SPECT is a technique that provides images of areas of increased or decreased brain activity related to blood flow. It may help localize the area of the brain causing seizures, even if your child has a normal MRI or CT scan.
The test can show an increased signal in the area where the seizure begins and a decreased signal in the abnormal area when your child is not actively experiencing a seizure. A technique can be used to subtract the two images which will better identity the true seizure source. There are two types of SPECT scans:
- Ictal SPECT- a procedure done while a seizure is occurring.
- Inter-ictal SPECT- a procedure done between seizures.
What to Expect
Your child will have an intravenous (IV) line inserted in the arm when you arrive to the EMU. A nuclear medicine technician or nurse will sit at the bedside starting in the morning waiting for your child to have a seizure. Once the seizure is confirmed on the EEG, the technician or nurse will inject a small amount of radioisotope through the IV.
The isotope is carried to the brain through the bloodstream and will last for six hours. It travels to the place in the brain where there is greatest blood flow, which may be the location of the seizure. After injection, your child will be taken to the nuclear medicine suite for a scan of the brain. This requires your child to lie flat on the scanning table with their head in a headrest to hold the head still. There is no pain during the test and it usually lasts 30 to 45 minutes. Once the testing is complete, your child will be taken back to the EMU.