Sonographic features of benign thyroid nodules: interobserver reliability and overlap with malignancy.
OBJECTIVE
To prospectively determine the sonographic findings of nodular hyperplasia of the thyroid, to compare these with reported findings associated with malignancy, and to assess interobserver reliability.


METHODS
Seventy thyroid nodules were scanned, and then biopsies of the nodules were performed under sonographic guidance with fine-needle cytologic analysis; in all cases images were reviewed by 2 experienced radiologists without knowledge of clinical outcome. Findings reported associated with malignancy were specifically assessed. Interobserver agreement between the expert and secondary readers for each finding was calculated by the kappa or weighted kappa statistic and the Fisher exact test of independence.


RESULTS
There were 68 benign and 2 malignant nodules in a population of 63 female and 7 male patients. The mean benign nodule size was 2.9 cm; 60% were solid; 54% were hypoechoic; 59% were microlobulated or macrolobulated; 47% had central vascularity; 24% contained calcifications; and 82% were elliptical in shape. There was very good interobserver reliability for the presence of calcium (kappa = 0.91) and good agreement for the presence and location of vascularity (kappa = 0.75) and the amount of cystic components (kappa = 0.62; all P < .01).


CONCLUSIONS
Sixty-nine percent of benign nodules had at least 1 finding reported previously as associated with malignancy. The interobserver reliability of the sonographic findings was good to very good for 3 of the 5 findings assessed.
Wienke
Jeffrey R
JR
Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Chong
Wui K
WK
Fielding
Julia R
JR
Zou
Kelly H
KH
Mittelstaedt
Carol A
CA
D044963:Biopsy, Fine-Needle; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology; D018615:Ultrasonography, Doppler, Color