Catheter-based angiography (with contrast) has proven to be the most accurate imaging technique: this test involves a catheter is inserted into a large artery and advanced until it reaches the vessel of question.[1] The catheter allows practitioners to view and measure the pressure of the artery aiding in the categorization and severity of the FMD diseased artery. According to Olin, “catheter-based angiography is the only imaging modality that can accurately identify the changes of FMD, aneurysm formation, and dissection in the branch vessels.” Practitioners believe it is important to utilize IVUS imaging because stenosis can sometimes only be detected through the methods of pressure gradient or IVUS imaging.[2] In addition, computed tomography angiography and magnetic resonance angiography are commonly used to evaluate arteries in the brain.