The Rate and Clinical Significance of Incidental Thyroid Uptake as Detected by Gallium-68 DOTATATE Positron Emission Tomography/Computed Tomography.
Gallium-68 (Ga-68) DOTATATE is a radiolabeled peptide-imaging modality that targets the somatostatin receptor (SSTR), especially subtype 2 (SSTR2). Benign and malignant thyroid tumors have been observed to express SSTR. The aim of this study was to evaluate the frequency and clinical significance of incidental atypical thyroid uptake as detected by Ga-68 DOTATATE positron emission tomography/computed tomography (PET/CT).



A retrospective analysis was conducted of a prospective study in which 237 patients underwent Ga-68 DOTATATE PET/CT as part of a work-up for metastatic and unknown primary neuroendocrine tumors. The types of uptake in the thyroid gland (focal/diffuse) and maximum standardized uptake value (SUVmax) levels were evaluated and compared with the background uptake in the liver and salivary glands.



Of 237 patients, 26 (11%) had atypical thyroid uptake as detected by Ga-68 DOTATATE PET/CT. There were no significant clinical or biochemical variables associated with atypical thyroid uptake. Fourteen (54%) patients had positive focal uptake, and 12 (46%) patients had diffuse uptake. Of the 14 patients with atypical focal uptake, 10 (71%) had thyroid nodules on the corresponding side, as detected by anatomic imaging. Three of 10 patients (21%) were found to have papillary thyroid cancer, and seven (70%) had adenomatoid nodules. Of the 12 patients with diffuse increased uptake, six (50%) had a history of hypothyroidism, five (42%) had chronic lymphocytic thyroiditis, and one (8%) had nontoxic multinodular goiter.



Patients with an incidental focal abnormal thyroid uptake on Ga-68 DOTATATE PET/CT scan should have further clinical evaluation to exclude a diagnosis of thyroid cancer.
1 Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland.
Pavel
P
Nockel
2 PET Department, Clinical Center, National Institutes of Health , Bethesda, Maryland.
Corina
C
Millo
1 Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland.
Xavier
X
Keutgen
3 Diabetes, Obesity, and Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland.
Joanna
J
Klubo-Gwiezdzinska
1 Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland.
Jasmine
J
Shell
1 Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland.
Dhaval
D
Patel
1 Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland.
Naris
N
Nilubol
2 PET Department, Clinical Center, National Institutes of Health , Bethesda, Maryland.
Peter
P
Herscovitch
4 Thoracic and Endocrine Surgery, University Hospitals of Geneva , Geneva, Switzerland .
Samira M
SM
Sadowski
1 Endocrine Oncology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland.
Electron
E
Kebebew
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging*; D005260:Female; D006042:Goiter / Q000000981:diagnostic imaging*; D006801:Humans; D007037:Hypothyroidism / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D000072078:Positron Emission Tomography Computed Tomography; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging*; D055815:Young Adult
D009942:Organometallic Compounds; C513399:gallium Ga 68 dotatate