Even though in our short-time observations, CP barrier function was intact, arguing against a possible in vivo leakage of contrast-enhancing agents into the CP cavities, a comparison of 5 min and 4 h post-intravenous (IV) administration of a single dose of gadolinium-based contrast agents in a small cohort of patients with clinically suspected endolymphatic hydrops revealed significant leakage of contrast agents into the CSF spaces only at 4 h, but not at 5 min post-IV35. Here, CP is linked to endolymphatic hydrops.