Endocrine Abstracts

Parathyroid adenomas are situated nearby thyroid gland or even intrathyroidal and could be confounded with thyroid nodules. Ultrasound elastography is a noninvasive technique that explores the elasticity and stiffness of different tissue.

Aim: To assess the value of 2D-shear wave elastography (2D-SWE), a new technique of sonoelastography, in the differentiation of parathyroid adenomas from thyroid nodules.

Subjects and methods: We studied 22 cases (F/M=19/3) with primary or tertiary hyperparathyroidism, diagnosed by specific tests, and 32 patients (F/M=28/4) with 52 thyroid nodules. Between patients with hyperparathyroidism, 20 cases presented a primary forms and two patients presented tertiary hyperparathyroidism due to chronic renal disease. In all the patients with hyperparathyroidism, the parathyroid lesions were detected by using ultrasound and at least another imaging technique (parathyroid scintigraphy or magnetic resonance imaging), postoperative pathology confirming the diagnosis. In cases with thyroid nodules, 13 lesions were malignant (25.5%). All the measurements were performed with an Aixplorer system (Supersonic Image Inc. France), using a linear high-resolution transducer 15-4 MHz. For each parathyroid lesion or thyroid nodule, three elastographic determinations were performed and a mean value of stiffness was quantitatively measured and expressed in kilopascals (kPa).

Results: The mean stiffness for parathyroid lesions was 10.18±4.85 kPa (6.6–15.9). In benign thyroid nodules the mean stiffness was 21.78±14.45 kPa and in malignant thyroid lesions −38.90±23.03 kPa, P=0.0119. The statistical analysis indicates that the mean stiffness assessed by 2D-SWE in parathyroid adenomas was significantly lower than in benign nodules (P<0.0001) or in malignant lesions (P=0.0004).

Conclusion: This new technique can quantitatively evaluate the stiffness of parathyroid adenomas, which was significantly lower when compared to that of thyroid nodules. These data indicate that the measurement of stiffness by 2D-SWE might be a new method that can help in preoperative localization of parathyroid adenomas.