Jason David Iannuccilli BA, Presenter: Nothing to Disclose

John J. Cronan MD, Abstract Co-Author: Nothing to Disclose

Jack M. Monchick MD, Abstract Co-Author: Nothing to Disclose

The aim of this study was to correlate US and color Doppler characteristics of thyroid nodules with the results of US-FNA biopsy to establish the relative importance of these features in predicting risk for malignancy.

We retrospectively analyzed the sonographic features of 34 malignant and 36 benign thyroid nodules with respect to size, echogenicity, echostructure, shape, border, calcification, and internal vascularity. Individual features, as well as combinations of features were analyzed for their correlation with benign or malignant pathology. A meta-analysis of several previously proposed methods for distinguishing between benign and malignant nodules using US criteria was also performed to determine their sensitivity and specificity in predicting nodule pathology within our study data.

The prevalence of malignancy in our study population was estimated to be almost 5.33%. Intra-group comparison of US features among benign and malignant nodules resulted in the identification of intrinsic calcification as the only statistically significant predictor of malignancy (35.3% sensitive, 94.4% specific;p < 0.005). Presence of a 'snowstorm' pattern of calcification was 100% specific for malignancy. Neither echogenicity, echostructure, shape, border classification, or grade of internal vascularity showed any significant difference between benign and malignant nodules in this study. Various combinations of features previously suggested to be significant predictors of malignancy were also analyzed and shown to have very little sensitivity or specificity in predicting benign or malignant pathology among thyroid nodules in our study population.

It appears as though the presence of intrinsic micro-calcification is the only statistically reliable criterion upon which to base increased suspicion for malignancy in incidentally-detected thyroid nodules. Clinical recommendation is therefore to biopsy all nodules larger than 1.0 cm in maximal diameter, regardless of sonographic appearance. Smaller nodules should be biopsied if they demonstrate the presence of intrinsic micro-calcification, particularly if calcifications resemble a ‘snowstorm’ appearance on US examination.

Iannuccilli, J, Cronan, J, Monchick, J, Thyroid Ultrasound: A Need For Biopsy.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4406343.html