What is it?
A cisternogram is an examination of the spinal fluid flow that surrounds the spinal cord. The spinal canal extends from the lumbar spine (lower back) into the brain and is filled with spinal fluid. By injecting a small amount of radioactivity into the spinal fluid, the flow of the spinal fluid from the spine into the brain can be evaluated.
Nuclear Medicine scans are performed using very small amounts of radioactive material. The radioactive material is usually bound to other non-radioactive elements. These combined elements are called "radionuclide". The radionuclide emit energy called "photons". Radionuclide can be directed to many organs and systems in the body. Once a radionuclide is distributed in an organ or system, the photon energy is collected by a "Gamma Camera". The Gamma Camera detects the pattern of distribution of the radionuclide in the body and sends this information to a computer. The computer processes the information and displays the information in the form of a picture.
Nuclear Medicine exams differ from other x-ray procedures because the energy (x-rays and photons) come from different sources. X-ray energy is created by the x-ray tube and pass through the body. Another major difference is that Nuclear Medicine exams best demonstrate body physiology (system function), whereas x-rays show anatomical detail.
What will happen to me?
The x-ray technologist will assist you to lie on your stomach on an x-ray table. Your legs and head will be supported with sponges and pillows. Your feet will be placed flat against a foot stand attached to the end of the table. An initial x-ray of your spine will be taken. The doctor will clean the injection site on your back with an antiseptic wash. A towel with a hole in the center will be placed across your back. The skin will then be numbed with a local anesthetic. Once the injections site is numb, the doctor will insert a special spinal needle through your skin and into the spinal canal. The doctor will guide the needle to the proper location by watching a fluoroscopic TV screen. Next, the doctor will inject a radionuclide into the spinal canal. You will be placed on a gurney for at least an hour after the injection and made as comfortable as possible. Six (6) hours after the radionuclide injection, you will have the first picture. The technologist will assist you to lie flat on a table and then position you under the Gamma Camera. The Gamma Camera will be very close to you to obtain the best picture. After the first picture you will return once each day for the next 3-4 days, for additional pictures. No additional spinal injections are needed.
How long will this test take?
The injection of the radionuclide into the spinal canal takes 20 - 30 minutes to complete. Each picture in the Nuclear Medicine Department will take 30 - 40 minutes to complete.
What will I feel, will it hurt?
You may feel a slight stinging sensation when the doctor numbs the skin where the spinal needle will be placed. You will feel some pressure as the spinal needle is placed into the spinal canal. The lights of the room will be turned down during the procedure, this helps the doctor to see the fluoroscopic TV screen. You will not feel any effects from the radionuclide injection. When your scan is begun, you will need to lay flat on a table. You will need to lay very still while the scan is being performed so that the best picture can be made. You will not feel any effects from the Gamma Camera. It does not create radiation, it only detects the radiation coming from your bones. The gamma camera is a large machine that collects the emitted photons from the radionuclide but produces very little sound. The Gamma Camera must be very close to you and will be moved over your body to obtain the pictures. The radiation will totally disappear from your body in about 10 days. The radiation exposure you receive for the cisternogram is no more than from a routine x-ray procedure.
What will the test show?
The cisternogram test shows the progressive flow of spinal fluid from the lower back into the brain. The spinal fluid is then absorbed by the brain. The rate of flow and absorption of spinal fluid can be determined by this exam.
How do I get ready?
You should not eat or drink anything after midnight the night before your exam. You should remove any metal such as belt buckle, earrings, necklaces, keys, etc., since these will interfere with the pictures.