The Incremental Diagnostic Value of [18F]Florbetaben PET and the Pivotal Role of the Neuropsychological Assessment in Clinical Practice.

BACKGROUND

Amyloid pathology is a key feature of Alzheimer's disease (AD) and can be assessed in vivo with amyloid positron emission tomography (PET) imaging.

OBJECTIVE

The objective of this study was to evaluate the incremental value of a PET scan with [18F]florbetaben, in terms of changes of diagnosis, diagnostic confidence, and treatment plan when added to a standardized diagnostic workup for cognitive disorders, with particular focus on the role of the neuropsychological assessment, including the Free and Cued Selective Reminding Test (FCSRT).

METHODS

A total of 104 patients (69 mild cognitive impairment, 35 dementia), with diagnostic uncertainty after diagnostic workup, were recruited from our memory clinic. [18F]florbetaben PET scans were interpreted as amyloid negative or positive on the basis of a semi-quantitative visual rating. Clinical diagnosis and diagnostic confidence for AD or non-AD dementia were rated before and after PET result disclosure, as was the impact of PET on the patient management plan.

RESULTS

There were 69/104 (66%) [18F]florbetaben positive scans, 51/62 (82%) patients were suspected as having AD before the PET scan and 18/42 (43%) were not. Overall, the data obtained at PET changed 18/104 diagnoses (17%) and increased diagnostic confidence from 69.1±8.1% to 83.5±9.1 (p < 0.001), with the greatest impact on diagnosis and confidence in PET negative patients with an initial diagnosis of AD (p < 0.01) and in early-onset patients (p = 0.01).

CONCLUSION

Amyloid PET represents a source of added value in dementia diagnosis, with a significant effect on diagnosis and diagnostic confidence. However, the use of a complete neuropsychological assessment has an add-on value on limiting the amyloid PET influence on change of diagnosis, and the real impact of amyloid PET should always be weighed up together with an accurate standardized diagnostic workup.