To determine the sensitivity and specificity of the visual assessment of tracer uptake in the Florbetaben PET images compared to histological verification of the presence or absence of cerebral β-amyloid in the respective histopathologic post mortem specimens as the standard of truth
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
218
Single intravenous injection 1-5ml, 300 MBq (+/- 20%)
Unnamed facility
Sun City, Arizona, United States
Unnamed facility
Stanford, California, United States
Unnamed facility
Tampa, Florida, United States
Sensitivity and Specificity of the Majority Read of Visual Assessment of Tracer Uptake Compared to Histological Verification of the Presence or Absence of Cerebral Beta-amyloid in Postmortem Specimens
The sensitivity/specificity of the visual assessment were calculated based on the majority read assessment of regional tracer uptake. This result was derived from assessments by 3 independent readers for brain regions of a subject where a Standard of Truth (SOT) was available. The SOT for this analysis was a centralized histopathological determination of β-amyloid presence/absence based on both Bielschowsky silver and immunohistochemical staining. Based on the PET images, a brain region was classified as "normal" or "abnormal" depending on the presence or absence of regional tracer uptake in the respective region. "Normal" therefore meant absence of β-amyloid and "abnormal" presence of β-amyloid. Sensitivity was defined as the percentage of abnormal brain regions from all regions where an SOT was available and the SOT was "β-amyloid present". Specificity was defined as the percentage of normal brain regions from all regions where an SOT was available and was "β-amyloid not present".
Time frame: 90-110 minutes post injection (PET image acquisition)
Sensitivity and Specificity of the Majority Read "Whole Brain" Visual Assessment in Detecting/Excluding Cerebral Neuritic β-amyloid Plaques Compared With the Histopathological Verification With Bielschowsky Silver Staining (SOT 1).
Sensitivity and specificity of the whole brain visual assessment were calculated. Any brain with a region classified as abnormal from PET imaging was to be classified as abnormal for the "whole brain" assessment. This result was derived from assessments by 3 independent readers for a subject where a Standard of Truth (SOT) was available. The SOT for this analysis was based on a centralized histopathological assessment of the presence/absence of β-amyloid based on Bielschowsky silver staining (SOT 1). The sensitivity was defined as the proportion of brains classified as abnormal from all brains where this SOT was available and was "β-amyloid present". The specificity was defined as the proportion of brains classified as normal from all brains where this SOT was available and was "β-amyloid not present".
Time frame: 90-110 minutes post injection (PET image acquisition)
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Unnamed facility
Teaneck, New Jersey, United States
Unnamed facility
Philadelphia, Pennsylvania, United States
Unnamed facility
Dallas, Texas, United States
Unnamed facility
Houston, Texas, United States
Unnamed facility
San Antonio, Texas, United States
Unnamed facility
Heidelberg, Victoria, Australia
Unnamed facility
Lille, France
...and 9 more locations
Sensitivity and Specificity of the Majority Read "Whole Brain" Visual Assessment in Detecting/Excluding Cerebral Neuritic β-amyloid Plaques Compared With Histopathological Verification With Bielschowsky Silver Staining and Immunohistochemistry (SOT 2).
Sensitivity and specificity of the whole brain visual assessment were calculated. Any brain with a region classified as abnormal from PET imaging was to be classified as abnormal for the "whole brain" assessment. This result was derived from assessments by 3 independent readers for a subject where a Standard of Truth (SOT) was available. The SOT for this analysis was based on a centralized histopathological assessment of the presence/absence of β-amyloid based on Bielschowsky silver staining and immunohistochemistry (SOT 2). The sensitivity was defined as the proportion of brains classified as abnormal from all brains where this SOT was available and was "β-amyloid present". The specificity was defined as the proportion of brains classified as normal from all brains where this SOT was available and was "β-amyloid not present".
Time frame: 90-110 minutes post injection (PET image acquisition)
Sensitivity and Specificity of the Majority Read "Whole Brain" Visual Assessment in Detecting/Excluding Cerebral Neuritic β-amyloid Plaques Compared With the Histopathological Verification According to CERAD Criteria (SOT 3).
Sensitivity and specificity of the whole brain visual assessment were calculated. Any brain with a region classified as abnormal from PET imaging was to be classified as abnormal for the "whole brain" assessment. This result was derived from assessments by 3 independent readers for a subject where a Standard of Truth (SOT) was available. The SOT for this analysis was based on a histopathological assessment of the presence/absence of β-amyloid according to CERAD Criteria (SOT 3). The sensitivity was defined as the proportion of brains classified as abnormal from all brains where this SOT was available and was "β-amyloid present". The specificity was defined as the proportion of brains classified as normal from all brains where this SOT was available and was "β-amyloid not present".
Time frame: 90-110 minutes post injection (PET image acquisition)
Sensitivity and Specificity of the Subject Level Composite SUVR Calculated Based on Pathology Results.
Sensitivity and specificity of subject level composite Standard Uptake Value Ratios (SUVR) by SOT for subjects with available brain tissue and 10 healthy volunteers. The SUVR were determined as a quantitative measure of tracer uptake. The SUV is defined as the ratio of the tissue radioactivity concentration c (in MBq/kg) at time point t, and the injected activity (in MBq), extrapolated to the same time (t) divided by the body weight (in kg). SUV numbers were then used to derive SUV ratios (SUVR) using the SUV from the cerebellar cortex as reference. SOTs comprised Bielschowsky silver staining (SOT 1), Bielschowsky silver staining with immunohistochemistry (SOT 2) and neuropathology assessment according to CERAD (SOT 3). SUVR analysis was performed for baseline and available follow-up scans. The optimal threshold for the distinction between β-amyloid present yes/no according to the respective SOT was derived based on ROC curve analyses and used to calculate sensitivity and specificity.
Time frame: 90-110 minutes post injection (PET image acquisition)
Subject Level Composite SUVRs by SOT for Baseline and Available Follow-Up Scans
Subject level composite SUVRs (calculated as mean of SUVRs from the frontal, parietal, lateral temporal, anterior and posterior cingulate, and occipital cortices) by SOT are reported for subjects with available brain tissue. The initial drug administration group includes additionally 10 healthy controls who were considered as ß-amyloid negative. The SOTs for deceased subjects were based on Bielschowsky silver staining (SOT 1), Bielschowsky silver staining in combination with immunohistochemistry (SOT 2) and neuropathology assessment according to CERAD (SOT 3). SUVR analysis was performed for baseline and available follow-up scans.
Time frame: 90-110 minutes post injection (PET image acquisition)