Rick Ian Feld MD, Presenter: Research support, Hitachi, Ltd

Daniel Arthur Merton, Abstract Co-Author: Advisory Board, Bracco Group Equipment support, SonoSite, Inc

Nobuhiro Fukunari MD,PhD, Abstract Co-Author: Nothing to Disclose

Kumi Tanaka MD, Abstract Co-Author: Nothing to Disclose

Cem Yucel MD, Abstract Co-Author: Nothing to Disclose

Flemming Forsberg PhD, Abstract Co-Author: Equipment support, Toshiba Corporation Equipment support, Siemens AG Research collaboration, General Electric Company Research collaboration, Ultrasonix Medical Corporation

To determine if the combination of grayscale ultrasound imaging (US), color Doppler imaging (CDI) and elastography can improve the characterization of thyroid nodules as benign or malignant.

Patients from two different institutions, one in the United States and one in Japan, scheduled either for fine needle biopsy or surgery of a suspicious thyroid nodule were evaluated with US, CDI and elastography.  All examinations were performed on an EUB-8500 scanner (Hitachi Medical Corporation, Tokyo, Japan).  A total of 100 nodules were evaluated, 50 from each institution.  Still images and video clips were digitally recorded for interpretation by 4 independent, experienced, blinded readers.  Each nodule was graded in random order, by all 4 readers, on a 5 point scale (definitely benign to definitely malignant), based on each US mode separately and then based on all three US modes, combined.  Based on final pathology, sensitivites, specifities, and accuracies were calculated and compared, using receiver operating characteristics (ROC) analysis and McNemar's test for correlated proportions.

Pathology proved 81 benign nodules and 19 malignancies.  Whe comparing the results of each reader, for one reader, the highest accuracy was achieved with elastography, 77%, and with all three modes combined, 83%, which was significant (p=0.005), however for the other three readers, there was no significant difference in the three modes.  Whe comparing the results of each mode, one reader achieved highest accuracy with color Doppler (90%), which was significant (p<0.002), one reader was more accurate than the other readers in gray scale (89%) (p=0.002), three readers were more accurate than the fourth in elastography (p<0.05), and two readers were more accurate than a third using all three modes (p<0.01).

A combination of gray scale ultrasound, color Doppler imaging and elastography has the potential to improve the characterization of thyroid nodules as benign or malignant.  However, there remains high inter-observer variability. More research if necessary to determine the ultimate utility of elastography.

Characterization of thyroid nodule as benign or malignant in order to determine the necessity to proceed with biopsy.

Feld, R, Merton, D, Fukunari, N, Tanaka, K, Yucel, C, Forsberg, F, Thyroid Nodule Evaluation with Grayscale Ultrasound, Color Doppler, and Elastography: An International Multicenter Trial.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6022408.html