RESUMO
ß-amyloid (Aß) pathology is not always coupled with Alzheimer's disease (AD) relevant cognitive decline. We assessed the accuracy of tau PET to identify Aß(+) individuals who show prospective disease progression. 396 cognitively unimpaired and impaired individuals with baseline Aß and tau PET and a follow-up of ≥ 2 years were selected from the Alzheimer's Disease Neuroimaging Initiative dataset. The participants were dichotomously grouped based on either clinical conversion (i.e., change of diagnosis) or cognitive deterioration (fast (FDs) vs. slow decliners (SDs)) using data-driven clustering of the individual annual rates of cognitive decline. To assess cognitive decline in individuals with isolated Aß(+) or absence of both Aß and tau (T) pathologies, we investigated the prevalence of non-AD comorbidities and FDG PET hypometabolism patterns suggestive of AD. Baseline tau PET uptake was higher in Aß(+)FDs than in Aß(-)FD/SDs and Aß(+)SDs, independently of baseline cognitive status. Baseline tau PET uptake identified MCI Aß(+) Converters and Aß(+)FDs with an area under the curve of 0.85 and 0.87 (composite temporal region of interest) respectively, and was linearly related to the annual rate of cognitive decline in Aß(+) individuals. The T(+) individuals constituted largely a subgroup of those being Aß(+) and those clustered as FDs. The most common biomarker profiles in FDs (n = 70) were Aß(+)T(+) (n = 34, 49%) and Aß(+)T(-) (n = 19, 27%). Baseline Aß load was higher in Aß(+)T(+)FDs (M = 83.03 ± 31.42CL) than in Aß(+)T(-)FDs (M = 63.67 ± 26.75CL) (p-value = 0.038). Depression diagnosis was more prevalent in Aß(+)T(-)FDs compared to Aß(+)T(+)FDs (47% vs. 15%, p-value = 0.021), as were FDG PET hypometabolism pattern not suggestive of AD (86% vs. 50%, p-value = 0.039). Our findings suggest that high tau PET uptake is coupled with both Aß pathology and accelerated cognitive decline. In cases of isolated Aß(+), cognitive decline may be associated with changes within the AD spectrum in a multi-morbidity context, i.e., mixed AD.
RESUMO
Background: Cognitive impairment is observed in up to 50% of patients with amyotrophic lateral sclerosis (ALS). The Edinburgh Cognitive and Behavioral ALS Screen (ECAS) is an ALS-specific multi-domain screening tool. Few studies have examined the relationship between ECAS scores and [18F]fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) findings. Objective: To assess the relationship between ECAS scores and glucose metabolism patterns on [18F]FDG -PET images in ALS. Methods: We collected [18F]FDG-PET images from 65 patients with ALS and 39 healthy controls. ECAS scores were collected on all patients and we calculated the correlation to [18F]FDG-PET in order to investigate the potential links between cognition and glucose metabolism. Results: We observed hypometabolism in the frontal cortex, insula, and limbic system, together with hypermetabolism in the cerebellum in patients with ALS compared to controls. A lower ECAS total score was associated with lower glucose metabolism in the right orbitofrontal gyrus and higher glucose metabolism in lateral occipital, medial occipital, and cerebellar regions, among patients with ALS. Similar results, although less widespread, were observed in the analyses of ECAS ALS-specific scores. Conclusions: The metabolic patterns in [18F]FDG -PET show that changes in the glucose metabolism of corresponding areas are related to cognitive dysfunction in ALS, and can be detected using the ECAS.
RESUMO
OBJECTIVES: Higher-educated patients with Alzheimer disease (AD) can harbor greater neuropathologic burden than those with less education despite similar symptom severity. In this study, we assessed whether this observation is also present in potential preclinical AD stages, namely in individuals with subjective cognitive decline and clinical features increasing AD likelihood (SCD+). METHODS: Amyloid-PET information ([18F]Flutemetamol or [18F]Florbetaben) of individuals with SCD+, mild cognitive impairment (MCI), and AD were retrieved from the AMYPAD-DPMS cohort, a multicenter randomized controlled study. Group classification was based on the recommendations by the SCD-I and NIA-AA working groups. Amyloid PET images were acquired within 8 months after initial screening and processed with AMYPYPE. Amyloid load was based on global Centiloid (CL) values. Educational level was indexed by formal schooling and subsequent higher education in years. Using linear regression analysis, the main effect of education on CL values was tested across the entire cohort, followed by the assessment of an education-by-diagnostic-group interaction (covariates: age, sex, and recruiting memory clinic). To account for influences of non-AD pathology and comorbidities concerning the tested amyloid-education association, we compared white matter hyperintensity (WMH) severity, cardiovascular events, depression, and anxiety history between lower-educated and higher-educated groups within each diagnostic category using the Fisher exact test or χ2 test. Education groups were defined using a median split on education (Md = 13 years) in a subsample of the initial cohort, for whom this information was available. RESULTS: Across the cohort of 212 individuals with SCD+ (M(Age) = 69.17 years, F 42.45%), 258 individuals with MCI (M(Age) = 72.93, F 43.80%), and 195 individuals with dementia (M(Age) = 74.07, F 48.72%), no main effect of education (ß = 0.52, 95% CI -0.30 to 1.58), but a significant education-by-group interaction on CL values, was found (p = 0.024) using linear regression modeling. This interaction was driven by a negative association of education and CL values in the SCD+ group (ß = -0.11, 95% CI -4.85 to -0.21) and a positive association in the MCI group (ß = 0.15, 95% CI 0.79-5.22). No education-dependent differences in terms of WMH severity and comorbidities were found in the subsample (100 cases with SCD+, 97 cases with MCI, 72 cases with dementia). DISCUSSION: Education may represent a factor oppositely modulating subjective awareness in preclinical stages and objective severity of ongoing neuropathologic processes in clinical stages.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Idoso , Feminino , Humanos , Masculino , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/epidemiologia , Amiloide , Peptídeos beta-Amiloides , Proteínas Amiloidogênicas , Biomarcadores , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/epidemiologia , Escolaridade , Estudos Longitudinais , Tomografia por Emissão de Pósitrons , Estudos Multicêntricos como Assunto , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
OBJECTIVES: To increase understanding of optimal imaging parameters [ 18 F]PSMA-1007 when imaging patients with prostate cancer and to determine interrater agreement using [ 18 F]PSMA-1007. METHODS: In this observational study, four independent physicians read reconstruction sets using bedtimes of 1, 2 and 3 minutes of patients undergoing [ 18 F]PSMA-1007. positron emission topography. Clear and equivocal lesions and their locations were recorded. Image noise was rated on a four-point scale. Lesion counts were compared using inter-class correlation whereas noise ratings were compared using generalized estimating equations. Repeated cases were used to assess intra-rater agreement. RESULTS: Sixty reconstruction sets of 16 consecutively examined participants were included. Participants had a mean age of 71.5 years, six of them were examined prior to any treatment, three had a history of radiotherapy and seven of prostatectomy. Median Gleason score of primary tumors was 7. Imaging was performed after a mean of 132â min using a mean 3.95 MBq/Kg body weight of [ 18 F] PSMA-1007. Neither the total number of lesions per location nor the proportion of equivocal lesions varied consistently between bedtimes. Inter-rater reliability scores varied depending on location from 0.40 to 1.0 and were similar for all bedtimes. Intra-rater reliability varied between 0.70 and 0.76 for the three different bedtimes. Noise ratings were significantly lower for 1 minute than 3 minutes per bed. CONCLUSION: In the setting of [ 18 F]PSMA-1007 PET CT, 1, 2 and 3 minutes per bed produce similar results unlikely to affect clinical interpretation. Image noise ratings favor 2 and 3 minutes per bed.
Assuntos
Niacinamida/análogos & derivados , Oligopeptídeos , Tomografia por Emissão de Pósitrons , Neoplasias da Próstata , Masculino , Humanos , Idoso , Reprodutibilidade dos Testes , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Neoplasias da Próstata/patologia , Radioisótopos de GálioRESUMO
Plasma biomarkers have shown promising performance in research cohorts in discriminating between different stages of Alzheimer's disease (AD). Studies in clinical populations are necessary to provide insights on the clinical utility of plasma biomarkers before their implementation in real-world settings. Here we investigated plasma biomarkers (glial fibrillary acidic protein (GFAP), tau phosphorylated at 181 and 231 (pTau181, pTau231), amyloid ß (Aß) 42/40 ratio, neurofilament light) in 126 patients (age = 65 ± 8) who were admitted to the Clinic for Cognitive Disorders, at Karolinska University Hospital. After extensive clinical assessment (including CSF analysis), patients were classified as: mild cognitive impairment (MCI) (n = 75), AD (n = 25), non-AD dementia (n = 16), no dementia (n = 9). To refine the diagnosis, patients were examined with [18F]flutemetamol PET (Aß-PET). Aß-PET images were visually rated for positivity/negativity and quantified in Centiloid. Accordingly, 68 Aß+ and 54 Aß- patients were identified. Plasma biomarkers were measured using single molecule arrays (SIMOA). Receiver-operated curve (ROC) analyses were performed to detect Aß-PET+ using the different biomarkers. In the whole cohort, the Aß-PET centiloid values correlated positively with plasma GFAP, pTau231, pTau181, and negatively with Aß42/40 ratio. While in the whole MCI group, only GFAP was associated with Aß PET centiloid. In ROC analyses, among the standalone biomarkers, GFAP showed the highest area under the curve discriminating Aß+ and Aß- compared to other plasma biomarkers. The combination of plasma biomarkers via regression was the most predictive of Aß-PET, especially in the MCI group (prior to PET, n = 75) (sensitivity = 100%, specificity = 82%, negative predictive value = 100%). In our cohort of memory clinic patients (mainly MCI), the combination of plasma biomarkers was sensitive in ruling out Aß-PET negative individuals, thus suggesting a potential role as rule-out tool in clinical practice.
Assuntos
Doença de Alzheimer , Transtornos Cognitivos , Disfunção Cognitiva , Humanos , Pessoa de Meia-Idade , Idoso , Peptídeos beta-Amiloides , Tomografia por Emissão de Pósitrons/métodos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/metabolismo , Disfunção Cognitiva/diagnóstico , Biomarcadores , Proteínas tauRESUMO
Importance: Amyloid positron emission tomography (PET) allows the direct assessment of amyloid deposition, one of the main hallmarks of Alzheimer disease. However, this technique is currently not widely reimbursed because of the lack of appropriately designed studies demonstrating its clinical effect. Objective: To assess the clinical effect of amyloid PET in memory clinic patients. Design, Setting, and Participants: The AMYPAD-DPMS is a prospective randomized clinical trial in 8 European memory clinics. Participants were allocated (using a minimization method) to 3 study groups based on the performance of amyloid PET: arm 1, early in the diagnostic workup (within 1 month); arm 2, late in the diagnostic workup (after a mean [SD] 8 [2] months); or arm 3, if and when the managing physician chose. Participants were patients with subjective cognitive decline plus (SCD+; SCD plus clinical features increasing the likelihood of preclinical Alzheimer disease), mild cognitive impairment (MCI), or dementia; they were assessed at baseline and after 3 months. Recruitment took place between April 16, 2018, and October 30, 2020. Data analysis was performed from July 2022 to January 2023. Intervention: Amyloid PET. Main Outcome and Measure: The main outcome was the difference between arm 1 and arm 2 in the proportion of participants receiving an etiological diagnosis with a very high confidence (ie, ≥90% on a 50%-100% visual numeric scale) after 3 months. Results: A total of 844 participants were screened, and 840 were enrolled (291 in arm 1, 271 in arm 2, 278 in arm 3). Baseline and 3-month visit data were available for 272 participants in arm 1 and 260 in arm 2 (median [IQR] age: 71 [65-77] and 71 [65-77] years; 150/272 male [55%] and 135/260 male [52%]; 122/272 female [45%] and 125/260 female [48%]; median [IQR] education: 12 [10-15] and 13 [10-16] years, respectively). After 3 months, 109 of 272 participants (40%) in arm 1 had a diagnosis with very high confidence vs 30 of 260 (11%) in arm 2 (P < .001). This was consistent across cognitive stages (SCD+: 25/84 [30%] vs 5/78 [6%]; P < .001; MCI: 45/108 [42%] vs 9/102 [9%]; P < .001; dementia: 39/80 [49%] vs 16/80 [20%]; P < .001). Conclusion and Relevance: In this study, early amyloid PET allowed memory clinic patients to receive an etiological diagnosis with very high confidence after only 3 months compared with patients who had not undergone amyloid PET. These findings support the implementation of amyloid PET early in the diagnostic workup of memory clinic patients. Trial Registration: EudraCT Number: 2017-002527-21.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Masculino , Feminino , Idoso , Doença de Alzheimer/psicologia , Encéfalo/metabolismo , Estudos Prospectivos , Tomografia por Emissão de Pósitrons , Amiloide/metabolismo , Proteínas Amiloidogênicas , Peptídeos beta-Amiloides/metabolismoRESUMO
INTRODUCTION: ß-synuclein is an emerging blood biomarker to study synaptic degeneration in Alzheimer´s disease (AD), but its relation to amyloid-ß (Αß) pathology is unclear. METHODS: We investigated the association of plasma ß-synuclein levels with [18F] flutemetamol positron emission tomography (PET) in patients with AD dementia (n = 51), mild cognitive impairment (MCI-Aß+ n = 18, MCI- Aß- n = 30), non-AD dementias (n = 22), and non-demented controls (n = 5). RESULTS: Plasma ß-synuclein levels were higher in Aß+ (AD dementia, MCI-Aß+) than in Aß- subjects (non-AD dementias, MCI-Aß-) with good discrimination of Aß+ from Aß- subjects and prediction of Aß status in MCI individuals. A positive correlation between plasma ß-synuclein and Aß PET was observed in multiple cortical regions across all lobes. DISCUSSION: Plasma ß-synuclein demonstrated discriminative properties for Aß PET positive and negative subjects. Our data underline that ß-synuclein is not a direct marker of Aß pathology and suggest different longitudinal dynamics of synaptic degeneration versus amyloid deposition across the AD continuum. HIGHLIGHTS: Blood and CSF ß-synuclein levels are higher in Aß+ than in Aß- subjects. Blood ß-synuclein level correlates with amyloid PET positivity in multiple regions. Blood ß-synuclein predicts Aß status in MCI individuals.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , beta-Sinucleína , Encéfalo/patologia , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/patologia , Tomografia por Emissão de Pósitrons/métodos , Peptídeos beta-Amiloides/metabolismo , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/patologia , BiomarcadoresRESUMO
Objective: Amyotrophic lateral sclerosis (ALS) is a clinically heterogenous disease, typically presenting with focal motor weakness that eventually generalizes. Weather there is a correlation between focal motor weakness and metabolic alterations in specific areas of the brain has not been thoroughly explored. This study aims to systematically investigate this by using fluorodeoxyglucose-positron emission tomography (FDG-PET), including longitudinal imaging. Methods: This observational imaging study included 131 ALS patients diagnosed and examined with FDG-PET at the ALS Clinical Research Center at the Karolinska University Hospital in Stockholm, Sweden. Thirteen ALS patients had a second scan and were analyzed longitudinally. The findings were compared to 39 healthy controls examined at the University Medical Center of Gröningen, the Netherlands. Results: There was a general pattern of brain metabolic alterations consistent with previously reported findings in ALS, namely hypometabolism in frontal regions and hypermetabolism in posterior regions. A higher symptom burden was associated with increased hypometabolism and decreased hypermetabolism. However, there was no clear correlation between focal motor weakness and specific metabolic alterations, neither when analyzing focal motor weakness with concomitant upper motor neuron signs or when including all focal motor weakness. Longitudinal FDG-PET imaging showed inconsistent results with little correlation between progression of motor weakness and metabolic alterations. Conclusion: Our results support the disease model of ALS as a diffuse process since no clear correlation was seen between focal motor weakness and specific metabolic alterations. However, there is need for further research on a larger number of patients, particularly including longitudinal imaging.
Assuntos
Esclerose Lateral Amiotrófica , Humanos , Esclerose Lateral Amiotrófica/complicações , Esclerose Lateral Amiotrófica/diagnóstico por imagem , Esclerose Lateral Amiotrófica/metabolismo , Fluordesoxiglucose F18/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Lobo FrontalRESUMO
INTRODUCTION: AMYPAD Diagnostic and Patient Management Study (DPMS) aims to investigate the clinical utility and cost-effectiveness of amyloid-PET in Europe. Here we present participants' baseline features and discuss the representativeness of the cohort. METHODS: Participants with subjective cognitive decline plus (SCD+), mild cognitive impairment (MCI), or dementia were recruited in eight European memory clinics from April 16, 2018, to October 30, 2020, and randomized into three arms: ARM1, early amyloid-PET; ARM2, late amyloid-PET; and ARM3, free-choice. RESULTS: A total of 840 participants (244 SCD+, 341 MCI, and 255 dementia) were enrolled. Sociodemographic/clinical features did not differ significantly among recruiting memory clinics or with previously reported cohorts. The randomization assigned 35% of participants to ARM1, 32% to ARM2, and 33% to ARM3; cognitive stages were distributed equally across the arms. DISCUSSION: The features of AMYPAD-DPMS participants are as expected for a memory clinic population. This ensures the generalizability of future study results.
RESUMO
Differential diagnosis of parkinsonism early upon symptom onset is often challenging for clinicians and stressful for patients. Several neuroimaging methods have been previously evaluated; however specific routines remain to be established. The aim of this study was to systematically assess the diagnostic accuracy of a previously developed 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) based automated algorithm in the diagnosis of parkinsonian syndromes, including unpublished data from a prospective cohort. A series of 35 patients prospectively recruited in a movement disorder clinic in Stockholm were assessed, followed by systematic literature review and meta-analysis. In our cohort, automated image-based classification method showed excellent sensitivity and specificity for Parkinson Disease (PD) vs. atypical parkinsonian syndromes (APS), in line with the results of the meta-analysis (pooled sensitivity and specificity 0.84; 95% CI 0.79-0.88 and 0.96; 95% CI 0.91 -0.98, respectively). In conclusion, FDG-PET automated analysis has an excellent potential to distinguish between PD and APS early in the disease course and may be a valuable tool in clinical routine as well as in research applications.
Assuntos
Diagnóstico por Computador , Transtornos Parkinsonianos/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Diagnóstico Diferencial , Humanos , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: [18F]flutemetamol PET scanning provides information on brain amyloid load and has been approved for routine clinical use based upon visual interpretation as either negative (equating to none or sparse amyloid plaques) or amyloid positive (equating to moderate or frequent plaques). Quantitation is however fundamental to the practice of nuclear medicine and hence can be used to supplement amyloid reading methodology especially in unclear cases. METHODS: A total of 2770 [18F]flutemetamol images were collected from 3 clinical studies and 6 research cohorts with available visual reading of [18F]flutemetamol and quantitative analysis of images. These were assessed further to examine both the discordance and concordance between visual and quantitative imaging primarily using thresholds robustly established using pathology as the standard of truth. Scans covered a wide range of cases (i.e. from cognitively unimpaired subjects to patients attending the memory clinics). Methods of quantifying amyloid ranged from using CE/510K cleared marked software (e.g. CortexID, Brass), to other research-based methods (e.g. PMOD, CapAIBL). Additionally, the clinical follow-up of two types of discordance between visual and quantitation (V+Q- and V-Q+) was examined with competing risk regression analysis to assess possible differences in prediction for progression to Alzheimer's disease (AD) and other diagnoses (OD). RESULTS: Weighted mean concordance between visual and quantitation using the autopsy-derived threshold was 94% using pons as the reference region. Concordance from a sensitivity analysis which assessed the maximum agreement for each cohort using a range of cut-off values was also estimated at approximately 96% (weighted mean). Agreement was generally higher in clinical cases compared to research cases. V-Q+ discordant cases were 11% more likely to progress to AD than V+Q- for the SUVr with pons as reference region. CONCLUSIONS: Quantitation of amyloid PET shows a high agreement vs binary visual reading and also allows for a continuous measure that, in conjunction with possible discordant analysis, could be used in the future to identify possible earlier pathological deposition as well as monitor disease progression and treatment effectiveness.
Assuntos
Doença de Alzheimer , Tomografia por Emissão de Pósitrons , Doença de Alzheimer/diagnóstico por imagem , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Compostos de Anilina , Benzotiazóis , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , HumanosRESUMO
BACKGROUND: Both dual time-point 99mTc-hexamethylpropylene amine oxime (HMPAO)-leukocyte scintigraphy and dual-tracer 99mTc-HMPAO-leukocyte scintigraphy (with the addition of 99mTc-nanocolloid bone marrow scintigraphy) have been used to diagnose prosthetic joint infection (PJI). A treatment evaluation of persistent PJI using these imaging protocols has yet to be presented. OBJECTIVE: The purpose of this study was to compare the accuracy of dual time-point 99mTc-HMPAO-leukocyte scintigraphy to the dual-tracer alternative of single time-point 99mTc-HMPAO-leukocyte scintigraphy or single-photon emission computed tomography/computed tomography (SPECT/CT) combined with a 99mTc-nanocolloid bone marrow scintigraphy or SPECT/CT, for treatment evaluation of PJI. MATERIAL AND METHODS: Thirty-one PJI patients under antibiotic treatment were included in this retrospective study. Examinations were organized into three settings. Setting one used dual time-point approach with delayed (2 h) and late (24 h) planar 99mTc-HMPAO-leukocyte scintigraphy, including both visual and semiquantitative analysis. Setting two used delayed (2 h) planar 99mTc-HMPAO-leukocyte scintigraphy combined with 99mTc-nanocolloid bone marrow scintigraphy and for setting three SPECT/CT replaced planar imaging. RESULTS: Accuracy was 0.68 for visual evaluation and 0.55 for semiquantitative evaluation of setting one; 0.71 for setting two; and 0.68 for setting three. Sensitivity was 0.54 for visual evaluation and 0.31 for semiquantitative evaluation of setting one; 0.38 for setting two; and 0.46 for setting three. Specificity was 0.78 for visual evaluation and 0.72 for semiquantitative evaluation of setting one; 0.94 for setting two; and 0.83 for setting three. CONCLUSION: No significant difference in accuracy, sensitivity, or specificity between the approaches for treatment evaluation of suspected persistent PJI in the hip or knee was observed.
Assuntos
Infecções Relacionadas à Prótese , Adulto , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tecnécio Tc 99m Exametazima , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
PURPOSE: To assess the clinical impact and incremental diagnostic value of 18F-fluorodeoxyglucose (FDG-PET) among memory clinic patients with uncertain diagnosis. METHODS: The study population consisted of 277 patients who, despite extensive baseline cognitive assessment, MRI, and CSF analyses, had an uncertain diagnosis of mild cognitive impairment (MCI) (n = 177) or dementia (n = 100). After baseline diagnosis, each patient underwent an FDG-PET, followed by a post-FDG-PET diagnosis formulation. We evaluated (i) the change in diagnosis (baseline vs. post-FDG-PET), (ii) the change in diagnostic accuracy when comparing each baseline and post-FDG-PET diagnosis to a long-term follow-up (3.6 ± 1.8 years) diagnosis used as reference, and (iii) comparative FDG-PET performance testing in MCI and dementia conditions. RESULTS: FDG-PET led to a change in diagnosis in 86 of 277 (31%) patients, in particular in 57 of 177 (32%) MCI and in 29 of 100 (29%) dementia patients. Diagnostic change was greater than two-fold in the sub-sample of cases with dementia "of unclear etiology" (change in diagnosis in 20 of 32 (63%) patients). In the dementia group, after results of FDG-PET, diagnostic accuracy improved from 77 to 90% in Alzheimer's disease (AD) and from 85 to 94% in frontotemporal lobar degeneration (FTLD) patients (p < 0.01). FDG-PET performed better in dementia than in MCI (positive likelihood ratios >5 and < 5, respectively). CONCLUSION: Within a selected clinical population, FDG-PET has a significant clinical impact, both in early and differential diagnosis of uncertain dementia. FDG-PET provides significant incremental value to detect AD and FTLD over a clinical diagnosis of uncertain dementia.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Doença de Alzheimer/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Diagnóstico Diferencial , Fluordesoxiglucose F18 , Humanos , Memória , Tomografia por Emissão de PósitronsRESUMO
Cross-sectional studies have indicated potential for positron emission tomography (PET) in imaging tau pathology in Alzheimer's disease (AD); however, its prognostic utility remains unproven. In a longitudinal, multi-modal, prognostic study of cognitive decline, 20 patients with a clinical biomarker-based diagnosis in the AD spectrum (mild cognitive impairment or dementia and a positive amyloid-beta PET scan) were recruited from the Cognitive Clinic at Karolinska University Hospital. The participants underwent baseline neuropsychological assessment, PET imaging with [18F]THK5317, [11C]PIB and [18F]FDG, magnetic resonance imaging, and in a subgroup cerebrospinal fluid (CSF) sampling, with clinical follow-up after a median 48 months (interquartile range = 32:56). In total, 11 patients declined cognitively over time, while 9 remained cognitively stable. The accuracy of baseline [18F]THK5317 binding in temporal areas was excellent at predicting future cognitive decline (area under the receiver operating curve 0.84-1.00) and the biomarker levels were strongly associated with the rate of cognitive decline (ß estimate -33.67 to -31.02, p < 0.05). The predictive accuracy of the other baseline biomarkers was poor (area under the receiver operating curve 0.58-0.77) and their levels were not associated with the rate of cognitive decline (ß estimate -4.64 to 15.78, p > 0.05). Baseline [18F]THK5317 binding and CSF tau levels were more strongly associated with the MMSE score at follow-up than at baseline (p < 0.05). These findings support a temporal dissociation between tau deposition and cognitive impairment, and suggest that [18F]THK5317 predicts future cognitive decline better than other biomarkers. The use of imaging markers for tau pathology could prove useful for clinical prognostic assessment and screening before inclusion in relevant clinical trials.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides , Compostos de Anilina , Biomarcadores , Disfunção Cognitiva/diagnóstico por imagem , Estudos Transversais , Humanos , Tomografia por Emissão de Pósitrons , Estudos Prospectivos , Quinolinas , Proteínas tauRESUMO
Introduction: The disconnection hypothesis of Alzheimer's disease (AD) is supported by growing neuroimaging and neurophysiological evidence of altered brain functional connectivity in cognitively impaired individuals. Brain functional modalities such as [18F]fluorodeoxyglucose positron-emission tomography ([18F]FDG-PET) and electroencephalography (EEG) measure different aspects of synaptic functioning, and can contribute to understanding brain connectivity disruptions in AD. Aim: This study investigated the relationship between cortical glucose metabolism and topographical EEG measures of brain functional connectivity in subjects along AD continuum. Methods: Patients diagnosed with mild cognitive impairment (MCI) and AD (n = 67), and stratified into amyloid-positive (n = 32) and negative (n = 10) groups according to cerebrospinal fluid Aß42/40 ratio, were assessed with [18F]FDG-PET and resting-state EEG recordings. EEG-based neuroimaging analysis involved standardized low-resolution electromagnetic tomography (sLORETA), which estimates functional connectivity from cortical sources of electrical activity in a 3D head model. Results: Glucose hypometabolism in temporoparietal lobes was significantly associated with altered EEG functional connectivity of the same regions of interest in clinically diagnosed MCI and AD patients and in patients with biomarker-verified AD pathology. The correlative pattern of disrupted connectivity in temporoparietal lobes, as detected by EEG sLORETA analysis, included decreased instantaneous linear connectivity in fast frequencies and increased lagged linear connectivity in slow frequencies in relation to the activity of remaining cortex. Conclusions: Topographical EEG measures of functional connectivity detect regional dysfunction of AD-vulnerable brain areas as evidenced by association and spatial overlap with the cortical glucose hypometabolism in MCI and AD patients. Impact statement The association between glucose hypometabolism, as evidenced by [18F]FDG-PET ([18F]fluorodeoxyglucose positron-emission tomography), and altered electroencephalography (EEG) functional connectivity metrics within temporoparietal lobes provides link between synaptic, neurophysiological, and metabolic impairment in mild cognitive impairment and Alzheimer's disease patients. This study reported alterations in EEG measures of both instantaneous and lagged linear connectivity across distinct frequency bands, both of which were shown to be important for inter- and intrahemispheric communication and function of memory systems in general. EEG-based imaging of brain functional connectivity has a potential to serve as a noninvasive, low-cost, and widely available alternative in assessing synaptic and network dysfunction in cognitively impaired patients.
Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Glucose/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/fisiopatologia , Eletroencefalografia , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Tomografia por Emissão de PósitronsRESUMO
OBJECTIVE: To perform a comprehensive characterization of a cohort of patients with chorea-acanthocytosis (ChAc) in Sweden. METHODS: Clinical assessments, targeted genetic studies, neuroimaging with MRI, [18F]-fluorodeoxyglucose (FDG) PET, and dopamine transporter with 123I FP-CIT (DaTscan) SPECT. One patient underwent magnetic resonance spectroscopy (MRS). RESULTS: Four patients living in Sweden but with different ethnical backgrounds were included. Their clinical features were variable. Biallelic VPS13A mutations were confirmed in all patients, including 3 novel mutations. All tested patients had either low or absent chorein levels. One patient had progressive caudate atrophy. Investigation using FDG-PET revealed severe bilateral striatal hypometabolism, and DaTscan SPECT displayed presynaptic dopaminergic deficiency in 3 patients. MRS demonstrated reduced N-acetylaspartate/creatine (Cr) ratio and mild elevation of both choline/Cr and combined glutamate and glutamine/Cr in the striatum in 1 case. One patient died during sleep, and another was treated with deep brain stimulation, which transiently attenuated feeding dystonia but not his gait disorder or chorea. CONCLUSIONS: Larger longitudinal neuroimaging studies with different modalities, particularly MRS, are needed to determine their potential role as biomarkers for ChAc.
RESUMO
BACKGROUND: Striatal dopamine deficiency and metabolic changes are well-known phenomena in dementia with Lewy bodies and can be quantified in vivo by 123 I-Ioflupane brain single-photon emission computed tomography of dopamine transporter and 18 F-fluorodesoxyglucose PET. However, the linkage between both biomarkers is ill-understood. OBJECTIVE: We used the hitherto largest study cohort of combined imaging from the European consortium to elucidate the role of both biomarkers in the pathophysiological course of dementia with Lewy bodies. METHODS: We compared striatal dopamine deficiency and glucose metabolism of 84 dementia with Lewy body patients and comparable healthy controls. After normalization of data, we tested their correlation by region-of-interest-based and voxel-based methods, controlled for study center, age, sex, education, and current cognitive impairment. Metabolic connectivity was analyzed by inter-region coefficients stratified by dopamine deficiency and compared to healthy controls. RESULTS: There was an inverse relationship between striatal dopamine availability and relative glucose hypermetabolism, pronounced in the basal ganglia and in limbic regions. With increasing dopamine deficiency, metabolic connectivity showed strong deteriorations in distinct brain regions implicated in disease symptoms, with greatest disruptions in the basal ganglia and limbic system, coincident with the pattern of relative hypermetabolism. CONCLUSIONS: Relative glucose hypermetabolism and disturbed metabolic connectivity of limbic and basal ganglia circuits are metabolic correlates of dopamine deficiency in dementia with Lewy bodies. Identification of specific metabolic network alterations in patients with early dopamine deficiency may serve as an additional supporting biomarker for timely diagnosis of dementia with Lewy bodies. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
Assuntos
Doença por Corpos de Lewy , Encéfalo , Estudos de Coortes , Dopamina , Humanos , Corpos de Lewy , Doença por Corpos de Lewy/diagnóstico por imagemAssuntos
Neoplasias Ósseas/diagnóstico por imagem , Imagem Multimodal/métodos , Doses de Radiação , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Neoplasias Ósseas/secundário , Osso e Ossos/diagnóstico por imagem , Estudos de Viabilidade , Feminino , Humanos , MasculinoRESUMO
One of the most commonly used imaging techniques for diagnosing pulmonary embolism (PE) is ventilation/perfusion (V/P) scintigraphy. The aim of this study was to evaluate the performance of the currently used imaging protocols for V/P single photon emission computed tomography (V/P SPECT) at two nuclear medicine department sites and to investigate the effect of altering important protocol parameters. The Monte Carlo technique was used to simulate 4D digital phantoms with perfusion defects. Six imaging protocols were included in the study and a total of 72 digital patients were simulated. Six dually trained radiologists/nuclear medicine physicians reviewed the images and reported all perfusion mismatch findings. The radiologists also visually graded the image quality. No statistically significant differences in diagnostic performance were found between the studied protocols, but visual grading analysis pointed out one protocol as significantly superior to four of the other protocols. Considering the study results, we have decided to harmonize our clinical protocols for imaging patients with suspected PE. The administered Technegas and macro aggregated albumin activities have been altered, a low energy all purpose collimator is used instead of a low energy high resolution collimator and the acquisition times have been lowered.