Tetsuya Inoue MD, Presenter: Nothing to Disclose

Tohru Shiga MD, PhD, Abstract Co-Author: Nothing to Disclose

Yuya Onodera MD, Abstract Co-Author: Nothing to Disclose

Koichi Morita, Abstract Co-Author: Nothing to Disclose

Keiichiro Yoshinaga, Abstract Co-Author: Nothing to Disclose

Kakuko Kanegae MD, Abstract Co-Author: Nothing to Disclose

Kenji Hirata, Abstract Co-Author: Nothing to Disclose

Shozo Okamoto MD, Abstract Co-Author: Nothing to Disclose

Nagara Tamaki MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

We have reported that the combination of F-18 FDG-PET (FDG-PET) and I-131 scinitigraphy is the method of choice for detecting metastatic thyroid cancer after total thyroidectomy. Diffusion-weighted image (DWI) has recently reported to be useful in several cancers. The aim of the present study is to evaluate the clinical significance of whole-body DWI in differentiated thyroid cancer and to compare the results with those obtained by FDG-PET and I-131 scinitigraphy.

This study included 25 patients with differentiated thyroid cancer (20 cases of papillary cancer, 5 cases of follicular cancer) after total thyroidectomy. An overall histological or clinical evaluation was performed, including pathological findings after surgical resection, FNA, serum thyroglobulin level, sonography, conventional MRI and CT, to allow a comparison with functional imaging results for each patient. Metastatic lesions were divided into four areas: neck, lung, bone and other. Multiple lesions in one area were defined as one lesion.

Histological or clinical study confirmed 34 metastatic lesions. Of 34 lesions, 28 lesions (82%) were detected either by whole-body DWI, FDG-PET or I-131 scinitigraphy. Whole-body DWI detected only 15 lesions (44%). Twenty five lesions (74%) and 14 lesions (41%) were diagnosed by FDG-PET and I-131 scinitigraphy, respectively. There were no lesions that were detected in whole-body DWI without abnormality in FDG-PET. The combination of whole-body DWI and FDG-PET, and that of whole-body DWI and I-131 scinitigraphy detected 25 lesions (74%) and 22 lesions (65%), respectively. On the other hand, the combination of FDG-PET and I-131 scinitigraphy detected 28 lesions (82%).

Whole-body DWI was not superior to FDG-PET in diagnosis of recurrent or metastatic thyroid cancer. The combination study of FDG-PET and I-131 scinitigraphy is still a method of choice for detecting metastatic thyroid cancer after total thyroidectomy.

The combination study of FDG-PET and I-131 scinitigraphy is still a method of choice for detecting metastatic thyroid cancer after total thyroidectomy.

Inoue, T, Shiga, T, Onodera, Y, Morita, K, Yoshinaga, K, Kanegae, K, Hirata, K, Okamoto, S, Tamaki, N, et al, , et al, , Comparison of Whole Body DWI,F-18 FDG-PET, and I-131 Scintigraphy in Diagnosis of Metastatic Thyroid Cancer.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5006640.html