The aim of this study was to compare the diagnostic and prognostic values of 99mTc-MDP-planar bone scintigraphy (99mTc-MDP-BS), 131I single-photon emission computed tomography/computed tomography (131I-SPECT/CT) and 18F-fluorodeoxyglucose (18F-FDG)-PET/CT for the detection of bone metastases from differentiated thyroid cancer (DTC).
Eighty patients with DTC with suspected bone metastases from DTC were retrospectively analysed. All patients were examined with 99mTc-MDP-BS, 131I-SPECT/CT and 18F-FDG-PET/CT, with a maximum interval of 2 months between scans. The diagnostic performances of 99mTc-MDP-BS, 131I-SPECT/CT and 18F-FDG-PET/CT were investigated and compared. Univariate and multivariate analyses were carried out to evaluate the effects of variables on the survival of patients.
Out of the 80 patients with 148 foci, 43 with 106 foci were diagnosed as being true positive for bone metastases from DTC. In patient-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of 99mTc-MDP-BS were 79.07, 83.78, 85.00, 77.50 and 81.25%, respectively; those of 131I-SPECT/CT were 93.02, 97.30, 97.56, 92.31 and 95.00%, and those of 18F-FDG-PET/CT were 86.05, 94.59, 94.87, 85.36 and 87.80%, respectively. In lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of 99mTc-MDP-BS were 72.64, 73.81, 87.50, 51.67 and 72.97%, respectively; those of 131I-SPECT/CT were 92.45, 97.62, 98.99, 83.67 and 93.92%, and those of 18F-FDG-PET/CT were 85.85, 88.10, 94.50, 71.15 and 86.49%, respectively. Comparing the receiver-operating characteristic area using the McNemar test, both 131I-SPECT/CT and 18F-FDG-PET/CT were found to be superior to 99mTc-MDP-BS for the detection of bone metastases from DTC in patient-based and lesion-based analyses (P<0.05). Patient-based analysis showed that there were no significant differences between 131I-SPECT/CT and 18F-FDG-PET/CT (P=0.087) but lesion-based analysis revealed that 131I-SPECT/CT was superior to 18F-FDG-PET/CT (P=0.002). For the association between these image patterns and the prognosis of DTC patients, 18F-FDG positivity was the factor predicting a poor prognosis.
131I-SPECT/CT and 18F-FDG-PET/CT demonstrated high diagnostic performance in detecting bone metastases from DTC. 99mTc-MDP-BS might be completely replaced by 131I-SPECT/CT in combination with 18F-FDG-PET/CT in the management of DTC patients with bone metastases. 18F-FDG-PET/CT positivity was an independent factor associated with poor prognosis.
Department of Nuclear Medicine, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
Correspondence to Quan-Yong Luo, MD, Department of Nuclear Medicine, Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, 600 Yishan Road, 200233 Shanghai, People’s Republic of China Tel: +86 21 64369181; fax: +86 21 64701361; e-mail: firstname.lastname@example.org
Received February 3, 2012
Accepted August 2, 2012