with acute stage disease severity and chronic stage neuropsychological results. Cine MRI is useful for assessing the chronic hydrocephalus that may lead to neuropsychological deficits in cryptococcal meningoencephalitis patients.

Observed Changes in Quality of Life Measures and Cerebrospinal Fluid Flow Parameters in Migraine Subjects Receiving Chiropractic Care

Subject’s must be or have: 1. Male or female, 21 to 65 years of age. 2. Sign written informed consent. 3. Naive to Upper Cervical Chiropractic care. 4. Migraine with or without aura according to the International Classification of Headache Disorders (ICHD). 5. Ten to twenty-six headache days per month over the last 4 months. 6. Be suitable candidates for therapeutic intervention as assessed by NUCCA investigator.

Measuring CSF flow dynamics in spontaneous intracranial hypotension with phase-contrast magnetic resonance imaging: Potential implications for diagnosis and treatment

Certain magnetic resonance (MR) techniques are flow sensitive, and phase-contrast magnetic resonance imaging (PC-MR) has been utilized both qualitatively and quantitatively to evaluate cerebrospinal fluid (CSF) flow in a variety of clinical conditions (1). Although spontaneous intracranial hypotension (SIH) is, by definition, a disorder of CSF homeostasis typically resulting from a spinal CSF leak, PC-MR has been studied very little in this setting. An initial case report in 2004 first documented decreased systolic and diastolic CSF flow volume at the level of the cerebral aqueduct using PC-MR in a patient with SIH (2). Although confined to a single patient, the findings were compelling because normalization was documented following resolution of SIH. A number of years elapsed before a more systematic study of PC-MR in SIH was completed when Hasiloglu et al. showed a change in CSF flow dynamics in 25 SIH patients compared with controls and further related the PC-MR findings to clinical findings and opening pressure (3). The manuscript entitled Usefulness of PhaseContrast Magnetic Resonance Imaging for Diagnosis and Treatment Evaluation in Patients with SIH by Tung et al. is a welcome addition to the existing body of literature (4). The discriminating power of some of the measured CSF flow parameters at the level of the cerebral aqueduct rivals that of the more widely accepted anatomic imaging features of SIH. Moreover, there may be potential for PC-MR to identify SIH patients who lack characteristic MR findings such as dural enhancement. The change in CSF flow witnessed with treatment suggests that PC-MR may also be beneficial for monitoring patient progress during treatment for SIH. The authors point out that results with PC-MR are known to vary in subjects in relation to age, sex, body mass index, cardiac function, and technical parameters (i.e. velocity encoding gradient, anatomic site, MR scanner, etc.). As a result, the impact of these variables will need to be more fully defined in SIH patients, as has been conducted for healthy subjects. Appropriately, the authors also recognize multiple potential technical limitations in their study. However, moving forward, a number of considerations unique to the use of PC-MR in SIH patients will need to be considered. Although correlation of CSF flow dynamics with patient symptoms and validated imaging findings in SIH is useful, a quantifiable relationship with opening pressure would be preferred. No lumbar punctures were performed in the current study to allow for correlation of opening pressure with CSF flow dynamics as measured by PC-MR (4). When patient presentation and imaging findings strongly suggest headache due to SIH, it is increasingly common in clinical practice to forego lumbar puncture for opening pressure measurement. Indeed, this approach is also endorsed in the International Classification of Headache Disorders, 3rd edition (beta version), which states that dural puncture to directly measure CSF pressure is not necessary in patients with positive MR findings (5). However, it would be ideal for future research studies using PC-MR in SIH to report opening pressures as much as possible. Applying PC-MR to SIH is a relatively new application of existing technology. Hasiloglu et al. demonstrated a significant positive correlation between opening pressure and multiple CSF flow parameters (CSF flow

Magnetic resonance 4D flow analysis of cerebrospinal fluid dynamics in Chiari I malformation with and without syringomyelia

To analyse cerebrospinal fluid (CSF) hydrodynamics in patients with Chiari type I malformation (CM) with and without syringomyelia using 4D magnetic resonance (MR) phase contrast (PC) flow imaging. 4D-PC CSF flow data were acquired in 20 patients with CM (12 patients with presyrinx/syrinx). Characteristic 4D-CSF flow patterns were identified. Quantitative CSF flow parameters were assessed at the craniocervical junction and the cervical spinal canal and compared with healthy volunteers and between patients with and without syringomyelia. Compared with healthy volunteers, 17 CM patients showed flow abnormalities at the craniocervical junction in the form of heterogeneous flow (n = 3), anterolateral flow jets (n = 14) and flow vortex formation (n = 5), most prevalent in patients with syringomyelia. Peak flow velocities at the craniocervical junction were significantly increased in patients (-15.5 ± 11.3 vs. -4.7 ± 0.7 cm/s in healthy volunteers, P < 0.001). At the level of C1, maximum systolic flow was found to be significantly later in the cardiac cycle in patients (30.8 ± 10.3 vs. 22.7 ± 4.1%, P < 0.05). 4D-PC flow imaging allowed comprehensive analysis of CSF flow in patients with Chiari I malformation. Alterations of CSF hydrodynamics were most pronounced in patients with syringomyelia.

Quantitative analysis of cerebrospinal fluid flow in complex regions by using phase contrast magnetic resonance imaging

AbstractTo develop a method for segmenting cerebrospinal fluid (CSF) regions with complex, inhomogeneous pulsatile patterns in phase contrast magnetic resonance imaging (PC‐MRI) sequences. Our approach used various temporal features of flow behavior as input attributes in an unsupervised k‐means classification algorithm. CSF flow parameters for the cervical subarachnoid spaces and the pontine cistern were calculated in 26 healthy volunteers. Background and aliasing corrections were applied automatically. The algorithm's reproducibility was determined by calculating two parameters (area and stroke volume) while varying the initially selected seed point. The influence of background correction on these parameters was also assessed. The method was highly reproducible, with coefficients of variation of 3 and 4% for the cervical stroke volume and area, respectively. In an analysis of variance, background correction did not have a statistically significant effect on either the stroke volume (p = 0.32) or the CSF net mean flow (p = 0.69) at the C2C3 level. The method presented here enables rapid, reproducible, quantitative analysis of CSF flow in complex regions such as the C2C3 subarachnoid spaces and the pontine cistern. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 290–297, 2011;

Longitudinal MRI shows no cerebral abnormality in chronic fatigue syndrome

MRI has previously provided conflicting results when used to search for brain abnormalities in sufferers of chronic fatigue syndrome (CFS). Eighteen CFS patients and nine healthy volunteers each underwent MRI on two occasions, one year apart. The resulting images were examined for abnormalities in brain atrophy, deep white matter hyperintensities (WMH) and cerebral blood and cerebrospinal fluid (CSF) flow. Mean proportionate CSF volume was not significantly different between subject groups. All participants showed a slight increase in CSF between scans, but no significant difference was found between those with CFS and those without. Between-group comparisons of ventricular volume revealed no significant differences at study commencement and no significant change over the year. No significant inter-group differences were found for any of the cerebral blood and CSF flow parameters. Low levels of WMH were found in all participants. Objective scoring of WMH using Scheltens' scale revealed no change in summary components (prosencephalic deep white matter hyperintensities, basal ganglia hyperintensities and infratentorial hyperintensities) or in individual component variables between the baseline and 1 year follow-up scans. No abnormal patterns in rate and extent of brain atrophy, ventricle volume, white matter lesions, cerebral blood flow or aqueductal CSF flow were detected in the CFS population. These results throw open the debate into whether MRI scanning can reveal diagnostic signs of CFS and clinically questions the diagnoses of CFS made on the basis of previous research conclusions.

Relationship between cerebrospinal fluid and blood dynamics in healthy volunteers and patients with communicating hydrocephalus.

Using magnetic resonance imaging (MRI), we investigated cerebral blood and cerebrospinal fluid (CSF) flows in patients with communicating hydrocephalus (CH) and in healthy volunteers to determine the contribution of CSF flow to brain pressure regulation in CH patients. Cine phase-contrast MRI data from 16 healthy volunteers and 12 patients with CH characterized by hyperdynamic aqueductal CSF flow were analyzed using in-house image-processing software that automatically measured flow curves. Amplitude and temporal CSF and blood flow parameters were compared in the 2 groups. Jugular peak flow occurred significantly earlier (P < 0.01) in the CH patients than in the healthy volunteers. Cervical CSF oscillations were not significantly different between the 2 groups. Venous vessel compression and/or changes in intracranial subarachnoid CSF flow produce an increase in ventricular CSF flush that compensates for vascular brain expansion in patients with CH.