Interventional Neuroradiology
Minimally Invasive Surgery for the Brain
Interventional Neuroradiology Service
Wake Forest University School of Medicine
Division of Radiologic Sciences
Department of Radiology
Tel: 336-716-4525 (Office)
Fax: 336-716-2029
Emergencies Night & Weekends: 336-716-2011/336-713-3603
Director: P. P. Morris, MB, BCh
e-mail: pmorris@wfubmc.edu
Introduction
The Interventional Neuroradiology Service at Wake Forest University School of Medicine offers a full array of the most advanced and innovative minimally invasive therapeutic procedures for disorders of the central nervous system. Our service works in close collaboration with the neurosurgery and neurology departments at WFUSM to assure that our patients have the benefit of a full consideration of their risks and therapeutic options before a treatment decision is made. In fact, many treatment programs or strategies for difficult disorders require a combination of neurointerventional procedures with neurosurgical or other procedures. Our facilities at WFUSM include two biplane neuroangiographic suites, an 11-bed neurointensive care unit, four dedicated spiral CT scanners, and four 1.5 Tesla MR imaging scanners with advanced capabilities in MR imaging diffusion, perfusion, and spectroscopy. Our department also includes an internationally recognized SPECT and PET center with which we collaborate closely. Because so many of the diseases with which we deal (stroke, aneurysms, arteriovenous malformations, etc.) involve significant risks to patients, the neurosciences departments at WFUSM provide the most modern and up-to-date facilities providing the greatest array of options to maximize quality of care and to minimize risk.
Illustrations of typical procedures follow:
Aneurysm Embolization with Guglielmi Detachable Coils (GDC)
Aneurysm Embolization with Detachable Balloons
Arteriovenous Malformation (AVM) Embolization
Tumor Embolization
Carotid Artery and Vertebral Artery Angioplasty and Stenting
Vertebroplasty
Carotid Cavernous Fistulas
Emergency Stroke Therapy
Aneurysm Embolization with Guglielmi Detachable Coils (GDC)
A middle-aged patient presented with headache. Twenty years ago an aneurysm of the brain ruptured and was clipped surgically. Her angiogram now shows regrowth of the aneurysm (arrow) with the overlapping surgical clip (arrowhead in A). Because of her previous operation, another operation would have been very difficulty. Consequently, it was decided in collaboration with the neurosurgery department that embolization would be a less risky option. After GDC coil embolization of the aneurysm (B), her recovery was excellent.
Aneurysms of the brain occur as a result of a weakness of the arteries that allows a bulge to develop in the arterial wall. Sometimes an aneurysm can cause headache or other symptoms, but unfortunately, most patients do not realize that they have an aneurysm until it ruptures into the coverings of the brain or around the brain. This can cause a severe neurological injury or even death, but many patients can make quite a good recovery with intensive neurosurgical care. Traditionally this treatment has involved a major brain operation with closure of the aneurysm using a surgical clip. Some patients are unsuitable for surgery or have an aneurysm that involves a high element of risk because of the location of the aneurysm, the condition of the patient, or other factors. Closure of such aneurysms (ruptured and unruptured) can often be accomplished now through embolization by means of platinum GDC coils. Under general anesthesia, a catheter is advanced from the groin to the neck within the carotid or vertebral artery. From there a microcatheter is then advanced within the main catheter with great care until the tip lies within the aneurysm. Platinum coils with a consistency less than that of a human hair can then be advanced sequentially into the aneurysm until the aneurysm is completely filled with coil material. This technology is now in worldwide use and demonstrates very satisfactory results.
Aneurysm Embolization with Detachable Balloons
Some aneurysms are unsuitable for either surgical management or embolization with GDC coils. This is particularly true for aneurysms at the base of the skull or for very large aneurysms. Occasionally, closure of a large aneurysm is managed with the least risk when a number of detachable balloons can be placed near the aneurysm. Often this involves permanent closure of the artery in question; therefore, patients must be tested in advance to assure that they can tolerate occlusion of this artery (a test occlusion). Patients who cannot tolerate loss of the artery will often need a bypass procedure before closure of the vessel. Use of detachable silicone balloons was approved by the FDA in the United States in 1998. Use of previously available latex balloons will therefore probably diminish.
Arteriovenous Malformation (AVM) Embolization
A middle-aged patient presented with an AVM near the visual area of the left hemisphere, which hemorrhaged once. Presurgical embolization was conducted to reduce the size of the AVM. Comparison of preembolization image A and postembolization image B shows the substantial reduction in size. The patient had an excellent outcome from surgery.
Arteriovenous malformations of the brain or spine are dangerous entities which can be difficult to treat. Typically AVM symptoms are due to heavy bleeding into or around the brain, most commonly in young adults. Sometimes they can cause headaches or other symptoms, but sometimes they can be identified on CT or MR imaging scans performed for other reasons. Left untreated, they have a risk of bleeding of about 4% per year. Safe surgical excision of AVMs often requires partial or complete closure of the AVM in advance using embolization techniques. This preparation improves the safety, efficacy, and outcome of surgery.
Tumor Embolization
Certain tumors of the brain and its coverings can bleed enormously during surgery. This bleeding can make the neurosurgeon's task difficult and even impossible. Surgical management for certain patients can be facilitated greatly prior to surgery by embolization of the blood vessels feeding these tumors. This can be accomplished by injecting the feeding arteries with nontoxic agents such as particles (PVA) or coils, so that the neurosurgeon is able to achieve a more complete and thorough excision of the tumor during surgery. Occasionally, malignant tumors require embolization with more caustic media such as alcohol or chemotherapy agents.
Carotid Artery and Vertebral Artery Angioplasty and Stenting
An elderly man with an occluded left carotid artery demonstrates a tight stenosis of the left external carotid artery (arrow in A). Because he had multiple occluded vessels, this was an important vessel for his tenuous blood supply. The stenosis was opened with a balloon catheter and help open with a stent (B). A magnified view of the stent shows how tiny these devices can be.
New technology developed within recent years has greatly improved our ability to open arteries using balloon catheters and stents in locations which were previously untreatable. For certain patients at risk for stroke, or those who have had previous strokes, the treatment option of least risk may involve dilating the diseased arteries with specially constructed balloons. Occasionally, it may be desirable or necessary to keep the dilated blood vessel open with a stent (a tubular wire cage) inserted over a balloon catheter. Newer devices and stents are in constant evolution, promising to make this an important option in the future treatment of stroke patients.
Vertebroplasty
An MR image shows the spine in an elderly patient (A) with advanced osteoporotic fracture due to long-standing corticosteroid treatment. Because of severe intractable pain, the patient was treated successfully at multiple levels by vertebroplasty. A view from another patient (B) shows the large needle (arrowhead) advanced into the vertebral body and the cement (arrow) as it extrudes into the bone. A CT scan in this patient (C) shows the difference between the weakened bone (arrowhead) and the dense cement (arrow).
Vertebroplasty is a relatively new procedure designed to help patients with osteoporosis of the spine. Patients lose mineralization of the bones, making them prone to compression fractures which can be very painful. It has been found that injecting the affected vertebral bodies with a special preparation of orthopedic cement can greatly relieve this pain. Furthermore, those vertebral bodies which are weakened but not yet fractured can be strengthened by injecting this cement, thus preventing future problems. Patients can usually go home from the hospital the next morning.
Carotid Cavernous Fistulas
A middle-aged patient had a carotid cavernous fistula as a result of a car accident. His right eye became swollen and distended. A loud pulsatile noise was audible over the right side of his forehead. A right carotid artery injection shows abnormal opacification of the veins of the cavernous sinus (arrows in A) due to a tear in the carotid artery resulting in the CCF. For technical reasons, the patient could not be treated successfully with balloons. Consequently, the patient was treated with coils placed in the veins around the carotid artery (arrows in B and C), completely closing the fistula. His eye then recovered satisfactorily.
A carotid cavernous fistula (CCF) occurs when a tear in the internal carotid artery behind the eye results in an abnormal communication between the artery and the surrounding veins. A similar lesion that can occur in that region with similar symptoms is a dural arteriovenous malformation (dAVM). This is a single communication or multiple small communications between arteries and veins in the dural coverings of the brain. Symptoms of a CF or of a dAVM can include headache, seizure, swelling over the eye, and the sensation of a loud, pulsatile sound within the patient's head. The ease or difficulty of treatment for this group of disorders varies greatly. Sometimes a combination of embolization and surgical techniques, either at separate times or synchronously, is necessary. This group of disorders may require treatment using a variety of devices including balloons, coils, etc., placed via either the arteries or veins.
Emergency Stroke Therapy
An elderly patient presented with acute stroke of the left cerebral hemisphere resulting in loss of speech and paralysis of the right side of her body. A left carotid angiogram (A) demonstrates that the left middle cerebral artery (arrow in A) has only one branch where it should have at least two. A microcatheter was advanced into the obstructed branch of the middle cerebral artery and a powerful clot dissolving agent, urokinase, was infused slowly. This resulted in prompt reopening of the obstructed branch (B).
|
|
A young, pregnant patient presented with neurological collapse and loss of consciousness. This was due to a clot in the basilar artery (arrows in A) at the back of the brain. With further neurological deterioration, there was no choice but to treat her aggressively. A microcatheter (arrowhead in B) was advanced into the clot. Infusion of urokinase resulted in complete reopening of the basilar artery and its branches (arrows in B). The patient made a full recovery and subsequently delivered a healthy baby.
A stroke or cerebrovascular accident (CVA), results when the brain is deprived of adequate blood supply for a critical period of time. Once this happens, brain cells begin to swell and die. Patients may experience headache, loss of strength on one side of the body, or loss of ability to communicate verbally. Strokes in some areas of the brain might be clinically silent; in other areas patients may suddenly lose consciousness completely.
Newer drugs and devices allow treatment options for stroke patients who can be brought to the hospital within a few hours of the onset of the stroke. These include administration of clot-dissolving drugs either by an intravenous infusion or by direct injection of the drug into the blocked artery. Attempting to break up the clot within the artery with a curved microwire sometimes seems to accelerate this process enormously. More effective devices that aim to break up the clot with a rotatory tip or with a powerful microjet of fluid are in development.
The information on this Website is provided for general informational purposes only and SHOULD NOT be relied upon as a substitute for sound professional medical advice, evaluation or care from your physician or other qualified healthcare provider. If you have a medical problem or a health-related question, consult your physician or call Health On-Call at 336-716-2255 or 1-800-446-2255.
Copyright: Wake Forest University School of Medicine
Division of Radiologic Sciences
P. Pearse Morris, M.B., B.Ch
All rights reserved.
Medical Center Boulevard
Winston-Salem, NC 27157
(336) 716-4525