April 20, 2001
WESTPORT (Reuters Health) - Single photon
emission computed tomography (SPECT) can increase
the likelihood of an accurate diagnosis of Alzheimer's disease,
according to a report in the April 10th issue of Neurology.
Dr. William Jagust, from the University of California Davis
Medical Center, and colleagues prospectively collected clinical data
and SPECT images on 70 patients with dementia, who
were followed to autopsy. In addition, they collected data on 14
control subject subjects who were followed to autopsy and on 71
controls on whom no autopsies were performed.
Analysis revealed that among all the patients and controls, a
clinical diagnosis of probable Alzheimer's disease was associated
with an 84% likelihood of pathologic Alzheimer's disease.
Using SPECT imaging, the likelihood of
Alzheimer's disease was raised to 92% when the
SPECT scan was positive. If the scan was negative
the likelihood of Alzheimer's disease was reduced to 70%, Dr.
Jagust's group reports.
When the clinical diagnosis was possible Alzheimer's disease,
the likelihood of Alzheimer's disease was 84% when
SPECT imaging was positive and 52% when it was
negative. Without SPECT the likelihood of
Alzheimer's disease among these patients was 67%, the investigators
The use of SPECT to increase the likelihood
of a correct diagnosis of Alzheimer's disease may be essential
because "some potential therapeutic options (eg., antiamyloid
agents, vaccination, or neural transplantation) might be associated
with high risks, necessitating accurate diagnoses," Dr. Jagust and