INTERVENTIONAL NEURORADIOLOGY: APPLICATIONS, RISKS, LATEST ADVANCEMENTS, AND MORE

Medically Reviewed by Dr. Rosmy Barrios

Interventional Neuroradiology (INR) is a rapidly growing field that has revolutionized the treatment of neurological conditions. This minimally invasive approach uses image-guided procedures to identify and correct a wide variety of neurological disorders, including stroke, aneurysms, and spinal disorders. With shorter hospital stays, faster recovery times, and reduced potential for complications, INR has become an integral part of neurological care.

This article probes the role of interventional neuroradiology in neurological care, its benefits, procedures, advancements, and how it compares to traditional neurosurgery.

What is Interventional Neuroradiology?

Interventional Neuroradiology (INR) is a subspecialty of radiology that concentrates on the diagnosis and treatment of neurological conditions using minimally invasive image-guided surgical procedures.

Most of these procedures involve using catheters inserted into blood vessels in the brain to deliver treatment directly to the affected area. This precise navigation allows for targeted therapy and lessens potential damage to nearby tissue.^[1]

The most significant difference between INR and neurosurgery lies in the approach used. As mentioned above, INR is minimally invasive, which can minimize damage and speed recovery time, whereas traditional neurosurgery is invasive, involving larger incisions and more extensive procedures.

INR procedures are performed by interventional neuroradiologists, who are highly trained and specialized in this field. They use advanced imaging techniques such as angiography and CT scans to guide their procedures and ensure the accurate placement of catheters.

Types of Interventional Neuroradiologists

Interventional neuroradiologists can specialize in different areas, such as stroke, vascular conditions, or spinal compression treatment.

Each type of interventional neuroradiologist has specific expertise in treating conditions related to their specialty. Common examples include:

• Stroke: These interventional neuroradiologists specialize in treating stroke-related complications, such as blocked arteries in the brain.
• Vascular: Vascular interventional neuroradiologists focus on treating conditions related to the blood vessels, such as aneurysms and arteriovenous malformations (AVMs).
• Vertebral: Interventional neuroradiologists specialized in correcting herniated discs, spinal stenosis, and other spinal conditions.

Typical INR Applications

INR procedures have applications in diagnosing and treating many neurological conditions. Some of the most common applications of INR include:

• Stroke Treatment: INR procedures can treat ischemic strokes by delivering medication directly to the affected area to dissolve blood clots.
• Brain Tumor Treatment: INR can deliver chemotherapy or radiation directly to a brain tumor, helping to preserve healthy brain tissue.
• Spinal Disorders: INR procedures can correct spinal disorders such as herniated discs^[2] and spinal stenosis.
• Arteriovenous Malformation (AVM) Treatment: AVMs are abnormal blood vessel tangles that can cause brain bleeding. INR procedures can block off these vessels and prevent bleeding.
• Aneurysms: An aneurysm is a bulge in the wall of a blood vessel due to weakening, which can rupture. INR procedures can divert blood away from the area and help to repair it.

Types of INR procedures include diagnostic procedures and treatment options, which can help those with all the above conditions.

Diagnostic Procedures

• Angiography: Involves injecting contrast dye into blood vessels and using X-rays to create detailed vasculature images. This helps identify blockages, aneurysms, AVMs, and other vascular abnormalities.
• CT Angiography (CTA): Combines a CT scan with the injection of a contrast dye. This procedure provides even more explicit images of blood vessels than standard angiography.^[3]
• Intravascular Ultrasound (IVUS): A tiny ultrasound probe is placed on a catheter and inserted into a blood vessel to get detailed images from within.^[4]

Treatment Procedures

• Thrombectomy: Used for acute ischemic stroke treatment. A specialist guides the catheter to the blood clot in the brain, which is removed mechanically or with clot-dissolving drugs (thrombolysis).
• Aneurysm Coiling: Used to prevent the rupture of a brain aneurysm. A catheter reaches the aneurysm and fills it with a tiny platinum coil, reducing blood flow and preventing a potential rupture.^[5]
• Aneurysm Flow Diversion: A more advanced aneurysm treatment. A mesh-like stent is placed across the neck of the aneurysm, redirecting blood flow away from it and promoting healing.^[6]
• Embolization: Used to cut off blood supply to areas like tumors or arteriovenous malformations (AVMs). Various materials, including coils, glue, or tiny beads, are injected through a catheter to block the blood vessels.
• Ultrasound-Guided Heat Therapy: Ultrasound-guided heat ablation therapy is a minimally invasive procedure that utilizes ultrasound imaging to direct the precise delivery of heat to target tissues, such as brain tumors. This therapy shows great promise in the treatment of various conditions, offering a safe and effective alternative to traditional surgical methods.^[7]
• Angioplasty and Stenting: Used to widen narrowed or blocked blood vessels. A radiologist inserts a catheter with a balloon tip, inflating the balloon to open the vessel. A well-placed stent may keep the vessel open. This technique can prevent extra cuts and other catheter complications when working in finer areas.
• Vertebroplasty and Kyphoplasty: Used to treat vertebral compression fractures in the spine. Cannulas and needles are used to inject bone cement directly into the fractured vertebrae, providing stability and pain relief.^[8]

How are Interventional Neuroradiology Procedures Performed?

All INR procedures are minimally invasive and typically occur on an outpatient basis with an endovascular approach. This means that most procedures work from within blood vessels to reach the brain and that patients can go home the same day, minimizing their hospital stay and promoting faster recovery. Patients can continue regular activities within a few days. The minimally invasive nature of INR also means less pain and discomfort during and after the procedure.

Fluoroscopy (real-time X-ray), CT scans, MRI, or ultrasound are used throughout all procedures to guide precise catheter placement, device deployment, and monitor treatment. INR procedures are sometimes known as endovascular surgeries.

The procedure begins with the administration of a local anesthetic that numbs the area around the insertion site of the catheter. The interventional neuroradiologist creates a small incision, usually in the leg, and inserts the catheter into a blood vessel. The catheter navigates blood vessels to reach the affected area, or near enough to treat it, using advanced imaging techniques.

Once the catheter is in place, the interventional neuroradiologist can perform the necessary treatment, such as delivering medication to dissolve a blood clot or positioning a stent to widen a blocked artery. After the main objective is complete, the surgeon removes the catheter and closes the incision.

Imaging techniques ensure accuracy and safety while monitoring the entire procedure.

Risks, Side Effects

As with any medical procedure, INR poses a few potential risks and side effects.

Common side effects that often occur just after the procedure include:

• Discomfort at the Insertion Site: Pain, bruising, and mild swelling at the catheter insertion site are common and usually subside within a few days.
• Headache and nausea: These may occur temporarily after the procedure.

The risk of complications after an INR procedure is significantly lower than with open neurosurgery. The complications may include:

• Contrast dye reactions: Allergic reactions to the contrast dye used for imaging can occur, including nausea, hives, or, in rare cases, more severe reactions.
• Infection: There's a small risk of infection at the insertion site.
• Bleeding: There's a risk of bleeding at the insertion site or, more rarely, within the blood vessels in the brain.
• Stroke: Though INR procedures can treat stroke, there is a small risk of stroke occurring during the procedure itself if blood clots get dislodged or the blood vessels get damaged.
• Vessel perforation: The catheter could puncture a blood vessel, leading to bleeding.
• Kidney damage: Contrast dye can tax the kidneys, especially for patients with pre-existing kidney problems.

In addition to these complications, some risks pertain to specific INR procedures.

• Aneurysm coiling/flow diversion: Ruptured aneurysms can re-bleed even after treatment, and there's a small risk of devices moving out of place.
• Embolization: Non-target embolization means the embolic material accidentally blocks an unintended blood vessel.

It is helpful to discuss the potential risks and side effects with your interventional neuroradiologist before undergoing a procedure. They will also provide instructions and precautions for the patient before and after the procedure to ensure a successful outcome.

Latest Advancements in Interventional Neuroradiology

INR is a rapidly evolving field, with continuous new advancements improving patient outcomes. Some of the latest advancements in INR include:

• Robotic Assistance: Robotic assistance during some INR procedures, such as aneurysm coiling procedures, improves their precision and reduces the risk of complications.^[9]
• Personalized Treatment: With 3D printing^[10] and AI-assisted interventions, interventional neuroradiologists can create personalized treatment plans for each patient, resulting in better outcomes.
• Gene Therapy: INR is being used in gene therapy to deliver genetic material directly to the brain, potentially treating conditions such as Parkinson's disease and Alzheimer's disease. While gene-based therapies show promise in animal studies, there are still many hurdles to overcome with INR administration, such as blood-brain barrier resistance.^[11]
• Stem Cell Therapy: INR also has applications in stem cell therapy to deliver stem cells directly to the brain, potentially treating conditions and their complications, including stroke and traumatic brain injury. Better delivery methods are currently under development, such as the use of spherical cell clusters or spheroids.^[12]
• Mapping Neurovascular Pathways: With advancements in imaging techniques, interventional neuroradiologists can now map the neurovascular pathways in the brain, allowing for more precise treatment.
• Biocompatible Steerable Catheter: Researchers developed a steerable catheter (inspired by insect legs) that continuously compresses saline solution into the tip. This simple design minimizes risks associated with conventional catheters, including the odds of malfunction and bleeding if the catheter leaks saline through a breach. Controlled by a handheld device, it enables precise navigation of brain blood vessels, potentially treating conditions such as difficult-to-reach aneurysms.^[13]

Conclusion

Interventional Neuroradiology has revolutionized the treatment of neurological conditions, benefiting patients with shorter hospital stays, faster recovery times, and reduced potential for complications. With advancements in technology and techniques, INR continues evolving, providing patients with personalized treatment options and improved outcomes. While it does not replace traditional neurosurgery, INR offers a minimally invasive alternative for treating a wide range of neurological conditions. If you or a loved one is facing a neurological condition, consider consulting with an interventional neuroradiologist to explore your treatment options.

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