Patients with suspected dementia that remains unclarified after PET imaging with the standard radiotracer fluordeoxyglucose (FDG) should be sent for amyloid-busting PET with florbetaben (FBB), as the latter is highly useful in establishing a final diagnosis in such situations.

Matthias Brendel, MD, of Ludwig-Maximilian University Hospital in Munich and colleagues published the findings behind the conclusion online Sept. 20 in the European Journal of Nuclear Medicine and Molecular Imaging.

The researchers looked at the cases of all patients who underwent FDG-PET at their institution after presenting with symptoms of neurodegenerative disease.

An interdisciplinary dementia board determined that 107 patients (mean age 69.4 ± 9.7 years) had persistently uncertain diagnoses and so should be sent for additional imaging with FBB-PET.

After classifying the results as amyloid-positive (65 of the 107) or amyloid-negative, the team compared the individual clinical diagnoses before and after the FBB-PET.

They found that a final diagnosis was reached through FBB-PET in 83 percent of the formerly unclear cases, and the most likely prior diagnosis was changed in 28 percent of cases.

Meanwhile, the highest impact was observed for distinguishing Alzheimer’s dementia from frontotemporal dementia.

Here the FBB-PET altered the most likely diagnosis in some 41 percent of cases.

“FBB-PET has a high additive value in establishing a final diagnosis in suspected dementia cases when prior investigations such as FDG-PET are inconclusive,” Brendel et al. conclude. “The differentiation between Alzheimer’s disease and frontotemporal dementia was particularly facilitated by amyloid-PET, predicting a considerable impact on patient management, especially in the light of upcoming disease-modifying therapies.”