| Ojectives:Presence of high-affinity somatostatin (SST) receptors in most endocrine tumor cells allow in vivo scintigraphic visualization of these neoplasms after intravenous administration of a radionuclide-labeled somatostatin analog.68Ga-1,4,7,10-tetraazacyclododecane-N,N’,N",N’"-tetraacetic acid-D-Phe1,Tyr3-octreotate (DOTATATE), a novel selective somatostatin receptor2PET ligand, is at present the progressing used substance for imaging of the SST receptor expression in vivo. Our study is aim to investigate the clinical value of DOTATATE in pituitary adenoma and residual pituitary gland.Patients and Methods:A total of62patients with pituitary adenoma were recruited, including17adrenocorticotropic hormone-secreting adenoma (ACTH adenoma),19growth hormone-secreting adenoma (GH adenoma),7prolactin-secreting adenoma and19non-functioning adenoma (NF adenoma). The finial diagnosis was based on the histology and clinical information. The tumor volume, the maximum and mean of standardized uptake value (SUVmax/mean) and the active tumor volume (ATV), which is obtained by SUVmean×tumor volume,were established in all tumors. Twenty-one patitents of34with full blood serum test and clear pituitary gland were divided into two groups (normal function group and hypo-function group) for comparison.Results:Tumor volume of non-secreting adenoma is higher than that of secreting adenoma((U=168.5,p=0.0003), whereas SUVmax and SUVmean show no significant statistical difference between them(U=311,p=0.13and U=331.5,p=0.24).Tumor volume of GH adenoma and PRL adenoma is higher than that of ACTH adenoma and the SUVmax/mean among these tumors is equivalent(H=2.5, p=0.27;H=2.6, p=0.28). A strong correlation between the ATV and the serum PRL level (n=7, r=0.96,p=0.003) and IGF-1level were found (n=19, r=0.96,p<0.0001). No correlation was found between the ATV and24-h urinary cortisol level. In21patients, DOTATATE uptake in pituitary gland in normal function group was significant higher than these in hypo-function group (U=10.0,p=0.002). According to the ROC, when a SUVmax of4.9was used as an optimal criterion for predicting hypo-function, the diagnostic sensitivity, specificity, and accuracy were88.8%,91.6%, and95.2%, respectively.Conclusions:The DOTATATE uptake in various pituitary adenomas is equivalent. Statistical analysis of the data could find the correlation between endocrine activity of the pituitary tumors and the scintigraphically proven somatostatin receptor2expressions in vivo. DOTATATE in combination with cutoff value of SUVmax might be helpful in evaluating pituitary preservation function clinically. Objectives:Detection of residual pituitary gland and pituitary recurrent tumor after the pituitary adenoma resection may be helpful for a second and more operation. Although F-FDG PET/CT can differentiate recurrent pituitary adenoma from postoperative scar formation, it is hard to identify the residual pituitary gland. This study is aim to distinguish residual pituitary gland and pituitary tumor from postoperative remodeling tissueby use of68Ga-1,4,7,10-tetraazacyclododecane-N,N’,N",N’"-tetraacetic acid-D-Phe,Tyr3-octreotate (DOTATATE) in combination with18F-fluorodeoxyglucose (FDG).Methods:Thirty-five patients with pituitary tumors were evaluated postoperative by DOTATATE and FDG, either because of biological evidence of active residual tumor or MRI demonstration of non-functional adenoma growth. We studied25secreting adenomas and ten non-functional adenomas, which underwent both FDG PET/CT and DOTATATE PET/CT within one week. The final diagnosis was based on the pathology and review of operative notes.Results:DOTATATE uptake in pituitary gland (5.80±1.23)was higher than that in pituitary adenoma(3.30±1.00) and scar tissue(1.08±0.33)(U=23.0,p=0.0003and U=0.00,p=0.0006).FDG uptake in pituitary adenoma(8.06±2.21) was higher than that in pituitary gland(2.96±0.92) and scar tissue(1.87±0.99)(U=11.0, p=0.001and U=10.0, p=0.001)。In pituitary gland, DOTATATE uptake was higher than FDG uptake (5.80±1.23vs2.96±0.92,p=0.0005),DOTATATE/FDG>1.In pituitary adenoma, FDG uptake was higher than DOTATATE uptake (8.06±2.21vs3.30±1.00, p=0.01),DOTATATE/FDG is0.60±0.31.In33patients, DOTATATE in combination with FDG detected pituitary gland confirmed by operative notes and MRI.In13out of these, MRI did not differentiate residual pituitary gland from pituitary tumor and scar formation. In another group of20patients, both DOTATATE in combination with FDG and MRI detected residual pituitary gland. In two cases, neither MRI nor DOTATATE detected residual pituitary gland. For recurrent tumor, DOTATATE in combination with FDG detected abnormally hypermetabolic tissue confirmed by histopathology in34patients. In14out of these, MRI did not different residual tumor from scar formation. In another group of20patients, both MRI and DOTATATE in combination with FDG detected recurrent tumor. In one case, neither MRI nor DOTATATE in combination with FDG detected recurrent tumor. Additionally, DOTATATE uptake in residual tumor was variable:25showed moderate to intense uptake (SUV>4.0),9showed minimal uptake (SUV<4.0) and1showed void uptake.Conclusion:Different degree of uptake of DOTATATE and FDG PET/CT in residual pituitary gland and pituitary adenoma indicated that combining analysis of DOTATATE and FDG PET/CT might be of clinical value in differentiating this tissue and may be a sensitive technique complementary to MRI. |
PDF Full Text Request