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Due to the availability of 18F-FDG in PET centers, this article aims to advocate and promote the standardization of 18F-FDG PET brain imaging in dementia in order to improve the reliability, repeatability and comparison of the imaging process and results. It is also provided to guide the PET imaging operation standard and to give suggestions on image interpretation.
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Objective:To explore the potential application of combining 18F-FDG PET imaging and radiomics in the diagnosis of Parkinson′s disease (PD) and atypical parkinsonian syndromes (APS). Methods:A total of 154 subjects of two cohorts (training set and validation set) were enrolled from Huashan Hospital, Fudan University from March 2015 to August 2020 in this cross-sectional study, including 40 normal controls (NC; 23 males and 17 females, age: (60.2±10.5) years), 40 PD patients (20 males and 20 females, age: (64.7±6.3) years), 40 progressive supranuclear palsy (PSP) patients (20 males and 20 females, age: (64.1±5.9) years), and 34 multiple system atrophy (MSA) patients (19 males and 15 females, age: (65.0±9.2) years). 18F-FDG PET images and clinical scale were selected, and one-way analysis of variance was used to compare differences of clinical scale among groups. Radiomic features extraction and feature selection were carried out. Two and three classification models were constructed based on logistic regression, and the ROC curves of clinical model, radiomics model and combined model were calculated. Independent classification tests were conducted 100 times with 5-fold cross validation in two cohorts. Results:There were significant differences in the scores of unified PD Rating Scale (UPDRS) and Hoehn-Yahr rating scale (H&Y) among different groups in cohort 1 and cohort 2 respectively ( F values: 4.83-17.95, all P<0.05). A total of 2 444 imaging features were extracted from each subject, and after features selection, 15 features for classification were obtained. In the two classification experiment, the AUCs of the three models in binary classification of PD/MSA/PSP/NC group were 0.56-0.68, 0.74-0.93 and 0.72-0.93, respectively. The classification effects of the radiomics model were significantly better than those of the clinical model ( z values: 1.71-2.85, all P<0.05). In the three classification experiment, the sensitivity of the radiomics model reached 80%, 80% and 77% for PD, MSA and PSP, respectively. Conclusion:18F-FDG imaging combined with radiomics has potential in the diagnosis of PD and APS.
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Multi-centre clinical trials on PET/CT brain imaging are complex to organize and require careful co-ordination and management. This article describes considerations, which are necessary when designing and starting a multi-centre clinical trial on PET/CT brain imaging, based on guidelines and multi-center clinical brain imaging studies, providing references for further studies.
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Objective:To investigate characteristics and differences of cerebral glucose metabolism in patients with anti- N-methyl- D-aspartate receptor (NMDAR) encephalitis from the perspective of different trigger factors of antibodies. Methods:A total of 15 patients (8 males, 7 females, age (30.5±17.7) years) with anti-NMDAR encephalitis between January 2016 and January 2019 in Huashan Hospital, Fudan University were recruited retrospectively. All patients underwent resting state cerebral 18F-FDG PET imaging. The characteristics of brain glucose metabolism were analyzed, and the SUV ratio (SUVR) was semi-quantitatively compared with that in 12 healthy subjects (HS; 7 males, 5 females, age (51.5±9.6) years). Independent-sample t test was used to analyze the data. Results:Among 15 patients, 5 patients were viral encephalitis-related anti-NMDAR encephalitis, showing focal decreased metabolism in unilateral temporal lobe or basal ganglia (SUVR: patients: 0.659±0.219; HS: 1.754±0.203; t=-9.58, P<0.001), with increased metabolism in contralateral temporal lobe or basal ganglia (SUVR: patients: 2.275±0.244; HS: 1.960±0.227; t=2.55, P=0.022) in 18F-FDG PET imaging. Six patients were cryptogenic anti-NMDAR encephalitis, showing asymmetric increased metabolism in frontal, temporal, parietal and basal ganglia (SUVR: patients: 2.482±0.395; HS: 1.754±0.203; t=5.23, P<0.001), with decreased metabolism in bilateral occipital lobes. The remaining 4 cases were paraneoplastic origin accompanied by teratoma, showing increased metabolism in bilateral temporal and basal ganglia (SUVR: patient: 2.359±0.181; HS: 1.960±0.227; t=3.16, P=0.007), with mild decreased metabolism in bilateral occipital lobe. Conclusions:The abnormal changes of cerebral glucose metabolism in patients with anti-NMDAR encephalitis can be divided into at least three patterns according to different trigger factors. A comprehensive understanding of these characteristic metabolic changes is helpful for detecting disease, and may provide potential value in indicating different causes.
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Objective:To investigate the clinical, neuropsychological, and neuroimage characteristics in patients with corticobasal syndrome (CBS), and to elucidate the exact diagnosis of CBS patients.Methods:Twelve CBS cases admitted to the Department of Neurology, Huashan Hosiptal,Fudan University from April 2019 to July 2021 were retrospectively enrolled in this study. Those data, including clinical features (demographic data and clinical characteristics of cortical dysfunction and movement disorder), neuropsychological assessment [Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scales score], brain magnetic resonance imaging (MRI) and multi-mode positron emission tomography (PET)/CT, were collected and carefully reviewed. Exact diagnosis of these patients was given according to the disease diagnosis criteria.Results:Cortical dysfunction and asymmetrical movement disorders were found in all cases, with poor response to levodopa. Patients suffered from cognitive impairment (MMSE score 16.16±9.82, MoCA score 13.44±7.35). The cranial MRI demonstrated significant asymmetric atrophy of frontal and parietal lobes, especially in the pre- and post-central gyrus. Fluorodeoxyglucose PET of 12 patients showed asymmetric frontal lobe and basal ganglia (especially caudate and putamen) hypometabolism (obviously on the contralateral side of the affected limb). Tau PET was implemented in 11 patients and displayed that abnormal tau protein deposition was positive in the cortex and/or subcortex in all patients. Of the 4 cases, who completed amyloid PET, amyloid protein deposition was positive in the cortex of 2 patients. As a result, 6 patients were diagnosed as progressive supranuclear palsy, 1 patient was diagnosed as corticobasal degeneration, and 5 patients were diagnosed as Alzheimer′s disease.Conclusions:The etiology of CBS is heterogeneous. The combination of clinical manifestation, cranial MRI and multi-mode PET/CT helps the differential diagnosis of CBS.
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Objective:To investigate whether the presynaptic dopamine neuronal depletion in different striatal subregions predicts future development of wearing-off (WO) in Parkinson′s disease (PD) patients.Methods:A retrospective longitudinal study included 57 PD patients who were referred to the Department of Neurology of Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from January 2019 to September 2020, and completed 11C-2β-carbomethoxy-3β-(4-fluorophenyl) tropane dopamine transporter (DAT) positron emission tomography scans at the initial evaluation and received dopaminergic drugs for at least 12 months during follow-up. The time of starting dopaminergic drug treatment and the occurrence of WO were recorded. After adjusting for clinical related factors, the predictive value of DAT uptake and related parameters in striatal subregions for WO was evaluated by Cox proportional hazards model. Results:During a median follow-up period of 23 months, 10 patients (18.18%) developed WO. Patients with WO exhibited less DAT uptake in the caudate nucleus and anterior putamen nucleus (0.66±0.52 vs 1.08±0.42, t=2.76, P=0.008 and 0.66±0.20 vs 0.87±0.28, t=2.27, P=0.027 respectively), especially in these subregions contralateral to the less-affected side of the body, compared to those without WO. Cox proportional hazard models revealed that after adjusting for gender, age, course of disease, baseline Unified Parkinson′s Disease Rating Scale Ⅲ score and increment of levodopa equivalent dosage, the lower the DAT uptake of the caudate ipsilateral to the less-affected side of the body ( HR=0.20, 95% CI 0.07-0.63, P=0.006), as well as the lower the DAT uptake of the caudate nucleus and posterior putamen nucleus ( HR=0.28, 95% CI 0.11-0.69, P=0.006 and HR=0.08, 95% CI 0.01-0.64, P=0.018 respectively) and the higher the ratio of putamen/caudate contralateral to the less-affected side of the body ( HR=2.33, 95% CI 1.02-5.33, P=0.045), the higher the risk of WO. Conclusion:The presynaptic dopamine neuronal loss, particularly bilateral caudate nucleus dopaminergic depletion at the early stage, has predictive value of development of WO in PD.
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Objective:To reveal the abnormal topology of brain network in Alzheimer′s disease (AD), and evaluate the laterality of tau protein deposition in brains of AD patients based on 18F-APN-1607 PET brain imaging combined with graph theory. Methods:From November 2018 to January 2020, 23 clinically diagnosed AD patients (9 males, 14 females; age (61.3±10.7) years) and 13 normal controls (NC) (9 males, 4 females; age (61.6±4.5) years) who underwent 18F-APN-1607 PET imaging in Huashan Hospital, Fudan University were analyzed in this cross-sectional study. The brain network analysis method based on graph theory was used to construct the tau network of the NC group and the AD group, the network attributes (clustering coefficient, shortest path length, local efficiency, and small-worldness) were calculated, and the asymmetry index (AI) of each group to evaluate the laterality of tau protein deposition was obtained. Permutation test (1 000 times) was used to analyze the differences in brain network parameters between the NC group and the AD group. Results:The tau network of the AD group had obvious topological disorder, and the connections in the olfactory cortex and temporal lobe were weakened, while in the posterior cingulate gyrus, anterior wedge, and parietal occipital lobe, the connections were enhanced. Compared with NC group, clustering coefficient ( t values: 2.28-2.69), local efficiency ( t values: 2.34-3.06) and small-worldness ( t values: 2.26-3.32) were significantly decreased in AD group (all P<0.05) with the sparsity of 20%-50%, while the shortest path length was significantly increased ( t values: 2.13-2.85; all P<0.05). There was significant tau laterality in the posterior cingulate gyrus, superior parietal gyrus, paracentral lobule, superior temporal gyrus and middle temporal gyrus (AI: 10.5%(8.1%, 13.9%), 14.1%(7.6%, 20.3%), -12.4%(-15.7%, -7.8%), -10.8%(-15.3%, -2.1%) , -12.1%(-17.9%, -6.6%), respectively). Conclusion:The tau network analysis based on 18F-APN-1607 may be used to reveal abnormal topological changes of AD patients, and the tau deposition in the posterior cingulate gyrus, superior parietal gyrus, paracentral lobule, superior temporal gyrus and middle temporal gyrus has obvious laterality in AD patients.
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Objective:Exploring tau related disease pattern (tauRDP) in the brain of Alzheimer′s disease (AD) patients based on 18F-APN-1607 PET scan. Methods:18F-APN-1607 PET images were collected from 17 AD patients (6 males and 11 females, age: (61.7±12.3) years, Mini-Mental State Examination (MMSE) score: 17.6±7.9) and 10 normal controls (NC; 6 males and 4 females, age: (61.2±4.7) years) from Huashan Hospital of Fudan University. The scaled subprofile model (SSM) based on principal component analysis (PCA) technique was used to construct the tauRDP. Then the expression value of tauRDP in each sample was calculated. The differences on tauRDP expression values between AD patients and NC were compared by independent-sample t test. Pearson correlation analysis was used to analyze the correlation between tauRDP expression values and MMSE values in AD patients. Results:The tauRDP area mainly included: precentral gyrus, dorsolateral superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus of opercular part, inferior frontal gyrus of triangular part, supplementary motor area, medial superior frontal gyrus, left median cingulate and paracingulate gyri, right cuneus, superior occipital gyrus, middle occipital gyrus, postcentral gyrus, superior parietal gyrus inferior parietal, but supramarginal and angular gyri, supramarginal gyrus, angular gyrus, precuneus and middle temporal gyrus. There were significant differences ( t=4.395, P<0.001) between AD group (12.6±8.0) and NC group (0.0±1.0) in tauRDP expression values. The tauRDP expression values were correlated with MMSE values in AD group significantly ( r=-0.566, P=0.018). Conclusions:TauRDP established basing on SSM/PCA method can be used to quantitatively express the abnormal spatial distributions of tau deposition. Expression value of tauRDP has the potential to initially assess the severity of AD.
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Objective@#To investigate the value of statistical parametric mapping (SPM) analysis of 18F-fluorodeoxyglucose (FDG) PET imaging in the differential diagnosis of Parkinsonism in single-case level.@*Methods@#SPM software was used to retrospectively analyze the 18F-FDG PET images of 160 patients (104 males, 56 females, age: 30-82 years) who were suspected with Parkinsonism at baseline and were clinical confirmed by follow-up from April 2010 to December 2017. 18F-FDG PET images of patients was compared with those of age-matched healthy controls in single-case level using two-sample t test in SPM software to obtain the imaging diagnosis. By comparing imaging diagnosis with the final clinical diagnosis, the diagnostic accuracy of SPM in the overall cohort as well as the early subcohort (duration of disease less than 2 years (56 males, 22 females, age: 50-82 years)) were calculated respectively.@*Results@#Among 160 patients with Parkinsonism, 146(91.2%) had the same 18F-FDG PET diagnosis as their final clinical diagnosis. The diagnostic sensitivity for Parkinson′s disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and cortical basal ganglia degeneration (CBD) were 93.5%(86/92), 92.3%(24/26), 84.0%(21/25) and 15/17, respectively. The specificity were 95.6%(65/68), 95.5%(128/134), 96.3%(130/135) and 100%(143/143), respectively. In the early subcohort, the analysis also achieved similar differential diagnosis effectiveness(92.3%).@*Conclusion@#The single-case 18F-FDG PET imaging SPM analysis can be helpful in the early differential diagnosis of Parkinsonism effectively.
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Objective@#To explore the topological abnormality of brain metabolic network in patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) and compare it with the topology of brain metabolic network in patients with Parkinson′s disease (PD).@*Methods@#The 18F-fluorodeoxyglucose (FDG) PET brain images of 19 patients with iRBD diagnosed with polysomnography (PSG) (iRBD group; 15 males, 4 females, average age: 64.9 years), 19 patients with PD (PD group; 12 males, 7 females, average age: 62.2 years) and 19 gender and age-matched healthy controls (HC group; 15 males, 4 females, average age: 63.1 years) in Huashan Hospital from September 2014 to June 2015 were retrospectively analyzed. According to the complex brain network method based on graph theory, the brain metabolic networks of each group was constructed and the network parameters (clustering coefficient, characteristic path length, local efficiency, global efficiency and small-world property, etc) were evaluated quantitatively. The 500 times non-parametric permutation test was used to determine the differences in network parameters between groups.@*Results@#The brain metabolic networks of iRBD group and PD group both had abnormal topological structure, which showed that the characteristic path length (for example, when sparsity=34%, HC vs iRBD vs PD groups: 1.517 vs 1.552 vs 1.561) and local efficiency (for example, when sparsity=30%, HC vs iRBD vs PD groups: 0.802 vs 0.824 vs 0.831) were significantly increased (both P<0.05), the global efficiency (for example, when sparsity=36%, HC vs iRBD vs PD groups: 0.672 vs 0.658 vs 0.656) was significantly decreased (P<0.05). The topology was more aggravated in PD group compared with that in iRBD group.@*Conclusion@#The graph-based complex brain network analysis can reveal the abnormal topological structure of the brain metabolic network in which iRBD progresses to PD.
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Objective@#To study the effect of short-term treatment of subthalamic nucleus (STN) deep brain stimulation (DBS) on cerebral glucose metabolism in patients with Parkinson′s disease (PD) and its relationship with the change of brain motor-related nerve pathways.@*Methods@#Five patients (2 males, 3 females; age: (63.6±11.8) years) with PD who underwent STN DBS between January 2014 and December 2018 were enrolled in this study. All patients underwent 18F-fluorodeoxyglucose (FDG) PET in " DBS-off" state before and 3 months after operation. Quantitative expression of PD-related metabolic pattern (PDRP) were calculated by scaled subprofile model/principal component analysis (SSM/PCA) on PET images. Brain regions with changes of glucose metabolism after DBS were located by statistical parametric mapping (SPM) paired t test.@*Results@#Compared with pre-operation, PDRP expression (5.1±1.3 vs 2.9±1.8) and unified Parkinson′s disease rating scale (UPDRS) motor score (50.2±8.2 vs 28.0±5.4) of PD patients were significantly decreased 3 months after STN DBS (t values: 6.17 and 3.88, both P<0.05). After DBS, the glucose metabolism of bilateral globus pallidus/putamen, caudate nucleus, thalamus, insula, pons and cerebellum decreased, while the glucose metabolism of bilateral prefrontal motor area and parietooccipital lobe increased (t=3.75, P<0.01).@*Conclusions@#Short-term STN DBS therapy can inhibit the cortico-striatum-pallidum-hypothalamus-cortex motor loop, which is abnormally excitable in the brain of PD. PDRP, as an imaging characterization of the regulation of this loop, is expected to become an imaging marker for monitoring the treatment of PD.
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Objective To study the effect of short-term treatment of subthalamic nucleus ( STN ) deep brain stimulation (DBS) on cerebral glucose metabolism in patients with Parkinson's disease (PD) and its relationship with the change of brain motor-related nerve pathways. Methods Five patients ( 2 males, 3 females;age:(63.6±11.8) years) with PD who underwent STN DBS between January 2014 and December 2018 were enrolled in this study. All patients underwent 18F-fluorodeoxyglucose (FDG) PET in "DBS-off"state before and 3 months after operation. Quantitative expression of PD-related metabolic pattern (PDRP) were calculated by scaled subprofile model/principal component analysis ( SSM/PCA) on PET images. Brain regions with changes of glucose metabolism after DBS were located by statistical parametric mapping (SPM) paired t test. Results Compared with pre-operation, PDRP expression (5.1±1.3 vs 2.9±1.8) and unified Parkinson's disease rating scale (UPDRS) motor score (50.2±8.2 vs 28.0±5.4) of PD patients were significantly decreased 3 months after STN DBS (t values:6.17 and 3.88, both P<0.05). After DBS, the glucose metabolism of bilateral globus pallidus/putamen, caudate nucleus, thalamus, insula, pons and cer-ebellum decreased, while the glucose metabolism of bilateral prefrontal motor area and parietooccipital lobe increased ( t=3.75, P<0.01) . Conclusions Short-term STN DBS therapy can inhibit the cortico-striatum-pallidum-hypothalamus-cortex motor loop, which is abnormally excitable in the brain of PD. PDRP, as an imaging characterization of the regulation of this loop, is expected to become an imaging marker for monito-ring the treatment of PD.
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Objective To investigate the value of statistical parametric mapping (SPM) analysis of 18F-fluorodeoxyglucose (FDG) PET imaging in the differential diagnosis of Parkinsonism in single-case level.Methods SPM software was used to retrospectively analyze the 18F-FDG PET images of 160 patients (104males,56 females,age:30-82 years) who were suspected with Parkinsonism at baseline and were clinical confirmed by follow-up from April 2010 to December 2017.18F-FDG PET images of patients was compared with those of age-matched healthy controls in single-case level using two-sample t test in SPM software to obtain the imaging diagnosis.By comparing imaging diagnosis with the final clinical diagnosis,the diagnostic accuracy of SPM in the overall cohort as well as the early subcohort (duration of disease less than 2 years (56 males,22 females,age:50-82 years)) were calculated respectively.Results Among 160 patients with Parkinsonism,146(91.2％) had the same 18F-FDG PET diagnosis as their final clinical diagnosis.The diagnostic sensitivity for Parkinson's disease (PD),multiple system atrophy (MSA),progressive supranuclear palsy (PSP) and cortical basal ganglia degeneration (CBD) were 93.5％ (86/92),92.3％ (24/26),84.0％(21/25) and 15/17,respectively.The specificity were 95.6％(65/68),95.5％(128/134),96.3％ (130/135) and 100％(143/143),respectively.In the early subcohort,the analysis also achieved similar differential diagnosis effectiveness(92.3％).Conclmion The single-case 18F-FDG PET imaging SPM analysis can be helpful in the early differential diagnosis of Parkinsonism effectively.
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Objective To explore the topological abnormality of brain metabolic network in patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) and compare it with the topology of brain metabolic network in patients with Parkinson's disease (PD).Methods The 18F-fluorodeoxyglucose (FDG) PET brain images of 19 patients with iRBD diagnosed with polysomnography (PSG) (iRBD group;15 males,4 females,average age:64.9 years),19 patients with PD (PD group;12 males,7 females,average age:62.2 years) and 19 gender and age-matched healthy controls (HC group;15 males,4 females,average age:63.1 years) in Huashan Hospital from September 2014 to June 2015 were retrospectively analyzed.According to the complex brain network method based on graph theory,the brain metabolic networks of each group was constructed and the network parameters (clustering coefficient,characteristic path length,local efficiency,global efficiency and small-world property,etc) were evaluated quantitatively.The 500 times non-parametric permutation test was used to determine the differences in network parameters between groups.Results The brain metabolic networks of iRBD group and PD group both had abnormal topological structure,which showed that the characteristic path length (for example,when sparsity =34％,HC vs iRBD vs PD groups:1.517 vs 1.552 vs 1.561) and local efficiency (for example,when sparsity=30％,HC vs iRBD vs PD groups:0.802 vs 0.824 vs 0.831) were significantly increased (both P＜0.05),the global efficiency (for example,when sparsity =36％,HC vs iRBD vs PD groups:0.672 vs 0.658 vs 0.656) was significantly decreased (P＜0.05).The topology was more aggravated in PD group compared with that in iRBD group.Conclusion The graph-based complex brain network analysis can reveal the abnormal topological structure of the brain metabolic network in which iRBD progresses to PD.
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Objective To identify abnormal cerebral glucose metabolism characteristics in patients with corticobasal degeneration (CBD) using 18 F-fluorodeoxyglucose (FDG) PET imaging. Methods From January 2014 to January 2017, resting-state brain 18 F-FDG PET imaging was performed in 10 CBD patients (5 males, 5 females; average age: (63.4±6.2) years) and 20 age-matched healthy subjects (8 males, 12 female; average age: (63.6±6.2) years). Voxel-based statistical parametric mapping (SPM) was used to analyze images to obtain the CBD-related brain metabolic characteristics. The regional cerebral metabolic rate of glucose (rCMRglc) was compared between 2 groups by two-sample t test. Results Compared with healthy controls, CBD group demonstrated asymmetrically decreased glucose metabolism mainly in the cere-bral hemisphere opposite to the more clinically affected body side, including the superior, middle and inferi-or frontal gyrus, the precentral gyrus, the superior and inferior parietal lobule, the angular gyrus, the supra-marginal gyrus, the precuneus, the middle occipital gyrus, the middle and inferior temporal gyrus, Heschl gyrus, the fusiform gyrus, the insula and the thalamus. And relatively increased glucose metabolism was present in ipsilateral precentral and postcentral gyrus, hippocampus, insula and putamen, bilateral cerebel-lum, paracentral lobules and pontine. The rCMRglc in those regions was significantly different between CBD patients and healthy controls (t values: 4.236-9.044, all P<0.01). Conclusion The asymmetric cerebral glucose metabolism features in CBD based on 18 F-FDG PET imaging contribute to the differential diagnosis between CBD patients and healthy subjects.
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Rapid eye movement sleep behavior disorder (RBD) is a condition characterized by rap id eye movement sleep without atonia and with complex behaviors associated with dreams.Numerous studies have revealed that idiopathic RBD is the prodromal manifestation of neurodegenerative disorders,especially those mediated by α-synuclein.The structural and functional imaging of RBD,including transcranial sonog raphy (TCS),MRI,SPECT,PET,are increasingly becoming the hot issues.This review summarizes the radionuclide imaging in RBD,which may be one of the most promising modalities to detect the biomarkers for early diagnosis of neurodegenerative disorders.
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Neuroinflammation has been a key pathological process in many neurodegenerative disorders including Parkinson′s disease (PD), while the microglial activation is not only involved in but also regarded as a hallmark of the neuroinflammation. With PET, it has become possible to image in vivo the changes of microglia cells under different pathophysiological conditions. In this review, the basic theory of translocator protein (TSPO)-targeting PET (TSPO-PET) imaging is well described and its intriguing applications in PD are also elaborated.
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Objective To investigate the neural activity in the central auditory pathway by using a tinnitus an-imal model .Methods Twenty -four rats were randomly divided into the control ,acute salicylate treatment ,chronic salicylate treatment ,and recovery groups .The gap prepulse inhibition of acoustic startle test was used to confirm tinnitus -like behavior .After delivery of an intravenous bolus of fluorine -18 fluorodeoxyglucose (18F -FDG ) , small animal positron emission tomography scans were performed on rats .Results Only rats in chronic salicylate -treatment group showed evidence of experiencing tinnitus .The SUV ratios of the AC were significantly greater in the acute salicylate treatment group than in the control group (P<0 .01) ,suggesting relatively increased metabolism in the two brain regions of the rats in this group .The SUV ratios of the IC and AC (P<0 .01) ,but not of the CRB (P>0 .05) were greater in the chronic salicylate treatment group than in the control groups .There was a significant difference in whole brain SUVs between the control and acute salicylate treatment groups (P<0 .01) ,the whole brain SUVs in chronic salicylate treatment group were a little higher but showed no significant difference (P>0 .05) .There was no significant difference in the SUVs between the control and recovery groups (P>0 .05) .Conclu-sion These findings indicate that long -term salicylate administration induced tinnitus in rats and may have en-hanced neural activity corresponded to the up -regulated metabolic rate in our study .Alterations to neuroplasticity of the CNS may lead to tinnitus .
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Objective To synthesize 18 F-DPA-714 and to study its labeling rate, radiochemical purity, stability and biological characteristics. Methods 18F-was reacted with K2CO3/K2.2.2 and then en-gaged in nucleophilic substitution with DPA-714. The crude product was purified by aluminum column and semi-preparation HPLC. The stability of 18 F-DPA-714 was identified in PBS and plasma. The lipid-water partition coefficient (LogP) was determined. Biodistribution analysis and microPET imaging were performed on mice and rats respectively. Results It took about 25 min for synthesizing 18 F-DPA-714, the radiochemi-cal yield was 31.6% (decay not corrected), and the radiochemical purity was ≥99%. The product re-mained stable within 4 h. The LogP of 18 F-DPA-714 was 2.71. Pharmacokinetics of 18 F-DPA-714 was more in line with the two compartment model, with the distribution half-life ( T1/2α) of 2.40 min and the elimina-tion half-life( T1/2β) of 69.15 min. 18 F-DPA-714 was quickly uptaken by tissues after the tail vein injection. It mainly distributed in the lungs, kidneys, and heart, with the radioactive uptake values of (17.85±7.52)%ID/g, (15.41±1.80) %ID/g and (10.56±0.94) %ID/g at 30 min post-injection, respectively. 18F-DPA-714 was mainly metabolized through the liver, and excreted by the kidneys. The uptake in bones was stable. PET dynamic scanning showed that 18 F-DPA-714 accumulated in the brain of aged rats and cleared slowly within 60 min. Conclusions 18 F-DPA-714 prepared in this study has high labeling rate, short synthesis time and small precursor dosage. It displays good biological distribution and blood-brain barrier permeability characteristics.
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Objective To validate the reproducibility of abnormal cerebral metabolic characteristics in PD patients from different medical centers using 18F-FDG PET imaging.Methods A total of 108 subjects who were referred for resting-state brain 18 F-FDG PET imaging were retrospectively reviewed.Thirtythree PD patients (15 males,18 females,age:38-79 years) and 33 age-matched healthy controls (15 males,18 females,age:40-77 years) underwent evaluation at Shanghai Huashan Hospital Affiliated to Fudan University.Seventeen PD patients (10 males,7 females,age:44-74 years) and 17 age-matched healthy controls (6 males,11 females,age:42-67 years) underwent evaluation at the First Affiliated Hospital of Sun Yat-sen University.SPM was used to investigate the cerebral metabolic characteristics of the patients with two-sample t test.Statistically significant voxels were obtained by using familywise error rate (FWE;P＜0.05).Two sets of PD patients with abnormal glucose metabolism of brain regions were obtained and the cerebral metabolic characteristics were compared.Results Regarding the PD patients from Shanghai Huashan Hospital,the features of cerebral glucose metabolism by SPM analysis were demonstrated as follows:increased metabolism was found in the region of pons,cerebellum,thalamus,putamen and pallidum,while decreased metabolism was displayed in the region of parietal lobe and occipital lobe.The increased regions referred to 8 110 voxels and decreased regions referred to 2 810 voxels (P＜0.05).The similar metabolic pattern was found in PD patients from the First Affiliated Hospital of Sun Yat-sen University.The increased metabolism was shown in the regions of pons,cerebellum,thalamus,putamen and pallidum,and referred to 15 573 voxels.The metabolism-decreased regions included parietal lobe,occipital lobe and frontal lobe,and referred to 3 945 voxels (P＜0.05).Conclusions 18F-FDG PET/CT imaging results demonstrate similar metabolic pattern in PD patients from different medical centers,in whom the metabolism-increased regions are found in the pons,cerebellum,thalamus and pallidum and decreased regions were demonstrated in the parietal lobe and occipital lobe.The reproducibility from 18F-FDG PET/CT imaging provides reliable evidence for the multi-center study in the differential diagnosis of PD.