Clinical Study Of ⁶⁸Ga-DOTATATE PET/CT In Bone Metastasis Of Neuroendocrine Neoplasms

Objective:To investigate the anatomical and ⁶⁸Ga-DOTATATE uptake features of bone metastases on ⁶⁸Ga-DOTATATE PET/CT and its clinical value for neuroendocrine neoplasms?NENs?.Methods:Enrolled in this retrospective analysis were 74 patients,all of whom underwent ⁶⁸Ga-DOTATATE PET/CT?35 men,39 women;mean±SD age 52±12 years,range 17–82 years?,including 18 cases of gastrointestinal NENs,29 cases of pancreatic NENs,7 cases of lungs NENs,6 cases of unknown primary tumor,6 cases of thyroid NENs,4 cases of thymic NENs,3cases of adrenal NENs and 1 case of meningiomas.The patients'age,sex,primary tumor location,and pathological grade were collected.The imaging features including distribution,number,size,⁶⁸Ga-DOTATATE uptake characteristics of the bone metastases and the relationship between SUVmax and size were evaluated.The bone metastases of different primary locations and different grades of NENs were compared.In addition,the sensitivity and accuracy of ⁶⁸Ga-DOTATATE PET/CT,⁶⁸Ga-DOTATATE PET and CT alone in the diagnosis of bone metastases in NENs were compared.Results:32 patients with NENs were diagnosed with bone metastases?17men,15 women;mean±SD age 51.8±12.2 years,range 31–82 years?.Of these,11 patients had gastrointestinal NENs bone metastases,accounting for61.1%of all gastrointestinal NENs;Pancreatic NENs bone metastasis in 9 cases?28.1%,9/32?,accounting for 31.0%?9/29?of all pancreatic NENs patients;pulmonary NENs bone metastasis in 4 cases?12.5%,4/32?,accounting for all57%?4/7?of lung NENs;3 cases of unknown primary lesions?9.4%,3/32?,accounting for 50%?3/6?of all primary unknown lesions;2 cases of thyroid NENs bone metastases?6.3%,2/32?,accounting for 33.3%?2/6?of all thyroid NENs;2 cases of thymic NENs?6.3%,2/32?,accounting for 50%?2/4?of all thymic NENs;1 case of adrenal NENs?3.1%1/32?,accounting for 33.3%?1/3?of the adrenal gland NENs.Among the 32 patients,⁶⁸Ga-DOTATATE PET/CT found a total of 268 lesions,of which 234 were malignant lesions and 34 were benign lesions.There were 234 bone metastases,including 140 vertebrae?74lumbar,51 thoracic,15 cervical?,54 pelvis,23 ribs,14 limbs,and 3 skulls.PET detected 208 bone metastases lesions,SUVmax was 3.1±2.5,26 lesions had no imaging agent uptake,no lesion imaging agent uptake was level 1,164lesions imaging agents were level 2,and 18s lesion imaging agents uptake was level 3;CT detected 192 bone metastases lesions with a diameter of about?1.0±0.4?cm;both PET and CT could measure 166 bone metastases lesions with an average size of?1.1±0.5?cm,SUVmax of 2.9±2.3,and there was a correlation between size and SUVmax?r=0.34,P<0.05?.In all bone metastatic lesions,CT showed osteogenic,osteolytic,mixed,and no abnormal bone density,and the SUVmax was 2.7±2.1,3.7±2.9,1.7±0.1,4.1±3.1,respectively,there were significant differences between the 4 groups of SUVmax?F=4.32,P=0.006?;the pairwise comparison between the groups showed that the SUVmax of the osteogenic group was lower than that of the osteolytic bone destruction group and no abnormal bone density?P=0.04,0.002?.However,there was no statistical difference between the SUVmax and the mixed group?P=0.495?.The skulls,vertebrae,ribs,pelvis,limbs bone metastases SUVmax were 1.3±0,3.2±2.5,3.5±3.0,2.9±2.1,2.9±1.0,respectively,and there was no significant difference between the five groups?F=0.513,P=0.726?.Gastrointestinal,pancreatic,lung,and other primary NENs bone metastases SUVmax were 1.9±0.7,2.1±0.7,5.5±3.1,3.2±2.5,respectively.There were significant differences in SUVmax between the four groups?F=11.247,P=0.000?;Pairwise comparison,the SUVmax of gastrointestinal NENs bone metastases were lower than that of lung and other primary NENs bone metastases SUVmax,the difference were statistically significant?P=0.000,0.001?,but there were not statistically significant compared with pancreatic NENs bone metastases SUVmax?P=0.696?;SUVmax of lung NENs bone metastases were higher than that of pancreas and other NENs bone metastases,the difference was statistically significant?P=0.000,0.000?;there was no significant difference in pancreatic NENs bone metastases and other primary NENs bone metastases?P=0.77?.SUVmax of bone metastases in G1,G2,and G3 NENs were 4.0±1.1,3.3±2.5,and 2.6±2.1,respectively.The differences in SUVmax between the three groups were statistically significant?F=8.345,P=0.000?;The bone metastases SUVmax of G1 were significantly higher than that of G2 and G3,and the differences were statistically significant?P=0.003,0.000?;there was no significant difference between the G2 group and the G3 group?P=0.051?.The sensitivity,specificity,accuracy,positive predictive value,and negative predictive value of⁶⁸Ga-DOTATATE PET,CT,and ⁶⁸Ga-DOTATATE PET for detecting bone metastases in NENs were 88.9%,94.1%,89.6%,99.0%,55.2%;82.1%,67.6%,80.2%,94.6%,34.3%;and 100.0%,97.1%,99.6%,99.6%,100.0%,respectively.Conclusion:?1?The incidence of bone metastases in NENs in this study was 47.3%;?2?NENs in the gastrointestinal,lung,and thymic glands were relatively prone to bone metastases,and bone metastases in pancreatic NENs were relatively low.?3?NENs bone metastases were predominantly vertebrae?especially the lumbar?,followed by the pelvis,ribs,limbs and skulls;Bone metastases are mainly osteogenic,and osteolytic and mixed types are relatively rare;In addition,SUVmax of osteolytic lesions were higher than osteogenic lesions;?4?G1 NENs bone metastases have the highest SUVmax;?5?NENs bone metastases diameter were positively correlated with SUVmax;?6?⁶⁸Ga-DOTATATE PET/CT is a sensitive and specific method for the diagnosis of bone metastases in NENs.