18F-FDG PET/CT in patients with suspected recurrent or metastatic well-differentiated thyroid cancer.

Full Abstract

PET using 18F-FDG has been shown to effectively detect various types of cancer by their increased glucose metabolism. The aim of this study was to evaluate the use of coregistered PET and CT (PET/CT) in patients with suspected thyroid cancer recurrence.

METHODS:
After total thyroidectomy followed by radioiodine ablation, 61 consecutive patients with elevated thyroglobulin levels or a clinical suspicion of recurrent disease underwent 18F-FDG PET/CT. Of these, 59 patients had negative findings on radioiodine (131I) whole-body scintigraphy (WBS). Fifty-three of the 61 patients had both negative 131I WBS findings and elevated thyroglobulin levels. PET/CT images were acquired 60 min after intravenous injection of 400-610 MBq of 18F-FDG using a combined PET/CT scanner. Any increased 18F-FDG uptake was compared with the coregistered CT image to differentiate physiologic from pathologic tracer uptake. 18F-FDG PET/CT findings were correlated with the findings of histology, postradioiodine WBS, ultrasound, or clinical follow-up serving as a reference. The diagnostic accuracy of 18F-FDG PET/CT was evaluated for the entire patient group and for those patients with serum thyroglobulin levels of less than 5, 5-10, and more than 10 ng/mL.

RESULTS:
Thirty patients had positive findings on 18F-FDG PET/CT; 26 were true-positive and 4 were false-positive. In 2 patients, increased 18F-FDG uptake identified a second primary malignancy. 18F-FDG PET/CT results were true-negative in 19 patients and false-negative in 12 patients. The overall sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 68.4%, 82.4%, and 73.8%, respectively. The sensitivities of 18F-FDG PET/CT at serum thyroglobulin levels of less than 5, 5-10, and more than 10 ng/mL were 60%, 63%, and 72%, respectively. Clinical management changed for 27 (44%) of 61 patients, including surgery, radiation therapy, or chemotherapy.

CONCLUSION:
Coregistered 18F-FDG PET/CT can provide precise anatomic localization of recurrent or metastatic thyroid carcinoma, leading to improved diagnostic accuracy, and can guide therapeutic management. In addition, the findings of this study suggest that further assessment of 131I WBS-negative, thyroglobulin-positive patients by 18F-FDG PET/CT may aid in the clinical management of selected cases regardless of the thyroglobulin level.

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Author information

Author/s: Shammas, Amer (A); Degirmenci, Berna (B); Mountz, James M (JM); McCook, Barry M (BM); Branstetter, Barton (B); Bencherif, Badreddine (B); Bencherif, Badreddine B (BB); Joyce, Judith M (JM); Carty, Sally E (SE); Kuffner, Haruko A (HA); Avril, Norbert (N);

Affiliation: Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.

Journal and publication information

Publication Type: Journal Article

Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med), published in United States. (Language: eng)

Reference: 2007-Feb; vol 48 (issue 2) : pp 221-6

Dates: Created 2007/02/01; Completed 2007/04/06; Revised 2007/04/09;

PMID: 17268018, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

Comments and Corrections

ErratumIn: J Nucl Med. 2007 Mar;48(3):412. (Note: Bencherif, Badreddine B [corrected to Bencherif, Badreddine])

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adolescent
Adult
Aged
Aged, 80 and over
False Negative Reactions
False Positive Reactions
Female
Fluorodeoxyglucose F18 - diagnostic use
Humans
Image Processing, Computer-Assisted

Iodine Radioisotopes - diagnostic use
Male
Middle Aged
Neoplasm Metastasis
Neoplasm Recurrence, Local
Radiopharmaceuticals - diagnostic use
Thyroglobulin - analysis
Thyroid Gland - pathology; radiography; radionuclide imaging
Thyroid Neoplasms - pathology; radiography; radionuclide imaging
Whole Body Imaging

Associated Chemicals: Iodine Radioisotopes (0) ; Radiopharmaceuticals (0) ; Fluorodeoxyglucose F18 (63503-12-8) ; Thyroglobulin (9010-34-8)

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