What are normal variants in EEG?
The phrases “electroencephalogram (EEG) variant waves” or “normal EEG variants” refer to waves that are rare or unusual but not generally abnormal. They may be unusual in shape or in distribution. These variant waveforms include waveforms and patterns that are rare or unusual but are known to be generally benign.
What is the difference between a PET scan and EEG?
Electroencephalography (EEG) is used to show brain activity under certain psychological states, such as alertness or drowsiness. Positron emission tomography (PET) scans show brain processes by using the sugar glucose in the brain to illustrate where neurons are firing.
What waves are used in PET scans?
The radioactive substance most commonly used in PET scanning is a simple sugar (like glucose) called FDG, which stands for “fluorodeoxyglucose”. It is injected into the bloodstream and accumulates in the body where it gives off energy in the form of gamma rays.
How are CT and PET scans different?
How is a PET-CT scan different than a CT scan? A CT scan shows detailed pictures of the organs and tissues inside your body. A PET scan can find abnormal activity and it can be more sensitive than other imaging tests. It may also show changes to your body sooner.
What do sharp waves on an EEG mean?
Spikes or sharp waves are terms commonly seen in EEG reports. If these happen only once in a while or at certain times of day, they may not mean anything. If they happen frequently or are found in specific areas of the brain, it could mean there is potentially an area of seizure activity nearby.
Are Pleds seizures?
In keeping with their epileptiform morphology, PLEDS have a close association with clinical seizures, and on average about 80% of patients with PLEDS have clinical seizures. Periodic lateralized epileptiform discharges (PLEDS), regional left centrotemporal.
Is fMRI better than PET scan?
An fMRI scan can produce images of brain activity as fast as every second,whereas PET usually takes 40 seconds or much longer to image brain activity. Thus, with fMRI, scientists can determine with greater precision when brain regions become active and how long they remain active.
Is EEG radioactive?
At a period remote from the radiotherapy of tinea capitis in childhood (dose on the brain 1.3 Gy), increased beta power on EEG was recognized as a “radiation trace”; however, the routine EEG pattern was changed moderately.
What are the disadvantages of a PET scan?
Limitations of a PET Scan A PET scan is less accurate in certain situations: Slow-growing, less active tumors may not absorb much tracer. Small tumors (less than 7mm) may not be detectable. High levels of blood sugar can cause the cells to absorb this normal sugar rather than the radioactive, injected kind.
What cancers do not show up on a PET scan?
On the other hand, tumors with low glycolytic activity such as adenomas, bronchioloalveolar carcinomas, carcinoid tumors, low grade lymphomas and small sized tumors have revealed false negative findings on PET scan.
Can a EEG show past seizures?
An EEG can usually show if you are having a seizure at the time of the test, but it can’t show what happens to your brain at any other time. So even though your test results might not show any unusual activity it does not rule out having epilepsy.
What happens if EEG is abnormal?
Abnormal EEG results can show up in two ways. First, normal brain activity may be suddenly interrupted and changed. This happens in epileptic seizures. In partial seizures, only part of the brain shows the sudden interruption.