Objective:To explore the application of OTSU-based self-attenuation correction PET (sacPET) reconstruction technology in 18F-florbetapir (AV45) imaging. Methods:From November 2018 to December 2019, 7 confirmed Alzheimer′s disease (AD) patients (4 males, 3 females, age (69.6±4.5)years) and 3 healthy controls (HC; 1 male, 2 females, age (68.0±4.6) years) were recruited prospectively for 18F-AV45 PET imaging in the First Affiliated Hospital of Sun Yat-Sen University. Original data collected by PET acquisition was processed with sacPET reconstruction and then compared with standard PET images by visual analysis and semi-quantitative analysis. Fisher exact test, Kappa test and Pearson correlation analysis were used to analyze data. Results:In HC group and AD group, the radioactive distribution showed by sacPET images and that by standard PET images were similar, and the contrast of gray-white matter in sacPET images was weaker than that in standard PET images. Moreover, the positive uptake area of the cortex in the AD group was smaller than that in standard PET images. Visual analysis showed 19 positive regions in sacPET images and 22 in standard PET images, with no statistical difference of positive rates of the sub-regions in the cortex between the two PET images (all P>0.05), and the overall consistency of 88.00% (44/50; Kappa=0.75 (95% CI: 0.57-0.94), P<0.05). Semi-quantitative analysis showed that the standardized uptake value ratio (SUVR) of frontal lobe and cingulate gyrus measured by sacPET was lower than that measured by standard PET (0.93±0.06 vs 0.96±0.06 and 0.99±0.04 vs 1.01±0.04; t values: 5.30 and 5.10, both P<0.01), while SUVR of parietal lobe, temporal lobe and occipital lobe measured by sacPET was higher than that measured by standard PET (0.78±0.08 vs 0.68±0.07, 0.97±0.07 vs 0.91±0.08 and 0.94±0.11 vs 0.71±0.12; t values: 6.27, 7.36 and 16.90, all P<0.01). The overall SUVR of sacPET images was significantly correlated with the standard PET images ( r=0.75, P<0.001). Conclusion:For 18F-AV45 imaging, sacPET reconstruction technology can obtain reliable and effective PET images without CT data, but its accuracy and precision still need to be improved.

Objective:To explore the relationship between vesicular monoamine transporter 2(VMAT2) density in the striatum and the non-motor symptoms(NMSs) in patients with Parkinson′s disease(PD).Methods:From December 2018 to December 2019, 29 normal controls (16 males, 13 females, age: (48.8±14.2) years), 31 patients with PD at the Hoehn-Yahr (mH-Y) Ⅱ stage (16 males, 15 females, age: (53.4±8.5) years) and 36 patients with PD at mH-Y Ⅲ stage (19 males, 17 females, age: (63.1±8.2) years) in the First Affiliated Hospital of Sun Yat-sen University were prospectively enrolled in this study. All subjects underwent 18F-fluoropropyl-(+ )-dihydrotetrabenazine( 18F-FP-(+ )-DTBZ, 18F-AV133) PET/CT imaging, then the specific uptake ratios (SURs) of striatal subregions were measured with the occipital cortex as the reference background region. The clinical data, laboratory data and imaging results were collected. The NMSs of each patient were evaluated with Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale (HAMD), Parkinson′s Disease Sleep Scale (PDSS), Montreal Cognitive Assessment (MoCA), Parkinson′s Disease Quality of Life Questionnaire (PDQL) and Non-Motor Symptoms Scale (NMSS). The independent-sample t test and one-way analysis of variance (the least significant difference t test) were used to compare data differences. Finally, the association of the striatal SURs with the clinical symptom scores were evaluated with Pearson correlation analysis and multivariable stepwise regression analysis. Results:Significant differences were found in depression (3.51±1.34 vs 11.36±3.87), anxiety (2.35±1.45 vs 6.00±3.32), sleep disorder (132.90±12.26 vs 110.34±19.69) and life quality (7.58±3.37 vs 24.01±10.15) scores between the mH-Y stage Ⅱ and the stage Ⅲ patients ( t values: from -10.573 to 5.439, all P<0.05), while cognitive scores did not differ significantly between the 2 PD groups ( t=1.067, P>0.05). Compared with healthy control group (1.28±0.22), the PD groups displayed a more marked decrease of SURs in the bilateral putamen and in the caudate nucleus (0.65±0.16 and 0.31±0.14; F=83.11, P<0.05), and the SURs of patients at stage Ⅱ were higher than those of the patients at stage Ⅲ ( t=9.116, P<0.05). NMSs scores of PD patients, with the exception of cognition scores, were correlated with striatal SURs ( r values: from -0.647 to -0.426, all P<0.05). Regression analysis showed that total striatum SURs was the best predictor of PDSS and NMSS scores ( R2 values: 0.234, 0.378, both P<0.001), while contralateral caudate nucleus SURs were best predictor of HAMD scores ( R2=0.402, P<0.001). The SURs of contralateral putamen were best variables for predicting HAMA scores ( R2=0.204, P<0.001). Conclusion:The correlation between the decreased striatal VMAT2 and a broad spectrum of NMSs in patients with PD is established, suggesting that the defect in dopamine supply may be an early abnormality promoting mechanisms leading to the development of NMSs in PD.

Objective To investigate the application and value of entacapone in 6-18F-fluoro-L-dopa (18F-DOPA) PET/CT imaging on Parkinson's disease (PD).Methods From July 2016 to September 2017,44 PD patients (24 males,20 females,age:(51.3±11.0) years) and 14 healthy volunteers (7 males,7 females,age:(57.6± 14.4) years) who underwent 18F-DOPA PET/CT imaging were enrolled.They were divided into 4 groups:PD1 group with entacapone treatment (n=24);PD2 group without entacapone treatment (n=20);healthy control group with entacapone treatment (HC1,n=6);healthy control group without entacapone treatment (HC2,n =8).The striatal-to-occipital ratio (SOR) was calculated.Two-sample t test and receiver operating characteristic (ROC) curve analysis were used to analyze the data.Results The striatum was more clear and the uptake of cerebral cortex decreased significantly in PD1 and HC1 groups.The SOR of contralateral anterior putamen,posterior putamen and caudate nucleus in PD1 group were 15％,14％ and 15％ higher (t values:2.92,3.11,2.49,all P＜0.05) than those in PD2 group,and SOR of ipsilateral anterior putamen,posterior putamen and caudate nucleus in PD1 were 17％,21％ and 17％ higher (t values:2.90,3.56,3.00,all P＜0.05).SOR of left anterior putamen,posterior putamen and caudate nucleus in HC1 group were improved 29％,35％ and 27％ (t values:3.64,3.48,4.48,all P＜0.05) compared to those in HC2 group,and SOR of right anterior putamen,posterior putamen and caudate nucleus in HC1 group were improved 29％,28％ and 29％ (t values:2.92,2.73,3.61,all P＜0.05).The area under curve (AUC) for SOR of the left anterior and posterior putamen and the right posterior putamen in subjects with entacapone treatment were 0.999,0.999 and 0.972,which were far greater than 0.865,0.889 and 0.848 (z values:3.24,3.03,2.77,all P＜0.01) in those without entacapone treatment.The AUC for SOR of the right anterior putamen,the left caudate nucleus and the right caudate nucleus subjects with entacapone treatment were 0.927,0.941 and 0.906,respectively,which were also significantly greater than 0.754,0.766 and 0.696 (z values:2.01,2.36,2.17,all P＜0.05) in subjects without entacapone treatment.Conclusion Entacapone can increase the uptake of 18F-DOPA in the striatum of patients with PD,and it can improve the efficiency of 18F-DOPA to distinguish patients with PD from normal people.

Objective To investigate the clinical values of L-6-18 F-fluoro-3,4-dihydroxyphenylala-nine ( 18 F-DOPA) PET in the diagnosis and severity assessment of early-stage Parkinson's disease ( PD) . Methods Thirty-eight patients (24 males, 14 females; age:34-74 years) with early-stage PD (Hoehn-Yahr ( H-Y) staging:1-2) and 5 age-matched healthy volunteers ( all males;age:45-65 years) from July 2016 to March 2017 were included and underwent 18 F-DOPA PET scan in this retrospective study. The stria-tal-to-occipital ratio ( SOR) was calculated and compared between PD patients and healthy volunteers. The unified PD rating scale ( UPDRS) Ⅲ score and H-Y staging were used to evaluate the clinical symptoms. Two-sample t test and Pearson correlation analysis were used. Results In the control group, 18 F-DOPA SORs in bilateral putamen and caudate nucleus were 2.50±0.24 and 2.61±0.23, respectively. In PD group, the SORs of ipsilateral and contralateral putamen nucleus were 2.02±0.27 and 1.80±0.26 respectively, lower than those in the control group ( t values:-4.006,-5.440, both P<0.01) . The SORs of ipsilateral and contralater-al caudate nucleus were 2.16±0.32 and 2.08±0.28 respectively, lower than those in the control group ( t val-ues:-2.990,-4.047, both P<0.01). The SORs of contralateral putamen and caudate nucleus were signifi-cantly lower than those of the ipsilateral striatum respectively (t values:-6.431,-3.837, both P<0.01). Fur-thermore, the SORs in the striatum (putamen and caudate nucleus) were negatively correlated with UPDRSⅢscore, H-Y staging, and duration of disease (r values:from-0.526 to-0.369, all P<0.05). Conclusions 18F-DOPA PET can reflect the changes in the striatum neurons, and it may be an important method in the diag-nosis and assessment of early-stage PD patients.