The Cerebrovascular Lab at Harborview performs ultrasound testing that aids physicians in diagnosis and treatment of issues related to blood flow in the vessels of the head and neck. The tests offered at the Cerebrovascular Lab look at velocity, directionality and patency of major intracranial vessels using ultrasound, a safe non-invasive imaging technology. The tests are painless and require no preparation.
The Cerebrovascular Lab at Harborview has served the community since 1988, setting the standard for specialty diagnostic procedures that require the highest level of expertise. Our neurosurgeons have a combination of ability, knowledge and experience unparalleled in the region. They seamlessly combine cutting edge neurosurgical technology and compassionate patient care to solve complex cerebrovascular conditions of the brain, spine and neck. Every sonographer on our team is a Registered Vascular Technologist with the American Registry of Diagnostic Medical Sonography (ARDMS) and is specifically trained in the latest cerebrovascular ultrasound technologies. Together, our sonographers have over 45 years of experience. The Cerebrovascular Lab is fully accredited by the Intersocietal Accreditation Commission (IAC) for intracranial testing.
The Cerebrovascular Lab at Harborview offers a full spectrum of tests for the assessment of cerebrovascular disease and injury. The results of these tests give your physician or neurosurgeon important information about the blood vessels that supply your brain. If you have had a stroke, cerebral hemorrhage or cerebral bypass surgery, your physician may refer you to the Cerebrovascular Lab for testing or a post-procedure evaluation. You may also be referred for screening for thrombosis, embolism and aneurysm or neurologic symptoms that suggest vascular disease.
Please note that appointments are by referral only.
Diagnostics and testing
Agitated Saline Study (Bubble Study)
An agitated saline study evaluates the flow of blood through the chambers of the heart. During an agitated saline study, your physician introduces microscopic saline bubbles into your circulation. You will then be asked to perform a “valsalva maneuver” or straining motion such as when trying to make your ears pop. In a normal heart, bubbles remain on the right side of the heart. If bubbles are seen in one of the left chambers of the heart, it means that they took a shortcut instead of proceeding directly into the lungs (where the bubbles dissipate). The finding indicates a right to left shunt at the level of the atria, a patent foramen ovale (a small slit in the heart’s upper chambers), or at the level of the ventricles, a ventricular septal defect. If you do have a shunt, an agitated saline study will often be able to quantify its size.
A carotid duplex exam uses ultrasound to evaluate blood flow in the carotid arteries of the neck. The exam may also look at the vertebral and subclavian arteries. A carotid duplex exam can detect and quantify blockage (occlusion) or narrowing (stenosis) caused by a blood clot (thrombus) or plaque, as well as identify and characterize plaque. A carotid duplex can also detect and locate a torn artery wall (dissection).
CO2 Challenge (Vasomotor Reactivity)
A CO2 challenge or vasomotor reactivity study determines your brain’s capacity to regulate its own blood flow in response to changes in CO2 levels. Blood flow to the brain may be reduced due to disease, stenosis or completely blocked arteries. A CO2 challenge is able to identify those issues (without the use of radioactive dye), and screen for patients at risk of stroke and/or in need of (neuro)surgery.
After a cerebral bypass surgery, ultrasound is used to monitor the extracranial to intracranial bypass graft, including graft patency and function as well as flow dynamics within the graft. Ultrasound is non-invasive, relatively inexpensive and allows patients to avoid the radiation of a computer tomography angiography (CTA).
Head Rotation Study
Rotation of the head and neck has been known to stress blood vessels in certain circumstances such as when vertebral bone spurs, degenerative changes or malformations can pinch off blood flow. A head rotation study is a diagnostic tool used to determine the extrinsic compression of the vertebral or carotid arteries during head turning.
Tilt Autoregulation Studies
A tilt autoregulation test determines the brain’s ability to keep a steady blood supply (autoregulation) by measuring your blood pressure and pulse as you lie on a table and you sit up while being monitored with ultrasound and blood pressure. Your doctor may use this information to understand how best to manage your blood pressure.
Transcranial Doppler (TCD) and Transcranial Imaging (TCI)
Transcranial Doppler and transcranial imaging exams use ultrasound to evaluate the direction and velocity of blood flow through the blood vessels in the brain. A TCD or TCI can detect narrowing of the blood vessels (stenosis), coagulation or clotting (thrombosis) or blockage (vascular occlusion). Often these exams are used to serially follow intracranial stenosis and look for recanalization post tPA (tissue plasminogen activator). Transcranial Doppler and transcranial imaging exams also detect the narrowing of vessels known as vasospasm that can appear after a subarachnoid hemorrhage (bleeding from a burst aneurysm or head injury).
Transcranial Doppler Emboli Monitoring
Transcranial Doppler emboli monitoring uses ultrasound to detect particulates within the bloodstream (emboli) that may block a vessel in the brain and cause a transient ischemic attack (TIA) or stroke. Emboli reflect ultrasound more intensely than surrounding red blood cells and typically generate a characteristic sound; the presence of embolic signals helps to detect the migration of clots or plaque from injured or diseased vessels, infected heart valves (endocarditis), deep venous thrombosis (DVT), femur fracture, or from a cardiac source in the intracranial circulation.
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