Multimodal MRI Assessment of Brain Fluid Circulation in Idiopathic Intracranial Hypertension

A Clinical Study Using Multimodal MRI to Evaluate the Effects of Choroid Plexus Function, Glymphatic Function, and Blood-Brain Barrier Function on Cerebrospinal Fluid Circulation in Patients With Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a neurological disorder characterized by increased pressure inside the skull without an identifiable cause. It can lead to headaches, swelling of the optic nerve, and visual impairment. Alterations in cerebrospinal fluid circulation and fluid exchange within the brain may contribute to this condition, but the underlying mechanisms remain incompletely understood.

This prospective observational study aims to investigate brain fluid circulation in patients with IIH using multimodal magnetic resonance imaging (MRI).A total of 105 participants will be enrolled, including 65 patients with IIH and 40 healthy controls. Healthy controls will be recruited to achieve comparable distributions of age, sex, and body mass index at the group level.

The primary objective is to compare MRI measures related to the choroid plexus, cerebrospinal fluid flow, glymphatic function, cerebral perfusion, and water exchange across the blood-brain barrier between patients with IIH and healthy controls. Secondary objectives are to assess changes in these measures after clinical treatment and examine their associations with intracranial pressure, optic nerve swelling, visual function, and clinical symptoms.

Patients with IIH will undergo clinical, ophthalmological, and MRI assessments at baseline and approximately 3 and 6 months after treatment. Healthy controls will undergo baseline assessments only.

This study will not assign treatments. All clinical management decisions will be made independently by treating physicians. Research MRI examinations will not require contrast agents, and no invasive procedures will be performed solely for research purposes.

Study Overview

• Status: Not yet recruiting
• Conditions: Idiopathic Intracranial Hypertension

Detailed Description

This is a single-center, prospective observational study designed to characterize brain fluid circulation-related abnormalities in patients with idiopathic intracranial hypertension (IIH) through multimodal MRI and to investigate their clinical relevance and longitudinal changes following routine clinical treatment.

A total of 105 participants will be enrolled, including 65 patients with IIH and 40 healthy controls. Healthy controls will be recruited to achieve comparable distributions of age, sex, and body mass index at the group level. Baseline comparisons will assess differences in imaging markers representing several complementary aspects of brain fluid homeostasis.

Multimodal MRI examinations will include structural T1- and T2-weighted imaging, magnetic resonance venography, phase-contrast MRI, diffusion MRI, resting-state functional MRI, arterial spin labeling, and vascular water exchange imaging (VEXI).

The imaging assessment will include choroid plexus volume, cerebral aqueduct cerebrospinal fluid flow parameters, perivascular space burden, diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) index, free-water fraction, diffusion tensor imaging-estimated periventricular diffusivity (DTI-EstPVeD), global blood oxygen level-dependent signal-cerebrospinal fluid coupling, cerebral blood flow, and the apparent water exchange rate across the blood-brain barrier (AXR_BBB).

Clinical evaluations in patients with IIH will include cerebrospinal fluid opening pressure, visual acuity, visual field mean deviation, Frisén papilledema grade, retinal nerve fiber layer thickness, and standardized assessments of headache, tinnitus, quality of life, and cognitive function. Trans-stenotic pressure gradients and other invasive clinical measurements will be recorded when available from clinically indicated procedures.

Patients with IIH will undergo repeated clinical, ophthalmological, and multimodal MRI assessments at baseline, 90 ± 14 days, and 180 ± 30 days after clinical treatment. Healthy controls will undergo baseline assessments only. Treatment, including medical management or venous sinus stenting when clinically indicated, will be determined independently by treating physicians and will not be assigned by the study protocol.

The primary analysis will compare baseline imaging measures between patients with IIH and healthy controls, adjusting for age, sex, and body mass index. Longitudinal analyses will evaluate within-patient changes in imaging measures and their associations with changes in intracranial pressure, papilledema, visual function, and clinical symptoms. Comparisons between treatment subgroups will be considered exploratory because treatment allocation is not randomized.

The study aims to provide a comprehensive multimodal imaging characterization of brain fluid circulation-related abnormalities in IIH and to identify potential imaging markers for future disease assessment and treatment monitoring.

• Study Type: Observational
• Enrollment (Estimated): 105

Contacts and Locations

• Study Contact: Name: Dapeng Mo, PhD; Phone Number: 18811039300; Email: bjttmodp@163.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100070
      • Beijing Tiantan Hospital, Capital Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

This single-center prospective observational study will enroll 105 participants, including 65 patients with idiopathic intracranial hypertension (IIH) and 40 healthy controls. Patients with IIH will be recruited at Beijing Tiantan Hospital. Healthy controls will be selected for comparison based on age, sex, and body mass index. Patients with IIH will undergo baseline and follow-up assessments, while healthy controls will undergo baseline assessments only.

Description

Inclusion Criteria:

Patients with Idiopathic Intracranial Hypertension (IIH):

Aged 18-60 years.

Clinical manifestations consistent with or highly suggestive of IIH, such as headache, visual disturbance, papilledema, pulsatile tinnitus, or diplopia.

No hydrocephalus, intracranial mass, or other structural cause of increased intracranial pressure on CT or MRI.

Normal cerebrospinal fluid composition.

Lumbar puncture opening pressure ≥250 mmH₂O.

Ability to complete standardized baseline MRI examinations.

Provision of written informed consent.

Healthy Controls:

Aged 18-60 years.

Comparable age, sex, and body mass index to the IIH group.

No history of IIH or symptoms suggestive of increased intracranial pressure.

No papilledema or significant visual or neuro-ophthalmological abnormalities.

No history of major neurological disorders.

Ability to complete standardized multimodal MRI examinations.

Provision of written informed consent.

Exclusion Criteria:

Patients with IIH:

Secondary intracranial hypertension due to cerebral venous sinus thrombosis, intracranial infection, mass lesions, hydrocephalus, or other identifiable causes.

Previous surgical or endovascular procedures substantially affecting intracranial pressure or cerebral venous drainage.

Ophthalmological or neuro-ophthalmological disorders that may interfere with visual assessment.

Recent head trauma or intracranial surgery, major brain abnormalities, or neurological disorders that may substantially affect MRI assessments; long-term use of medications considered likely to interfere with intracranial pressure or fluid metabolism.

Pregnancy or breastfeeding.

Severe systemic illness or MRI contraindications.

Inadequate baseline MRI quality or substantial missing clinical data preventing reliable analysis.

Any other condition considered unsuitable for participation by the investigator.

Healthy Controls:

History of IIH, cerebral venous disorders, intracranial mass lesions, hydrocephalus, or other neurological conditions potentially affecting brain fluid dynamics.

Ophthalmological or neuro-ophthalmological disorders that may interfere with visual assessment.

Pregnancy or breastfeeding.

MRI contraindications.

Severe systemic illness preventing completion of study examinations.

Any other condition considered unsuitable for participation by the investigator.

Study Plan

How is the study designed?

Design Details

• Observational Models: CASE_CONTROL
• Time Perspectives: PROSPECTIVE

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
IIH Patients; Sixty-five patients with idiopathic intracranial hypertension (IIH) will undergo baseline clinical, ophthalmological, and multimodal MRI assessments. Follow-up assessments will be performed at 90 ± 14 days and 180 ± 30 days after clinical treatment. Treatment, including medical management or venous sinus stenting when clinically indicated, will be determined independently by treating physicians and will not be assigned by the study protocol.
Healthy Controls; Forty healthy controls will be recruited to achieve comparable distributions of age, sex, and body mass index to those of the IIH group at the group level. Healthy controls will undergo baseline demographic assessment, noninvasive screening, and multimodal MRI only. No longitudinal follow-up or study-related invasive procedures will be performed in healthy controls.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Choroid Plexus Volume	Total bilateral choroid plexus volume (mm³) measured using structural MRI.	Baseline
Whole-Brain-Normalized Choroid Plexus Volume	Choroid plexus volume normalized to whole-brain volume, expressed as a dimensionless ratio.	Baseline
Peak Systolic Cerebrospinal Fluid Velocity in the Cerebral Aqueduct	Peak systolic cerebrospinal fluid velocity (cm/s) in the cerebral aqueduct measured using phase-contrast MRI.	Baseline
Peak Diastolic Cerebrospinal Fluid Velocity in the Cerebral Aqueduct	Peak diastolic cerebrospinal fluid velocity (cm/s) in the cerebral aqueduct measured using phase-contrast MRI.	Baseline
Mean Cerebrospinal Fluid Velocity in the Cerebral Aqueduct	Mean cerebrospinal fluid velocity (cm/s) in the cerebral aqueduct measured using phase-contrast MRI.	Baseline
Net Cerebrospinal Fluid Flow Rate Through the Cerebral Aqueduct	Net cerebrospinal fluid flow rate (mL/min) through the cerebral aqueduct measured using cardiac-gated phase-contrast MRI.	Baseline
Total Perivascular Space Volume Fraction	Ratio of MRI-visible perivascular space volume to intracranial volume, derived from structural MRI.	Baseline
Overall Diffusion Tensor Imaging Along the Perivascular Space Index	Overall diffusion tensor imaging along the perivascular space (DTI-ALPS) index derived from diffusion MRI, expressed as a dimensionless ratio.	Baseline
White Matter Free-Water Fraction	Extracellular free-water fraction in cerebral white matter estimated using diffusion MRI.	Baseline
Diffusion Tensor Imaging-Estimated Periventricular Diffusivity Index	Periventricular diffusivity (PVeD) index estimated from the transverse tensor ratio (TTR) in periventricular white matter using diffusion tensor MRI.	Baseline
Global Blood Oxygen Level-Dependent Signal-Cerebrospinal Fluid Coupling	Pearson correlation coefficient (r) between the global gray-matter BOLD signal and the CSF inflow signal derived from resting-state functional MRI.	Baseline
Whole-Brain Cerebral Blood Flow	Mean whole-brain cerebral blood flow (mL/100 g/min) measured using arterial spin labeling MRI.	Baseline
Gray Matter Cerebral Blood Flow	Mean cerebral blood flow (mL/100 g/min) in gray matter measured using arterial spin labeling MRI.	Baseline
White Matter Cerebral Blood Flow	Mean cerebral blood flow (mL/100 g/min) in white matter measured using arterial spin labeling MRI.	Baseline
White Matter Apparent Blood-Brain Barrier Water Exchange Rate	Apparent blood-brain barrier water exchange rate (AXR_BBB) in cerebral white matter estimated using vascular water exchange imaging (VEXI).	Baseline
Deep Gray Matter Apparent Blood-Brain Barrier Water Exchange Rate	Apparent blood-brain barrier water exchange rate (AXR_BBB) in deep gray matter estimated using vascular water exchange imaging (VEXI).	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cerebrospinal Fluid Opening Pressure	Cerebrospinal fluid opening pressure (mmH₂O) measured during clinically indicated lumbar puncture in patients with IIH.	Baseline
Trans-Stenotic Venous Pressure Gradient	Pressure gradient (mmHg) across venous sinus stenosis measured during clinically indicated venous manometry in patients with IIH.	Baseline
Visual Acuity	Visual acuity recorded as a numerical measure during ophthalmological examination in patients with IIH.	Baseline
Visual Field Mean Deviation	Visual field mean deviation (dB) measured using automated perimetry in patients with IIH.	Baseline
Frisén Papilledema Grade	Papilledema severity assessed using the Frisén grading scale (0-5), with higher grades indicating greater severity.	Baseline
Retinal Nerve Fiber Layer Thickness	Retinal nerve fiber layer thickness (µm) measured using optical coherence tomography.	Baseline
Headache Impact Test-6 Score	Total score on the six-item Headache Impact Test (HIT-6), ranging from 36 to 78, with higher scores indicating greater headache-related impact.	Baseline
Tinnitus Handicap Inventory Score	Total score on the Tinnitus Handicap Inventory (THI), ranging from 0 to 100, with higher scores indicating greater tinnitus-related handicap.	Baseline
EuroQol 5-Dimension Index Score	Health-related quality of life measured using the EQ-5D index value, with higher scores indicating better health status.	Baseline
Mini-Mental State Examination Score	Total score on the Mini-Mental State Examination (MMSE), ranging from 0 to 30, with higher scores indicating better cognitive performance.	Baseline
Montreal Cognitive Assessment Score	Total score on the Montreal Cognitive Assessment (MoCA), ranging from 0 to 30, with higher scores indicating better cognitive performance.	Baseline
Oral Symbol Digit Modalities Test Score	Number of correct responses on the Oral Symbol Digit Modalities Test (Oral SDMT), with higher scores indicating better information processing speed.	Baseline
Trail Making Test Part A Completion Time	Completion time (seconds) for the Trail Making Test Part A (TMT-A), with longer times indicating slower performance.	Baseline
Trail Making Test Part B Completion Time	Completion time (seconds) for the Trail Making Test Part B (TMT-B), with longer times indicating slower performance.	Baseline
Stroop Color-Word Interference Completion Time	Completion time (seconds) for the interference condition of the Stroop Color-Word Test, with longer times indicating poorer performance.	Baseline
Backward Digit Span Score	Number of digit sequences correctly recalled in reverse order, with higher scores indicating better working memory performance.	Baseline

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in Whole-Brain-Normalized Choroid Plexus Volume	Change from baseline in choroid plexus volume normalized to whole-brain volume, measured using structural MRI.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Net Cerebrospinal Fluid Flow Rate Through the Cerebral Aqueduct	Change from baseline in net cerebrospinal fluid flow rate (mL/min) through the cerebral aqueduct measured using phase-contrast MRI.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Total Perivascular Space Volume Fraction	Change from baseline in the ratio of MRI-visible perivascular space volume to intracranial volume.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Overall DTI-ALPS Index	Change from baseline in the overall DTI-ALPS index derived from diffusion MRI.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in White Matter Free-Water Fraction	Change from baseline in white matter extracellular free-water fraction estimated using diffusion MRI.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Global BOLD-CSF Coupling	Change from baseline in the Pearson correlation coefficient between the global gray-matter BOLD signal and the CSF inflow signal.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Whole-Brain Cerebral Blood Flow	Change from baseline in mean whole-brain cerebral blood flow (mL/100 g/min) measured using arterial spin labeling MRI.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in White Matter Apparent Blood-Brain Barrier Water Exchange Rate	Change from baseline in apparent blood-brain barrier water exchange rate in white matter estimated using VEXI.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Frisén Papilledema Grade	Change from baseline in papilledema severity assessed using the Frisén grading scale (0-5).	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)
Change From Baseline in Visual Field Mean Deviation	Change from baseline in visual field mean deviation (dB) measured using automated perimetry.	Baseline, 90 ± 14 days and 180 ± 30 days after clinical treatment (IIH patients only)

Collaborators and Investigators

• Sponsor: Beijing Tiantan Hospital
• Investigators: Principal Investigator: Dapeng Mo, PhD, Beijing Tiantan Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): February 1, 2028
• Study Completion (Estimated): August 1, 2028

Study Registration Dates

• First Submitted: October 29, 2026
• First Submitted That Met QC Criteria: October 29, 2026
• First Posted (Actual): November 4, 2026

Study Record Updates

• Last Update Posted (Actual): November 4, 2026
• Last Update Submitted That Met QC Criteria: October 29, 2026
• Last Verified: October 1, 2026

More Information

Terms related to this study

• Keywords: Glymphatic System; Blood-Brain Barrier; Idiopathic Intracranial Hypertension; DTI-ALPS; Multimodal Magnetic Resonance Imaging; Choroid Plexus; Cerebrospinal Fluid Dynamics; Perivascular Spaces
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Intracranial Hypertension; Pseudotumor Cerebri
• Other Study ID Numbers: HX-B-2026054

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

There is currently no plan to share individual participant data outside the study team.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No