Objective:To explore the value of 18F-FDG PET brain imaging in the auxiliary diagnosis of autoimmune encephalitis (AE) before treatment, and to analyze the regional and course-related characteristics of brain metabolic changes. Methods:The 18F-FDG PET brain imaging data of 49 AE patients (26 males, 23 females, age 48.0(29.0, 61.0) years) who did not receive first-line immunotherapy were retrospectively analyzed. Patients were collected from Renji Hospital, Shanghai Jiao Tong University School of Medicine, between July 2015 and December 2023. Forty-nine age- and gender-matched healthy subjects who underwent routine physical examination at the same time period were selected as the healthy controls (HC). The statistical parametric mapping (SPM) 8 two-sample t test ( P<0.001, k=50) was used to compare the imaging results of AE patients with those of HC. The screening results were adjusted by the cluster-level family-wise error rate (FWER) for P<0.05. Metabolic abnormalities associated with AE were identified, and differences in metabolic patterns at different stages of the disease course (short: ≤1 month; medium: >1 month and ≤3 month; long: >3 month) were compared by subgroup analysis. Mann-Whitney U test was used to analyze the data. Results:In the included AE patients, regions with elevated metabolism were mainly located in the limbic lobe, insula, putamen, and amygdala ( t values: 3.18-5.07, Z values: 3.17-4.76), while local metabolic reduction was observed in the frontal, parietal, and occipital lobes ( t values: 3.18-5.43, Z values: 3.23-5.06), with most of these regions passing FWER correction. In patients with anti- N-methyl- D-aspartate receptor (NMDAR) encephalitis, local metabolism increased in the right superior temporal gyrus ( t values: 3.55-4.79, Z values: 3.67-3.86) and decreased in the left middle temporal gyrus and inferior frontal gyrus ( t values: 3.55-5.43, Z values: 3.45-4.21), but the results did not pass the FWER correction. Subgroup analysis showed that in patients with short disease course ( n=17), regions with locally elevated metabolism included the brainstem, limbic lobe, and cerebellum ( t values: 3.37-5.27, Z values: 3.52-4.44), while regions with reduced metabolism were mainly located in the frontal, parietal, and occipital lobes ( t values: 3.37-6.77, Z values: 3.34-5.30), and these abnormal results all passed FWER correction. In patients with medium ( n=7) to long ( n=25) disease course, the regions with metabolic abnormalities were significantly reduced and did not pass FWER correction. Conclusions:18F-FDG PET can accurately identify brain metabolic abnormalities in AE patients, demonstrating significant regional and course-related characteristics. Metabolic abnormalities are more pronounced in patients with short disease course, while they are relatively less obvious in patients with medium to long disease course.

Objective:To explore the impact of phosphatase and tensin homologue deleted on chromosome 10 (PTEN)/tumor protein 53 (TP53) expression on the 68Ga-prostate specific membrane antigen (PSMA)-11 and 18F-FDG molecular imaging phenotypes in primary prostate cancer. Methods:A retrospective study was conducted on 75 prostate cancer patients (age (67.9±6.3) years) who received both 68Ga-PSMA-11 and 18F-FDG PET/CT imaging on initial diagnosis and subsequent radical prostatectomy at Renji Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, between Auguest 2018 and July 2022. The correlation between PTEN and TP53 expression in prostate cancer and molecular imaging phenotype was analyzed by χ2 test, Kruskal-Wallis rank sum test and Bonferroni method based on the uptake of imaging agents in primary lesions and the results of immunohistochemical analysis of surgical specimens. Results:In prostate cancer tissues with PTEN expression loss, the positive rates of 18F-FDG uptake and 68Ga-PSMA uptake were 14/14 and 11/14, with the SUV max of 7.70(6.15, 11.05) and 15.55(6.75, 23.49) respectively. In prostate cancer tissues with TP53 expression loss, the positive rates of 18F-FDG uptake and 68Ga-PSMA uptake were 10/10 and 6/10, with the SUV max of 7.70(6.95, 8.05) and 9.50(5.38, 19.89) respectively. In prostate cancer tissues with different expression patterns of PTEN and TP53, there were significant differences in the positive rates of 18F-FDG uptake ( χ2=20.45, P< 0.001), 68Ga-PSMA-11 uptake ( χ2=14.97, P=0.002), and the SUV max of 68Ga-PSMA-11 uptake ( H=9.62, P=0.022). Additionally, patients with concurrent loss of PTEN and TP53 expression in the primary tumor had significantly lower SUV max of 68Ga-PSMA-11 uptake compared to those with expression of both PTEN and TP53 (5.70(4.40, 11.70) vs 20.95(13.73, 37.58); P=0.003 (Bonferroni method corrected)). Conclusion:PTEN/TP53 expression is associated with the 68Ga-PSMA-11 and 18F-FDG molecular imaging phenotype in primary prostate cancer.

Objective:To compare the diagnostic efficacy of 18F-fibroblast activation protein inhibitor (FAPI) PET/MR and contrast-enhanced CT in detecting metachronous ovarian metastasis after gastric signet-ring cell carcinoma (GSRCC) surgery, and to evaluate its impact on clinical decision-making. Methods:This study employed a diagnostic test design. A retrospective analysis was conducted on 26 female patients with suspected metachronous ovarian metastasis following GSRCC resection between January 2023 and June 2025 in Renji Hospital, Shanghai Jiao Tong University School of Medicine. All patients underwent both 18F-FAPI PET/MR and contrast-enhanced CT within 2 weeks. Using histopathology or clinical imaging follow-up (≥6 months) as the reference standard, the diagnostic performance of both modalities was compared (McNemar test, Fisher exact test and Delong test), and changes in clinical management were analyzed. Results:Metachronous ovarian metastasis was confirmed in 12 patients (22 lesions). 18F-FAPI PET/MR showed significantly higher sensitivity (90.9%(20/22) vs 72.7%(16/22); χ2=4.10, P=0.043), specificity (100%(30/30) vs 50.0%(15/30); χ2=13.01, P<0.001), and accuracy (96.2%(50/52) vs 59.6%(31/52); χ2=15.43, P<0.001), compared to contrast-enhanced CT, with a significantly higher AUC (0.964 vs 0.815; Z=2.85, P=0.015). It also demonstrated superior detection of extraovarian metastases, including anastomotic recurrence, peritoneal spread, and lymph node involvement ( P values: 0.004-0.031), and identified 5 additional rare-site metastases in 3 patients that were missed by contrast-enhanced CT. Based on 18F-FAPI PET/MR findings, clinical management was adjusted in 6 patients with metastasis. Conclusion:18F-FAPI PET/MR outperforms contrast-enhanced CT in diagnosing metachronous ovarian metastasis and performing whole-body restaging in post-surgical GSRCC patients, therapy provides critical evidence for informing decision-making.

Objective To investigate correlations of the ratio of specific brain region volume to total brain volume(ratio％),standard uptake value(SUV)of specific brain region based on 18F-FDG PET/MR examination in Alzheimer disease(AD)patients,as well as the relationship between changes of these two.Methods Fifty AD patients were retrospectively collected.Based on FDG PET/MR,the ratio％and the mean SUV(SUVmean)of 40 specific brain regions were obtained,and the correlation between ratio％and SUVmean for each region were evaluated.According to a database of normal brains,Z-scores for ratio％and SUVmean were calculated to represent structural and functional changes in AD patients,and the correlation between these 2 Z-scores was assessed.Results Correlations were found between ratio％and SUVmean,also between Z-scores of these two parameters in 29 brain regions(r=0.288 to 0.778,all P＜0.05).Among them 7 brain regions,i.e.bilateral middle temporal gyrus,right fusiform gyrus,right hippocampus,right precuneus,left lingual gyrus and right parahippocampal gyrus exhibited correlation coefficients greater than 0.6.Conclusion There were some relationships between brain structural and metabolic functions and their changes in AD patients showed on FDG PET/MR.

Objective To investigate correlations of the ratio of specific brain region volume to total brain volume(ratio％),standard uptake value(SUV)of specific brain region based on 18F-FDG PET/MR examination in Alzheimer disease(AD)patients,as well as the relationship between changes of these two.Methods Fifty AD patients were retrospectively collected.Based on FDG PET/MR,the ratio％and the mean SUV(SUVmean)of 40 specific brain regions were obtained,and the correlation between ratio％and SUVmean for each region were evaluated.According to a database of normal brains,Z-scores for ratio％and SUVmean were calculated to represent structural and functional changes in AD patients,and the correlation between these 2 Z-scores was assessed.Results Correlations were found between ratio％and SUVmean,also between Z-scores of these two parameters in 29 brain regions(r=0.288 to 0.778,all P＜0.05).Among them 7 brain regions,i.e.bilateral middle temporal gyrus,right fusiform gyrus,right hippocampus,right precuneus,left lingual gyrus and right parahippocampal gyrus exhibited correlation coefficients greater than 0.6.Conclusion There were some relationships between brain structural and metabolic functions and their changes in AD patients showed on FDG PET/MR.

Objective:To explore the value of 18F-FDG PET brain imaging in the auxiliary diagnosis of autoimmune encephalitis (AE) before treatment, and to analyze the regional and course-related characteristics of brain metabolic changes. Methods:The 18F-FDG PET brain imaging data of 49 AE patients (26 males, 23 females, age 48.0(29.0, 61.0) years) who did not receive first-line immunotherapy were retrospectively analyzed. Patients were collected from Renji Hospital, Shanghai Jiao Tong University School of Medicine, between July 2015 and December 2023. Forty-nine age- and gender-matched healthy subjects who underwent routine physical examination at the same time period were selected as the healthy controls (HC). The statistical parametric mapping (SPM) 8 two-sample t test ( P<0.001, k=50) was used to compare the imaging results of AE patients with those of HC. The screening results were adjusted by the cluster-level family-wise error rate (FWER) for P<0.05. Metabolic abnormalities associated with AE were identified, and differences in metabolic patterns at different stages of the disease course (short: ≤1 month; medium: >1 month and ≤3 month; long: >3 month) were compared by subgroup analysis. Mann-Whitney U test was used to analyze the data. Results:In the included AE patients, regions with elevated metabolism were mainly located in the limbic lobe, insula, putamen, and amygdala ( t values: 3.18-5.07, Z values: 3.17-4.76), while local metabolic reduction was observed in the frontal, parietal, and occipital lobes ( t values: 3.18-5.43, Z values: 3.23-5.06), with most of these regions passing FWER correction. In patients with anti- N-methyl- D-aspartate receptor (NMDAR) encephalitis, local metabolism increased in the right superior temporal gyrus ( t values: 3.55-4.79, Z values: 3.67-3.86) and decreased in the left middle temporal gyrus and inferior frontal gyrus ( t values: 3.55-5.43, Z values: 3.45-4.21), but the results did not pass the FWER correction. Subgroup analysis showed that in patients with short disease course ( n=17), regions with locally elevated metabolism included the brainstem, limbic lobe, and cerebellum ( t values: 3.37-5.27, Z values: 3.52-4.44), while regions with reduced metabolism were mainly located in the frontal, parietal, and occipital lobes ( t values: 3.37-6.77, Z values: 3.34-5.30), and these abnormal results all passed FWER correction. In patients with medium ( n=7) to long ( n=25) disease course, the regions with metabolic abnormalities were significantly reduced and did not pass FWER correction. Conclusions:18F-FDG PET can accurately identify brain metabolic abnormalities in AE patients, demonstrating significant regional and course-related characteristics. Metabolic abnormalities are more pronounced in patients with short disease course, while they are relatively less obvious in patients with medium to long disease course.

Objective:To explore the impact of phosphatase and tensin homologue deleted on chromosome 10 (PTEN)/tumor protein 53 (TP53) expression on the 68Ga-prostate specific membrane antigen (PSMA)-11 and 18F-FDG molecular imaging phenotypes in primary prostate cancer. Methods:A retrospective study was conducted on 75 prostate cancer patients (age (67.9±6.3) years) who received both 68Ga-PSMA-11 and 18F-FDG PET/CT imaging on initial diagnosis and subsequent radical prostatectomy at Renji Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, between Auguest 2018 and July 2022. The correlation between PTEN and TP53 expression in prostate cancer and molecular imaging phenotype was analyzed by χ2 test, Kruskal-Wallis rank sum test and Bonferroni method based on the uptake of imaging agents in primary lesions and the results of immunohistochemical analysis of surgical specimens. Results:In prostate cancer tissues with PTEN expression loss, the positive rates of 18F-FDG uptake and 68Ga-PSMA uptake were 14/14 and 11/14, with the SUV max of 7.70(6.15, 11.05) and 15.55(6.75, 23.49) respectively. In prostate cancer tissues with TP53 expression loss, the positive rates of 18F-FDG uptake and 68Ga-PSMA uptake were 10/10 and 6/10, with the SUV max of 7.70(6.95, 8.05) and 9.50(5.38, 19.89) respectively. In prostate cancer tissues with different expression patterns of PTEN and TP53, there were significant differences in the positive rates of 18F-FDG uptake ( χ2=20.45, P< 0.001), 68Ga-PSMA-11 uptake ( χ2=14.97, P=0.002), and the SUV max of 68Ga-PSMA-11 uptake ( H=9.62, P=0.022). Additionally, patients with concurrent loss of PTEN and TP53 expression in the primary tumor had significantly lower SUV max of 68Ga-PSMA-11 uptake compared to those with expression of both PTEN and TP53 (5.70(4.40, 11.70) vs 20.95(13.73, 37.58); P=0.003 (Bonferroni method corrected)). Conclusion:PTEN/TP53 expression is associated with the 68Ga-PSMA-11 and 18F-FDG molecular imaging phenotype in primary prostate cancer.

Objective:To compare the diagnostic efficacy of 18F-fibroblast activation protein inhibitor (FAPI) PET/MR and contrast-enhanced CT in detecting metachronous ovarian metastasis after gastric signet-ring cell carcinoma (GSRCC) surgery, and to evaluate its impact on clinical decision-making. Methods:This study employed a diagnostic test design. A retrospective analysis was conducted on 26 female patients with suspected metachronous ovarian metastasis following GSRCC resection between January 2023 and June 2025 in Renji Hospital, Shanghai Jiao Tong University School of Medicine. All patients underwent both 18F-FAPI PET/MR and contrast-enhanced CT within 2 weeks. Using histopathology or clinical imaging follow-up (≥6 months) as the reference standard, the diagnostic performance of both modalities was compared (McNemar test, Fisher exact test and Delong test), and changes in clinical management were analyzed. Results:Metachronous ovarian metastasis was confirmed in 12 patients (22 lesions). 18F-FAPI PET/MR showed significantly higher sensitivity (90.9%(20/22) vs 72.7%(16/22); χ2=4.10, P=0.043), specificity (100%(30/30) vs 50.0%(15/30); χ2=13.01, P<0.001), and accuracy (96.2%(50/52) vs 59.6%(31/52); χ2=15.43, P<0.001), compared to contrast-enhanced CT, with a significantly higher AUC (0.964 vs 0.815; Z=2.85, P=0.015). It also demonstrated superior detection of extraovarian metastases, including anastomotic recurrence, peritoneal spread, and lymph node involvement ( P values: 0.004-0.031), and identified 5 additional rare-site metastases in 3 patients that were missed by contrast-enhanced CT. Based on 18F-FAPI PET/MR findings, clinical management was adjusted in 6 patients with metastasis. Conclusion:18F-FAPI PET/MR outperforms contrast-enhanced CT in diagnosing metachronous ovarian metastasis and performing whole-body restaging in post-surgical GSRCC patients, therapy provides critical evidence for informing decision-making.

Objective:To evaluate the values of 18F-PI-2620 PET/CT brain imaging with SUV ratio (SUVR) in the assessment of tau protein deposition in the brain of patients with different cognitive disorders and its correlation with cognition. Methods:This was a cross-sectional study. From December 2019 to November 2022, a total of 67 subjects including 54 patients with Alzheimer′s disease (AD; 21 males, 33 females, age (68.6±7.8) years), 7 patients with mild cognitive impairment (MCI; 1 male, 6 females, age (63.1±11.2) years) and 6 healthy controls (HC; 4 males, 2 females, age (69.0±5.8) years) were enrolled retrospectively in Renji Hospital. All participants were examined by 18F-PI-2620 PET/CT. SUVRs of brain regions were obtained, including frontal lobe, temporal lobe, occipital lobe, parietal lobe, insular lobe, whole brain, as well as 10 independent brain ROIs (amygdala, orbitofrontal cortex, cingulate gyrus, superior occipital gyrus, superior parietal gyrus, inferior angular gyrus, precuneus, inferior temporal gyrus, entorhinal cortex and parahippocampal gyrus), with inferior cerebellum cortex as the reference region. All participants were estimated by cognitive scales(mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA)). One-way analysis of variance and the least significant difference t test were used to compare the differences of SUVR in each brain region among HC, MCI and AD groups. ROC curve analysis was used to determine the optimal cut-off values of SUVR in each brain region for the differential diagnosis of AD-MCI and AD-HC. Pearson correlation analysis was employed to examine the correlations of SUVR with cognitive scale scores. Results:The SUVR of whole brain was 1.40±0.31 in AD group, 1.08±0.19 in MCI group, and 1.01±0.12 in HC group. SUVR analysis in the whole brain and each brain region could distinguish AD from HC, AD from MCI ( F values: 1.76-10.09, t values: 2.98-7.47, all P<0.05), but could not distinguish HC from MCI ( t values: 0.17-1.53, all P>0.05). ROC curve analysis showed that the best cut-off value of SUVR was 1.18 for whole brain (AUC=0.89), 1.13 for amygdala (AUC=0.94) and 1.26 for parahippocampal gyrus (AUC=0.94) for differential diagnosis of AD and HC, which was 1.06 for whole brain (AUC=0.82), 1.18 for amygdala (AUC=0.88) and 1.28 (AUC=0.88) for infratemporal gyrus to differential diagnosis of AD and MCI. SUVRs of the whole brain, frontal, occipital, parietal, temporal and insula were significantly negatively correlated with MMSE and MoCA cognitive scale scores ( r values: from -0.64 to -0.40, all P<0.05). Conclusions:SUVR quantitative analysis in 18F-PI-2620 PET imaging can assist the differential diagnosis of AD and HC, AD and MCI. The SUVRs of whole brain and five lobes show negative correlations with MMSE and MoCA scores.

Objective:To evaluate the detection rate and distribution characteristics of lesions in patients with biochemical recurrence (BCR) after radical prostatectomy for prostate cancer by 68Ga-prostate specific membrane antigen (PSMA)-11 PET/CT. Methods:From January 2020 to March 2024, 68Ga-PSMA-11 PET/CT examination results of 172 patients (age (69.4±6.5) years) with BCR after radical prostatectomy in Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine were retrospectively analyzed. The relationship between prostate specific antigen (PSA) levels and 68Ga-PSMA-11 PET/CT detection rate was explored. The location and quantity of lesions detected by 68Ga-PSMA-11 PET/CT were analyzed in BCR patients with clear location after local treatment, and data were analyzed by Fisher exact test. Results:The detection rate of 68Ga-PSMA-11 PET/CT in patients with BCR was 70.35%(121/172). The positive detection rate increased with the increase of PSA level, with detection rates of 0.2 μg/L≤PSA<0.5 μg/L, 0.5 μg/L≤PSA<1.0 μg/L, 1.0 μg/L≤PSA<1.5 μg/L and PSA≥1.5 μg/L groups of 49.12%(28/57), 67.24%(39/58), 15/16 and 95.12%(39/41), respectively. After local treatment, 64 cases were diagnosed with 95 recurrent and metastatic lesions. Among them, 22(34.38%) had simple prostate bed recurrence, 23(35.94%) had simple lymph node metastasis, 7(10.94%) had simple bone metastasis, and 12(18.75%) had multi regional metastasis. The proportion of bone metastasis (18.75%, 12/64) was significantly lower than that of prostate bed recurrence and lymph node metastasis (both 50.00%(32/64); both P=0.002). Conclusions:68Ga-PSMA-11 PET/CT has a high detection rate in patients with BCR after radical prostatectomy, especially in patients with high PSA levels. The lesions are mainly distributed in the prostate bed and lymph nodes, while bone metastases are relatively rare, which provide a theoretical basis for the selection of more accurate treatment plans for BCR patients in the future.