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Paper 27 (0830)
PRE-OPERATIVE EVALUATION OF THYROID NODULES WITH 18FDG-PET/CT
Background: Fine needle aspiration (FNA) is currently the critical step in determining which thyroid nodules require surgical resection. Unfortunately, the Results: are often indeterminate leading to unnecessary surgery for benign lesions in many cases. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) has become an important tool in the post-operative follow up of differentiated thyroid cancer. However, the utility of this imaging modality in the pre-operative assessment of thyroid nodules is not yet established. This study was designed to determine whether 18FDG-PET/CT improves the preoperative diagnosis of thyroid nodules.
The 26th Annual Meeting of the American
Association of Endocrine Surgeons
April 3rd- 5th,2005 - Paradisus Riviera Cancun.
F. Grant, MD; J. Mitchell, MD; A. Evenson, MD; A. Parker, MD, PhD,
P. Hasselgren, MD, PhD; MD; S.Parangi, MD
Beth Israel Deaconess Medical Center, Boston, MA
Methods: A total of 27 patients with 46 lesions were examined using fine needle aspiration biopsy (FNA) and PET/CT prior to surgical resection of thyroid nodules. Images were obtained using a GE Discover LS PET/CT scanner one hour after the intravenous administration of 18FDG. Standard uptake values (SUV's) were calculated for regions of increased 18FDG uptake. CT scans were evaluated to identify thyroid pathology. Final pathologic diagnoses from operative specimens were compared to PET/CT Results: to determine the sensitivity and specificity of the PET/CT.
Results: Of the 46 lesions examined, 13 were malignant (all papillary carcinomas) and 33 were benign. Of the 13 malignant lesions, 9 were 18FDG-avid, for a sensitivity of 69%. The 4 malignant lesions missed by 18FDG-PET/CT included 2 microscopic cancers = 0.1cm, and 2 papillary cancers in a patient with thyroid metastases from renal cell carcinoma. Of the 33 benign lesions, 24 were 18FDG-cold, for a specificity of 73%. The positive predictive value of 18FDG-PET/CT was 50%, while the negative predictive value was 86%.
Conclusions: The evaluation of thyroid nodules by 18FDG-PET/CT provides a high negative predictive value for malignancy, making this a potentially useful tool in the pre-operative evaluation of thyroid nodules with indeterminate FNA. Additionally, information from pre-operative 18FDG-PET/CT may facilitate post-operative follow up of these patients. However, given the failure to detect one large cancer in this series, further studies with larger sample sizes are needed to determine its true efficacy.