Positron emission tomography (PET) is a highly sensitive and low invasive technology for cancer biological imaging. Integrated PET/computed tomography (PET/CT) cameras combine functional and anatomical information in a synergistic manner that improves diagnostic interpretation. The role of 18F FDG PET/CT in differentiated thyroid cancer (DTC) is well established, particularly in patients presenting with elevated thyroglobulin (Tg) levels and negative radioactive iodine scan. This review presents the evidence supporting the use of 18F FDG PET/CT throughout the diagnosis and management of thyroid cancer, and provides suggestions for its clinical uses.
ObjectiveTo evaluate whether thyroglobin (Tg) value by radioimmunoassay (Tg-RIA) can be used as a complementary marker in differentiated thyroid cancer (DTC) patients, as serum Tg value is the key marker for the follow-up of patients with DTC, and endogenous antithyroglobulin (TgAb) interferes with serum Tg value by immunometric assay (Tg-IMA). MethodsFifty-five in-hospital patients with DTC after total thyroidectomy and 131I ablation during September and December 2012 were enrolled. Tg-IMA tests and Tg-RIA tests were performed separately. Diagnostic criteria about relapse, metastasis or disease-free status of thyroid carcinoma were established by serum Tg, diagnostic whole body scan (D-WBS), neck ultrasonography, chest CT and patients' history. ResultsTwo DTC patients showed false negative Tg-IMA and true positive Tg-RIA. Five patients had false negative Tg-RIA because of low sensitivity of RIA. Four patients with weak positive Tg-IMA (1.07-4.09 μg/L) required follow-up. Among the 11 DTC patients with strong TgAb positivity (>115 kU/L), two patients with positive Tg-IMA and positive Tg-RIA received second operation or radioiodine therapy, seven patients had positive Tg-RIA and negative Tg-IMA. Five of the seven patients with strong positive TgAb needed further follow-up, and two of them received radioiodine therapy. ConclusionTg value with radioimmunoassay is a complementary marker to find false negative Tg-IMA in follow-up patients with DTC.
The aim of this study is to analyze the concordance between EDV, ESV and LVEF values derived from 18F-FDG PET, GSPECT and ECHO in patients with myocardial infarction. Sixty-four patients with coronary artery disease (CAD) and myocardial infarction were enrolled in the study.. Each patient underwent at least two of the above mentioned studies within 2 weeks. LVEF、 EDV and ESV values were analyzed with dedicated software. Statistical evaluation of correlation and agreement was carried out EDV was overestimated by 18F-FDG PET compared with GSPECT [(137.98±61.71) mL and (125.35±59.34) mL]; ESV was overestimated by 18F-FDG PET (85.89±55.21) mL and GSPECT (82.39±55.56) mL compared with ECHO (68.22±41.37) mL; EF was overestimated by 18F-FDG PET (41.96%±15.08%) and ECHO (52.18%±13.87%) compared with GSPECT (39.75%±15.64%), and EF was also overestimated by 18F-FDG PET compared with GSPECT. The results of linear regression analysis showed good correlation between EDV, ESV and LVEF values derived from 18F-FDG PET, GSPECT and ECHO (r=0.643-0.873, P=0.000). Bland-Altman analysis indicated that 18F-FDG PET correlated well with ECHO in the Left ventricular function parameters. While GSPECT correlated well with 18F-FDG PET in ESV, GSPECT had good correlation with Echo in respect of EDV and EF; whereas GSPECT had poor correlation with PET/ECHO in the remaining left ventricular function parameters. Therefore, the clinical physicians should decide whether they would use the method according to the patients' situation and diagnostic requirements.
ObjectiveTo compare the diagnostic efficacy of serum thyroglobulin (Tg), diagnostic 131I whole-body scan (D-WBS), neck ultrasound for diagnosing metastasis and recurrence of differentiated thyroid carcinoma (DTC). MethodsFrom May to June 2011, fifty follow-up DTC patients were collected retrospectively 6 months or more after 131I ablation therapy following total-thyroidectomy or near-total thyroidectomy. The diagnostic standard for DTC metastasis and relapse were based on serum Tg, D-WBS, neck ultrasound and chest CT. Diagnostic 2 by 2 table was employed for calculating the sensitivity, specificity, accuracy of the methods. ResultsThe sensitivity, specificity, accuracy, positive predictive value, negative predictive value of TgIMA and D-WBS parallel experiments were 100.0%, 92.9%, 96.0%, 91.7%, and 100.0% respectively. ConclusionTgIMA combined with D-WBS parallel test in diagnosis of DTC metastasis and recurrence has the highest accuracy.