Reply: Do we still need positron emission tomography for early Alzheimer’s disease diagnosis?

Sir,Great progress has been made in the field of Alzheimer’s disease biomarkers, which have made it possible to accurately diagnose Alzheimer’s disease in both early and late stages of the disease. This has revolutionized clinical practice, clinical research and clinical trials in this field (Mattsson et al. , 2015 a ). In a recent study we showed that CSF analysis may detect amyloid-β accumulation before PET using 18F-florbetapir in early stages of Alzheimer’s disease (Palmqvist et al. , 2016). In response to Drs Lewczuk and Kornhuber’s comment ‘Do we still need positron emission tomography for early Alzheimer’s disease diagnosis?’ we would like to highlight some advantages and disadvantages of CSF versus PET methods to detect and quantify amyloid-β pathology in Alzheimer’s disease.CSF biomarkers may be used to determine if an individual has disturbed metabolism of amyloid-β42 in the CNS. As Lewczuk and Kornhuber (2016) point out there is a very high concordance between amyloid PET imaging and CSF measures of amyloid-β (Blennow et al. , 2015) and they have similarly high accuracy for diagnosing Alzheimer’s disease (Palmqvist et al. , 2015). Both amyloid PET and CSF biomarkers are already used in many countries in diagnostic work-ups of patients with cognitive symptoms (Vandenberghe et al. , 2013; Palmqvist et al. , 2014). We expect that both CSF and PET modalities will be increasingly used as they undergo further development and standardization. This include new methods to translate results between different amyloid PET tracers (Klunk et al. , 2015 …