What is Neuroradiology

Is a subspecialty of radiology devoted to diagnosis and treatment of conditions affecting the brain, spine, and other parts of the nervous system. Training in neuroradiology involves an additional 1-2 years of fellowship after successful completion of a 4-year radiology residency. Texas Radiology Associates is fortunate in having several highly skilled neuroradiologists in the group, all of whom have been recognized with the American Board of Radiology’s Certificate of Added Qualification in neuroradiology.

Common diagnostic procedures in neuroradiology include CT scanning (originally known as CAT scanning), magnetic resonance imaging (MRI), myelography, discography, and arteriography. Interventional procedures in neuroradiology are quite diverse, ranging from spinal biopsy to complex vascular procedures. A brief overview of the most common procedures in neuroradiology is given here. If you have been scheduled to undergo one of these procedures and have questions, please feel free to contact us for more information.

Angiography

Arteriography

Blood patch

This procedure is done in selected cases after lumbar puncture or another similar procedure. A few patients who’ve undergone lumbar puncture may have a prolonged headache that isn’t responsive to pain medication. We think this is due to continued leakage of spinal fluid from the puncture site. A ‘blood patch’ is designed to plug the leak and allow the volume of spinal fluid to return to normal, alleviating the headache. The procedure for blood patch is very similar to lumbar puncture itself (see below). Once the needle is in place, a small amount of the patient’s blood is injected right next to the hole from the previous puncture. It then clots and seals the hole. Preparation and precautions for blood patch are identical to those for lumbar puncture. 

CT scanning

CT scanning, originally known as CAT scanning, is used to obtain cross-sectional images of the brain, spine, or other parts of the body. It is probably the most frequently performed test in neuroradiology. 

Cisternography

This procedure is done to evaluate the flow of CSF (cerebrospinal fluid) within the central nervous system. CSF is the clear, colorless fluid that cushions the brain and spinal cord. Normal flow patterns can be disrupted in various conditions affecting the brain or spinal cord, and diagnosis of the particular flow problem can be important in determining appropriate therapy for the underlying condition. 

Cisternography is a nuclear medicine procedure that involves injecting a small amount of a radiotracer, or isotope, into the spinal column in the lower back. Movement of the tracer is then observed by taking images of the head and spine with a special camera that detects the tiny amounts of radiation from the isotope. Preparation for this procedure…..
No special precautions are needed afterwards other than those described below for lumbar puncture.

Discography

Discography is a specialized procedure designed to help determine which level in the spine is causing a patient’s pain or other symptoms. It is particularly useful when there are several levels that are abnormal but it’s not clear which one is most important based on the imaging studies alone. Discography can be done in all parts of the spine, including the cervical (neck), thoracic (upper back), and lumbar (lower back) regions.

Discography involves placing a small needle into one or more spinal discs, followed by injection of a small amount of dye into the disc itself. The discs are like cushions between the bones of the spine, and are prone to rupture or ‘herniation’, which can put pressure on nerves and cause pain and other symptoms. The procedure is done by a radiologist in a fluoroscopy suite so that needle placement can be carefully monitored. The radiologist is assisted by a nurse, who closely monitors the patient, and a technologist, who helps run the fluoroscopy equipment and provides needed items to the physician. The patient’s response to dye injection at a given level (ie, reproduction of pain or other symptoms) helps determine the significance of any abnormal findings at that level on other tests, such as MRI or myelography. 

Embolization

Embolization is an arteriographic procedure (see arteriography) that is done to block off or reduce flow in abnormal blood vessels. This may be needed due to bleeding from trauma or other causes, or to reduce blood flow to an area prior to surgery. Other indications for embolization include treatment of aneurysms (small balloon-like areas in an artery due to weakness in the vessel wall) and arteriovenous malformations (abnormal connections between arteries and veins that can cause bleeding and other complications). During embolization, small particles of a sponge-like material or other agents are injected into the abnormal blood vessels, causing clot to form within them. This eliminates or greatly reduces the flow in the abnormal vessels. In neuroradiology, embolization is often done in conjunction with surgery to treat arteriovenous malformations, tumors, and other conditions.

Intrathecal chemotherapy

This procedure involves injecting a chemotherapy drug (or a combination of several drugs) into the spinal fluid. Certain types of cancer can involve the spinal fluid or the surface of the brain or spinal cord, areas that are impossible to treat with conventional, intravenous chemotherapy. In this procedure, a lumbar puncture is performed, generally by a radiologist with fluoroscopic guidance, and the drugs are injected after removing a small amount of spinal fluid. Preparation and precautions for this procedure are similar to those for lumbar puncture.

Lumbar puncture

Lumbar puncture (‘spinal tap’) may be done for a variety of reasons. In most cases, the reason is to obtain a small amount of spinal fluid for laboratory analysis. This is important in cases of suspected spinal fluid infection (meningitis) or certain other conditions in which the fluid may be abnormal (such as multiple sclerosis, certain types of cancer, and many others).

The procedure involves placing a tiny needle into the spinal canal in the lower back, generally with the patient lying flat on his/her stomach. Fluoroscopy may be used to guide needle placement, or placement may be guided by palpation of anatomic landmarks. Once the needle is in place, fluid is withdrawn and placed in sterile tubes. These are sent to the lab for any tests that have been ordered by the patient’s physician or by the radiologist performing the procedure. The needle is then removed, and a bandage placed on the puncture site. 

No special preparation is needed prior to lumbar puncture. Afterwards, some patients may have a headache. This can be avoided in most cases by lying flat for 4 hours after the procedure. No other special precautions are required. 

Magnetic resonance imaging (MRI)

MRI is a relatively new method of making images of any part of the body without using x-rays. It uses the inherent magnetic properties of body tissues to create images based on their response to the magnetic field of the scanner, and has had a huge impact on neuroradiology. MRI is tremendously valuable in assessing the brain and spinal cord, as well as the bony spine itself and the nerve roots that travel from the spinal cord to various parts of the body.

MRI has been shown to be quite safe, except for certain patients. Patients who have cardiac pacemakers should NOT undergo MRI, as the powerful magnetic field of the scanner can cause the pacemaker to malfunction. Certain other types of implants, such as neural stimulators and cochlear implants are also affected by the strong magnetic field, and patients with these devices also should not undergo MRI. Artificial joints, most surgical clips, artificial heart valves, and most metallic vascular devices (such as filters and stents) are not affected and patients with these devices can have MRI safely. One important exception to this is surgical clips used to treat aneurysms in the brain; patients who have such clips generally should not undergo MRI. If you have an implant of any kind and are concerned about whether you can undergo a study ordered by your doctor, please contact us or your physician for more information.

Myelography

Myelography involves injecting a small amount of water-soluble contrast (‘dye’) into the spinal canal. The initial part of this procedure is identical to lumbar puncture (see above). After the contrast is injected, x-rays of the spine are taken. Finally, a CT scan of the spine is done for complete evaluation of the area. 

Myelography is often done to evaluate the nerves running from the spinal cord to the body. Each of these nerves passes between two vertebral bodies in the spine, and can be ‘pinched’ when the space they pass through (the neural foramen) becomes narrowed. This can be due to degenerative joint disease with spur formation, rupture or herniation of a disc into the neural foramen, trauma, certain types of tumors, and other causes. There are also some conditions affecting the spinal cord itself that are best evaluated with myelography, including vascular malformations, tumors, and others.

Vertebral biopsy

This procedure may be done when an abnormality is found in one of the vertebrae (the bones that make up the spine). It involves inserting a needle into the abnormal bone and taking a small sample, which is then analyzed by a pathologist to determine the cause of the problem. Vertebral biopsy is generally done on an outpatient basis, but does require a recovery period of a few hours. It is done with the assistance of a Certified Registered Nurse Anesthetist (CRNA), who provides pain medication during the procedure. In most cases, vertebral biopsy is done by using CT scans to guide needle placement, reducing the complication risk.

Vertebroplasty

Vertebroplasty is a revolutionary procedure that allows a person who has suffered a spinal compression fracture to resume a more normal and often pain-free existence quickly, without the long period of bed rest often prescribed in such cases. The vertebrae, or vertebral bodies, are the major weight-bearing bones in the spine. These bones can become weakened and prone to collapse (compression fracture) due to osteoporosis or other causes. In some cases, only one vertebra may be compressed; in other cases, several vertebrae are fractured. These fractures can be very painful, and can contribute to loss of height and the so-called ‘dowager hump’ deformity of the upper back often seen in elderly women with severe osteoporosis.
Vertebroplasty involves placing a needle into the affected vertebra and then directly injecting bone cement into the fracture, stabilizing the bone and healing it. The cement used is methyl methacrylate, the same material used by orthopedic surgeons when installing certain artificial joints. The procedure is done in a ‘special procedures’ suite within the radiology department, which allows the use of fluoroscopy (a closed-circuit x-ray video system) to monitor and guide each step of the process. We add sterile tungsten or barium powder to the cement to make it visible on the fluoroscopy screen. Fluoroscopy allows us to attain the precise needle placement within the vertebral body that is critical for successful vertebroplasty, and making the cement visible on x-rays ensures that just the right amount is injected in each case. A radiologist who is specifically trained in vertebroplasty performs the procedure. He or she should be proficient in neuroradiology and interventional radiological procedures, since vertebroplasty requires skills and experience that are integral to both of these radiological subspecialties.
We usually perform vertebroplasty on an outpatient basis, with all patients staying for at least 2 to 3 hours afterwards for observation. We work closely with allied personnel, including a certified registered nurse anesthetist (CRNA) to administer intravenous medications to control pain, as well as radiologic technologists who are trained in use of the specialized fluoroscopy equipment this procedure requires.
The procedure itself takes approximately 20 minutes for each level that is treated. No sutures are needed. Up to 3 vertebrae, or levels, can be treated during one procedure.

Vertebroplasty FAQ 

1. When is vertebroplasty indicated?
Vertebroplasty was invented to treat painful metastatic cancer in the spine. While this is still an important indication, the procedure is now more frequently done to treat vertebral fractures due to osteoporosis. These fractures usually occur in elderly women, and are often the result of very minimal trauma, such as vigorous coughing. Some patients can tolerate these fractures with pain relief in the form of oral medication, and over several months to a year, the pain will subside. However, many vertebral fractures are painful enough that the patient is bedridden and/or requires more medication than is desirable. Vertebroplasty is revolutionary for the treatment of such fractures.
By far the most important requirement for successful vertebroplasty is that the fracture be relatively recent. Ideally, it should be less than 4 to 6 weeks old, although substantial pain relief can be provided even for fractures up to 3 months old. Treatment of fractures between 3-6 months old is less successful, and those more than 6 months need to be considered individually.
When performed promptly in an appropriate patient, vertebroplasty can provide dramatic relief of pain (> 90%). 


2. Why vertebroplasty?
Until recently, patients with painful compression fractures had few treatment options other than to take pain medication. While relieving pain is always important, removing the cause of that pain is even more so. Elderly patients can suffer side effects from prolonged courses of strong pain medication. In addition, these drugs can interact with other medications, which can cause problems for patients who require treatment for multiple conditions.
In general, treatment for any type of fracture involves immobilization to allow the broken bone to heal. If we suffer a broken forearm, for instance, we can immobilize the arm in a cast for several weeks and still live our daily lives, albeit with temporary restrictions. Such immobilization is not practical for fractures of the spine, as this would require complete bed rest. In most cases, it’s just not possible to keep the spine at complete rest for as long as it takes to heal adequately. Elderly patients suffer the most when restricted to bed rest, and are at risk for blood clots, pneumonia, bedsores and other illnesses. In addition, most elderly patients do not have the reparative capabilities to heal a vertebral fracture without intervention.


3. When is vertebroplasty not indicated?
As we mentioned, above, vertebroplasty is not generally performed on fractures that are more than 6 months old, and almost never on fractures more than one year old.
Young patients, for instance less than 50 years of age, often have the reparative ability to heal a vertebral fracture without intervention, unless there is a complicating medical condition.

4. What tests are necessary before vertebroplasty?
All patients will have x-rays, or radiographs, taken, which is how the vertebral fracture is initially diagnosed. Radiographs are only a start, however, and magnetic resonance imaging (MRI) of the affected portion of the spine is mandatory for the following reasons: we can tell whether or not the fracture is new or old based on its appearance on the MRI scan, something not evident on radiographs; and we examine the spine to make sure that there is not another existing condition that would require a completely different type of treatment. For example, if the spinal cord is compressed, neurosurgical treatment may be necessary.
For patients who are unable to undergo MRI for medical reasons, such as having a cardiac pacemaker, a nuclear medicine test called a bone scan, coupled with a CT scan, is almost equivalent.

5. What are the possible risks?
The risk of injury from needle placement includes bleeding or infection, and most importantly, potential injury to the spinal cord or aorta. For this reason, vertebroplasty is performed in a radiology suite, where the progress of the needle tip can be monitored very closely, using millimeter increments, so that it stays within the confines of the desired vertebra.
The bone cement injected is viscous and hardens quickly, so that it stays where it is injected, although there is a risk of spillage into the spinal canal and spinal cord compression, or spillage into the space between two vertebrae and nerve root compression. For this reason, the physician performing the procedure should be experienced in fluoroscopic procedures incorporating the injection of contrast materials. Experience as an angiographer is ideal.
On occasion, patients experience temporary neurologic deficits from the procedure. This is often due to nerve root irritation from the cement, and subsequent swelling of the nerve itself. This can usually be successfully treated without any permanent loss of function. In our experience with vertebroplasty to date, we have not incurred any serious or neurological complications.

6. How do I learn more about vertebroplasty?
Your personal physician can be the best initial resource. He or she may know where vertebroplasty is performed successfully, and can refer you to that center, and discuss whether vertebroplasty is appropriate.
Feel free to email me at aksinghal@texasradiology.com