Shigeki Nagamachi MD, PhD, Presenter: Nothing to Disclose

Hideyuki Wakamatsu MD, Abstract Co-Author: Nothing to Disclose

Syogo Kiyohara, Abstract Co-Author: Nothing to Disclose

Seigo Fujita MD, Abstract Co-Author: Nothing to Disclose

Kiyohisa Kamimura MD, Abstract Co-Author: Nothing to Disclose

Shigemi Futami, Abstract Co-Author: Nothing to Disclose

Ryuichi Nishii MD, PhD, Abstract Co-Author: Nothing to Disclose

Shozo Tamura MD, PhD, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

The aim of this study was to evaluate the clinical significance of FDG PET/CT in predicting prognosis of differentiated thyroid cancer (DTC) and to compare the results with those obtained from chest and neck DWI or Tc-99m MIBI scintigraphy.

In 65 patients (22 men, 43 women; 27-71yr; mean age, 55.3y) with differentiated thyroid cancer (DTC) after total thyroidectomy, whole-body FDG PET/CT, Tc-99m-MIBI scintigraphy and chest and neck diffusion weighted MRI (DWI) was performed before I-131 therapy. We defined as ‘The poor prognoses by referencing either (1) or (2) condition. (1)The value of serum thyroglobulin (Tg) re-increased during follow up periods after I-131 therapy (2) The tumor volume or number of lesion’s increased during follow up periods. Patients without above the both conditions were defined as ‘The good prognoses. Mean follow up periods after 131I-therapy was 3.1±0.8 years. We compared the possible influencing factors, age, gender, Tg level, therapy number, histological differentiation, stage of the disease, between the two groups.

In the correlation analysis with prognostic capability, gender (male), age (>45) and histological differentiation (poor) were also significant determinant for the poor prognoses. In addition, FDG positivity, Tc-99m-MIBI positivity and DWI high signal intensity were statistically significant prognostic determinant for the poor prognoses respectively.

In the prediction of DTC’s prognosis, either FDG positivity or Tc-99m-MIBI positivity or existence of DWI high signal intensity lesions tended to be poor prognosis. Because DWI provides similar information with FDG PET/CT, the combination of IWBS and DWI will be the alternative method for monitoring after I-131 therapy and for predicting prognosis.

Because FDG PET/CT, Tc-99m-MIBI and DWI provide similar information regarding prognosis in DTC, we may choose relevant modality in accordance with the institute circumstance.  

Nagamachi, S, Wakamatsu, H, Kiyohara, S, Fujita, S, Kamimura, K, Futami, S, Nishii, R, Tamura, S, et al, 0, Comparison of Prognostic Capability among I-131 Whole Body Scintigraphy, FDG-PET/CT, Tc-99m-MIBI Scintigraphy, and Diffusion-weighted MR in Postoperative Thyroid Cancer.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8011185.html