Pinpointing epileptic foci
Of the nation's approximately 2 million patients with epilepsy, an estimated
80,000 suffer from focal (partial) epilepsy that cannot be controlled with medication.
These patients may be good candidates for resection of the affected area of the
brain; however, it is very difficult to accurately identify the epilepsy
focus. Inserting depth electrode implants is one method of locating the
foci, but it is expensive, highly invasive, and associated with high rates
of mortality, morbidity and infection.
PET FDG imaging is a non-invasive and cost-effective aid in predicting the prognosis
and in surgical planning for resection procedures. By revealing areas of
increased and decreased glucose utilization, PET helps surgeons pinpoint the
surgical site.
Diagnosing dementia
PET is being used as a tool in diagnosing a wide variety of dementias, including Senile
Dementia of the Alzheimer's Type (SDAT) - the leading cause of dementia in
the United States, which incapacitates 10% of people over age 65. However,
more than 90% of all suspected Alzheimer's cases are classified as "indefinite
diagnosis" on the basis of current tests.
PET shows a distinct pattern of decreased glucose consumption in the temporal/
parietal regions of the brain, characteristic of Alzheimer's. By providing early
detection of the disease, PET can help eliminate both the uncertainty associated
with indefinite diagnosis and the need for multiple expensive tests.
Evaluating movement disorders
Involuntary movement disorders such as Parkinson's Disease, Huntington's Disease,
and Tourette Syndrome can be difficult to diagnose. In many cases, structural
images are normal or unrevealing.
PET studies can help diagnose these diseases by revealing abnormal uptake
patterns in the brain's dopamine receptors. For example, Parkinson's disease
is identified by decreased uptake of 18F-DOPA in the caudate and
putamen regions of the brain.
As new treatments for epilepsy, dementias, and movement disorders are
developed, the need for early diagnoses provided by PET exams should likewise
grow.
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