Analysis of Neuroradiologic Findings in Idiopathic Intracranial Hypertension-A Population-Based Study.

Background: Idiopathic intracranial hypertension (IIH) has been associated with several MRI features. We assessed types of MRI findings and clinical-radiologic correlations in patients with IIH from one hospital system.

Methods: A retrospective chart review of IIH and control patients was conducted. Brain MRI/magnetic resonance venogram features were enumerated and assessed for correlation with body mass index (BMI) and lumbar puncture opening pressure (LPOP). Sensitivity, specificity, positive predictive value (PPV), and likelihood ratios (LRs) were calculated for each MRI sign. Significance was set at P < 0.05.

Results: One hundred one patients diagnosed with IIH, and 119 control patients had complete files and were included. Patients with IIH were predominantly female (92.8% vs 59.7%; P = <0.001), younger (30.6 years vs 46.4 years; P < 0.001), and more obese (mean BMI = 35.2 vs 29.3; P < 0.001) than controls. Mean (SD) number of MRI findings was 2.21 (1.8) in IIH and 0.6 (1.2) in controls; (P < 0.001). Vertical nerve tortuosity (44.1%; P < 0.001), TVSS (37.8%; P < 0.001), sheath expansion (36.0%; P < 0.001), globe flattening (22.5%; P < 0.001), slit ventricles (18.9%; P < 0.001), optic disc protrusion (9.9%; P = 0.007), and complete empty sella (12.6%; P < 0.042) were observed more in patients with IIH than control patients. In the IIH group, mean (SD) LPOP was 33.6 (11.11) cmH2O and weakly correlated with number of MRI findings (rho = 0.182, P = 0.057). TVSS (sensitivity 37.84%; confidence interval [CI] 29.3%-47.2%, specificity 98.32%; CI 93.5%-99.6%) had the highest PPV (95.45%) and positive LR (22.51) for IIH diagnosis.

Conclusions: These results are consistent with IIH predominance in young, obese females. In patients with IIH, the number of MRI findings exceeded controls and positively correlated with LPOP. TVSS was most predictive of IIH.