Learn how a SPECT scan helps identify where seizures start in the brain.
Key points
A SPECT scan is takes pictures of the blood flow in your child's brain during a seizure.
The scan takes place during a stay at the epilepsy monitoring unit and has two parts: an ictal scan during a seizure and an interictal scan between seizures.
Before an ictal scan, your child's team may lower your child's anti-epileptic drugs for a short time and inject your child with a small amount of radioactive liquid to better show blood flow during a seizure.
You may discuss the results of the SPECT scan with your child's doctor about four to six weeks after the test.
Introduction
A single photon emission computed tomography (SPECT) scan takes pictures of the blood flow in your child’s brain. When a seizure starts, more blood flows to the brain. The SPECT scan shows the part of the brain where seizures start as a “hotspot” for blood flow.
About the test
The SPECT scan is done during your child’s stay at the epilepsy monitoring unit (EMU). Your child will need two types of SPECT scan:
an ictal scan while your child is having a seizure
an interictal scan between seizures.
Each scan takes about 45 minutes. When they are both complete, your child’s team will compare the different levels of blood flow.
Single photon emission computed tomography (SPECT) machine
Why does my child need a SPECT scan?
The SPECT scan will tell the doctor where seizure starts in the brain. It will provide additional information to clarify or confirm the location of seizures, especially in patients where the other tests such as EEG, MEG or PET scan are not clear, when the MRI is normal or when the MRI findings are unclear.
Risks of the test
Does the SPECT scan have any risks or side effects?
There is a low risk from the radioactive liquid your child receives for the SPECT scan. The dose of liquid given to your child equals about two to four years of natural background radiation, depending on your child’s age and weight. Your child’s body will break down the radioactive liquid very quickly and pass it out in urine within 24 hours.
The potential benefits of the test outweigh any potential risk from the radiation.
Preparing for the test
How do I prepare my child for a SPECT scan?
As the scan is done while your child is staying in the EMU, you will not need to do any special preparation.
Will my child need to be sedated for the scan?
Some children may need a sedative (medicine to keep them calm) to help them lie still during the scan.
Test
Ictal scan
An ictal scan is done while your child is having a seizure.
What happens before the ictal scan?
Your child’s team may lower or stop your child’s epilepsy medication for a short time during your child’s EMU stay.
A technologist will place EEG electrodes on your child’s scalp.
An intravenous (IV) line will be placed in your child’s arm.
As soon as your child starts having a seizure, a small amount of radioactive liquid will be injected into the IV line. The radioactive liquid makes the blood flow easier to see.
What happens during the ictal scan?
Your child will have the SPECT scan two to four hours after receiving the radioactive liquid through the IV. This scan will show the blood flow in the brain at the moment the liquid was injected.
During the scan, your child must lie very still to make sure the images are clear.
Interictal scan
This scan shows the typical blood flow in your child’s brain. It is also done during your child’s stay in the EMU and may take place before or after an ictal SPECT scan, usually on a different day.
Two types of SPECT scans of the brain
May I stay with my child during the SPECT scan?
The EMU is a
care-by-parent unit, which means you can stay with your child during the SPECT scan. Because of the radioactive liquid given to your child, women who are pregnant or believe they may be pregnant should stay outside the scan room. Another parent or caregiver can stay with your child.
After the test
What should I expect after a SPECT scan?
After a SPECT scan (ictal or interictal), the technologist will remove the IV line and the EEG electrodes and wires.
Once your child has recovered from any sedative, they may go back to their normal activities and eat their usual diet in the hospital.
Follow-up care
When will I get the test results?
Your doctor will receive the report of the SPECT scan results and discuss them with you and your child at a follow-up appointment, usually four to six weeks after the scan.
At SickKids
At SickKids
If your doctor has told you that your child needs a sedative for the SPECT scan, someone from the nuclear medicine department will contact you with instructions on when your child needs to stop eating and drinking before the SPECT appointment.
If the SPECT is booked without arranging a sedative, but you think your child will need it, please contact the nuclear medicine department at 416-803-7654 ext. 206065.
