To determine the sensitivity of the visual assessment of BAY94-9172 PET images in detecting cerebral β-amyloid in individuals with Down Syndrome (DS) and specificity in individuals without DS. Given that individuals with Down Syndrome develop β-amyloid pathology over the age of 40, the clinical diagnosis of Down Syndrome will serve as the standard of truth.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
109
300 megabecquerels (MBq) as single IV injection of 2 to 10 mL
Unnamed facility
Sun City, Arizona, United States
Unnamed facility
New Haven, Connecticut, United States
Sensitivity of the Independent Visual Assessment of Detecting Cerebral Amyloid-beta in Individuals With Down Syndrome and Specificity in Subjects Without Down Syndrome
The primary variables are sensitivity (percentage of DS subjects positive for cerebral beta-amyloid) and specificity (percentage of healthy volunteers negative for cerebral beta-amyloid) of brain uptake of florbetaben based on the majority read of the visual assessment by three independent blinded readers of PET images obtained 100 to 120 minutes post-injection of florbetaben.
Time frame: 100-120 min
Sensitivity Results in the Down Syndrome Age Subgroups
The majority read sensitivity (percentage of DS subjects positive for cerebral beta-amyloid by majority read) was computed for the group of DS subjects with age equal to or below the median age (DS-young) and for DS subjects with age above the median age (DS-old). The median age was 46 yrs, with 3 subjects being exactly 46 yrs old. As defined, these subjects were assigned to the DS-young group.
Time frame: 100 - 120 min
Quantitative Parameters Standard Uptake Value Ratio
The Standard Uptake Value Ratios for florbetaben signal in the frontal cortex, posterior cingulate, lateral temporal cortex, parietal cortex, and cerebellum (white matter) were determined as a quantitative measure of tracer uptake. The SUV is defined as the ratio of (1) the tissue radioactivity concentration c (in MBq/kg) at time point t, and (2) the injected activity (in MBq, extrapolated to the same time t) divided by the body weight (in kg). These SUV numbers from regions of interest were then used to derive SUV ratios (SUVR) using the SUV from the cerebellar cortex as reference.
Time frame: 100 - 120 min p.i.
Consistency Between Visual and Quantitative Efficacy
For a comparison of the results of the visual assessment with the quantitative assessment, descriptive Standardized Uptake Value Ratio (SUVR) statistics were computed separately for DS subjects with an abnormal/normal majority read of the PET scan (DS-PET+/DS-PET-). The SUV is defined as the ratio of (1) the tissue radioactivity concentration c (in MBq/kg) at time point t, and (2) the injected activity (in MBq, extrapolated to the same time t) divided by the body weight (in kg). These SUV numbers from regions of interest were then used to derive SUV ratios (SUVR) using the SUV from the cerebellar cortex as reference.
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Time frame: 100 - 120 min