Advanced Neuroimaging in Idiopathic Intracranial Hypertension

Pathophysiological Evaluation of Idiopathic Intracranial Hypertension Using Glymphatic and Connectomic Imaging

Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure leading to symptoms like papilledema, headache, and cognitive dysfunction. While the etiology is complex, abnormal cerebrospinal fluid dynamics due to venous outflow restriction from transverse sinus stenosis (TSS) is common. TSS may disrupt the glymphatic system, a brain-wide network facilitating cerebrospinal fluid and interstitial fluid exchange, by impairing CSF absorption, altering perivascular space dynamics, and disrupting pressure gradients crucial for waste clearance. Venous sinus stenting (VSS) can improve symptoms in many patients by alleviating venous congestion, but its effects on glymphatic function are unclear. This prospective study aims to evaluate novel quantitative brain imaging metrics as surrogate markers to better understand IIH pathophysiology before and after VSS in patients with refractory IIH and TSS. The investigators will use advanced MRI techniques, including MR elastography (MRE) to assess brain stiffness, diffusion tensor imaging (DTI) to evaluate water diffusion, arterial spin labeling (ASL) imaging to measure blood-brain barrier (BBB) permeability, and functional MRI to analyze pain networks. The investigators hypothesize that 1) these noninvasive imaging metrics will correlate with the degree of venous congestion and changes after venous sinus stenting (VSS) and 2) the imaging findings will correlate with clinical treatment outcomes. By correlating imaging markers with venous pressures and symptom changes, the investigators aim to gain insights into IIH mechanisms, expand diagnostic tools, and potentially guide clinical decision-making and treatment response monitoring. The overarching goal is to better understand IIH's underlying pathophysiology, which could lead to improved diagnostic criteria, more targeted treatments, and better prediction of treatment outcomes for patients with this challenging condition.

Inclusion Criteria:

• Refractory IIH patients who require and plan to have a venous sinus stenting

Exclusion Criteria:

• History of head trauma and shunting or leak repair
• Major concurrent, active non-cephalic pain syndrome
• Contradictions for MRIs