ABSTRACT
Objective:To evaluate the value of 68Ga-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (DOTA)-fibroblast activating protein inhibitor (FAPI)-04 PET/CT on assessing different pathological grades in patients with renal fibrosis. Methods:A total of 25 patients (11 males, 14 females; age (39.3±13.9) years) diagnosed with renal fibrosis in the Affiliated Hospital of Southwest Medical University from September 2020 to August 2021 were retrospectively analyzed. All patients underwent renal puncture examination and 68Ga-DOTA-FAPI-04 PET/CT examination. The pathological results of kidney puncture were as the " gold standard" to divide the patients into mild fibrosis (Ⅰ), moderate fibrosis (Ⅱ), and severe fibrosis (Ⅲ). At the same time, 20 patients (10 males, 10 females; age (47.5±13.2) years) who underwent 68Ga-DOTA-FAPI-04 PET/CT examination showed no abnormal uptake of radioactivity in bilateral kidneys and no history of urinary system related diseases were enrolled as normal controls. Parameters including the maximum standardized uptake value (SUV max) of both kidneys, the mean standardized uptake value (SUV mean) of the liver, target/background ratio (TBR), glomerular filtration rate (GFR), and serum creatinine (Scr) were collected. Kruskal-Wallis rank sum test and Bonferroni correction method were used to compare the differences of SUV max, SUV mean, TBR and Scr among groups. One-way analysis of variance and least significant difference (LSD) t test were used to compare the difference of GFR among groups. The receiver operating characteristic (ROC) curve analysis was used to analyze the diagnostic efficacy of SUV max for the degree of renal fibrosis. Results:Of 25 patients, 22 had increased imaging agent uptake and the sensitivity of 68Ga-DOTA-FAPI-04 PET/CT in diagnosing renal fibrosis was 88%. The SUV max and TBR of patients with fibrosis grade Ⅰ, Ⅱ and Ⅲ were significantly higher than those of controls (SUV max: 4.40(3.30, 4.50), 5.90(4.28, 6.48), 8.50(7.50, 9.73) and 1.44(1.38, 1.68); TBR: 6.340±2.389, 8.097±1.420, 11.343±2.002 and 2.986±0.645; H values: 33.685, 32.368, all adjusted P<0.05 (Bonferroni correction method)). The Scr of patients with fibrosis grade Ⅰ and Ⅲ were significantly different (70.1(55.4, 92.5) and 174.1(161.4, 498.2) μmol/L; H=9.770, adjusted P<0.05 (Bonferroni correction method)). The liver SUV mean of patients with renal fibrosis grades Ⅱ and Ⅲ were significantly higher than that of controls (0.673±0.129, 0.751±0.170 and 0.514±0.142; H=15.609, both adjusted P<0.05 (Bonferroni correction method)). The GFR of patients with fibrosis grade Ⅲ had significant differences with grade Ⅰ and Ⅱ ((27.867±15.747), (87.756±31.657) and (63.160±29.556) ml/min; F=8.298, both P<0.05). ROC curve analysis showed that the area under curve was 0.946 7 (95% CI: 0.899 6-0.993 8, P<0.001). Conclusion:68Ga-DOTA-FAPI-04 PET/CT has a certain value in evaluating the degree of renal fibrosis, which can be used as a supplementary examination method for diagnosing renal fibrosis.
ABSTRACT
Objective:To exploring the uptake of fibroblast activation protein (FAP) inhibitor (FAPI) in pancreatic cancer through 68Ga-FAPI-04 PET/CT imaging, and provide a basis for the FAP-targeted imaging of pancreatic cancer. Methods:Pancreatic cancer-patient-derived tumor xenograft (PDX) mouse models ( n=8) were developed, then 68Ga-FAPI-04 and 18F-FDG microPET/CT imaging were performed (4 in each group). The differences of percentage activity of injection dose per gram of tissue (%ID/g) of 68Ga-FAPI-04 and 18F-FDG were analyzed by independent-sample t test. 68Ga-FAPI-04 and 18F-FDG PET/CT imaging were performed in 5 patients (4 males, 1 female, age: 46-74 (63.0±11.9) years) with pancreatic cancer, and the maximum standardized uptake value (SUV max) of 68Ga-FAPI-04 and 18F-FDG in primary pancreatic cancer and the SUV max ratio of liver metastases to liver tissue were compared by paired t test. Results:MicroPET/CT imaging showed that 68Ga-FAPI-04 was obviously uptaken at all time points in the tumor of PDX mice. The uptake of 68Ga-FAPI-04 in PDX mice 60 min after injection was significantly higher than that of 18F-FDG ((6.58±0.44) and (4.29±0.13) %ID/g; t=4.152, P=0.008 9). PET/CT showed that the SUV max of 68Ga-FAPI-04 in pancreatic cancer was significantly higher than that of 18F-FDG (16.82±3.08 and 5.14±2.20; t=6.893, P=0.000 1) and the SUV max ratio of liver metastases to liver tissue of 68Ga-FAPI-04 was also significantly higher than that of 18F-FDG (4.57±1.47 and 1.30±0.16; t=3.803, P=0.019 1). Conclusion:68Ga-FAPI-04 can be highly uptaken in pancreatic cancer, suggesting that FAP can be a potential target for PET/CT imaging of pancreatic cancer.
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Objective:To explore the diagnostic value of 68Ga-fibroblast activation protein inhibitor (FAPI) PET for the restaging of patients with colorectal cancer and its impact on treatment strategy. Methods:Patients with colorectal cancer who underwent 68Ga-FAPI PET imaging in the PET Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from June 2020 to June 2021 were retrospectively analyzed. PET images were evaluated by 3 experienced imaging physicians. Biopsy or postoperative pathology, clinical and imaging follow-up results were as the gold standard. The diagnostic value of PET was compared with conventional imaging (CT/MR), and the impact of 68Ga-FAPI PET on guiding treatment was evaluated. χ2 test and Fisher exact test were used to compare the differences between groups. Results:A total of 33 patients were included (17 males, 16 females, age (52.8±12.3) years), of which 24 were finally diagnosed as recurrence/metastases/progression. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of 68Ga-FAPI PET in detecting recurrence/metastases/progression of colorectal cancer were 93.9%(31/33), 100%(24/24), 7/9, 92.3%(24/26) and 7/7, respectively. Its accuracy, sensitivity and negative predictive value were significantly higher than those of conventional imaging (64.5%(20/31), 56.5%(13/23) and 7/17; χ2 values: 8.549 and 10.786, all P<0.05). Compared with the clinical or pathological stage before examination, 68Ga-FAPI PET led upstaging to stage Ⅳ in 12 patients (50.0%, 12/24). Of the 31 patients who were correctly diagnosed by 68Ga-FAPI PET, the treatment regimen of 22 patients (71.0%) was changed because of 68Ga-FAPI PET imaging. Conclusion:68Ga-FAPI PET has good diagnostic performance in the restaging of colorectal cancer, which is helpful to further guide clinical treatment strategy.
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Objective:To investigate the radiation dosimetry and biodistribution of 68Ga-FAPI-04 PET/CT in patients with hepatobiliary tumor. Methods:A total of six patients with hepatic lesions who underwent PET/CT examination in Peking Union Medical College Hospital were enrolled. After intravenous injection of radiotracer 68Ga-FAPI-04 at (170.57 ± 14.43) MBq, whole-body imaging were performed at the time points of 3, 10, 15, 20, 30 and 60 min, respectively. Biodistribution pattern was observed. Regions of interest were manually delineated. Radiation dosimetry of all target organs were calculated by Olinda/EXM software. Results:The radioactive uptake dissipated gradually in liver whereas it was relatively stable in tumor lesions. The average SUV max of tumor lesions reached the maximum value (13.87± 2.55) at 20 min after injection. The target-to-background ratio increased with time, reaching the maximum value (10.09 ± 8.17) at 30 min after injection. The average effective dose in total body was (0.020 ± 0.002) mSv/MBq and organ with the highest effective dose was bladder wall at (0.146 ± 0.035) mSv/MBq. Conclusions:The effective dose in total body of 68Ga-FAPI-04 was similar to that of 18F-FDG. 68Ga-FAPI-04 is expected to be a PET/CT radiotracer for hepatobiliary tumors in consideration of rapid tumor uptake, low accumulation of liver background, and no influence of blood sugar levels.