CT scan of a colloid<unk>  The diagnostic process typically begins with a medical history workup followed by a medical examination by a physician. Imaging tests, such as CT scans and MRIs, help provide a clearer picture. The physician typically looks for fluid (or other bodily substance) filled sacs to appear in the scans, as is shown in the CT scan of a colloid<unk> . A primary health care provider will refer an individual to a neurologist or neurosurgeon for further examination. Other diagnostic methods include radiological examinations and macroscopic examinations. After a diagnosis has been made, immunohistochemistry may be used to differentiate between epithelial<unk> s and arachnoid<unk> s. These examinations are useful to get a general idea of possible treatment options, but can be unsatisfactory to diagnose CNS<unk> s. Professionals still do not fully understand how<unk> s form; however, analyzing the walls of different<unk>  types, using electron microscopes and light microscopes, has proven to be the best diagnostic tool. This has led to more accurate<unk>  classification and correct course of action for treatments that are<unk>  specific. In the past, before imaging scans or tests were available, medical professionals could only diagnose<unk> s via exploratory surgery.
Central nervous system cyst
Glial tumor
Chiari malformation
Brain metastasis
Choroid plexus tumor
Brain stem tumor
Primary central nervous system lymphoma
Central nervous system cavernous hemangioma