Positive predictive values of sonographic features of solid thyroid nodule

Hong, Yoo Jin; Son, Eun Ju; Kim, Eun-Kyung; Kwak, Jin Young; Hong, Soon Won; Chang, Hang-Seok

doi:10.1016/j.clinimag.2008.10.034

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Volume 34, Issue 2 , Pages 127-133, March 2010

Positive predictive values of sonographic features of solid thyroid nodule☆

Yoo Jin Hong
- Department of Diagnostic Radiology, The Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea
Eun Ju Son
- Department of Diagnostic Radiology, The Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea
- Corresponding author. Department of Radiology, Yonsei University, College of Medicine, Gangnam Severance Hospital, 146-92 Dogok-Dong, Kangnam-Gu, Seoul 135-270, South Korea. Tel.: +82 2 2019 3510; fax: +82 2 3462 5472.
Eun-Kyung Kim
- Department of Diagnostic Radiology, The Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea
Jin Young Kwak
- Department of Diagnostic Radiology, The Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea
Soon Won Hong
- Department of Diagnostic Pathology, The Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea
Hang-Seok Chang
- Department of General Surgery, The Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea

Received 1 August 2008; accepted 10 October 2008. published online 14 September 2009.

Abstract

Aim

The purpose of this study was to assess the positive predictive value of the suspicious sonographic features of solid nodules of the thyroid.

Materials and methods

After approval by our institutional review board, we evaluated 594 sonographically detected nodules on which fine needle aspiration biopsy had been performed from January to December 2005. Among these, pure cystic lesions and inadequate pathologic results were excluded. The remaining 530 solid thyroid nodules were analyzed by two radiologists. Each lesion was classified based on four sonographic features that suggested malignancy: microcalcifications; an irregular or microlobulated margin; marked hypoechogenicity; and a shape that was taller than wide. The sensitivity, specificity, positive predictive value, and negative predictive value of the each sonographic feature were calculated.

Results

Final pathologic results showed that 97 (18.3%) of 530 nodules were malignant. The positive predictive values for malignancy in each sonographic feature were microcalcifications, 38.6% (39/101); an irregular or microlobulated margin, 28.2% (70/248); marked hypoechogenecity, 49.4% (38/77); taller than wide shape, 59.8% (49/82). In terms of relative risk, microcalcification [P<.01, relative risk (RR)=3.115, 95% CI: 1.724–5.628], hypoechogenecity (P<.01, RR=2.510, 95% CI: 1.290–4.881). The shape of nodule which was taller than wide (P<.01, RR=7.624, 95% CI: 4.156–13.986) revealed the highest predictive sonographic finding suggesting malignancy. However, margin is the least significant feature of detection of thyroid malignancy (P=.27, RR=1.395, 95% CI: 0.777–2.505).

Conclusion

The three sonographic features of solid thyroid nodule, that is, microcalcifications, marked hypoechogenecity, and a taller than wide shape are meaningful findings in the diagnosis of thyroid malignancy. The shape that was taller than wide was the most reliable sonographic feature for predicting malignancy.

Keywords: Solid thyroid nodule, Malignancy, Ultrasonography