Neurointerventional Radiology (NIR) is a specialized field focused on diagnosing and treating central nervous system diseases using minimally invasive techniques. This specialty combines advanced medical imaging with endovascular procedures to address problems within the brain, spine, neck, and associated structures. Physicians use the body’s circulatory system—the blood vessels—as a pathway to reach and treat neurological conditions from inside the arteries or veins. This approach allows for targeted therapeutic action, offering an alternative to traditional, open neurosurgery.
The Core Concept of Neurointerventional Radiology
The methodology in Neurointerventional Radiology relies on real-time, sophisticated imaging to guide precise navigation within the body’s vasculature. Procedures begin with a small puncture, typically in the femoral artery or the radial artery, which serves as the access point. This small entry point eliminates the need for large incisions or opening the skull (craniotomy) to reach the treatment site.
A thin, flexible guide catheter is inserted through the puncture and threaded through the arteries toward the cerebral circulation. Real-time imaging, such as digital subtraction angiography (DSA) or biplane fluoroscopy, uses X-rays and contrast dye to create a detailed map of the vessels, allowing the physician to steer the instruments. Specialized microwires and micro-catheters are then advanced through the guide catheter to the exact location of the disease or blockage. This endovascular approach is performed entirely from within the blood vessel, contrasting with open surgical methods.
Neurological Conditions Addressed
Neurointerventional Radiology primarily treats vascular diseases that disrupt blood flow to the brain and spine. A common application is treating cerebral aneurysms—weak, bulging spots in a vessel wall that risk rupturing and causing a hemorrhagic stroke. NIR techniques stabilize the compromised vessel, addressing both saccular and fusiform aneurysms.
The field is also essential in managing acute ischemic stroke, which occurs when a blood clot obstructs an artery. Neurointerventionalists rapidly clear these blockages to restore blood flow and minimize brain damage. The specialty also addresses complex congenital abnormalities like Arteriovenous Malformations (AVMs) and Arteriovenous Fistulas (AVFs). These are abnormal connections between arteries and veins that bypass the capillary network, potentially causing bleeding. Beyond vascular disorders, NIR is used for targeted treatment of spinal compression fractures and to reduce the blood supply to highly vascularized head, neck, and spinal tumors before traditional surgery.
Common Therapeutic and Diagnostic Procedures
A foundational diagnostic procedure is cerebral angiography, which involves injecting contrast material into the blood vessels and capturing detailed X-ray images. This maps the blood flow and identifies abnormalities such as narrowing or malformations, often serving as the first step in planning intervention.
Mechanical thrombectomy is the standard of care for many large vessel acute ischemic strokes. During this intervention, a specialized clot-retrieval device, often a stent retriever, is deployed past the clot via a micro-catheter. The device expands into the clot, allowing the physician to pull the blockage out of the vessel and restore blood flow to the brain tissue.
Two main endovascular methods treat cerebral aneurysms: coiling and flow diversion. Coiling involves filling the aneurysm sac with tiny platinum coils that promote clotting, sealing the bulge off from circulation and preventing rupture. Flow diversion uses a specialized stent placed across the neck of the aneurysm. This slows blood flow into the sac, diverting it along the parent artery. Over time, this encourages a new vessel wall barrier to form, permanently excluding the bulge.
Another common therapeutic action is embolization, which intentionally blocks blood flow to specific areas. This technique treats AVMs and AVFs by injecting liquid embolic agents or microscopic particles directly into the abnormal vessels. Embolization is also employed pre-operatively to reduce blood loss during the surgical removal of highly vascular tumors.
Comparing Neurointerventional Radiology to Open Surgery
Neurointerventional Radiology procedures offer advantages compared to traditional open neurosurgery, such as a craniotomy for aneurysm clipping. The endovascular approach is performed through a small skin puncture, avoiding large incisions and trauma to surrounding healthy tissue.
This reduced invasiveness leads to a lower risk of complications, including infection and blood loss. Patients typically experience shorter hospital stays, often requiring only a day or two of observation. The recovery period is also faster, allowing patients to return to normal activities sooner than the weeks or months required after open brain surgery.