158 Chapter 7 METHODS Population We included cognitively normal participants with subjective cognitive decline (SCD) from the Subjective Cognitive Impairment Cohort (SCIENCe) at the Alzheimer Center Amsterdam who had two [18F]florbetapir PET scans available (n=92). Individuals were referred to the memory clinic (n=85) by their general physician, a neurologist or a geriatrician, and underwent an extensive standardized diagnostic workup that included a neurologic and neuropsychological examination, laboratory testing, and brain MRI. In a consensus meeting, participants were labelled SCD when cognitive performance appeared within normal limits, and criteria were not met for mild cognitive impairment (MCI), dementia, or other neurological or psychiatric diseases that could possibly cause cognitive complaints. In addition, seven participants were included via the Dutch Brain Research Registry (hersenonderzoek.nl). They experienced cognitive complaints in absence of objective impairment and received the same baseline work-up. At annual follow-up visits, neuropsychological testing was repeated and diagnoses were re-evaluated. PET and MRI acquisition Baseline dynamic [18F]florbetapir PET scans were acquired on a Philips Ingenuity TF PET-CT (n=82) or a Philips Gemini TF PET-CT (n=10; Philips, Best, the Netherlands) scanner. These scanners were calibrated to each other. The scan protocol started with a low-dose CT for attenuation correction. Dynamic PET scans of 90 minutes (n=82) were obtained starting directly after tracer injection of approximately 370 MBq [18F]florbetapir. During the course of the study, we demonstrated that scan duration could be reduced without compromising the reliability of results (10). Therefore, subsequent scans had a duration of 70 minutes (n=9). One scan was terminated early after 79 minutes due to participant related issues. All underwent a follow-up [18F] florbetapir PET with a mean follow-up time of 2.5 ± 0.7 years (n=17 90-minute scan; n=75 a 70-minute scan). All scans were visually assessed as ‘positive’ or ‘negative’ by a trained nuclear physician, blinded to the amyloid status at the other time point. Baseline dynamic [18F]flortaucipir PET scans were acquired on a Philips Ingenuity TF PET-CT scanner (Philips, Best, the Netherlands, n=44). The scan protocol started with a low-dose CT for attenuation correction. Starting simultaneously with tracer injection of approximately 240 MBq [18F]flortaucipir, a 60-minute dynamic emission scan was initiated. After a 20-minute break and following a second low-dose CT for attenuation correction, an additional dynamic emission scan was performed during the interval 80-130 minutes post-injection. This dual time point protocol was validated
RkJQdWJsaXNoZXIy MjY0ODMw