SNM: PET scans may improve accuracy of dementia diagnosis
PET scans may improve the accuracy of dementia diagnoses early in disease onset for more than one out of four patients, according to research presented Monday at the 2009 SNM meeting in Toronto.

More than five million people annually are newly diagnosed with dementia, which includes Alzheimer's disease, frontotemporal dementia and Lewy body dementia.

The study identified 66 patients with mild dementia or mild cognitive impairment who were evaluated through standard neurological testing and anatomic brain imaging. Three clinical experts reviewed the results of these data to make diagnoses of either Alzheimer's disease, frontotemporal dementia or dementia with Lewy bodies.

Patients underwent PET scans for amyloid deposits and for dopamine nerve integrity. Patients' initial diagnoses changed more than 25 percent of the time after PET imaging, according to the study authors. PET scans provided images of important signals for disease that other examinations missed, such as deposits of amyloid plaque, which are a common indicator of Alzheimer's disease, and damage to dopamine nerves in Lewy body dementia.

"Routine clinical assessments do not accurately identify the root causes of dementia in the early stages," said the study's lead author Kirk A. Frey, MD, from division of nuclear medicine at the University of Michigan Hospitals in Ann Arbor. "Our preliminary results clearly indicate that molecular imaging technologies, such as PET scans, can help diagnose a patient's specific type of dementia. This is critical for providing the best possible care. Additionally, PET's ability to pinpoint neurological underpinnings of different forms of dementia could lead to new, more targeted drugs and therapies."

The study will track patients for two years to confirm the accuracy of their diagnoses.