Higher Standardized Uptake Value Ratio Research Articles

Development and Preclinical Evaluation of a Copper-64-Labeled Antibody Targeting Glycine-Alanine Dipeptides for PET Imaging of C9orf72-Associated Amyotrophic Lateral Sclerosis/Frontotemporal Dementia.

Aggregating poly(glycine-alanine) (poly-GA) is derived from the unconventional translation of the pathogenic intronic hexanucleotide repeat expansion in the C9orf72 gene, which is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Poly-GA accumulates predominantly in neuronal cytoplasmic inclusions unique to C9orf72 ALS/FTD patients. Poly-GA is, therefore, a promising target for PET/CT imaging of FTD/ALS to monitor disease progression and therapeutic interventions. A novel 64Cu-labeled anti-GA antibody (mAb1A12) targeting the poly-GA protein was developed and evaluated in a transgenic mouse model. It was obtained with high radiochemical purity (RCP), radiochemical yield (RCY), and specific activity, and showed high stability in vitro and ex vivo and specifically bound to poly-GA. The affinity of NODAGA-mAb1A12 for poly-GA was not affected by this modification. [64Cu]Cu-NODAGA-mAb1A12 was injected into transgenic mice expressing GFP-(GA)175 in excitatory neurons driven by Camk2a-Cre and in control littermates. PET/CT imaging was performed at 2, 20, and 40 h post-injection (p.i.) and revealed a higher accumulation in the cortex in transgenic mice than in wild-type mice, as reflected by higher standardized uptake value ratios (SUVR) using the cerebellum as the reference region. The organs were isolated for biodistribution and ex vivo autoradiography. Autoradiography revealed a higher cortex-to-cerebellum ratio in the transgenic mice than in the controls. Results from autoradiography were validated by immunohistochemistry and poly-GA immunoassays. Moreover, we confirmed antibody uptake in the CNS in a pharmacokinetic study of the perfused tissues. In summary, [64Cu]Cu-NODAGA-mAb1A12 demonstrated favorable in vitro characteristics and an increased relative binding in poly-GA transgenic mice compared to wild-type mice in vivo. Our results with this first-in-class radiotracer suggested that targeting poly-GA is a promising approach for PET/CT imaging in FTD/ALS.

Evaluation of glymphatic system activity using diffusion tensor image analysis along the perivascular space and amyloid PET in older adults with objectively normal cognition: a preliminary study.

Diffusion tensor image analysis along the perivascular space (DTI-ALPS) is a recently introduced method for the assessment of the glymphatic system without the need for contrast injection. The purpose of our study was to assess the glymphatic system in cognitively normal older adults with or without subjective cognitive decline (SCD) using DTI-ALPS, and correlating with amyloid PET. To evaluate the glymphatic system in cognitively normal older adults using DTI-ALPS, we built a prospective cohort including a total of 123 objectively cognitively normal older adults with or without SCD. The ALPS index was calculated from DTI MRI and was assessed by correlating it with standardized uptake value ratios (SUVRs) from amyloid PET and clinically relevant variables. The study subjects were also divided into amyloid "positive" and "negative" groups based on the result of amyloid PET, and the ALPS indices between those two groups were compared. The ALPS index was not significantly different between the normal and SCD groups (P = 0.897). The mean ALPS index from the amyloid positive and amyloid negative group was 1.31 and 1.35, respectively, which showed no significant difference (P = 0.308). Among the SUVRs from variable cortices, that of the paracentral cortex was negatively correlated with the ALPS index (r = -0.218, P = 0.016). Multivariate linear regression revealed that older age (coefficient, -0.007) and higher SUVR from the paracentral cortex (coefficient, -0.101) were two independent variables with a significant association with a lower ALPS index (P = 0.015 and 0.045, respectively). DTI-ALPS may not be useful for evaluation of the glymphatic system in subjects with SCD. Older age was significantly associated with lower ALPS index. Greater amyloid deposition in the paracentral cortex was significantly associated with lower glymphatic activity in cognitively normal older adults. These results should be validated in future studies on the relationships between ALPS index and other fundamental compartments in glymphatic system, such as perivenous space and the meningeal lymphatic vessels.

Image‐based primary age‐related tauopathy as a risk of dementia: a five‐year longitudinal study

AbstractBackgroundTo investigate cognitive and pathological (amyloid and tau) changes of image‐based primary age‐related tauopathy (PART) in a long‐term follow‐up cohort study.MethodIn this study, a total of 108 patients who were both negative in amyloid and tau PET images were enrolled. All participants completed the same two PET scans (18F‐flortaucipir for tau and 18F‐florbetaben for Aβ), and neuropsychological tests at least twice over 5 years. We defined PART+ as those who had a higher standardized uptake value ratio (SUVR) in the entorhinal cortex than the cutoff calculated by the Youden index. We investigated the cognitive and 18F‐florbetaben and 18F‐flortaucipir SUVR changes longitudinally between PART+ and PART‐ participants while adjusting for age, sex, education, and ApoE4.ResultCompared with PART‐, PART+ participants had more rapid worsening of MMSE (β=‐0.274, p<0.001), CDR‐SB (β=0.081, p<0.001), and memory function (β=‐0.140, p=0.008). No significant differences were observed in the language, visuospatial, frontal‐executive, attention domains, and total cognitive battery score. In PART+ participants, the annual Aβ accumulation rate from whole cortical SUVR was also increased (β=0.016, p=0.003), and a more rapid accumulation rate was observed in Alzheimer’s disease (AD) specific hot meta‐region‐of‐interest (meta‐ROI) SUVR, compared with PART‐ participants (β=0.019, p=0.001). The annual tau accumulation rate of PART+ was higher than PART‐ in the entorhinal cortex (β=0.010, p<0.001), however, no differences were observed in whole cortical SUVR tau.ConclusionThe PART+ participants showed a rapid cognitive decline in memory function as well as MMSE, and CDR‐SB, than those of PART‐. In addition, amyloid was accumulated at a faster rate in PART+ participants and tau was accumulated more rapidly in the medial temporal area. In conclusion, our longitudinal study suggests that image‐based entorhinal tau defined as a PART+ could be an earlier stage than the preclinical stage of AD.

PET Imaging of P2X7 Receptor (P2X7R) for Neuroinflammation with Improved Radiosynthesis of Tracer [18F]4A in Mice and Non-human Primates.

The P2X7 receptor (P2X7R) is a key neuroinflammation target in a variety of neurodegenerative diseases. Improved radiosynthesis was developed according to the previously reported P2X7R antagonist GSK1482160. Biodistribution, radiometabolite, and dynamic positron emission tomography/computed tomography-magnetic resonance imaging (PET/CT-MRI) of the lipopolysaccharide (LPS) rat model and the transgenic mouse model of Alzheimer's disease (AD) revealed a stable, low uptake of [18F]4A in the brain of healthy rats but a higher standardized uptake value ratio (SUVR) in LPS-treated rats (1.316 ± 0.062, n = 3) than in sham (1.093 ± 0.029, n = 3). There were higher area under curves (AUCs) in the neocortex (25.12 ± 1.11 vs 18.94 ± 1.47), hippocampus (22.50 ± 3.41 vs 15.90 ± 1.59), and basal ganglia (22.26 ± 0.81 vs 15.32 ± 1.76) of AD mice (n = 3) than the controls (n = 3) (p < 0.05). Furthermore, 50 min dynamic PET in healthy nonhuman primates (NHPs) indicated [18F]4A could penetrate the blood-brain barrier (BBB). In conclusion, [18F]4A from this study is a potent P2X7R PET tracer that warrants further neuroinflammation quantification in human studies.

Baseline biomarker (tau PET) characteristics from TANGO: A phase 2 trial of gosuranemab (BIIB092) in early Alzheimer's disease

AbstractBackgroundGosuranemab is a humanized monoclonal antibody that is hypothesized to neutralize extracellular tau and prevent the trans‐neuronal propagation of tau pathology across the brain. The TANGO study is an ongoing randomized, placebo‐controlled, global Phase 2 study evaluating safety and clinical efficacy of gosuranemab in individuals diagnosed with mild cognitive impairment (MCI) due to Alzheimer’s disease (AD) or mild AD dementia. The TANGO study included two biomarker sub‐studies: cerebrospinal fluid (CSF) sub‐study and Tau positron emission tomography (PET) sub‐study; the baseline characteristics of the Tau PET sub‐study are described below.MethodTANGO enrolled 654 individuals aged 50‐80 years, diagnosed with MCI or mild AD, who were amyloid positive as assessed by amyloid PET or CSF testing. Approximately 350 patients enrolled in the longitudinal 18F‐MK‐6240 Tau PET sub‐study. Randomization was stratified by biomarker sub‐study participation among other factors. Baseline standardized uptake value ratio (SUVR) was measured in composite brain regions of interest (ROIs) corresponding to Braak I‐II, Braak III‐IV, and Braak V‐VI regions using superior‐eroded cerebellum as the reference region. Tau extent (percentage of supra‐threshold voxels within an ROI relative to reference region), an exploratory measure of the spatial extent of 18F‐MK‐6240 binding, was also investigated.ResultThe baseline demographics of the Tau PET sub‐study population were consistent with the overall TANGO study population including clinical stage (MCI vs. mild AD), age, gender, APOE4, and clinical scores. At baseline, average SUVR (±SD) was 1.92±0.6 in Braak I‐II, 1.90±0.7 in Braak III‐IV and 1.75±0.8 in Braak V‐VI composite ROIs. The Braak composite SUVRs were positively associated with disease stage (i.e. higher SUVR with increasing disease severity). Exploratory analyses of extent were supportive of the SUVR results.ConclusionAt study baseline, tau SUVR was highest in Braak I‐II, followed by Braak III‐IV, then Braak V‐VI. Cross‐sectionally, higher tau PET SUVR was associated with increasing disease severity and worse clinical scores, as expected. The TANGO Tau PET sub‐study will aid our understanding of gosuranemab’s effect on tau pathology and further inform on the value of tau PET in clinical trials.

18F-MK-6240 tau-PET in genetic frontotemporal dementia.

Tau is one of several proteins associated with frontotemporal dementia. While knowing which protein is causing a patient’s disease is crucial, no biomarker currently exists for identifying tau in vivo in frontotemporal dementia. The objective of this study was to investigate the potential for the promising 18F-MK-6240 PET tracer to bind to tau in vivo in genetic frontotemporal dementia.We enrolled subjects with genetic frontotemporal dementia, who constitute an ideal population for testing because their pathology is already known based on their mutation. Ten participants (three with symptomatic P301L and R406W MAPT mutations expected to show tau binding, three with presymptomatic MAPT mutations and four with non-tau mutations who acted as disease controls) underwent clinical characterization, tau-PET scanning with 18F-MK-6240, amyloid-PET imaging with 18F-NAV-4694 to rule out confounding Alzheimer’s pathology, and high-resolution structural MRI.Tau-PET scans of all three symptomatic MAPT carriers demonstrated at least mild 18F-MK-6240 binding in expected regions, with particularly strong binding in a subject with an R406W MAPT mutation (known to be associated with Alzheimer’s like neurofibrillary tangles). Two asymptomatic MAPT carriers estimated to be 5 years from disease onset both showed modest 18F-MK-6240 binding, while one ∼30 years from disease onset did not exhibit any binding. Additionally, four individuals with symptomatic frontotemporal dementia caused by a non-tau mutation were scanned (two C9orf72; one GRN; one VCP): 18F-MK-6240 scans were negative for three subjects, while one advanced C9orf72 case showed minimal regionally non-specific binding. All 10 amyloid-PET scans were negative. Furthermore, a general linear model contrasting genetic frontotemporal dementia subjects to a set of 83 age-matched controls showed significant binding only in the MAPT carriers in selected frontal, temporal and subcortical regions.In summary, our findings demonstrate mild but significant binding of MK-6240 in amyloid-negative P301L and R406W MAPT mutation subjects, with higher standardized uptake value ratio in the R406W mutation associated with the presence of NFTs, and little non-specific binding. These results highlight that a positive 18F-MK-6240 tau-PET does not necessarily imply a diagnosis of Alzheimer’s disease and point towards a potential use for 18F-MK-6240 as a biomarker in certain tauopathies beyond Alzheimer’s, although further patient recruitment and autopsy studies will be necessary to determine clinical applicability.

Functional Abnormality Associated With Tau Deposition in Alzheimer’s Disease – A Hybrid Positron Emission Tomography/MRI Study

Objective: To investigate the characteristics of tau deposition and its impact on functional connectivity (FC) in Alzheimer’s disease (AD).Methods: Hybrid PET/MRI scans with [18F]-THK5317 and neuropsychological assessments were undertaken in 26 participants with AD and 19 healthy controls (HC). The standardized uptake value ratio (SUVR) of [18F]-THK5317 PET imaging was compared between the AD and HC groups. Significant clusters that revealed higher tau deposition in the AD group compared to the HC group were selected as regions of interest (ROI) for FC analysis. We evaluated the difference in the FC between the two groups for each ROI pair. The clinical and radiological characteristics were compared between the AD patients with negative FC and AD patients with positive FC for exploratory analysis.Results: The bilateral inferior lateral temporal lobe, dorsal prefrontal cortex, precuneus, posterior cingulate cortex, hippocampus, and occipital lobe showed significantly higher [18F]-THK5317 accumulation in AD patients. Decreased FC in regions with higher SUVR was observed in AD patients, and the FC strength was negatively correlated with regional SUVR. Patients with a positive FC exhibited older ages, better cognitive performances, and a lower SUVR than patients with a negative FC.Conclusions: An impact of tau deposition was observed on FC at the individual level in AD patients. Our findings suggested that the combination of tau-PET and rs-fMRI might help predict AD progression.

F-18 ML-104 tau PET imaging in mild cognitive impairment.

This study was undertaken to evaluate the tau distribution patterns in patients with amnestic mild cognitive impairment (aMCI) using PET radiotracer F-18 ML-104. Thirty patients, clinically diagnosed as aMCI [mini mental state evaluation ≥24] in the neurology or geriatric memory clinics, were included in the study. Each aMCI patient underwent F-18 fluorodeoxyglucose and F-18 ML-104 tau PET. Standardized uptake value ratios for cortical gray matter regions were evaluated for F-18 ML-104 tau PET and compared with normal controls and with early Alzheimer's disease (AD) patients (used from a previous study). aMCI revealed significantly higher standardized uptake value ratios in both medial temporal cortices, precuneus and posterior cingulate cortices in comparison to normal controls and a significantly lesser binding in bilateral medial and lateral temporal, precuneus and posterior cingulate cortices in comparison to early AD. A negative correlation was noted between F-18 fluorodeoxyglucose uptake and F-18 ML-104 retention in the precuneus and posterior cingulate cortices in aMCI, while F-18 ML-104 retention and mini mental state evaluation scores revealed a moderate negative correlation in the posterior cingulate cortices. We could demonstrate a significant increase in cortical tau deposition in aMCI patients in comparison to normal controls, thus providing in vivo evidence of the underlying pathological process in this subgroup of patients with high probability of conversion to AD.

Apolipoprotein E genotype and in vivo amyloid burden in middle-aged Hispanics.

To examine in vivo amyloid burden in relation to APOEε4 genotype in middle-aged Hispanics. We hypothesize higher amyloid levels among APOE ε4 carriers vs APOE ε4 noncarriers. This is a cross-sectional study in a community-based sample of 249 middle-aged Hispanics in New York City who underwent a 3T brain MRI and PET with the amyloid radioligand 18F-florbetaben. APOE genotype was the primary exposure. The primary outcome was amyloid positivity. The secondary outcome was subthreshold amyloid levels examined as a continuous variable. APOE ε4 carriers (n = 85) had a higher frequency (15.3%) of amyloid positivity compared to APOE ε4 noncarriers (n = 164, 1.8%). In the subthreshold group of amyloid-negative participants (n = 233), APOE ε4 carriers (n = 72) had a 0.02 (95% confidence interval [CI] 0.01-0.04) higher global brain amyloid standardized uptake value ratio (SUVR) compared to APOE ε4 noncarriers (n = 161). Compared to participants with the ε3/ε3 genotype, participants with ε4/ε4 had the highest frequency of amyloid positivity (28.6%), followed by those with ε3/ε4 (11%). Among amyloid-negative participants (n = 233), compared to participants with ε3/ε3 (n = 134), those with ε4/ε4 (n = 5) had a 0.12 (95% CI 0.07-0.17) higher global brain amyloid SUVR, and those with ε3/ε4 had a 0.02 higher SUVR (95% CI 0.003-0.04). Results were similar when a median split was used for elevated amyloid, when continuous amyloid SUVR was analyzed in all participants, and in nonparametric Mann-Whitney comparisons. Middle-aged Hispanic APOE ε4 carriers have higher in vivo brain amyloid burden compared with noncarriers, as reported in non-Hispanics.

Abstract WP350: Detecting Endogenous Neurogenesis After Ischemic Stroke: A F-18-fluorothymidine PET Study

Background and Purpose: Adult neural stem cells (NSCs) can be activated after stroke, but currently noninvasive imaging technique to visualize cerebral neurogenesis is lacking. F-18-fluorothymidine (FLT) has been used as a PET tracer to image cell proliferation and could detect endogenous NSCs in vivo . In this study, we assessed the change in cerebral FLT uptake in a rat model of ischemic stroke. Methods: Cerebral FLT PET was performed in rats subjected to transient middle cerebral artery occlusion (MCAO). PET data were semiquantitatively analyzed and expressed as average mean standardized uptake value ratios (SUVRs) of regions of interest using cerebellar cortex as the reference region. Neurological function was assessed via modified Neurological Severity Score (mNSS) 1 day after MCAO, and infarct volume was analyzed by 2,3,5-Triphenyltetrazolium chloride staining method 7 days after MCAO. Results: Seven days after MCAO, rats exhibited a higher number of Ki67 immunoreactive cells at the subventricular zone, striatum, frontal and temporal cortices in the infarcted brain, indicating promotion of neurogenesis (Figure 1A). The FLT PET showed higher SUVR in the infarcted brain compared to the unaffected side (Figure 1B; Striatum: 1.03±0.36 vs 0.74±0.16, p=0.001; Frontal: 1.14±0.27 vs 0.96±0.13, p=0.004; Temporal: 1.16±0.26 vs 1.00±0.15, p=0.01). The cerebral FLT binding activity gradually declined from post MCAO day 7 to day 28 in the infarcted brain (Figure 1C and D). The FLT binding ratio (global SUVR in the infarcted brain divided by that in the contralateral side) was positively correlated to the severity of stroke, including mNSS (r=0.70, p&lt;0.001) and infarct volume (r=0.90, p&lt;0.001). Conclusion: In vivo FLT PET can detect NSCs in a rat model of ischemic stroke. The promising results of FLT PET suggest that it can be potentially applied in clinical studies as noninvasive longitudinal monitoring and quantification of endogenous NSC activation in the human brain.

Neural Signature for Auditory Hallucinations in Schizophrenia: A High-Resolution Positron Emission Tomography Study with Fludeoxyglucose (18F).

ObjectiveAuditory hallucinations (AHs) are a core symptom of schizophrenia. We investigated the neural signature of AHs by comparing hallucinating patients with schizophrenia with non-hallucinating patients with schizophrenia.MethodsWe recruited hallucinating patients with schizophrenia meeting the criteria for persistent, prominent, and predominant AHs (n=10) and non-hallucinating patients with schizophrenia (n=12). Various clinical assessments were performed incluing Psychotic Symptom Rating Scale for Auditory Hallucinations. Using fludeoxyglucose (18F) positron emission tomography, regional differences in neural activity between the groups were analyzed.ResultsThe regions of interest analysis showed significantly lower standardized uptake value ratio (SUVR) in the superior, middle, and inferior frontal gyri, and higher SUVR in the putamen in patients with AHs versus patients without AHs. These findings were confirmed in the voxel-wise analysis.ConclusionOur findings indicate that hypoactivity in the frontal and cingulate gyri, coupled with hyperactivity in the temporal gyrus and putamen, may contribute to the pathophysiology of AHs.

Cerebral Amyloid Angiopathy and Cerebral Amyloid Angiopathy-Related Inflammation: Comparison of Hemorrhagic and DWI MRI Features

Cerebral amyloid angiopathy (CAA) can be associated with primary vasculitis of small/medium-sized leptomeningeal and cortical arteries, called CAA-related inflammation (CAA-ri). To compare hemorrhagic and diffusion-weighted imaging (DWI) MRI features in CAA and CAA-ri. We prospectively scored in a consecutive CAA and CAA-ri cohort: presence/number of chronic intracerebral hemorrhage (ICH), cerebral microbleeds (CMB), and cortical superficial siderosis (CSS) on initial T2*-weighted imaging, and DWI lesions on both initial and follow-up imaging. In a subgroup, ApoE, CSF, and 18F-florbetaben-positron emission tomography (FBB-PET) were also analyzed. In CAA-ri, CMB presence was more frequent (100% versus 40%, p < 0.001) and CMB numbers higher (mean 137 versus 8, p < 0.001). No difference was observed for chronic ICH or CSS. DWI lesions were more frequent in acute compared to chronic CAA-ri (p = 0.025), whereas no such difference was observed between acute and chronic CAA (p = 0.18). Both ApoE4 (genotyping available in 22 CAA-ri and 48 CAA patients) carriers and homozygosity were more frequent in CAA-ri (48% versus 19% [p = 0.014] and 32% versus 2% [p < 0.001] respectively). CSF biomarker analyses (performed in 20 CAA-ri and 45 CAA patients) showed lower Aβ42 levels in CAA-ri compared to CAA (median 312 versus 422 pg/mL, p = 0.0032). FBB-PET (performed in 11 CAA-ri and 20 CAA patients) showed higher standardized uptake value ratios in CAA-ri compared with CAA, only significant when the pons was used as reference (p = 0.037). Compared to CAA, CAA-ri was associated with higher CMB numbers, more frequent ApoE4 carriers and homozygotes, lower CSF Aβ42 levels, and more severe amyloid load on FBB-PET.

SURFACE-BASED ANALYSIS OF SUB-CORTICAL STRUCTURES IN TAU AND AMYLOID PET IMAGING: AN ALZHEIMER'S DISEASE STUDY

The extracellular amyloid plaques and neurofibrillary tangles are important hallmarks of Alzheimer disease (AD) spectrum. The recent development of positron emission tomography (PET) tracers has enabled human to detect neuritic plaques or neurofibrillary tangles in vivo. In this study, we recruited cognitive normal (CN) subjects (6 normal control and 27 subjective memory impairment subjects), 54 mild cognitive impairment (MCI) patients, 26 AD patients with T1-weighted brain magnetic resonance imaging (MRI), amyloid PET and tau PET. We constructed subcortical surface meshes and registered to the template mesh in order to provide vertex correspondences. Each vertices of subcortical surface acquired standardized uptake value ratios (SUVR) normalized by mean uptake of cerebellar cortex from PET images which were registered to the T1-weighted MRI images. We performed group comparison between three groups using permutation test and false discovery rate (FDR) correction. In the amyloid PET study, AD patients showed significant increased SUVR in the bilateral caudate nucleus, the bilateral putamen, the left globus pallidus, the right amygdala compared with CN subjects. Also SUVR in these subcortical regions and the right globus pallidus were higher in the MCI patients than CN subjects. Whereas SUVR of the bilateral hippocampus was higher in the CN subjects than AD patients. MCI patients had higher SUVR in the left hippocampus than AD patients. In the tau PET study, AD patients exhibited greater SUVR in the bilateral amygdala, the left hippocampus and the left putamen relative to CN subjects. Except for the left putamen, MCI patients had greater SUVR in the same regions relative to CN subjects. Contrary to the amyloid PET study, AD patients had greater SUVR in the left hippocampus than MCI patients.

The ARIC-PET amyloid imaging study: Brain amyloid differences by age, race, sex, and APOE.

To evaluate differences in amyloid deposition in a community-based cohort without dementia by age, sex, race, education, and APOE ε4 allele status. Recruited from the longitudinal Atherosclerosis Risk in Communities study, 329 participants without dementia, ages 67-88 years, were imaged using florbetapir PET at 3 US community sites (Washington County, Maryland; Forsyth County, North Carolina; and Jackson, Mississippi). Standardized uptake value ratios (SUVRs) were calculated; global cortical SUVR >1.2 was evaluated as the primary outcome. Age, race, sex, education level, and number of APOE ε4 alleles were evaluated in multivariable models including vascular risk factors, brain white matter hyperintensity and total intracranial volume, and cognitive status. A total of 141 of the participants (43%) were black. In multivariable models, odds of elevated SUVR was increased in participants with increasing age (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.01-2.65 per 10 years of age) and black race (OR 2.08, 95% CI 1.23-3.51) but did not differ by educational level. Each ε4 allele was associated with increased odds of elevated SUVR (OR 2.65, 95% CI 1.61-4.39). In this community-based cohort without dementia, florbetapir uptake is associated with older age and APOE genotype. Black race was associated with higher SUVR, after adjusting for demographics, vascular risk factors, cognitive status, white matter hyperintensity volume, and APOE genotype, with effect sizes nearing those seen for APOE ε4. Replication of these findings is needed in other cohorts, and reasons for and consequences of these observed differences by race warrant further study.

SAT0167 Vascular Standardized Uptake Value of FDG-PET/CT Correlates with Indices of LVV Activity.

Background18F-Fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography [PET/CT] is a useful tool to diagnose large vessel vasculitis (LVV) but its role in distinguishing between active and inactive disease is still debated.ObjectivesTo...