Structural MRI Biomarkers of Intracranial Pressure in IIH: Linking Optic Nerve Sheath, Pituitary Morphology, and Hormonal Changes

Purpose: To investigate the relationship between intracranial pressure (ICP), anterior pituitary hormones, and structural brain changes in women with idiopathic intracranial hypertension (IIH). Methods: Eighteen women with therapy-refractory IIH underwent lumbar puncture, endocrine assessment, and high-resolution brain MRI. Serum levels of pituitary hormones were correlated with ICP and radiological parameters including pituitary volume, flattening, and optic nerve sheath (ONS) volume. Group comparisons, partial correlations, and regression models were used to evaluate associations. Results: ICP was significantly associated with higher thyroid-stimulating hormone (TSH) levels ( r  = 0.628, p  = 0.0163), which emerged as a robust predictor of ICP in both linear (β = 4.8348, p  = 0.017) and Huber regression models (coefficient = 0.070817, p  < 0.001). Growth hormone (GH) was negatively associated with ICP ( r = -0.602, p  = 0.023) and reached significance in robust modeling (coefficient = -0.023842, p  = 0.041). Insulin-like Growth Factor 1 (IGF-19 and testosterone levels were significantly lower in patients with elevated ICP (IGF-1: p = 0.039; testosterone: p  = 0.027). Volumetric MRI revealed no group difference in pituitary volume, but flattening and complete empty sella were more frequent in patients with elevated ICP. ONS volumes correlated with ICP only in the normal ICP group (left: r  = 0.804, p  = 0.054; right: r  = 0.797, p = 0.058), suggesting a ceiling effect at higher pressures. Conclusion: Elevated ICP in IIH is linked to functional changes in the thyroid and somatotropic axes, as well as structural alterations in the pituitary gland and ONS. Combining quantitative MRI with endocrine profiling may improve diagnostic accuracy, help identify patients at risk, and support individualized treatment strategies.