Objective:To assess the β-amyloid (Aβ) deposition of voxel-based PET imaging in Alzheimer′s disease (AD) and its relationships with blood biomarkers (Aβ).Methods:From January 2015 to December 2018, a total of 23 AD patients (9 males, 14 females, age (68.5±9.0) years; duration: (40.9±23.3) months; 8 mild patients, 15 moderate or severe patients) who underwent Aβ PET and with positive imaging results in Daping Hospital, Army Medical University were retrospectively enrolled. The information of Mini-Mental State Examination (MMSE) and Clinical Dementia Rating (CDR) were collected. Blood level of Aβ42, Aβ40 were measured. Differences of those metrics including Aβ42/Aβ40 between mild and moderate or severe patients were compared. For all 11C-Pittsburgh compound B (PIB) PET images, voxel-based one-sample independent t test analyses were performed. Voxel-based two-sample independent t test analyses were also performed between mild and moderate or severe patients. The voxel-based Pearson correlation analyses were run to assess the associations between blood metrics and Aβ deposition of 11C-PIB PET. Results:Comparing with mild patients, moderate or severe patients had lower MMSE (9.67±4.37 vs 17.13±2.80; t=4.349, P<0.001) and longer duration ((48.8±23.8) vs (26.0±13.5) months; t=-2.489, P<0.05). On voxel-wise analysis, amyloid PET illustrated brain Aβ deposition in bilateral frontal, right temporal, right occipital and posterior cingulate regions ( t values: 0.44-0.67, all P<0.001). Within AD, Aβ42/Aβ40 ( r values: from -0.62 to -0.41, 0.41-0.66, all P<0.05) were associated with amyloid PET, but not associated with Aβ42 ( r values: from -0.33 to 0, all P>0.05) or Aβ40 ( r values: from -0.41 to 0, all P>0.05). Conclusions:Based on voxel-wise analysis, 11C-PIB PET has comparable value for brain Aβ deposition. Aβ42/Aβ40 has the potential to predict brain Aβ deposition.

Objective:To investigate the diagnostic value of 11C-Pittsburgh compound B (PIB) in patients with mild cognitive impairment (MCI) and Alzheimer′s disease (AD) and explore the factors that may affect the binding of 11C-PIB. Methods:From January 2017 to December 2019, the 11C-PIB uptake of 6 patients with normal cognitive (NC; 3 males, 3 females, age: (64.5±12.3) years), 11 patients with MCI (4 males, 7 females, age: (64.5±9.8) years) and 21 patients with AD (7 males, 14 females, age: (68.1±9.1) years) from Daping Hospital, Army Medical University were retrospectively analyzed. Regional 11C-PIB binding was assessed by using standardized uptake value ratio (SUVR) and visual reading of 11C-PIB scan. Clinical data, including age, gender, education level, cognitive impairment, neuropsychological scale score, vascular risk factors (VRF), apolipoprotein E (ApoE) gene, were collected and differences among groups were analyzed by using one-way analysis of variance, least significant difference t test or Fisher exact test. Factors that affected the 11C-PIB binding were analyzed by multiple linear regression. Results:SUVR of cerebral lobe among NC, MCI and AD groups were significantly different (range of mean SUVR: 1.16-1.26, 1.19-1.35 and 1.40-1.61; F values: 5.331-9.279, all P<0.05). For positive PIB patients, SUVR of posterior cingulate and precuneus were increased in MCI group compared with NC group (1.20±0.15 vs 1.50±0.12, 1.18±0.15 vs 1.59±0.13; F values: 6.389 and 10.668, t values: -2.33 and -3.10, both P<0.05), and there were no significant differences in all lobes between MCI and AD group ( t values: from -1.29 to -0.51, all P>0.05). Visual analysis showed that the positive rates of PIB in frontal lobe (85.7%(18/21)), posterior cingulate (85.7%(18/21)), precuneus (81.0%(17/21)), temporal lobe (81.0%(17/21)) and occipital lobe (47.6%(10/21)) in AD were higher than those in MCI (4/11, 4/11, 4/11, 3/11 and 1/11, respectively; all P<0.05). Multiple linear regression showed that the degree of cognitive impairment were independent risk factors for SUVR of all lobes ( b values: 0.377-0.536, all P<0.05). The ApoE ε4 gene was independent risk factor for SUVR of precuneus ( b=0.290, P<0.05). Conclusion:11C-PIB is helpful for clinical diagnosis of MCI and AD patients and the degree of cognitive impairment and ApoE ε4 gene may be independent risk factors for increasing 11C-PIB binding.

Purpose To explore the application value of combining 18F-FDG PET images with interpretable deep learning radiomics(IDLR)models in the differential diagnosis of primary Parkinson's disease(IPD)and atypical Parkinson's syndrome.Materials and Methods This cross-sectional study was conducted using the Parkinson's Disease PET Imaging Benchmark Database from Huashan Hospital,Fudan University from March 2015 to February 2023.A total of 330 Parkinson's disease patients underwent 18F-FDG PET imaging,both 18F-FDG PET imaging and clinical scale information were collected for all subjects.The study included two cohorts,a training group(n=270)and a testing group(n=60),with a total of 211 cases in the IPD group,59 cases in the progressive supranuclear palsy(PSP)group,and a group of 60 patients with multiple system atrophy(MSA).The clinical information between different groups were compared.An IDLR model was developed to extract feature indicators.Under the supervision of radiomics features,IDLR features were selected from the features collected by neural network extractors,and a binary support vector machine model was constructed for the selected features in images of in testing group.The constructed IDLR model,traditional radiomics model and standard uptake ratio model were separately used to calculate the performance metrics and area under curve values of deep learning models for pairwise classification between IPD/PSP/MSA groups.The study conducted independent classification and testing in two cohorts using 100 10-fold cross-validation tests.Brain-related regions of interest were displayed through feature mapping,using gradient weighted class activation maps to highlight and visualize the most relevant information in the brain.The output heatmaps of different disease groups were examined and compared with clinical diagnostic locations.Results The IDLR model showed promising results for differentiating between Parkinson's syndrome patients.It achieved the best classification performance and had the highest area under the curve values compared to other comparative models such as the standard uptake ratio model(Z=1.22-3.23,all P<0.05),and radiomics model(Z=1.31-2.96,all P<0.05).The area under the curve values for the IDLR model in differentiating MSA and IPD were 0.935 7,for MSA and PSP were 0.975 4,for IPD and PSP were 0.982 5 in the test set.The IDLR model also showed consistency between its filtered feature maps and the visualization of gradient-weighted class activation mapping slice thermal maps in the radiomics regions of interest.Conclusion The IDLR model has the potential for differential diagnosis between IPD and atypical Parkinson's syndrome in 18F-FDG PET images.

Objective:To compare the effects of different reference brain regions on the semi-quantitative SUV ratio (SUVR) of 18F-Florzolotau PET images of Alzheimer′s disease (AD). Methods:The 18F-Florzolotau PET images of 28 (13 males, 15 females, age (57.3±9.5) years) normal controls (NC), 19 patients (4 males, 15 females, age (73.3±7.3) years) with β-amyloid (Aβ)-positive mild cognitive impairment (MCI) and 40 patients (19 males, 21 females, age (61.9±9.1) years) with AD were collected from Huashan Hospital, Fudan University between November 2018 and July 2020. Six semi-quantitative reference brain regions were defined, including whole cerebellum (WC), cerebellar gray matter (GM), cerebellar white matter (WM), parametric estimation of reference signal intensity (PERSI), WC after partial volume correction (WC_pvc), cerebellar GM after partial volume correction (GM_pvc). SUVR was calculated for 14 ROIs, which included the whole brain defined by the automated anatomical labeling (AAL) template, fusiform, inferior temporal, lingual, middle temporal, occipital, parahippocampal, parietal, posterior cingulate, precuneus defined by the AAL template, and Meta ROI composed of the above brain regions, and braak_Ⅰ-Ⅱ, braak_Ⅲ-Ⅳ, braak_Ⅴ-Ⅵ defined by the Desikan Killiany template. AUC was used to evaluate the classification ability of SUVR, and the correlation between SUVR and clinical scale scores were assessed by Spearman rank correlation analysis. Results:The SUVRs of most brain regions showed a steady upward trend in the AD disease spectrum. In the classification task of NC and MCI, the overall performance of SUVR based on WC_pvc was relatively optimal (AUCs: 0.975-1.000). In the classification task of NC and AD, SUVRs of 10 ROIs based on the WC_pvc method showed the relatively best performance (AUCs: 0.976-1.000). The correlation between SUVR of fusiform based on cerebellar WM and mini-mental state examination (MMSE) score was the strongest ( rs=-0.72, P<0.001), and the SUVR of precuneus based on WC_pvc showed the strongest correlation with clinical dementia rating (CDR) score ( rs=0.78, P<0.001). Conclusion:The SUVR based on WC_pvc method performs well in classification and correlation tasks, and is recommended to be used in semi-quantification of 18F-Florzolotau PET images of AD.

BACKGROUND:Kidney deficiency and blood stasis syndrome are common traditional Chinese medicine syndromes observed in knee osteoarthritis,which serve as fundamental pathogenesis factors.There exists a significant connection between the two.Previous studies have demonstrated that kidney deficiency and blood stasis syndrome effectively contribute to knee joint cartilage degeneration and the progression of knee osteoarthritis.However,the mechanisms underlying the promotion of knee joint cartilage damage remain unclear and require further investigation. OBJECTIVE:To investigate the influence of kidney deficiency and blood stasis syndrome on the progression of knee osteoarthritis in Sprague-Dawley rats. METHODS:Sixteen Sprague-Dawley rats were randomly divided into two groups:a model observation group and a control group,with eight rats in each group.Animal models of kidney deficiency were induced by ovary removal in the model observation group,while the control group was given a sham procedure for ovarian removal.Two months after modeling,both groups underwent modified HULTH surgery to induce knee osteoarthritis.One week after modified HULTH surgery,the model observation group was subcutaneously given adrenaline hydrochloride to make blood stasis models,while the control group was subcutaneously given normal saline.At the 5th week after modified HULTH surgery,blood rheology,coagulation parameters,triiodothyronine,tetraiodothyronine,and estradiol levels were measured.Knee joint X-ray images were taken,and knee joint sections were stained with safranin O-fast green,hematoxylin-eosin,and immunohistochemistry. RESULTS AND CONCLUSION:Compared with the control group,the model observation group exhibited significant increases in whole blood viscosity at low,medium,and high shear rates,as well as increased plasma viscosity.Fibronectin levels in the coagulation parameters were significantly increased,while prothrombin time and activated partial thromboplastin time were significantly decreased.Triiodothyronine,tetraiodothyronine,and estradiol levels were all significantly decreased.Radiographic results showed that the model observation group exhibited more severe degree of knee joint space narrowing and surface roughness,with the appearance of high-density shadows.Hematoxylin-eosin and safranin O-fast green staining demonstrated more severe cartilage damage in the model observation group,with significantly higher OARSI and Mankin scores compared with the control group.Compared with the control group,immunohistochemistry results showed a significant reduction in the expression of extracellular matrix type II collagen and aggrecan protein in the cartilage of the model observation group rats.Moreover,there was a significant increase in the expression of matrix metalloproteinase 13 and aggrecanase 5,which are inflammatory factors.These results indicate that the Sprague-Dawley rat model of knee osteoarthritis with kidney deficiency and blood stasis was successfully established.Kidney deficiency and blood stasis syndrome further aggravate cartilage extracellular matrix degradation and cartilage degeneration by promoting the expression of inflammatory factors,thereby promoting the progression of knee osteoarthritis in rats.

Purpose To explore the value of the new generation tau PET tracer 18F-Florzolotau in Alzheimer's disease(AD)at different stages.Materials and Methods Twenty-five MCI patients and sixty-one AD patients with positive β-amyloid status in Huashan Hospital,Fudan University from February 2020 to January 2022 were retrospectively enrolled with 18F-Florzolotau PET imaging and demographic and clinical data.The pre-processed PET images were analyzed by SPM two-sample t-test between MCI and AD groups,and the standardized uptake value ratios(SUVR)were extracted from the region of interest defined by SPM analysis(P＜0.001);scaled subprofile model/principal component analysis was used to construct the different tau related patterns(MCItauRP,ADtauRP)and calculate the corresponding expression values.The classification efficiency of SUVR and MCItauRP,ADtauRP expression values was evaluated by receiver operating characteristic curve.Results Compared with MCI patients,tau protein deposition of AD patients was increased mainly in the bilateral temporal,occipital lobe(P＜0.001),and the SUVR of these brain region in the AD group was higher than that in the MCI group(Z=-3.164,P＜0.00l);the expression values of MCItauRP and ADtauRP were significantly different between the AD group and MCI group(t=3.72,Z=-3.51;both P＜0.001),and these expression values of AD patients were higher than those in the MCI group;the accuracy of tauRP expression values and SUVR for the differentiation between the AD and MCI group were 61.63％,65.12％and 65.12％,respectively;the sensitivity was 88.00％,96.00％and 100.00％,respectively;the specificity was 50.82％,52.46％and 50.82％,respectively.Conclusion The new tau PET can identify and distinguish the differences in tau protein deposition between AD and MCI patients.However,the classification and diagnosis efficiency is not high.In the future,it is necessary to find a more ideal analysis method.

Objective:To perform harmonization based on the ComBat method for PET brain imaging scanned by different types of scanners from the same manufacturer and explored its effect on center effect.Methods:The three-dimensional (3D) Hoffman brain model was scanned by two different PET/CT instruments (Siemens Biograph64 TruePoint and Biograph128 mCT). Fourteen healthy subjects (8 males, 6 females, age: (57.7±9.5) years) underwent 18F-FDG PET/CT on Siemens Biograph64 TruePoint and 12 healthy subjects (9 males, 3 females, age: (55.8±10.5) years) underwent 18F-FDG PET/CT on Siemens Biograph128 mCT (all from Huashan Hospital, Fudan University; from November 2020 to March 2023). The whole brain was divided into 116 brain regions based on the anatomical automatic labeling (AAL) brain template. The ComBat method was applied to harmonized the PET data from brain model and healthy subjects. Mann-Whitney U test was performed on the radioactive counts and SUV ratios (SUVR) before and after homogenization acquired by both PET/CT instruments. Voxel-based statistical parametric mapping (SPM) independent-sample t test was also performed on data of healthy subjects. Results:In 3D Hoffman brain model, radioactivity counts (5 590.33(4 961.67, 6 102.95) vs 6 116.03(5 420.97, 6 660.66); z=-9.35, P<0.001) and SUVR (1.35(1.19, 1.47) vs 1.37(1.21, 1.49); z=-3.63, P<0.001) were significantly different between the two PET/CT scanners before harmonization and not after harmonization (radioactivity counts: 5 845.95(5 192.68, 6 378.63) vs 5 859.17(5 193.84, 6 380.52); SUVR: 1.35(1.20, 1.48) vs 1.36(1.20, 1.49); both z=-0.68, both P=0.498). In the healthy subjects, radioactive counts in 19 brain regions (12 422.78(11 181.60, 13 424.28)-18 166.40(15 882.80, 18 666.27); z values: from -3.24 to -2.06, all P<0.05) and SUVR in 40 brain regions (1.46(1.41, 1.52)-2.28(2.16, 2.36); z values: from -3.65 to -1.70, all P<0.05) were significantly different between the two scanners before harmonization, while after homogenization there were no statistical differences for all 116 brain regions (radioactivity counts: 9 243.55(8 502.38, 9 854.87)-20 419.60(19 931.51, 21 179.43); z values: from -0.72 to 0, all P>0.05; SUVR: 1.04(1.01, 1.09)-2.32(2.24, 2.40); z values: from -0.82 to 0, all P>0.05). SPM showed that significant differences of glucose metabolism in the cerebral cortex, basal ganglia, midbrain and cerebellum were found in healthy subjects between the two PET/CT scanners before homogenization, and brain regions with obvious differences reduced after homogenization. Conclusion:ComBat harmonization method is efficient at removing the center effect among different types of PET/CT scanners from the same manufacturer and may provide a simple and easy-to-implement homogenization for multicenter brain imaging studies.

Presynaptic dopaminergic PET imaging is a useful method for the diagnosis of parkinsonism. Based on the expert consensus on operation and clinical application of dopamine transporter brain PET imaging technology published in 2020, this paper further recommends the relevant elements of result interpretation of presynaptic dopaminergic PET imaging.

BACKGROUND: Insufficient cerebral perfusion is suggested to play a role in the development of Alzheimer disease (AD). However, there is a lack of direct evidence indicating whether hypoperfusion causes or aggravates AD pathology. We investigated the effect of chronic cerebral hypoperfusion on AD-related pathology in humans. METHODS: We enrolled a group of cognitively normal patients (median age: 64 years) with unilateral chronic cerebral hypoperfusion. Regions of interest with the most pronounced hypoperfusion changes were chosen in the hypoperfused region and were then mirrored in the contralateral hemisphere to create a control region with normal perfusion. 11C-Pittsburgh compound-positron emission tomography standard uptake ratios and brain atrophy indices were calculated from the computed tomography images of each patient. RESULTS: The median age of the 10 participants, consisting of 4 males and 6 females, was 64 years (47-76 years). We found that there were no differences in standard uptake ratios of the cortex (volume of interest [VOI]: P = 0.721, region of interest [ROI]: P = 0.241) and grey/white ratio (VOI: P = 0.333, ROI: P = 0.445) and brain atrophy indices (Bicaudate, Bifrontal, Evans, Cella, Cella media, and Ventricular index, P > 0.05) between the hypoperfused regions and contralateral normally perfused regions in patients with unilateral chronic cerebral hypoperfusion. CONCLUSION Our findings suggest that chronic hypoperfusion due to large vessel stenosis may not directly induce cerebral β-amyloid deposition and neurodegeneration in humans.
Aged ; Alzheimer Disease/pathology* ; Amyloid beta-Peptides/metabolism* ; Arteries ; Atrophy ; Brain/metabolism* ; Cerebral Cortex/metabolism* ; Cerebrovascular Circulation ; Constriction, Pathologic/pathology* ; Female ; Humans ; Magnetic Resonance Imaging/methods* ; Male ; Middle Aged ; Positron-Emission Tomography/methods*

Objective: To investigate the correlations among striatal dopamine transporter (DAT) distribution, glucose metabolism and Parkinson′s disease (PD) clinical symptoms. Methods: Twenty-five clinically confirmed idiopathic PD patients (17 males, 8 females, age: (59.8±9.2) years) who underwent ¹¹C-2-beta-carbomethoxy-3-beta-(4-fluorophenyl)tropane (CFT) and ¹⁸F-fluorodeoxyglucose (FDG) PET imaging from January 2015 to December 2016 were reviewed. The detailed clinical scores were systematically collected from all patients. Correlations between DAT distribution, glucose metabolism and clinical symptoms were evaluated at global and voxel levels using Pearson correlation analysis. Results: There were significantly positive correlations between the PD-related pattern (PDRP) value and unified PD rating scale (UPDRS) motor scores, non-motor symptoms scale (NMSS) scores, activity of daily living scale (ADL) scores (r values: 0.580, 0.522, 0.557, all P<0.05). The CFT uptake of ipsilateral caudate nucleus, anterior putamen, and posterior putamen were negatively correlated with UPDRS motor scores (r values: -0.496, -0.492, -0.457, all P<0.05), while those had no significant correlations with NMSS scores (r values: -0.420, -0.402, -0.355, all P>0.05). The CFT uptake of ipsilateral caudate nucleus and anterior putamen were negatively correlated with ADL scores (r values: -0.502, -0.522, both P<0.05). There were no significant correlations between CFT uptake in contralateral striatal, anterior putamen, posterior putamen and PDRP values, UPDRS motor scores, NMSS scores and ADL scores(r values: from -0.466 to -0.129, all P>0.05). The presence of the significant correlations between UPDRS motor scores, ADL scores and the CFT radioactive count were confirmed in left caudate nucleus and left putamen (r values: from -0.90 to -0.47, all P<0.05). The metabolic PET imaging disclosed a set of brain regions correlating with the clinical symptoms. The presence of significant correlations between the metabolic PET imaging and CFT uptake were confirmed in bilateral caudate nucleus (r values: 0.47-0.90, both P<0.01), precentral gyrus and insula (r values: -0.90 to -0.47, all P<0.01). Conclusion The correlations between DAT distribution, glucose metabolism and PD clinical symptoms are complicated, which promote the understanding in the proper application of dopaminergic and metabolic PET imaging in PD and offer more evidences in PD pathophysiological mechanisms.