Diffusion Tensor Imaging Along the Perivascular Space Index in Idiopathic Intracranial Hypertension

Motivation: Idiopathic intracranial hypertension (IIH) is caused by elevated intracranial pressure of unknown etiology. In recent years, growing evidence has suggested that impaired glymphatic clearance may mediate IIH pathogenesis. Goal(s): We hypothesized that individuals with IIH would exhibit impaired glymphatic outflow, which could be directly measured using diffusion tensor imaging along the perivascular space (DTI-ALPS). Approach: This work used DTI-ALPS to investigate glymphatic clearance in individuals with IIH, and its association with symptom severity and comorbidities. Results: Impaired glymphatic clearance was directly related to the clinical severity of IIH, as suggested by a lower DTI-ALPS index. Impact: We employed perivascular diffusion tensor imaging to study glymphatic flow in IIH patients. Lower ALPS index correlated with greater clinical severity, offering insights into IIH's pathomechanism and its potential for diagnosis and treatment evaluation.