Comparison of 18F-FDG PET and bone scintigraphy in detection of bone metastases of thyroid cancer.

Abstract

UNLABELLED:

We compared the efficacies of (18)F-FDG PET and (99m)Tc-bone scintigraphy for the detection of bone metastases in patients with differentiated thyroid carcinoma (DTC).

METHODS:

We examined 47 patients (32 women, 15 men; mean age +/- SD, 57.0 +/- 10.7 y) with DTC who had undergone total thyroidectomy and were hospitalized to be given (131)I therapy. All patients underwent both whole-body (18)F-FDG PET and (99m)Tc-bone scintigraphy. The skeletal system was classified into 11 anatomic segments and assessed for the presence of bone metastases. Bone metastases were verified either when positive findings were obtained on >2 imaging modalities--(201)Tl scintigraphy, (131)I scintigraphy, and CT--or when MRI findings were positive if vertebral MRI was performed.

RESULTS:

Bone metastases were confirmed in 59 of 517 (11%) segments in 18 (38%) of the 47 study patients. The sensitivities (visualization rate) for bone metastases on a segment basis using (18)F-FDG PET and (99m)Tc-bone scintigraphy were 50 of 59 (84.7%) and 46 of 59 (78.0%), respectively; the difference between these values was not statistically significant. There were only 2 (0.4%) false-positive cases in a total of 451 bone segments without bone metastases when examined by (18)F-FDG PET, whereas 39 (8.6%) were false-positive when examined by (99m)Tc-bone scintigraphy. Therefore, the specificities of (18)F-FDG PET and (99m)Tc-bone scintigraphy were 449 of 451 (99.6%) and 412 of 451 (91.4%), respectively; the difference between these values was statistically significant (P < 0.001). The overall accuracies of (18)F-FDG PET and (99m)Tc-bone scintigraphy were 499 of 510 (97.8%) and 458 of 510 (89.8%), respectively; the difference between these was also statistically significant (P < 0.001).

CONCLUSION:

The specificity and the overall accuracy of (18)F-FDG PET for the diagnosis of bone metastases in patients with DTC are higher than those of (99m)Tc-bone scintigraphy, whereas the difference in the sensitivities of both modalities is not statistically significant. In comparison with (99m)Tc-bone scintigraphy, (18)F-FDG PET is superior because of its lower incidence of false-positive results in the detection of bone metastases of DTC.

• Authors: Shinji Ito, Katsuhiko Kato, Mitsuru Ikeda, Shingo Iwano, Naoki Makino, Masanori Tadokoro, Shinji Abe, Satoshi Nakano, Masanari Nishino, Takeo Ishigaki, Shinji Naganawa
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 48 Issue 6 Pg. 889-95 (Jun 2007) ISSN: 0161-5505 [Print] United States
• PMID: 17504877 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Iodine Radioisotopes
• Radiopharmaceuticals
• Fluorodeoxyglucose F18
• Technetium

Topics

• Adult
• Aged
• Bone Neoplasms (diagnostic imaging, secondary)
• Female
• Fluorodeoxyglucose F18
• Humans
• Iodine Radioisotopes
• Lung Neoplasms (diagnostic imaging, secondary)
• Lymphatic Metastasis
• Male
• Middle Aged
• Positron-Emission Tomography (methods)
• Radiopharmaceuticals
• Technetium
• Thyroid Neoplasms (diagnostic imaging, pathology)