Real-time shear wave ultrasound elastography (SWE) is a new technique, which evaluates elasticity and stiffness of the different structure.
Aim: To determine the values of the elasticity index (EI) measured by SWE in parathyroid gland pathology and to establish if this investigation can offer information to help in the preoperative localization of the parathyroid adenoma.
Subjects and Methods: We studied 50 cases (F/M = 42/8), 10 with primary or tertiary hyperparathyroidism diagnosed by specific tests, and 40 healthy volunteers. Between patients with hyperparathyroidism, 8 cases presented a parathyroid adenoma and two patients presented tertiary hyperparathyroidism due to chronic renal disease. In all these patients parathyroid adenomas were detected by using ultrasound and at least another imaging technique (parathyroid scintigraphy or magnetic resonance imaging). In six cases surgical removal of parathyroid adenomas was performed and the pathological results confirm the diagnosis. For each parathyroid lesion two or three elastographic determinations were performed and a mean value was calculated and expressed in kilopascals (kPa).
In healthy volunteers, thyroid parenchyma was evaluated, in order to compare the elasticity index of normal thyroid tissue with those of parathyroid adenomas. 3 elastography determinations were performed for each thyroid lobe and a mean value was calculated and expressed in kPa.
All the measurements were performed with an Aixplorer system (Supersonic Image Inc. France), using a linear high-resolution transducer 15-4 MHz.
Results: In 10 patients with primary or tertiary hyperparathyroidism, 11 parathyroid adenomas were evaluated by SWE. The mean EI for parathyroid lesions was 9.2±4.8 kPa (4.2-18.2).
In healthy volunteers the mean EI was similar in the right and left thyroid 19.9±6.6 kPa vs. 19.3±6.6 kPa, p=0.69, respectively. The statistical analysis indicates that the mean EI assessed by SWE in parathyroid adenomas was significantly lower than in nearby normal thyroid parenchyma: 9.2±4.8 kPa vs. 19.6±6.2 kPa, p<0.0001.
Conclusion: This new technique can evaluate the EI of parathyroid adenomas, which was significantly lower than EI of normal thyroid parenchyma. This preliminary study indicates that the determination of EI by SWE might be a new method that can help in preoperative localization of parathyroid adenomas.
