Brain Volume Changes After Targeted Closure of Spinal CSF Leak in Spontaneous Intracranial Hypotension

BACKGROUND AND PURPOSE: To characterize brain morphometric adaptations following targeted CSF leak closure using automated volumetry. MATERIALS AND METHODS: In this retrospective, single-center, longitudinal study, 61 patients with confirmed spontaneous intracranial hypotension (SIH) who underwent targeted treatment (neurosurgical repair for dural tears; endovascular embolization for CSF-venous fistulas) were included. Brain MRI was performed at baseline, 24 hours post-treatment (n=41), and at 3-month follow-up. Bern scores and automated volumetric Z-scores of CSF, gray matter, white matter, ventricular compartments, and brainstem subregions were derived using the DL-MorphoBox research application and compared longitudinally with Wilcoxon signed-rank tests and Bonferroni correction for multiple comparisons. RESULTS: Marked radio-clinical improvement was observed at 3 months post-treatment, with increased total CSF volume (ΔZ=+0.66; p<0.001) across all ventricular compartments (p<0.001). In parallel, brain parenchymal volume decreased (ΔZ=-0.60; p<0.001), presumably driven by gray matter contraction (ΔZ = -0.57; p<0.001), involving the temporal (ΔZ =-0.46; p < 0.001), frontal (ΔZ=-0.64; p=0.01), and prefrontal (ΔZ=-0.37; p=0.007) cortices. Finaly, brainstem volume decreased as well (ΔZ=-0.27; p=0.04). The MRI-based volumetric changes were detectable as early as 24 hours post-treatment, with lateral ventricular volume expansion continuing to 3 months. While the Bern score correlated with ventricular volume variations (p<0.001), it was unrelated to gray matter contraction. CONCLUSIONS: Targeted CSF leak closure induced a rapid, subtle reorganization of intracranial compartments, primarily characterized by ventricular expansion alongside gray matter and brainstem volume contraction. Gray matter volumetric modifications were detectable even in people with low-intermediate Bern scores. This establishes quantitative volumetry as an objective monitoring tool for treatment evaluation across the full spectrum of SIH severity.