White matter (WM) signal on ¹⁸F-florbetapir positron emission tomography (PET) is often regarded as nonspecific, yet its biological significance remains unclear. This study aimed to characterize the trajectory, clinical significance, and biomarker correlates of normal-appearing white matter (NAWM) ¹⁸F-florbetapir retention across the Alzheimer’s disease (AD) continuum. We analyzed NAWM ¹⁸F-florbetapir retention in 672 participants across the AD continuum from the Alzheimer’s Disease Neuroimaging Initiative and two Chinese cohorts. Longitudinal PET, plasma, and cerebrospinal fluid (CSF) biomarkers, as well as lecanemab treatment effects, were evaluated. NAWM retention followed a distinct trajectory from cortical amyloid, increasing during preclinical stages and plateauing in symptomatic phases. Elevated NAWM ¹⁸F-florbetapir retention independently predicted cognitive decline, correlated with plasma p-tau217 and CSF p-tau/Aβ42 ratio, and showed significant reductions following lecanemab therapy. Combined assessment of cortical and NAWM PET improved diagnostic accuracy for amyloid positivity to 92

Quantitative PET underpins diagnosis and treatment monitoring in neurodegenerative disease, yet systematic biases between PET-MRI and PET-CT preclude threshold transfer and cross-site comparability. We developed and validated the first unified, anatomically guided deep-learning framework to harmonize PET-MRI quantification to PET-CT standards across multiple tracers and scanner manufacturers. The model learns CT-anchored attenuation representations using a vision transformer autoencoder, aligns MRI features to the CT space via contrastive objectives, and performs attention-guided residual correction. In paired same-day scans (N = 70; 18F-FDG, 18F-florbetaben, and 18F-florzolotau), cross-platform bias fell by >80% while preserving inter-regional biological topology. The framework generalized zero-shot to held-out tracers (18F-florbetapir and 18F-FP-CIT) without retraining. Multicenter validation (N = 420; three sites, four vendors) reduced amyloid Centiloid discrepancies from 23.6 to 4.1 (close to, though slightly above, PET-CT test-retest variability) and aligned tau SUVR thresholds. These results support more consistent cross-platform diagnostic cut-offs and reliable longitudinal monitoring when patients transition between modalities, establishing a practical route to scalable, radiation-sparing quantitative PET in therapeutic workflows.

Positron Emission Tomography combined with Magnetic Resonance (PET-MR) imaging has emerged as a promising modality that offers both soft tissue and biochemical function information, while substantially reducing radiation exposure compared to PET-CT imaging. However, systematic clinical evaluations reveal notable discrepancies in standardized uptake value ratios between PET-MR and PET-CT scans, largely due to the inherent limitations of MR-based PET attenuation correction. To address this issue, we propose a unified uptake correction framework to harmonize PET-MR images with PET-CT scans across different tracers. This framework employs a three-stage training scheme. The first stage learns to represent CT features, aiming to capture condensed anatomical patterns associated with PET imaging. The second stage aligns MR features to the fixed CT features learned in the first stage, thereby enabling the transfer of anatomical prior knowledge from CT to MR features. The third stage integrates aligned MR features to guide PET-MR tracer uptake correction and uses a Multi-scale Pixel Routing module to mitigate interference among different tracers. We conduct comprehensive experiments on 70 patients with three distinct tracers to demonstrate the superiority of our framework over existing methods in PET-MR harmonization with PET-CT images. This work represents the first investigation and solution for multi-tracer quantification discrepancies between PET-MR and standard PET-CT, potentially advancing the clinical standardization of PET-MR imaging. Our code will be available at GitHub.

Background Asymmetry in motor dysfunction and associated dopaminergic deficit is a common characteristic of Parkinson's disease (PD), yet potential explanations remain mysterious. Hereby, we assessed whether asymmetry in the nasal cavity is related to dopaminergic dysfunction asymmetry in PD patients. Methods This cross-sectional, multi-center observational study included 761 PD patients from three cohorts. First, we analyzed data from the Huashan Parkinsonian PET Imaging Database (March 2011 to February 2020), which served as the primary cohort (n=333). Second, we collected de novo data from all PD inpatients in the Hongqiao Campus of Huashan Hospital as internal validation cohort (May 2023 to July 2024, n=77). Finally, we used data from the Parkinson's Progression Markers Initiative as an external validation cohort (n=351). All cohorts included imaging data of structural MRI or CT, as well as dopaminergic neuroimaging using 11C−CFT, 18F−FP−CIT, or 18F−DTBZ on PET or 123I−DaTscan on SPECT. Nasal cavity asymmetry was assessed by visually inspecting the position of nasal septum deviation in structural MRI or CT to determine the dominant side. Both qualitative and quantitative analyses were performed to evaluate the correlations between nasal cavity asymmetry and dopaminergic deficit asymmetry. Results In the primary cohort, 70.2% of patients exhibited consistency between the dominant side of the nasal cavity and the side with a more severe dopaminergic deficit in striatum (φ=0.40, p<0.001). The striatal−specific binding ratios of dopamine uptake were significantly lower on the side ipsilateral to the dominant nasal cavity, and a significantly inverse correlation was found between the asymmetry index of nasal cavity surface area and that of the dopaminergic deficit (r=−0.31, p<0.001). Similar patterns were observed in internal (78.6%, φ=0.57, p<0.001) and external validation cohorts (73.1%, φ=0.45, p<0.001). A stronger correlation was found in sporadic PD (φ=0.67, p<0.001) compared to genetic PD patients (φ=0.31, p=0.3). Conclusions We made a novel and robust observation that the nasal cavity asymmetry is correlated with asymmetry in striatal dopaminergic deficiency in PD patients. The finding may have significant implications for both the etiological and clinical research of PD, supporting the nasal pathway as a potential route for both environmental pathogens and PD treatment. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work received financial support from the Shanghai Municipal Science and Technology Major Project (grants No. 22JC1410402), National Natural Science Foundation of China (grants No. 82171421, 82371432, 92249302, 82272039, 82021002, 81971641, 81902282, 82171252, and 82371266), National Health Commission of China (grants No. Pro20211231084249000238), the Research project of Shanghai Health Commission (grants No. 2020YJZX0111), the Clinical Research Plan of SHDC (grants No. SHDC2020CR1038B), and the STI2030-Major Projects (grants No. 2022ZD0211600). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the Institutional Review Boards of Huashan Hospital. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

Dopamine transporter [11C]CFT PET is highly effective for diagnosing Parkinson’s Disease (PD), whereas it is not widely available in most hospitals. To develop a deep learning framework to synthesize [11C]CFT PET images from real [18F]FDG PET images and leverage their cross-modal correlation to distinguish PD from normal control (NC). We developed a deep learning framework to synthesize [11C]CFT PET images from real [18F]FDG PET images, and leveraged their cross-modal correlation to distinguish PD from NC. A total of 604 participants (274 with PD and 330 with NC) who underwent [11C]CFT and [18F]FDG PET scans were included. The quality of the synthetic [11C]CFT PET images was evaluated through quantitative comparison with the ground-truth images and radiologist visual assessment. The evaluations of PD diagnosis performance were conducted using biomarker-based quantitative analyses (using striatal binding ratios from synthetic [11C]CFT PET images) and the proposed PD classifier (incorporating both real [18F]FDG and synthetic [11C]CFT PET images). Visualization result shows that the synthetic [11C]CFT PET images resemble the real ones with no significant differences visible in the error maps. Quantitative evaluation demonstrated that synthetic [11C]CFT PET images exhibited a high peak signal-to-noise ratio (PSNR: 25.0–28.0) and structural similarity (SSIM: 0.87–0.96) across different unilateral striatal subregions. The radiologists achieved a diagnostic accuracy of 91.9

Discrepancies between PET/CT and PET/MRI scanners can affect the determination of amyloid beta (Aβ) deposition thresholds in patients with cognitive impairment. This study aimed to identify these differences and propose a calibration method to standardize Aβ quantification across imaging modalities. A total of 133 patients with cognitive impairment underwent Aβ PET imaging and were divided into four groups: a head-to-head PET/CT and PET/MRI cohort (group A, n = 6), an independent PET/CT cohort (group B, n = 48), an independent PET/MRI cohort (group C, n = 79), and another independent PET/MRI cohort (group D, n = 10). Standardized uptake value ratios (SUVR) of global cortical target (CTXsuvr) and centiloid (CL) values were compared within group A and between groups B and C. A whole cerebellum (WC)-referenced SUVR method was used to calibrate CL values in group C, with verification in group D. CTXsuvr values were significantly higher in PET/MRI than in PET/CT in both group A (P < 0.05) and group C versus group B (P < 0.001). Aβ-negative/positive cases showed mean ± variance of CTXsuvr as 1.023 ± 0.104/1.479 ± 0.203 in group B and 1.146 ± 0.100/1.743 ± 0.254 in group C, with cutoffs of 1.140 (CL = 20) and 1.401 (CL = 60), respectively. WC-referenced calibration adjusted PET/MRI cutoff to 1.132 (CL = 19) in group C, aligning it with PET/CT thresholds and validated in group D. WC-referenced SUVR calibration effectively mitigates differences in Aβ thresholds between PET/CT and PET/MRI, enhancing Aβ quantification standardization in multi-modal imaging.

INTRODUCTION:We aimed to evaluate the feasibility of the 2024 Alzheimer's Association Workgroup's integrated clinical-biological staging scheme in outpatient settings within a tertiary memory clinic. METHODS:The 2018 syndromal cognitive staging system, coupled with a binary biomarker classification, was implemented for 236 outpatients with cognitive concerns. The 2024 numeric clinical staging framework, incorporating biomarker staging, was specifically applied to 154 individuals within the Alzheimer's disease (AD) continuum. RESULTS:The 2024 staging scheme accurately classified 95.5% AD. Among these, 56.5% exhibited concordant clinical and biological stages (canonical), 34.7% demonstrated more advanced clinical stages than biologically expected (susceptible), and 8.8% displayed the inverse pattern (resilient). The susceptible group was characterized by a higher burden of neurodegeneration and inflammation than anticipated from tau, whereas the resilient group showed the opposite. DISCUSSION:The 2024 staging scheme is generally feasible. A discrepancy between clinical and biological stages is relatively frequent among symptomatic patients with AD. HIGHLIGHTS:The 2024 AA staging scheme is generally feasible in a tertiary memory clinic. A discrepancy between clinical and biological stages is relatively frequent in AD. The mismatch may be influenced by a non-specific pathological process involved in AD. Individual profiles like aging and lifestyles may contribute to such a mismatch. Matched and mismatched cases converge toward similar clinical outcomes.

Determination of isocitrate dehydrogenase (IDH) genotype is crucial in the stratification of diagnosis and prognostication in diffuse gliomas. We sought to build and validate radiomics models and clinical features incorporated nomogram for preoperative prediction of IDH mutation status and WHO grade of diffuse gliomas with l-[methyl-11C] methionine ([11C]MET) PET/CT imaging according to the 2016 WHO classification of tumors of the central nervous system. Consecutive 178 preoperative [11C]MET PET/CT images were retrospectively studied for radiomics analysis. One hundred six patients from PET scanner 1 were used as training dataset, and 72 patients from PET scanner 2 were used for validation dataset. [11C]MET PET and integrated CT radiomics features were extracted, respectively; three independent predictive models were built based on PET features, CT features, and combined PET/CT features, respectively. The SelectKBest method, Spearman correlation analysis, Least Absolute Shrinkage and Selection Operator (LASSO) regression, and machine learning algorithms were applied for feature selection and model building. After filtering the satisfactory predictive model, key clinical features were incorporated for the nomogram establishment. The combined [11C]MET PET/CT radiomics model, which consisted of four PET features and eight integrated CT features, was significantly associated with IDH genotype (p < 0.0001 for both training and validation datasets). Nomogram based on the [11C]MET PET/CT radiomics score, patients’ age, and dichotomous tumor location status showed satisfactory discrimination capacity, and the AUC was 0.880 (95

Human post mortem studies have described the topographical patterns of tau pathology in progressive supranuclear palsy (PSP). Recent advances in tau PET tracers are expected to herald the next era of PSP investigation for early detection of tau pathology in living brains. This study aimed to investigate whether 18F-Florzolotau PET imaging may capture the distribution patterns and regional vulnerability of tau pathology in PSP, and to devise a novel image-based staging system. The study cohort consisted of 148 consecutive patients with PSP who had undergone 18F-Florzolotau PET imaging. The PSP rating scale (PSPrs) was used to measure disease severity. Similarities and differences of tau deposition among different clinical phenotypes were examined at the regional and voxel levels. An 18F-Florzolotau pathological staging system was devised according to the scheme originally developed for post mortem data. In light of conditional probabilities for the sequence of events, an 18F-Florzolotau modified staging system by integrating clusters at the regional level was further developed. The ability of 18F-Florzolotau staging systems to reflect disease severity in terms of PSPrs score was assessed by analysis of variance. The distribution patterns of 18F-Florzolotau accumulation in living brains of PSP showed a remarkable similarity to those reported in post mortem studies, with the binding intensity being markedly higher in Richardson’s syndrome. Moreover, 18F-Florzolotau PET imaging allowed detecting regional vulnerability and tracking tau accumulation in an earlier fashion compared with post mortem immunostaining. The 18F-Florzolotau staging systems were positively correlated with clinical severity as reflected by PSPrs scores. 18F-Florzolotau PET imaging can effectively capture the distribution patterns and regional vulnerability of tau pathology in PSP. The 18F-Florzolotau modified staging system holds promise for early tracking of tau deposition in living brains.

Purpose We aimed to investigate the predictive models based on O-[2-(18F)fluoroethyl]-l-tyrosine positron emission tomography/computed tomography (18F-FET PET/CT) radiomics features for the isocitrate dehydrogenase (IDH) genotype identification in adult gliomas. Methods Fifty-eight consecutive pathologically confirmed adult glioma patients with pretreatment 18F-FET PET/CT were retrospectively enrolled. One hundred and five radiomics features were extracted for analysis in each modality. Three independent radiomics models (PET-Rad Model, CT-Rad Model and PET/CT-Rad Model) predicting IDH mutation status were generated using the least absolute shrinkage and selection operator (LASSO) regression analysis based on machine learning algorithms. All-subsets regression and cross validation were applied for the filter and calibration of the predictive radiomics models. Besides, semi-quantitative parameters including maximum, peak and mean tumor to background ratio (TBRmax, TBRpeak, TBRmean), standard deviation of glioma lesion standardized uptake value (SUVSD), metabolic tumor volume (MTV) and total lesion tracer uptake (TLU) were obtained and filtered for the simple model construction with clinical feature of brain midline involvement status. The area under the receiver operating characteristic curve (AUC) was applied for the evaluation of the predictive models. Results The AUC of the simple predictive model consists of semi-quantitative parameter SUVSD and dichotomized brain midline involvement status was 0.786 (95% CI 0.659-0.883). The AUC of PET-Rad Model building with three 18F-FET PET radiomics parameters was 0.812 (95% CI 0.688-0.902). The AUC of CT-Rad Model building with three co-registered CT radiomics parameters was 0.883 (95% CI 0.771-0.952). While the AUC of the combined 18F-FET PET/CT-Rad Model building with three CT and one PET radiomics features was 0.912 (95% CI 0.808-0.970). DeLong test results indicated the PET/CT-Rad Model outperformed the PET-Rad Model (p = 0.048) and simple predictive model (p = 0.034). Further combination of the PET/CT-Rad Model with the clinical feature of dichotomized tumor location status could slightly enhance the AUC to 0.917 (95% CI 0.814-0.973). Conclusion The predictive model combining 18F-FET PET and integrated CT radiomics features could significantly enhance and well balance the non-invasive IDH genotype prediction in untreated gliomas, which is important in clinical decision making for personalized treatment.

Objective:To establish O-(2-[ 18F]fluoroethyl)- L-tyrosine( 18F-FET) PET radiomics features-based model and investigate its predictive efficacy for isocitrate dehydrogenase type 1 (IDH1) genotyping in untreated gliomas. Methods:From November 2017 to February 2019, 58 pathologically confirmed glioma patients (36 males, 22 females; age (41.8±15.1) years) with preoperative 18F-FET PET/CT imaging in Huashan Hospital, Fudan University were retrospectively enrolled. PyRadiomics software package was used to extract 105 radiomics features. Least absolute shrinkage and selection operator (LASSO) algorithm with 5-fold cross-validation was used to build the logistic regression model. And radiomic scores (RS) of each lesion were calculated according to their weighted coefficients. The area under the receiver operating characteristic (ROC) curve was used for evaluating the predictive efficacy for IDH1 prediction. The predictive efficacies of radiomics model and traditional semi-quantitative parameters including tumor-to-background ratio (TBR; maximum TBR (TBR max), mean TBR (TBR mean), peak TBR (TBR peak)), metabolic tumor volume (MTV) and total lesion tracer uptake (TLU), were compared by Delong test. Results:Seven radiomics features including maximum 2-dimensional (2D) diameter slice, first order_maximum, first order_range, gray level co-occurrence matrix (GLCM)_joint energy, GLCM_inverse variance, gray level dependence matrix (GLDM)_dependence entropy and GLDM_large dependence low gray level emphasis were selected for the LASSO regression model building and RS calculation. ROC analysis results showed that the predictive accuracy of RS for IDH1 genotyping (mutation, n=20; wild-type, n=38) was 81.0%(47/58), with sensitivity of 65.0%(13/20), specificity of 89.5%(34/38), and area under curve (AUC) of 0.842, respectively. The traditional 18F-FET semi-quantitative parameter TLU ranked the second regarding the diagnostic performance, with accuracy of 60.3%(35/58), sensitivity of 85.0%(17/20), specificity of 47.4%(18/38), and AUC of 0.661( z=3.426, P<0.01). Conclusion:Radiomics analysis based on 18F-FET PET images can improve the predictive efficacy for IDH1 genotyping in untreated adult glioma patients.

目的 探究阿尔茨海默病(AD)患者脑部[18F]-APN-1607 PET显像的tau蛋白沉积与MRI的脑皮质萎缩的相关性.方法 纳入25例AD患者为AD组和10例健康受试者为对照组.受试者均行脑部[18F]-APN-1607 PET显像和头颅MRI T1显像.计算受试者各脑区tau蛋白负荷及大脑皮质萎缩程度,分析tau蛋白标准摄取值比值(SUVR)与相对灰质萎缩比值的相关性.结果 AD组在大脑皮质(额、顶、颞、枕、前后扣带回)存在弥漫性tau蛋白沉积,tau蛋白SUVR均显著高于对照组,且上述各脑区的相对灰质萎缩比值均低于对照组.AD组的tau蛋白SUVR与相对灰质萎缩比值在除前扣带回以外的所有脑区存在显著相关性(P<0.05,R=0.402～0.572).结论 [18F]-APN-1607 PET显像可反映AD患者tau蛋白异常沉积与大脑皮质萎缩之间的密切相关性.

目的:探讨并验证术前11C-MET PET不同PET重建算法对胶质瘤分级判断的影响.方法:共计纳入113例胶质瘤病例,分别以FBP及OSEM算法重建,基于颅内病灶获得11C-MET半定量摄取值.结果:OSEM重建方法获得的半定量参 数均高于FBP重建法,且两者存在高度相关性.两种重建方法下,SUVmax、SUVpeak、TBRmax以及TBRpeak在HGG组与LGG组均具有显著差异(P<0.0001);前述参数在两两组间比较时也具有统计学差异(P<0.01).基于OSEM重建的单参数SUVmax及TBRmax对预测高、低级别胶质瘤效果最为满意,后者AUC值略低于前者(0.776 vs 0.765).结论:基于OSEM重建法获得的11C-MET半定量参数较FBP重建法呈整体性偏移增高,两者具有良好相关性,不会对高、低级别胶质瘤的鉴别效能产生实质影响.

目的 制备tau蛋白显像剂[18F]-APN-1607([18F]-PM-PBB3),鉴定该显像剂化合物的标记率、放化纯、稳定性,并观察其在正常者和痴呆患者的脑内摄取情况.方法 将18F-富集在QMA柱,经K2.2.2/碳酸钾洗脱,加入到含有标记前体APN-0490的反应管中,亲核反应后水解,粗产物经半制备HPLC纯化和0.22μm微孔无菌滤膜过滤,制得[18F]-APN-1607.测定其放化纯和体外稳定性.分别在正常者和痴呆患者进行正电子发射断层(PET)显像研究.结果 [18F]-APN-1607的放化产率约20％,放化纯度>99％.避光室温放置4 h,放化纯仍>95％.正常者[18F]-APN-1607 PET显像仅见脉络丛部位非特异性放射性摄取,余大脑半球及小脑半球均无异常tau蛋白沉积.不同类型痴呆患者[18F]-APN-1607 PET显像可见具有不同特征的脑内tau蛋白异常沉积分布模式.结论 [18F]-APN-1607显像剂在人体tau蛋白的PET显像试验研究中具有标记率高、稳定性好等特点,可有效显示痴呆患者脑内的异常tau蛋白沉积.

Objective:To assess the preoperative 11C-methionine ( 11C-MET) PET imaging in glioma grading efficacy and its predictive value for isocitrate dehydrogenase enzyme 1 (IDH1) gene mutation status. Methods:A total of 118 glioma cases (70 males, 48 females; median age 45 years, age range: 10-71 years; Ⅱ grade 65 cases, Ⅲ grade 34 cases, Ⅳ grade 19 cases) received 11C-MET PET imaging in PET Center of Huashan Hospital from February 2012 to November 2017 were retrospectively analyzed. Lesion-based semi-quantitative analysis was conducted on the 11C-MET imaging. Maximum standardized uptake value (SUV max), peak standardized uptake value (SUV peak), tumor-to-background ratio (TBR; SUV max in lesion/mean standardized uptake value (SUV mean) in normal contralateral cortex) were calculated. Independent-sample t test and one-way analysis of variance were applied to assess the differentiating efficacy of 11C-MET PET imaging for different glioma groups. Based on IDH1 immunohistochemical staining results, predictive efficacy of 11C-MET PET diagnostic parameters on IDH1 mutation status in glioma patients was further analyzed with receiver operating characteristic (ROC) curve analysis. Results:Low-grade glioma (LGG; grade Ⅱ) group showed significant differences from high-grade glioma (HGG; grade Ⅲ-Ⅳ) group in SUV max(2.458±1.100 vs 3.828±1.540; t=5.624, P<0.01), SUV peak (2.160±0.991 vs 3.261±1.319; t=5.175, P<0.01) and TBR (2.283±0.942 vs 3.434±1.395; t=5.328, P<0.01). SUV max (2.458±1.100, 3.591±1.611 and 4.251±1.343; F=17.67, P<0.01), SUV peak(2.160±0.991, 3.040±1.335 and 3.656±1.225; F=15.48, P<0.01) and TBR (2.283±0.942, 3.010±1.242 and 4.192±1.358; F=22.73, P<0.01) were different in grade Ⅱ, Ⅲ and Ⅳ glioma subgroups. SUV max, SUV peak and TBR all showed significant differences between grade Ⅱ and grade Ⅲ gliomas, grade Ⅱ and grade Ⅳ gliomas, and there were also statistical differences between grade Ⅲ and grade Ⅳ glioma with TBR (all P<0.01). SUV max indicated the best single-parameter prediction performance (area under curve (AUC) =0.808, z=7.193, P<0.01), while the SUV max + SUV peak showed the best performance (AUC=0.852, z=9.115, P<0.01). In the subgroup of grade Ⅱ ( n=55), TBR of patients with IDH1 gene mutation ( n=41) was lower than that of patients with IDH1 wild-types ( n=14; 2.152±0.759 vs 2.793±1.208; t=2.326, P=0.02), while TBR of those with oligodendrogenic components ( n=26) was higher than that of patients with IDH1 gene mutation only ( n=18; 2.383±0.825 vs 1.854±0.478; t=2.447, P=0.02). Conclusions:Preoperative semi-quantitative parameters (SUV max, SUV peak, TBR) of 11C-MET brain PET imaging have satisfactory grading discrimination performance for glioma patients. SUV max is the best predictor for IDH1 mutation as a single parameter, while SUV max + SUV peak showed the most optimized predictive ability. The oligodendrogenic components in glioma can increase the uptake of 11C-MET, which may affect the effectiveness of 11C-MET in determining glioma grade to some extent.

1572 Purpose: Parkinson’s disease (PD) is a neurodegenerative disorder which is characterized by asymmetric movement syndrome. We also found several patients with bilateral-onset syndrome which has been validated by follow-up. In this work, we characterized cerebral glucose metabolism associated with different onset clinical syndrome in Parkinson’s disease (PD) using18 F-fluorodeoxyglucose (FDG) and dopamine transporter (DAT) Positron Emission Tomography (PET). Methods: Two PD cohorts were recruited in this study including PD patients with bilateral-onset (PD-B; n = 20) and with lateral-onset (PD-L; n = 45, with left side predominant syndrome). Two PD cohorts were matched for age, sex, duration (less than 3 years), UPDRS-III score and Hoehn and Yahr stage. An age-matched normal cohort was also recruited (NC; n = 20). All subjects underwent FDG-PET and DAT-PET study. Maps of regional metabolism and SUVR of DAT in the three groups were compared using statistical parametric mapping (SPM8) and scanvp software. Results: Both PD-B and PD-L cohorts exhibited areas of hypometabolism in the parietal and occipital lobes and areas of hypermetabolism in frontal, temporal and cerebellum compared with the NC cohort (p< 0.001). Furthermore, PD-B patients had areas of hypermetabolism in the right temporal, left parietal lobe and bilateral limibic lobe compared with PD-L cohort (p< 0.001), and exhibited limited metabolic reductions in left middle frontal gyrus and inferior parietal lobule (p< 0.001). From DAT PET analysis, we calculated the asymmetric index of 11C-CFT uptake, defined as (absolute value of bilateral SUVR difference / absolute value of bilateral SUVR average). And we found the asymmetric index of both anterior and posterior putamen were significantly different between PD-B and PD-L cohorts (p<0.005). Conclusions: Compared with NC cohort, both PD-B and PD-L showed similar hypometabolism and hypermetabolism areas. There were limited difference of metabolism and dopamine depletion between 2 patient cohorts, which might suggest the bilateral onset patients were another subtype of PD phenotype.

目的 利用18F-FDG正电子发射断层扫描(PET)成像分析行为变异型额颞叶痴呆(bvFTD)患者脑葡萄糖代谢特征以及在阿尔茨海默病(AD)鉴别诊断中的应用价值.方法 纳入临床确诊的bvFTD患者(bvFTD组,14例)、健康对照者(对照组,14例)和AD患者(AD组,14例),先将bvFTD和对照组的PET图像分别进行统计参数图(SPM)及尺度子轮廓模型/主要成分分析(SSM/PCA)分析,获得bvFTD患者脑部葡萄糖代谢图谱并建立bvFTD相关脑代谢网络模式(bvFTDRP);计算bvFTD组、对照组和AD组的bvFTDRP个体表达值,并进行ROC分析.结果 SPM和SSM/PCA分析均显示bvFTD组表现出双侧前额叶和基底节区葡萄糖代谢显著减低.bvFTDRP表达值在3组间差异均有显著统计学意义(ANOVA: F[2,39]=86.663,P＜0.001),且可有效鉴别bvFTD和AD患者.结论 bvFTD存在与疾病特异相关的脑葡萄糖代谢特征,为18F-FDG PET应用于痴呆诊断提供了客观依据.

Objective To study the effect of the reconstruction method on the semi-quantitative distribution of dopamine transporter (DAT) in the brain,2β-carbomethoxy-3β-(4-fluorophe-nyl)-(N-11C-methyl) tropane (11C-CFT) PET images of healthy subjects were reconstructed by different PET reconstruction methods.Methods From March 2014 to June 2015,the 11C-CFT PET images of 41 healthy subjects were reconstructed by filtering back projection(FBP) method and ordered subsets expectation maximization(OSEM) iterative method.The brain regions of interest (ROI),namely,caudate nucleus,anterior putamen,and posterior shell nucleus,were automatically sketched with the parietal and occipital cortex lacking of DAT distribution as reference regions.The semi-quantitative value of DAT distribution was calculated using the following formula:radioactivity count of ROI/radioactivity count of parietal and occipital cortex-1.Paired t-test was used to compare the semi-quantitative values of DAT distribution.Correlation analysis was performed using the Pearson correlation analysis.Results The values of DAT distribution based on OSEM were as follows:caudate nucleus (1.77-2.15),anterior putamen (2.17-2.39),and posterior putamen (1.71-2.06).The values of DAT distribution based on FBP were as follows:caudate nucleus (1.68-2.10),anterior putamen (2.07-2.37),and posterior putamen (1.62-1.96).In the bilateral caudate nucleus and anterior and posterior putamen,the 11C-CFT of DAT distribution by OSEM was significantly higher than that by FBP(t=9.658-15.859,all P=0.000).The Pearson correlation analysis showed that the semi-quantitative values of DAT distribution by FBP and OSEM were positively correlated with each other in the bilateral caudate nucleus and anterior and posterior putamen (R2=0.907-0.951,all P=0.000).The DAT distribution by OSEM and FBP decreased with aging in the caudate nucleus and anterior and posterior putamen.Conclusions A significant difference was found in the semi-quantitative value of the DAT distribution in the brain of healthy subjects by different PET reconstruction methods.Therefore,a consistent PET image reconstruction method should be used in a multicenter or longitudinal study.

Purpose: To assess the changes of brain glucose metabolism in early PD and validate PD-related pattern (PDRP) network as a measurement of early PD by 18F-FDG PET imaging. Methods: Ten early PD patients and 10 healthy controls were recruited to perform resting-state brain 18F-FDG PET imaging. Statistical Parametric Mapping (SPM) was used to investigate the metabolic changes and characteristics of glucose in the brain. To obtain the PDRP, principal component analysis (PCA) was used. Results: Compared with the control group, hyper-metabolism was observed in putamen,globus pallidus,thalamus, pons, cerebellum and primary motor cortex in early PD group. The value of PDRP expression in PD group (1.512±0.631) was significantly higher than that of healthy controls(0.000土0.548;t=10.731,P＜0.001). Conclusion: The PDRP based on 18F-FDG PET imaging is useful for identification of early PD patients from healthy controls, and it may help the early diagnosis of PD.

Purpose: The effect of spatial normalization to Parkinson's disease related pattern(PDRP) expression should be verified to be widely used in the clinic. Methods: The 18F-FDG PET images of 53 Parkinson's disease(PD) patients and 22 heath control subjects(HC) were normalized by SPM99, SPM2, SPM5 and SPM8, separately. Based on the PDRP from PET center, Huashan Hospital, the PDRP expressions of different algorithms were calculated by SSM/PCA software. Results: There was no difference of PDRP expression between four SPM versions(PD group: F3,208=0.001,P=1.000;HC group: F3,84=0.000,P=1.000). The PDRP expression of PD group was significantly higher than that of HC group(t9.875,P0.0001; Student's t-test). By Pearson correlation analysis, the PDRP expression of four SPM versions had significantly positive correlation with each other both in PD and HC(PD: r0.999, P0.0001; HC: r0.999, P0.0001). In addition, the PDRP expression had significantly positive correlation with PD patients' UPDRS motor function value(r0.670, P0.0001). Conclusion: The PDRP expression from different SPM normalization versions was with no significant difference. Additionally, the reconstruction algorithm can't affect the application of PDRP in diagnosis or assessment of PD, which was important information for domestic multi-center researches.