Changes In Cerebrospinal Fluid Dynamics Research Articles

Cerebrospinal Fluid Dynamics and Partial Pressure of Carbon Dioxide as Prognostic Indicators in Hypoxic-Ischemic Brain Injury Following Cardiac Arrest.

Changes in cerebrospinal fluid (CSF) dynamics can have adverse effects on neuronal function. We hypothesized that patients with hypoxic-ischemic brain injury (HIBI) showing poor neurological outcomes after cardiac arrest (CA) would exhibit changes in CSF dynamics, leading to abnormalities in gas diffusion within the CSF. Therefore, we investigated the prognostic value of the CSF partial pressure of carbon dioxide (PcsfCO2) in CA survivors who underwent targeted temperature management (TTM). We retrospectively analyzed the 6-month neurological outcomes, CSF, and arterial blood gas parameters of 67 CA survivors. Patients were divided into good and poor neurological outcome groups, and the predictive value of PcsfCO2 for poor neurological outcomes was assessed using receiver operating characteristic curve analysis. Among all patients, 39 (58.2%) had poor neurological outcomes. Significant differences in PcsfCO2 levels between the groups were observed, with lower PcsfCO2 levels on Day 1 showing the highest predictive value at a cutoff of 30 mmHg (area under the curve, sensitivity, and specificity were 0.823, 77.8%, and 79.0%, respectively). These results suggest that PcsfCO2 might serve not only as a unique marker for the severity of hypoxic-ischemic brain injury (HIBI), independent of extracorporeal CO2 levels, but also as an objective indicator of changes in CSF dynamics. This study highlights the potential prognostic and diagnostic utility of PcsfCO2 during TTM in CA survivors, emphasizing its importance in evaluating CSF dynamics and neurological recovery post CA. However, larger multicenter studies are warranted to address potential limitations associated with sample size and outcome assessment methods.

Why is delirium more frequent in the elderly?

An aging-related reduction in the brain’s functional reserve may explain why delirium is more frequent in the elderly than in younger people insofar as the reserve becomes inadequate to cover the metabolic requirements that are critically increased by stressors. The aim of this paper is to review the normal aging-related changes that theoretically compromise complex mental activities, neuronal and synaptic densities, and the neurocomputational flexibility of the functional reserve. A pivotal factor is diminished connectivity, which is substantially due to the loss of synapses and should specifically affect association systems and cholinergic fibres in delirious patients. However, micro-angiopathy with impaired blood flow autoregulation, increased blood/brain barrier permeability, changes in cerebrospinal fluid dynamics, weakened mitochondrial performance, and a pro-inflammatory involution of the immune system may also jointly affect neurons and their synaptic assets, and even cause the progression of delirium to dementia regardless of the presence of co-existing plaques, tangles, or other pathological markers. On the other hand, the developmental growth in functional reserve during childhood and adolescence makes the brain increasingly resistant to delirium, and residual reserve can allow the elderly to recover. These data support the view that functional reserve is the variable that confronts stressors and governs the risk and intensity of and recovery from delirium. Although people of any age are at risk of delirium, the elderly are at greater risk because aging and age-dependent structural changes inevitably affect the brain’s functional reserve.

Longitudinal analysis of cerebral aqueduct flow measures: multiple sclerosis flow changes driven by brain atrophy

BackgroundSeveral small cross-sectional studies have investigated cerebrospinal fluid (CSF) flow dynamics in multiple sclerosis (MS) patients and have reported mixed results. Currently, there are no longitudinal studies that investigate CSF dynamics in MS patients.ObjectiveTo determine longitudinal changes in CSF dynamics measured at the level of aqueduct of Sylvius (AoS) in MS patients and matched healthy controls (HCs).Materials and methodsForty (40) MS patients and 20 HCs underwent 3T MRI cine phase contrast imaging with velocity-encoded pulse-gated sequence at baseline and 5-year follow-up. For atrophy determination, MS patients underwent additional high-resolution 3D T1-weighted imaging. Measures of AoS cross-sectional area (CSA), average systolic and diastolic velocity peaks, maximal systolic and diastolic velocity peaks and average CSF flow rates were determined. Brain atrophy and ventricular CSF (vCSF) expansion rates were determined. Cross-sectional and longitudinal changes were derived by analysis of covariance (ANCOVA) and paired repeated tests. Confirmatory general linear models were also performed. False discovery rate (FDR)-corrected p-values lower than 0.05 were considered significant.ResultsThe MS population demonstrated significant increase in maximal diastolic peak (from 7.23 to 7.86 cm/s, non-adjusted p = 0.037), diastolic peak flow rate (7.76 ml/min to 9.33 ml/min, non-adjusted p = 0.023) and AoS CSA (from 3.12 to 3.69 mm2, adjusted p = 0.001). The only differentiator between MS patients and HCs was the greater AoS CSA (3.58 mm2 vs. 2.57 mm2, age- and sex-adjusted ANCOVA, p = 0.045). The AoS CSA change was associated with vCSF expansion rate (age- and sex-adjusted Spearman’s correlation r = 0.496, p = 0.019) and not with baseline nor change in maximal velocity. The expansion rate of the vCSF space explained an additional 23.8% of variance in change of AoS CSA variance when compared to age and sex alone (R2 = 0.273, t = 2.557, standardized β = 0.51, and p = 0.019).ConclusionMS patients present with significant longitudinal AoS enlargement, potentially due to regional atrophy changes and ex-vacuo expansion of the aqueduct.

Dynamic 11C-PiB PET Shows Cerebrospinal Fluid Flow Alterations in Alzheimer Disease and Multiple Sclerosis.

Cerebrospinal fluid (CSF) plays an important role in solute clearance and maintenance of brain homeostasis. 11C-Pittsburgh compound B (PiB) PET was recently proposed as a tool for detection of CSF clearance alterations in Alzheimer disease. The current study investigates the magnitude of 11C-PiB PET signal in the lateral ventricles of an independent group of Alzheimer and mild cognitive impairment subjects. We have also evaluated multiple sclerosis as a model of disease with CSF clearance alterations without amyloid-β tissue accumulation. Methods: A set of 11 Alzheimer and 12 mild cognitive impairment subjects and a set of 20 multiple sclerosis subjects with matched controls underwent MRI and dynamic 11C-PiB PET. Lateral ventricle regions of interest were generated manually from MRI data. PET data were analyzed using cerebellum or a supervised reference region for the Alzheimer and multiple sclerosis data sets, respectively. The magnitude of 11C-PiB signal in the lateral ventricles was calculated as area under the curve from 35 to 80 min and SUV ratio (SUVR) from 50 to 70 min. Compartmental modeling analysis was performed on a separate data set containing 11 Alzheimer and matched control subjects; this analysis included an arterial input function, to further understand the kinetics of the lateral ventricular 11C-PiB signal. Results: ANOVA revealed significant group differences in lateral ventricular SUVR across the Alzheimer, mild cognitive impairment, and healthy control groups (P = 0.004). Pairwise comparisons revealed significantly lower lateral ventricular SUVR in Alzheimer subjects than in healthy controls (P < 0.001) or mild cognitive impairment subjects (P = 0.029). Lateral ventricular SUVR was significantly lower in multiple sclerosis subjects than in healthy controls (P = 0.008). Compartmental modeling analysis revealed significantly lower uptake rates of 11C-PiB signal from blood (P = 0.005) and brain tissue (P = 0.004) to the lateral ventricles and significantly lower 11C-PiB signal clearance out of the lateral ventricles (P = 0.002) in Alzheimer subjects than in healthy controls. Conclusion: These results indicate that dynamic 11C-PiB PET can be used to observe pathologic changes in CSF dynamics. We have replicated previous work demonstrating CSF clearance deficits in Alzheimer disease associated with amyloid-β deposits and have extended the observations to include ventricular CSF clearance deficits in mild cognitive impairment and multiple sclerosis.

Can low b value diffusion weighted imaging evaluate the character of cerebrospinal fluid dynamics?

We aimed to investigate whether low b value diffusion-weighted imaging (DWI) can show the change of cerebrospinal fluid (CSF) dynamics. The subjects of this retrospective study consisted of patients with ventricular dilatation (n = 50) and controls (n = 50). The CSF signal intensity on the b = 500s/mm2 DWI was evaluated by a scoring method in the lateral, 3rd and 4th ventricles, the cerebral sulci and the Sylvian fissure. The signal void findings adjacent to the septum pellucidum were also evaluated. The CSF signal intensities were significantly less in lateral ventricle and 3rd ventricle of the ventricular dilatation subjects. In controls, the score for the signal void in the Sylvian fissure showed a significant positive correlation with age. However, other areas did not show a significant correlation with age. The appearance of the characteristic signal void adjacent to the septum pellucidum showed a significant correlation with ventricular dilatation. Our current study suggests that the CSF signal intensity on the b = 500s/mm2 DWI may show the changes in CSF dynamics and might be useful to evaluate the overlook of CSF dynamics.

Polycystic Ovarian Syndrome and Pseudotumor Cerebri Syndrome in Female Adolescents

Pseudotumor cerebri syndrome (PTCS) is characterized by elevated intracranial pressure, normal cerebrospinal fluid (CSF) content, and the lack of any identifiable causative mass on imaging of the central nervous system. This syndrome is usually characterized by headache and double vision, and typically occurs in obese women during their reproductive years. The pathogenesis of PTCS is unknown, although various etiologic factors have been proposed as the likely cause, including changes in CSF dynamics due to metabolic-hormonal derangements and/or increased venous blood pressure in the brain due to transverse sinus stenosis. PTCS has been reported in association with several comorbidities, including polycystic ovarian syndrome (PCOS). The mechanism that leads to increased intracranial pressure and PTCS in females with PCOS awaits elucidation; however, PCOS is typically associated with hyperaldosteronism and the latter has been considered in recent years an important risk factor for PTCS, likely due to an aldosterone-mediated elevation of CSF pressure. Nevertheless, further studies remain to be done to elucidate fully the etiology of PTCS in female adolescents affected by PCOS.

The presence of arachnoiditis affects the characteristics of CSF flow in the spinal subarachnoid space: A modelling study

Syringomyelia is a neurological disorder characterised by high pressure fluid-filled cysts within the spinal cord. As syringomyelia is associated with abnormalities of the central nervous system that obstruct cerebrospinal fluid (CSF) flow, it is thought that changes in CSF dynamics play an important role in its pathogenesis. Using three-dimensional computational models of the spinal subarachnoid space (SAS), this study aims to determine SAS obstructions, such as arachnoiditis, change in CSF dynamics in the SAS. The geometry of the SAS was reconstructed from a series of MRI images. CSF is modelled as an incompressible Newtonian fluid with a dynamic viscosity of 1mPas. Three computational models simulated CSF flow in either the unobstructed SAS, or with the SAS obstructed by a porous region simulating dorsal or circumferential arachnoiditis. The permeability of this porous obstruction was varied for the model with dorsal arachnoiditis. The results show that arachnoiditis increases flow resistance in the SAS and this is accompanied by a modest increase in magnitude and/or shift in timing (with respect to the cardiac cycle) of the CSF pressure drop across the region of arachnoiditis. This study suggests that syrinx formation may be related to a change in temporal CSF pulse pressure dynamics.

Biventricular Hydrocephalus Due to Idiopatic Occlussion of Foramina of Monro

Total congenital occlusion of the foramina of Monro in adults is extremely rare. Only 9 cases have been reported. Clinically, this manifest as a biventricular hydrocephalus and the most frequent presenting symptom is headache. The diagnosis can be confirmed by computed tomographic scan or magnetic resonance imaging. Regarding treatment, neuroendoscopy constitutes the procedure of choice. The prognosis is usually good. We describe a 35-year-old woman with a 2-month headache and sudden nausea, vomiting, and syncope. The patient was studied with computed tomograph, magnetic resonance imaging, and a ventricular infusion test, and subsequently treated with endoscopic foraminoplasty and a ventriculoperitoneal shunt. The protacted normal neurological history with late and rapid onset of symptoms speaks for a progressive restriction of the size of the foramina of Monro, which allows adaptation to the changes in cerebrospinal fluid dynamics. Regarding treatment, in almost every cases of bilateral occlusion of foramina of Monro reported to date, but in 1 case both: neuroendoscopy fenestration and the ventriculoperitoneal shunt were needed. Time is needed to allow cerebrospinal fluid dynamics and the ventricular system to normalize.

Contribution of brain distortion and displacement to CSF dynamics in experimental brain compression

The present study was designed to determine the contribution of brain distortion and displacement to changes in cerebrospinal fluid (CSF) dynamics [pressure-volume index (PVI), compliance (C), and outflow resistance (Ro)] during progressive brain compression and the effect of compression on brain mechanical properties. In 10 dogs measurements were made of CSF dynamics, brain elastic behavior, cerebral perfusion pressure, local cerebral blood flow, and suprainfratentorial intracranial pressure (ICP) during the incremental expansion of a supratentorial extradural balloon. PVI appeared more as a measure of the compressibility of the cerebral vascular compartment than of intracranial bulk compliance. Reciprocal changes in CSF dynamics behaved as expected when the balloon expanded predominantly supratentorially causing a moderate increase in ICP. A significant increase in ICP, however, caused a rise in PVI and a decrease in compliance. Under these conditions PVI alone could not differentiate between a falling cerebral perfusion pressure and an increasing suprainfratentorial ICP gradient. In contrast, the compliance decreased with balloon expansion while the outflow resistance showed an inverse correlation with compliance and a linear correlation with baseline ICP; Go, an elastic response parameter, consistently decreased, implying that C, Ro, and Go can be used as a trend of intracranial compensatory reserve during intracranial mass expansion.

Posttraumatic spinal cord cysts: clinical features and characterization with metrizamide computed tomography.

Sixteen patients with posttraumatic spinal cord cysts (PTSCC) were evaluated clinically and studied with metrizamide computed tomography (MCT). These patients presented months to years following a severe spinal cord injury, usually with new or progressively worsening neurological symptoms. The development of the PTSCC was unrelated to the location, type, and severity of injury, or to the time interval from the original injury. MCT showed that these cysts occur most frequently in normal or atrophic cords, they may be multiple, they most frequently are found in the dorsal portion of the cord, and they may vary along their length in width and position within the cord. Knowledge of this radiographic morphology is crucial to the surgical planning. The location of the cysts and the mode of their enlargement are correlated with anatomic features of the spinal cord and changes in cerebrospinal fluid dynamics. Cyst-to-subarachnoid space shunting relieves the majority of symptoms.

NORMAL CEREBROSPINAL FLUID DYNAMICS IN SPINAL CORD TUMOR SUSPECTS

II. SENSORIMOTOR NEUROLOGY: PERIPHERAL AND CRANIAL NERVES, SPINAL CORD, MEDULLA, CEREBELLUM AND CEREBRUM: PDF Only

NORMAL CEREBROSPINAL FLUID DYNAMICS IN SPINAL CORD TUMOR SUSPECTS

As the result of the efforts of Ayer 1 and Stookey, 2 the technic of eliciting abnormal changes in cerebrospinal fluid dynamics has become so refined that an obstruction in the spinal canal can be detected earlier in the disease than formerly. Cases have been reported, however, in which tumors were found that appeared large enough to block the entire canal but normal dynamics were shown by lumbar puncture. The question therefore arises, What size must a tumor be in relation to the spinal canal before there are any demonstrable changes in dynamics? Patients have frequently been known to suffer from pains for years which were thought due to rheumatism, sciatica, sacro-iliac disease or neuritis, before any objective symptoms were detected to suspect an intraspinal lesion. In such instances a problem as to the value of a lumbar puncture always arises, especially when the tumor does not obliterate the subarachnoid