Can ultrasonography be used to differentiate parathyroid masses abutting the thyroid gland from thyroid masses extending into the parathyroid area?

To determine the ultrasonographic (US) features that could help to distinguish between parathyroid masses abutting the thyroid gland and thyroid masses extending into the parathyroid area. Two blinded readers retrospectively evaluated the US images of 76 histopathologically confirmed parathyroid masses abutting the thyroid gland and 34 thyroid masses extending into the parathyroid area. Maximal diameter, transverse diameter/anterior-posterior diameter (T/AP) ratio, longitudinal diameter/AP diameter (L/AP) ratio, margin, shape, echogenicity, echotexture, and echogenic interface were evaluated and compared between the two groups. Echogenic interface (p2.0 were useful US features for differentiating parathyroid masses abutting the thyroid gland from thyroid masses extending into theparathyroid area.