Prognosticators of Optic Nerve Imaging in Malignant Pseudotumor Cerebri Syndrome.

Background: Pseudotumor cerebri (PTC) syndrome is a disorder of increased intracranial pressure, most commonly affecting overweight women of childbearing age. Malignant PTC (MPTC) is a rare presentation that involves rapidly worsening vision, often necessitating surgical intervention to prevent permanent vision loss. The goal of this study was to determine whether radiographic findings of PTC are predictive of MPTC and the final visual outcome.

Methods: Charts of patients diagnosed with PTC based on the modified Dandy criteria were reviewed. Snellen best-corrected visual acuity (BCVA), automated perimetry mean deviation (APMD), and papilledema grade were documented from the initial and final follow-up examinations. The MRI images were read by 2 neuroradiologists blinded to the clinical diagnosis, and consensus findings were obtained. The patients were classified into malignant and nonmalignant PTC groups. Malignant was defined as BCVA ≤ 20/200 or APMD ≤ -7 dB, and acute onset of symptoms. The sensitivity and specificity of each MRI finding for detecting MPTC was determined. Generalized linear model with random effect and backward model selection was performed to identify which radiographic findings were predictive of final BCVA, APMD, and papilledema grade.

Results: Overall, 114 eyes (57 malignant/57 nonmalignant) were included. No MRI finding has both sensitivity and specificity for MPTC reaching 60%. The highest sensitivity (86%) was flattening of the posterior globes and unilateral or bilateral transverse sinus stenosis. The highest specificities were completely empty sella (86%), enhancement (84%), and diffusion restriction (81%) of the prelaminar optic nerves. The presence of vertical tortuosity of the optic nerves was predictive of better final BCVA (P = 0.003) and better final APMD (P = 0.011). While papilledema grade was higher in MPTC, no MRI finding was predictive of papilledema grade.

Conclusions: No single MRI finding has both high sensitivity and specificity for diagnosing MPTC. Vertical tortuosity of the optic nerves may be predictive of better final BCVA and APMD.