Exploratory Research On The Use Of PET/CT In The Diagnosis Of A Series Of Rare Disease

Project I 68Ga-NOTA-Evans Blue PET/CT findings in lymphangioleiomyomatosis compared with 99mTC-ASC lymphoscintigraphy:a prospective studyObjective:Lymphangioleiomyomatosis(LAM)is a rare multisystem disease characterized by cystic lung disease and extrapulmonary manifestations,including lymphatic system disorder.The objective of this study was to investigate the findings of 68Ga-NOTA-Evans Blue(NEB)PET/CT in LAM and compare it with that of 99mTc-ASC lympphoscintigraphy.Methods:Ten patients diagnosed with LAM according to the American Thoracic Society/Japanese Respiratory Society guidelines for LAM were recruited in this study.PET/CT acquisition was performed at 20 to 40 minutes after subcutaneous injection of 68Ga-NEB into the first interdigital spaces of both feet(0.3 ml,37 MBq/foot).All subjects also underwent 99mTc-antimony sulfide colloid(ASC)lymphoscintigraphy within a week for comparison.Results:68Ga-NEB PET/CT displayed various lymphatic system abnormalities in 10(100%)of 10 patients.These included pulmonary lymphatic abnormalities in 10(100%)of 10 patients,enlarged lymph nodes in 5(50%),lymphangioleiomyomas in 2(20%),dilation of the lumbar trunk and/or iliac lymph vessels in 5(50%),thoracic duct dilation in 2(20%),chylous effusion in 1(10%).For pulmonary lymphatic abnormalities,the positive rates of 68Ga-NEB PET/CT and 99mTc-ASC lymphoscintigraphy were 100%(10/10)and 10%(1/10),respectively(P<0.001).As for the 7 patients with extrapulmonary lymphatic manifestations,68Ga-NEB PET/CT also presented more information than 99mTcASC lymphoscintigraphy.Conclusion:68Ga-NEB PET/CT visualized pulmonary lymphatic abnormality and displayed extrapulmonary lymphatic system disorders of LAM,and might play a role in the diagnosis and evaluation of the disease.68Ga-NEB PET/CT is advantageous over conventional 99mTc-ASC lymphoscintigraphy in LAM by providing more detailed information of lymphatic dysfunction.Project Ⅱ Head-to-head comparison of 68Ga-DOTA-TATE and 68Ga-DOTA-JR11 PET/CT in patients with Tumor-induced osteomalacia:a prospective studyObjective:The purpose of this study is to compare the sensitivity of 68Ga-DOTA-JR11 and 68Ga-DOTA-TATE PET/CT for detecting the responsible tumor of tumor-induced osteomalacia(TIO)and investigate if 68Ga-DOTA-JR11 PET/CT can identify the culprit tumor of TIO in multiple suspicious lesions in 68Ga-DOTA-TATE PET/CT.Methods:A total of 19 patients with suspected TIO were prospectively recruited in this study.Each patient underwent whole-body PET/CT scan 40-60 min post-injection using 68Ga-DOTA-TATE and 68Ga-DOTA-JR11 on the same PET/CT,respectively in sequence,and on consecutive days.The diagnosis of TIO was confirmed by the combination of the postsurgical pathological results of the tumor and clinical information.Results:Among the 19 patients with TIO who were included in this study,culprit tumors from all patients were confirmed pathologically.68Ga-DOTA-TATE PET/CT positively identified the causative tumor in 18/19 patients,whereas 68Ga-DOTA-JR11 PET/CT was positive in 11/19 patients(94.7%vs.57.9%,respectively;P<0.05).68Ga-DOTA-TATE PET/CT demonstrated more than one increased focal activity in 7 patients for a total of 16 lesions(3 lesions each in 2 patients and 2 lesions each in the rest 5 patients).However,Seven of these 16 lesions showed concordant results on 68Ga-DOTA-JR11 PET/CT by demonstrating increased activity(one lesion in each of the 7 patients).The surgical specimens of the lesions in these 7 patients confirmed the phosphaturic mesenchymal tumor.A total of 11 culprit tumors were positive in both 68Ga-DOTA-TATE and 68GaDOTA-JR11 PET/CT.The SUVmax of 11 culprit tumors was significantly higher on 68GaDOTA-TATE PET/CT compared with that on 68Ga-DOTA-JR11 PET/CT[17.8±12.5 vs 6.8±6.2;P<0.05].Conclusions:68Ga-DOTA-TATE PET/CT is more sensitive to 68Ga-DOTA-JR11 PET/CT in the detection of the culprit tumor of TIO.However,68Ga-DOTA-JR11 PET/CT might be helpful to identify the tumor in multiple suspicious lesions in 68Ga-DOTA-TATE PET/CT.Project Ⅲ Fibroblast activation protein targeted PET/CT with 68Ga-DOTA-FAPI04 for imaging SAPHO syndromeObjective:Synovitis,acne,pustulosis,hyperostosis,and osteitis(SAPHO)syndrome is a rare inflammatory disorder of bone,joints and skin,with various stages of bone lesions including inflammation and bone marrow fibrosis.Since the inflammation-induced fibrosis and bone marrow fibrosis are important features in SAPHO syndrome,we performed a prospective study to evaluate the performance of 68Ga-DOTA-FAPI-04,a novel PET agent targeting fibroblast activation protein,in SAPHO syndrome,and to explore the utility.Methods:68Ga-DOTA-FAPI-04 PET/CT was performed on a cohort of 21 patients with SAPHO syndrome.All patients underwent 68Ga-DOTA-FAPI-04 and 18F-FDG PET/CT on two consecutive days.The positive rates of the PET/CT scans in the current osteoarticular symptom sites of SAPHO syndrome,the uptake values and agreement with clinical osteoarticular symptom were compared.Results:In a total of 38 site involvements in the 21 patients,68Ga-DOTA-FAPI-04 PET/CT additionally detected 10/38(26.3%)pain involvements in 8/21(38.1%)patients compared with 18F-FDG PET/CT.68Ga-DOTA-FAPI-04 also demonstrated significantly higher uptake(7.3±2.0,5.1±2.7;P=0.05)and target-to-background ratio(TBR)(15.3±5.7,3.6±1.5;P<0.01)than 18F-FDG in the skeletal involvements.The agreement between 68Ga-DOTA-FAPI-04 positive lesions and current osteoarticular lesions was substantial(κ=0.79,p<0.001),whereas 18F-FDG had low to moderate agreement with clinical symptoms(κ=0.52,p<0.001).Conclusions:68Ga-DOTA-FAPI-04 might be a promising imaging agent for the evaluation of SAPHO syndrome.Project Ⅳ 18F-FDG PET/CT imaging features of patients with multicentric Castleman diseaseObjective:To investigate the role of 18F-FDG PET/CT in the evaluation of multicentric Castleman disease(MCD).Methods:Thirty-five patients with pathologically confirmed MCD who underwent 18FFDG PET/CT were retrospectively included.The FDG uptake and CT findings of lymph nodes,pulmonary involvement,spleen,and bone marrow were assessed and the maximum standardized uptake value(SUVmax)of each lesion was measured.The locations of lymph nodes were also evaluated.Results:18F-FDG PET/CT showed increased uptake in multiple nodal regions in 34/35 MCD patients.The most frequently involved nodal sites were the cervical,iliac,axillary,and inguinal areas,and the least common was paraaortic and abdominal nodes.The involved lymph nodes were not confluent and presented a relatively symmetric pattern on PET/CT images.The highest SUVmax of lymph nodes per patient ranged from 2 to 19 with a mean value of 5.61±3.12.Pulmonary manifestation including cysts,nodules,and interstitial lung disease,were found in 10 patients,8 of whom demonstrated mild to moderate uptake in the lungs.18F-FDG PET/CT also revealed other findings including hypermetabolic spleen(n=8)and bone marrow(n=23),elevated uptake in salivary glands(n=8).Four patients also underwent follow-up PET/CT scans after therapy,and 3 of them displayed decreased metabolism.Conclusions:18F-FDG PET/CT is a useful tool in the diagnosis,evaluation,and followup of MCD by providing systemic manifestations of lymphadenopathy,pulmonary involvement,and hypermetabolic spleen or bone marrow.Furthermore,the lymphadenopathy in MCD presented a predominantly peripheral distribution,relatively symmetric,moderately hypermetabolic,and not confluent pattern on 18F-FDG PET/CT.Project Ⅴ The value of multiparameter 18F-FDG PET/CT imaging in differentiating retroperitoneal paragangliomas from unicentric Castleman diseaseObjective:The aim of this study was to investigate the value of multiple parameters retrieved from the FDG PET/CT studies,including maximum standardized uptake value(SUVmax),mean standardized uptake value(SUVmean),peak standardized uptake value(SUVpeak),metabolic tumour volume(MTV),total lesion glycolysis(TLG),tumour size in differentiating retroperitoneal paragangliomas from unicentric Castleman disease(UCD).Methods:28 patients with solitary retroperitoneal masses who had undergone preoperative 18F-FDG PET/CT were retrospectively evaluated.Histopathology by surgical resection confirmed 17 paragangliomas and 11 UCDs.SUVmax,SUVmean,SUVpeak,MTV,TLG,and tumour size of 18F-FDG PET/CT were measured for each patient.Mann-Whitney Utest was used to assess differences in multiple parameters between paragangliomas and UCDs.The receiver operating characteristic(ROC)curve analysis was performed to determine the differential diagnostic value of these parameters.Results:Paragangliomas presented significantly higher SUVmax(16.7±9.8 vs 4.9±1.8,P<0.001),SUVmean(10.2±6.6 vs 3.1±1.2.P=0.001),SUVpeak(12.4±8.7 vs 3.7± 1.6,P<0.001),and TLG(495.4±409.2 vs 171.7±218.2,P=0.024)than UCDs,whereas no significant difference was observed in MTV.The AUCs for differentiating paragangliomas and UCDs were 0.920,0.888,0.909,and 0.765 for SUVmax,SUVmean,SUVpeak,and TLG,respectively.The SUVmax cut-off of 7.75 yielded 82.4%sensitivity and 100%specificity for predicting paragangliomas.Conclusions:This study indicated that 18F FDG PET/CT-derived multiple metabolic parameters are useful in distinguishing between paragangliomas and UCDs.SUVmax showed the best result for the differential diagnosis of these two diseases among multiple metabolic parameters.