Thyroid nodule ultrasound reports in routine clinical practice provide insufficient information to estimate risk of malignancy.

Purpose: Ultrasonographic characteristics of thyroid nodules play an important role in estimating the risk of malignancy (ROM). Guidelines mandate all thyroid nodules be characterized by six key ultrasonographic features to estimate the ROM. Our objective was to evaluate how frequently these characteristics were identified by radiologists and the ensuing utility to estimate ROM.

Methods: We retrospectively reviewed 1930 consecutive diagnostic thyroid ultrasound reports from a large community radiology practice. A total of 1339 individual patients were found to have one or more thyroid nodules. Each report was analyzed for six key ultrasonographic features. A utility score (UtS) was calculated (range 0-6) with a single point given for a comment on each feature.

Results: Of the 1339 patients, 75% of the studies reported more than one nodule (mean number of nodules = 3.4). Mean maximal diameter of the largest nodule per patient = 1.8 cm. The mean UtS was 2.57. Nodule size did not influence the UtS.: Nodule <1 cm (UtS: 2.53), 1-2 cm (UtS: 2.68) and >2 cm (UtS: 2.49). We believe a UtS of four or greater is needed to confidently estimate ROM: we found this in 13.7% of reports.

Conclusions: Our retrospective analysis of a large number of consecutive thyroid ultrasound reports in routine clinical practice suggests that the vast majority provide insufficient information to allow the clinician to risk stratify the nodules by estimating the ROM. This could lead to both over-diagnosis and over-treatment of benign/indolent thyroid lesions or under-diagnosis of clinically important thyroid cancers.