Arachnoid cysts represent benign cysts that occur in the cerebrospinal axis in relation to the arachnoid membrane and do not communicate with the ventricular system. They usually contain clear, colorless fluid that is most likely normal cerebrospinal fluid, but they rarely contain xanthochromic fluid. Most are developmental anomalies. On MRI, arachnoid cysts appear as well-defined nonenhancing intracranial masses that are isointense to CSF.
Dr.Sumer K Sethi, MD
Sr Consultant Radiologist ,VIMHANS and CEO-Teleradiology Providers