Monro-Kellie Hypothesis: Increase of Ventricular CSF Volume after Surgical Closure of a Spinal Dural Leak in Patients with Spontaneous Intracranial Hypotension

MDEFT sagittal image of a male patient after surgery (A) with the corresponding FreeSurfer segmentation of gray matter (red), white matter (white), brain stem (light blue), and ventricular CSF (purple) (B).

Female patient with a myleographically proved spinal CSF leak (not shown). Upper row, MR imaging performed before spinal surgery demonstrates typical findings of intracranial hypotension—SIH score = 8: pachymeningeal enhancement (2 points), engorgement of venous sinus (2 points), effacement of the suprasellar cistern (≤4.0 mm, 2 points), no subdural fluid collection (0 points), effacement of the prepontine cistern (≤5.0 mm, 1 point), and mamillopontine distance (≤6.5 mm, 1 point). Lower row, MR imaging performed after surgery demonstrates almost complete resolution of all findings: SIH score 2, due to residual dural enhancement. Note also the decrease in pituitary size (arrow).

Mean absolute and relative change in volume between baseline and after surgical closure of the dural breach in patients with spontaneous intracranial hypotension: ventricular CSF (left, mean relative change, +18.8%, P = .001), total gray matter (middle, mean relative change, −0.9%, P = .18), and total white matter (right, mean relative change, +0.8%, P = .27).