The purpose of this study is to use a wire with a Doppler tip to measure blood flow in vessels in the brain and determine hemodynamic factors associated with treatment success or failure. Many neurological diseases cause abnormal blood flow in the brain in specific vessels. The special wire used in this study is place into brain blood vessels during standard of care procedure to treat such diseases, and blood flow parameters (such as velocity and pressure) are measured to gain better understanding of these neurological diseases.

Current treatments of cerebral aneurysms are imperfect, and aneurysmal hemodynamics is an important factor in treatment failure. The identification of hemodynamic factors that influence treatment success could predict outcome. Published studies show that the hemodynamic environment of aneurysms changes after treatment, and there is limited retrospective evidence that the degree of change affects treatment success. However, previous hemodynamic calculations did not have access to patient-specific measurements of blood flow, which substantially reduced their accuracy. In addition, no prospective studies of the predictive value of post-treatment aneurysm hemodynamics have been done.

Methods: Prospectively test new aneurysm patients for hemodynamic predictors of treatment outcome based upon the hypothesis long-term aneurysm treatment outcome can be prospectively predicted by measuring the immediate hemodynamic effects of aneurysm treatment with novel patient-specific modeling techniques. Task 1: In a new cohort of patients undergoing aneurysm treatment, the investigators will again use Doppler guidewire measurements to create patient-specific hemodynamic models of treatment effects. By prospectively applying the knowledge of crucial hemodynamic changes the investigators will use immediate post-treatment hemodynamics to predict long-term treatment outcome.

Inclusion Criteria:

• Patient with an unruptured intracranial aneurysm ≥ 5mm in size undergoes endovascular treatment and subsequent angiographic follow-up

Exclusion Criteria:

-previously enrolled in the study

Patients will be eligible for this aim if they were not previously enrolled in the study, as this phase seeks to prospectively apply the tests generated by the previous retrospective cohort. Selection criteria will be similar in which a patient with an unruptured intracranial aneurysm ≥ 5mm in size undergoes endovascular treatment and subsequent angiographic follow-up.