Ultrasound (US) elastography, which shows a tissue stiffness estimation by measuring the degree of distortion under the application of an external force, has great potential to diagnose thyroid cancer and reveal thyroid nodules, according to study results published in the August issue of The Journal of Clinical Endocrinology & Metabolism.
The researchers from the Department of Endocrinology at the University of Pisa applied US elastrography to evaluate its ability to differentiate malignant from benign lensions.
The study involved 92 consecutive patients with a single thyroid nodule, who underwent surgery for compressive symptoms or suspicion of malignancy on fine needle aspiration (FNA) cytology.
The detection by US elastography of tissue stiffness ranges from one, indicating greatest elastic strain, to five, indicating no strain—a five-point scale.
US elastography scores one and two were found in 49 cases, and were all benign lesions; score three in 13 cases included one carcinoma and 12 benign lesions; and scores four and five in 30 cases were all carcinomas.
Elasticity scores four to five were highly predictive of malignancy, with a sensitivity of 97 percent, a specificity of 100 percent, a positive predictive value of 100 percent and a negative predictive value of 98 percent.
In comparison, in 32 patients with an indeterminate FNA result, a conventional US was not predictive of malignancy, while an US elastographic score of four to five was observed in six of seven patients (86 percent) with carcinoma on histology, and a score of one to three in all 25 patients with benign lesions.