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Neuroradiologists specialize in radiology of the spine, brain, head and neck. In the Vista Radiology group, there are four radiologists with 1 to 2 years of additional fellowship training in neuroradiology. Having extra training and experience in neuroanatomy and neurophysiology enhances their interpretation and performance of neuroradiological procedures. CT scans, MRI scans, nyelography, neuroanigiography and neurointerventional procedures are performed by neuroradiologists to help your doctor better understand and treat your condition.
Computerized Tomography (CT scan)
The first CT scanner was developed in 1975 and proved so useful in medicine that the technique was rapidly incorporated into mainstream medicine worldwide. CT scanning is performed for many different medical conditions including problems in the abdomen, chest, neck, brain, spine and sinuses. Like most radiological procedures, it is painless and the x-ray dose has been minimized through modern technological advances. CT scanning is particularly good for detecting hemorrhage in the brain and the procedure of choice for trauma to the head. It is frequently used in the initial evaluation of patients with stroke symptoms. It is also superior in identifying brain disorders and sinus abnormalities. In most cases, MRI has replaced CT scanning for evaluation of the spine. However, CT often provides valuable information that may complement MR imaging in patients with back problems.
How to prepare
Although most CT scans performed for neurological reasons are performed without intravenous contrast material (a substance that enhances x-ray and CT images), the doctor may determine that your condition requires using a contrast during scanning. Patients are routinely requested to refrain from eating four hours prior to their appointment. The contrast is better tolerated on an empty stomach. Also, to optimize imaging results, you may be asked to remove metallic jewelry, eyeglasses, removable dental work, etc. prior to scanning. As with any procedure in radiology, it’s important to tell the technologist if you think you are pregnant.
During the scan
Vista Radiology has state-of-the-art CT scanners that have substantially decreased the time for image acquisition. Scanning is usually completed in less than two minutes and may last only a few seconds. You will lie on a moving table that slides you through a large donut-shaped ring. As the table moves, a focused x-ray beam is emitted briefly from an x-ray source that spins around the patient. You will hear a whirling sound as the x-ray tube spins but you won’t feel the x-ray. It is important that you try not to move during the scan since patient movement could make it necessary to repeat the scan.
Most claustrophobic patients find that CT scanning is no problem. The ring is fairly wide and very short. In most cases, your head will only pass through the ring for a few seconds. If claustrophobic, you may want to keep your eyes closed.
If intravenous contrast material is required, the technologist will insert an IV prior to scanning. Allergic reactions to the contrast are very rare but can occur. It is important that you inform the technologist if you believe you’ve had an allergic reaction to contrast material in the past. Special arrangements may be needed for pretreatment prior to the injection. As the contrast is injected, you will feel a warm sensation in your arm that spreads through your body. Remember, it’s important to remain still. After the scan, the technologist will check the images and remove the IV. You can resume normal activities as soon as you leave the scanner.
Magnetic Resonance Imaging (MRI)
First developed in the 1980’s, MRI allows detailed images of internal structures without using x-rays or radioactive substances. The patient lies in a strong magnetic field and radiowaves are turned on and off to allow precise mapping of the body’s anatomy. MRI gives exquisite detail about the brain and spine and can be extremely useful in helping doctors establish the correct diagnosis. Even when a CT scan is negative, the MRI occasionally will pick up an abnormality that could explain the cause of your symptoms.
How to prepare
There is no need to alter your diet or medication prior to an MRI examination. You will be asked several questions to make sure you do not have a cardiac pacemaker, an aneurysm clip, implanted pump for medicine, or a cochlear implant in the ear. These items could cause you harm or at least stop working correctly when exposed to the MRI scanner.
People who tend to be claustrophobic find that the scan is very tolerable. However, if you are certain that you are claustrophobic, please tell your doctor so special arrangements can be made.
During the scan
When you arrive for your scan, you may be asked to change into a patient gown to avoid problems with metal zippers, belt buckles, buttons, etc. You will also be given a key to a cabinet or locker for your personal items. Watches, jewelry, keys, credit cards, ATM cards, hairpins, coins, hearing aids, glasses, removable dental work, and any other metallic object must be left in the locker. You may be given earplugs since the scanners usually make a loud taping or knocking sound during operation. You will lie on a moving table that will slide you into the magnetic field. As long as you do not have metal objects with you, you won’t feel any effects of the magnetic field.
The technologist will communicate with you in between scans. Each set of images takes 3 – 10 minutes to acquire. The complete examination takes 30 – 45 minutes. Try to be as still as possible during the scans since patient movement can cause artifacts and a decrease in image quality.
If necessary, the technologist may give you an intravenous injection of gadolinium contrast material. The gadolinium contrast is very safe and is a completely different material than the iodine-based contrast used in other x-ray tests and CT scanning. Even if you have a known allergy to iodinated contrast, gadolinium can be safely used without prior medication.
Myelography
The cause of back and neck pain is often very difficult to determine. If a cartilage disk bulges or herniates backwards into the spinal canal, it could “pinch” a nerve root or the spinal cord. Nerve roots can also be pinched by bone “spurs” or pain could be related to ostearthritis of the posterior (facet) joints of the spine. Rare causes of back or neck pain include tumors or cysts in and around the spinal canal. MRI (link) is usually the initial imaging test of choice for evaluation of back or neck problems, but occasionally MRI can leave certain questions unanswered and a myelogram is ordered to complement the MRI findings.
Myelography allows the visualization of the spinal cord and nerve roots within the spinal canal. The test requires injection of a contrast material into the spinal canal in order to obtain valuable information about which and how many nerve roots are being pinched and the severity of the pinch. CT scanning is usually performed immediately after myelography to help define bone spur formations, the degree of narrowing of the spinal canal, and the precise cause of the pinched nerves.
How to prepare
Patients are requested to consume only clear liquids after midnight prior to the exam. If you are diabetic, hold your insulin and/or oral hypoglycemic medicine until you are able to eat breakfast after the exam. However, take your other morning medications (especially if on a blood pressure pill). Let the nurse and technologist know if you have any allergies or if you think you might be pregnant.
During the procedure
The radiologist will discuss the details and risks of the procedure with you prior to the exam. Risks are minimal but the benefits of the study far outweigh the risks. Please feel free to ask the radiologist any questions about the exam. The radiologist will ask you to sign a consent form which states you have been informed of the details, risks, and benefits of the exam and that you agree to proceed.
You will lie on your stomach on the x-ray table. After numbing the skin, the radiologist will use x-ray to guide the needle into the spinal canal. Contrast material will be injected and several x-ray pictures will be obtained at a variety of angles. You will then be moved onto a stretcher and taken to the CT scanner for additional pictures.
After the exam, you will be monitored for 2 – 4 hours. If hungry, you can eat a regular meal during the monitoring period. You’ll need a family member or friend to drive you home. It is recommended that you rest for the remainder of the day.
Neuroangiography
X-ray pictures of the blood vessels of the head and neck can be obtained by neuroangiography. This procedure is most commonly performed to evaluate blockages or partial blockages of the carotid arteries which could lead to stroke if untreated. The carotid artery blockages are usually related to arteriosclerosis (“hardening of the arteries”) which decreases the blood flow to the brain. Plaque deposits of cholesterol and fat collect in the inner wall of the artery and narrow the lumen. Carotid Doppler ultrasound, magnetic resonance angiograms, or CT angiography are techniques which can sometimes give definitive information for the doctor to make treatment decisions. Physicians often need conventional angiography prior to surgery to confirm a finding from some other test. Neuroangiography is also utilized for evaluation of cerebral aneurysms, arteriovenous malformations, vasculities, and other cerebrovascular diseases.
How to prepare
Patients are instructed to have a light supper before the test, and only clear liquids after midnight on the morning of the exam. If you are diabetic, hold your insulin and/or oral hypoglycemic medicine until you are able to eat breakfast after the exam. However, take your other morning medications especially if on a blood pressure pill. Let the nurse and technologist know if you have any allergies or if you think you might be pregnant.
During the Procedure
The radiologist will meet with you and discuss the examination. This procedure has some associated risks that will be explained but the benefits far outweigh the risks. If you have any questions, please feel free to ask the radiologist. You will be asked to sign a consent form stating that you have been informed of the details, risks, and benefits of the exam and have agreed to proceed.
You will lie on your back on a sliding table. Your groins will be shaved on both sides. Several monitoring devices such as EKG, blood pressure, etc. will be applied at the start of the exam and you will be continuously monitored throughout the study. If you are uncomfortable or anxious, please inform the physician or technologist. Most of the time intravenous conscious sedation can safely be given to help a patient be more comfortable during the exam. After numbing the skin, the radiologist will place a needle into the leg artery and a plastic tub called a catheter will be placed inside the blood vessels to the level of the neck. You won’t feel the catheter inside the vessels. X-ray contrast material will be injected through the catheter and several series of pictures will be taken. The x-ray contrast may make you feel warm and you may get a strange taste in your mouth for a few seconds after the injections. When all the necessary pictures have been obtained, the catheter will be removed and pressure will be applied at the arterial puncture site for 10 to 15 minutes. Afterwards, you will lie flat in the bed for 4 to 8 hours and will be monitored by a nurse. If hungry, and you can eat lying down without choking, you can eat a regular meal (with assistance) during the monitoring period. Many patients spend the night in the hospital after neuroangiography. If you are allowed to go home, you will need a family member or friend to drive you home. Regardless, it is recommended that you rest for the remainder of the day.