A phase-contrast MRI study of acute and chronic hydrodynamic alterations after hydrocephalus induced by subarachnoid hemorrhage

Significant individual variation in cardiac-cycle-linked cerebrospinal fluid production following subarachnoid hemorrhage

BACKGROUND

Spontaneous subarachnoid hemorrhage (SAH) often results in altered cerebrospinal fluid (CSF) flow and secondary hydrocephalus, yet the mechanisms behind these phenomena remain poorly understood. This study aimed to elucidate the impact of SAH on individual CSF flow patterns and their association with secondary hydrocephalus.

METHODS

In patients who had experienced SAH, changes in CSF flow were assessed using cardiac-gated phase-contrast magnetic resonance imaging (PC-MRI) at the Sylvian aqueduct and cranio-cervical junction (CCJ). Within these regions of interest, volumetric CSF flow was determined for every pixel and net CSF flow volume and direction calculated. The presence of acute or chronic hydrocephalus was deemed from ventriculomegaly and need of CSF diversion. For comparison, we included healthy subjects and patients examined for different CSF diseases.

RESULTS

Twenty-four SAH patients were enrolled, revealing a heterogeneous array of CSF flow alterations at the Sylvian aqueduct. The cardiac-cycle-linked CSF net flow in Sylvian aqueduct differed from the traditional figures of ventricular CSF production about 0.30-0.40 mL/min. In 15 out of 24 patients (62.5%), net CSF flow was retrograde from the fourth to the third and lateral ventricles, while it was upward at the cranio-cervical junction in 2 out of 2 patients (100%). The diverse CSF flow metrics did not distinguish between individuals with acute or chronic secondary hydrocephalus. In comparison, 4/4 healthy subjects showed antegrade net CSF flow in the Sylvian aqueduct and net upward CSF flow in CCJ. These net CSF flow measures also showed interindividual variability among other patients with CSF diseases.

CONCLUSIONS

There is considerable inter-individual variation in net CSF flow rates following SAH. Net CSF flow in the Sylvian aqueduct differs markedly from the traditional ventricular CSF production rates of 0.30-0.40 mL/min in SAH patients, but less so in healthy subjects. Furthermore, the cardiac-cycle-linked net CSF flow rates in Sylvian aqueduct and CCJ suggest an important role of extra-ventricular CSF production.

Hydrocephalus and the neuro-intensivist: CSF hydrodynamics at the bedside

Hydrocephalus (HCP) is far more complicated than a simple disorder of cerebrospinal fluid (CSF) circulation. HCP is a common complication in patients with subarachnoid hemorrhage (SAH) and after craniectomy. Clinical measurement in HCP is mainly related to intracranial pressure (ICP) and cerebral blood flow. The ability to obtain quantitative variables that describe CSF dynamics at the bedside before potential shunting may support clinical intuition with a description of CSF dysfunction and differentiation between normal pressure hydrocephalus and brain atrophy. This review discusses the advanced research on HCP and how CSF is generated, stored and absorbed within the context of a mathematical model developed by Marmarou. Then, we proceed to explain the main quantification analysis of CSF dynamics using infusion techniques for deciding on definitive treatment. We consider that such descriptions of multiple parameters of measurements need to be significantly appreciated by the caring neuro-intensivist, for better understanding of the complex pathophysiology and clinical management and finally, improve of the prognosis of these patients with HCP.

In this review article, we present current and novel theories of CSF circulation and pathophysiology of hydrocephalus, along with results from infusion studies for evaluating CSF dynamics at the bedside.

Efficacy of translamina terminalis ventriculostomy tube in prevention of chronic hydrocephalus after aneurysmal subarachnoid hemorrhage

Background

Chronic shunt-dependent hydrocephalus is still a common complication after aneurysmal SAH (aSAH) and is associated with increased morbidity. Pathology of chronic shunt-dependent hydrocephalus after aSAH is complex and multifactorial which makes its prevention challenging. We thought to evaluate whether external ventricular drainage (EVD) through fenestrated lamina terminalis would decrease the rate of chronic shunt-dependent hydrocephalus after aSAH.

Methods

A retrospective analysis of 68 consecutive patients with aSAH who underwent microsurgical clipping of the ruptured aneurysm. Patients were divided into two groups: Group A included patients with lamina terminalis fenestration without insertion of ventriculostomy tube and Group B included patients with EVD through fenestrated lamina terminalis. Demographic, clinical, radiological, and outcome variables were compared between groups.

Results

Group A comprised 29 patients with mean age of 47.8 years and Group B comprised 39 patients with mean age of 46.6 years. Group B patients had statistically significant (P < 0.05) lower incidence of chronic shunt- dependent hydrocephalus than Group A patients (30.8% vs. 55.2%, respectively).

Conclusion

EVD through fenestrated lamina terminalis is safe and may be effective in decreasing the incidence of chronic shunt-dependent hydrocephalus after aSAH.

A sustained systemic inflammatory response syndrome is associated with shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage

OBJECTIVE

The authors sought to evaluate whether a sustained systemic inflammatory response was associated with shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage.

METHODS

A retrospective analysis of 193 consecutive patients with aneurysmal subarachnoid hemorrhage was performed. Management of hydrocephalus followed a stepwise algorithm to determine the need for external CSF drainage and subsequent shunt placement. Systemic inflammatory response syndrome (SIRS) data were collected for all patients during the first 7 days of hospitalization. Patients who met the SIRS criteria every day for the first 7 days of hospitalization were considered as having a sustained SIRS. Univariate and multivariate regression analyses were used to determine predictors of shunt dependence.

RESULTS

Sixteen percent of patients required shunt placement. Sustained SIRS was observed in 35% of shunt-dependent patients compared to 14% in non-shunt-dependent patients (p = 0.004). On multivariate logistic regression, female sex (OR 0.35, 95% CI 0.142-0.885), moderate to severe vasospasm (OR 3.78, 95% CI 1.333-10.745), acute hydrocephalus (OR 21.39, 95% CI 2.260-202.417), and sustained SIRS (OR 2.94, 95% CI 1.125-7.689) were significantly associated with shunt dependence after aneurysmal subarachnoid hemorrhage. Receiver operating characteristic analysis revealed an area under the curve of 0.83 for the final regression model.

CONCLUSIONS

Sustained SIRS was a predictor of shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage even after adjustment for potential confounding variables in a multivariate logistic regression model.

Aqueductal Cerebrospinal Fluid Stroke Volume Flow in a Rodent Model of Chronic Communicating Hydrocephalus: Establishing a Homogeneous Study Population for Cerebrospinal Fluid Dynamics Exploration

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a cause of dementia that can be reversed when treated timely with cerebrospinal fluid (CSF) diversion. Understanding CSF dynamics throughout the development of hydrocephalus is crucial to identify prognostic markers to estimate benefit/risk to shunts.

OBJECTIVE

To explore the cerebral aqueduct CSF flow dynamics with phase-contrast magnetic resonance imaging (MRI) in a novel rodent model of adult chronic communicating hydrocephalus.

METHODS

Kaolin was injected into the subarachnoid space at the convexities in Sprague-Dawley adult rats. 11.7-T Bruker MRI was used to acquire T2-weighted images for anatomic identification and phase-contrast MRI at the cerebral aqueduct. Aqueductal stroke volume (ASV) results were compared with the ventricular volume (VV) at 15, 60, 90, and 120 days.

RESULTS

Significant ventricular enlargement was found in kaolin-injected animals at all times (P < 0.001). ASV differed between cases and controls/shams at every time point (P = 0.004, 0.001, 0.001, and <0.001 at 15, 60, 90, and 120 days, respectively). After correlation between the ASV and the VV, there was a significant correlation at 15 (P = 0.015), 60 (P = 0.001), 90 (P < 0.001), and 120 days. Moreover, there was a significant positive correlation between the VV expansion and the aqueductal CSF stroke between 15 and 60 days.

CONCLUSIONS

An initial active phase of rapid ventricular enlargement shows a strong correlation between the expansion of the VV and the increment in the ASV during the first 60 days, followed by a second phase with less ventricular enlargement and heterogeneous behavior in the ASV. Further correlation with complementary data from intracranial pressure and histologic/microstructural brain parenchyma assessments are needed to better understand the ASV variations after 60 days.

Hydrocephalus after Subarachnoid Hemorrhage: Pathophysiology, Diagnosis, and Treatment

Hydrocephalus (HCP) is a common complication in patients with subarachnoid hemorrhage. In this review, we summarize the advanced research on HCP and discuss the understanding of the molecular originators of HCP and the development of diagnoses and remedies of HCP after SAH. It has been reported that inflammation, apoptosis, autophagy, and oxidative stress are the important causes of HCP, and well-known molecules including transforming growth factor, matrix metalloproteinases, and iron terminally lead to fibrosis and blockage of HCP. Potential medicines for HCP are still in preclinical status, and surgery is the most prevalent and efficient therapy, despite respective risks of different surgical methods, including lamina terminalis fenestration, ventricle-peritoneal shunting, and lumbar-peritoneal shunting. HCP remains an ailment that cannot be ignored and even with various solutions the medical community is still trying to understand and settle why and how it develops and accordingly improve the prognosis of these patients with HCP.

Communicating hydrocephalus, a long-term complication of dural tear during lumbar spine surgery

PURPOSE

Iatrogenic dural tears during lumbar spine surgery are not uncommon and may have multiple long-term sequelae if not managed promptly and definitively. Sequelae include pseudomeningocoeles due to a persistent cerebrospinal fluid leak, which may result in a subarachnoid hemorrhage or subdural hematoma. These, in turn, can lead to adult communicating hydrocephalus. The purpose of this study is to describe a case of an intraoperative iatrogenic dural tear leading to the formation of a pseudomeningocoele and progressing to hydrocephalus.

METHODS

We present a case of a 62-year-old female who had an iatrogenic dural tear during a lumbar decompression and instrumented fusion. Attempts at closure were unsuccessful, which led to the formation of a pseudomeningocoele and an ascending subdural hygroma, progressing into a communicating hydrocephalus which was treated with a ventriculoperitoneal shunt.

RESULTS

Imaging studies and clinical follow up after the incidental durotomy demonstrate complications arising from the persistent cerebrospinal fluid leak, beginning with the formation of the pseudomeningocoele and progression to hydrocephalus. Based on these imaging studies, it was possible to illustrate the development of each of the complications.

CONCLUSION

The need for prompt recognition and proper management of iatrogenic dural tears are emphasized in order to avoid future complications that may arise from inadequate or proper treatment.

Feasibility of 3-dimensional sampling perfection with application optimized contrast sequence in the evaluation of patients with hydrocephalus

PURPOSE

This study aimed to investigate the effectiveness and additive value of T2W 3-dimensional sampling perfection with application optimized contrast (3D-SPACE) with variant flip-angle mode in imaging of all types of hydrocephalus. Our secondary objective was to assess the reliability of 3D-SPACE sequence and correspondence of the results with phase-contrast magnetic resonance imaging (PC-MRI)-based data.

MATERIALS AND METHODS

Forty-one patients with hydrocephalus have undergone 3-T MRI. T2W 3D-SPACE sequence has been obtained in addition to routine hydrocephalus protocol. Cerebrospinal fluid circulation, presence/type/etiology of hydrocephalus, obstruction level scores, and diagnostic levels of confidence were evaluated separately by 2 radiologists. In the first session, routine sequences with PC-MRI were evaluated, and in another session, only 3D-SPACE and 3-dimensional magnetization prepared rapid acquisition gradient echo sequences were evaluated. Results obtained in these sessions were compared with each other and those obtained in consensus session.

RESULTS

Agreement values were very good for both 3D-SPACE and PC-MRI sequences (P < 0.001 for all). Also, the correlation of more experienced reader's 3D-SPACE-based scores and consensus-based scores was perfect (κ = 1, P < 0.001).The mean value of PC-MRI-based confidence scores were lower than those obtained in 3D-SPACE and consensus sessions.

CONCLUSIONS

T2W 3D-SPACE sequence provides morphologic cerebrospinal fluid flow data. It is a noninvasive technique providing extensive multiplanar reformatted images with a lower specific absorption rate. These advantages over PC-MRI make 3D-SPACE sequence a promising tool in management of patients with hydrocephalus.

An innovative approach to investigate the dynamics of the cerebrospinal fluid in the prepontine cistern: A feasibility study using spatial saturation-prepared cine PC-MRI

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An innovative sat-pulse based cine PC-MRI to investigate complex CSF dynamic.

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Compared to conventional sequence and validated in the PPC of hydrocephalus patients.

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No compromise neither on temporal nor on spatial resolution.

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Compared to conventional exam: the PPC has same area but lower flow stroke volume.

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It contributes to a better follow-up of patients with altered CSF circulation.

Purposes

Accurate measurements of the cerebrospinal fluid that flows through the prepontine cistern (PPC) are challenging due to artefacts originating from basilar artery blood flow. We aim to accurately quantify cerebrospinal fluid (CSF) flow and stroke volume in the PPC, which is essential before endoscopic third ventriculostomy.

Materials and methods

We developed a new PC-MRI sequence prepared with Hadamard saturation bands to accurately quantify CSF flow in the PPC by suppressing the blood signal in the surrounding vessels. In total, 28 adult hydrocephalic patients (age 59 ± 20 years) were scanned using conventional PC-MRI and our developed sequence. CSF was separately extracted from the PPC and the foramen of Magendie, and flow (min and max) and stroke volume were quantified.

Results

Our modifications result in a complete deletion of signal from flowing blood, resulting in significantly reduced CSF stroke volume (Conv = 446 ± 113 mm³, Dev = 390 ± 119 mm³, p = 0.006) and flow, both minimum (Conv = −1630 ± 486 mm³/s, Dev = −1430 ± 406 mm³/s, p = 0.005) and maximum (Conv = 2384 ± 657 mm³/s, Dev = 1971 ± 62 mm³/s, p = 0.002) compared with the conventional sequence, whereas no change in the area of interest was noted (Conv = 236 ± 65 mm², Dev = 249 ± 75 mm², p = 0.21).

Conclusions

Accurate and reproducible CSF flow and stroke volume measurements in the PPC can be achieved with sat-band prepared cine PC-MRI.