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PET scan using carbon 11-labeled Pittsburgh compound B may allow the noninvasive diagnosis of Alzheimer disease, according to a report in the online Archives of Neurology.

PET scan using carbon 11-labeled Pittsburgh compound B ((11C)PiB) may allow the noninvasive diagnosis of Alzheimer disease, according to a report in the August 11th online Archives of Neurology.

"This is a useful method for assessing beta-amyloid in brain, but it is not necessarily fully sensitive," Dr. Ville Leinonen from Kuopio University Hospital, Kuopio, Finland told Reuters Health. "It may become a diagnostic tool in the future."

A previous case report had suggested a correlation between (11C)PiB PET findings and postmortem assessment of beta-amyloid aggregates three months later, the authors note.

For the current report, Dr. Leinonen and colleagues performed (11C)PiB PET studies on ten patients who had previously undergone intracranial pressure monitoring and frontal cortical brain biopsy to rule out normal-pressure hydrocephalus. These patients' biopsy samples showed the presence (six patients) or absence (four patients) of beta-amyloid aggregates.

Patients with beta-amyloid aggregates in the frontal cortex showed significantly higher (11C)PiB uptake in the frontal, parietal, and lateral temporal cortices and striatum than did patients without beta-amyloid aggregates in the brain biopsy specimen, the authors report.

Moreover, the researchers note, (11C)PiB uptake in the right frontal cortex correlated closely with the amount of beta-amyloid aggregates in the right frontal cortical biopsy specimen.

"Our results indicate that beta-amyloid depositions in a frontal cortical biopsy specimen obtained during life is in line with the (11C)PiB uptake found in PET imaging, suggesting that (11C)PiB PET reflects brain beta-amyloid deposition," the investigators say.

"This study supports the use of (11C)PiB PET in the evaluation of beta-amyloid deposition in, for example, mild cognitive impairment, Alzheimer disease, or normal pressure hydrocephalus," the authors conclude.

"As a diagnostic aid, this may prove especially useful when assessing potential patients for anti-amyloid therapy and also for follow-up of drug trials," Dr. Leinonen added.

Arch Neurol 2008