Feasibility of Intra- and Post-operative Microdialysis During Neurosurgery for Central Nervous System Lesions

Inclusion Criteria:

* Age \>= 18 years
* Diagnosis of the following, based on clinical and radiographic evidence:

  * Any glioma
  * Metastatic brain tumor of any primary origin
  * Epileptic focus requiring surgical resection
* Planned neurosurgical procedure for purposes of biopsy or resection of suspected or previously diagnosed brain tumor (primary or metastatic) or epileptic focus as part of routine clinical care
* Willing to undergo neurosurgical resection or biopsy at Mayo Clinic \[Rochester, Minnesota (MN)\]
* For patients with gliomas recruited for post-operative microdialysis, willingness to stay in the hospital through post-operative day (POD) 3-5 (timing per physician and patient's shared decision making)
* Ability to understand and the willingness to sign a written informed consent document
* Enrollment into the Biobank study (IRB#12-003458)

Exclusion Criteria:

* Vulnerable populations: pregnant women, prisoners or the mentally handicapped
* Patients who are not appropriate candidates for surgery due to current or past medical history or uncontrolled concurrent illness