Preoperative localisation of parathyroid adenomas using ultrasound-guided methylene blue dye injection

Introduction
Primary hyperparathyroidism is mainly caused by parathyroid adenomas. Preoperative imaging can be performed using different imaging modalities, e.g. ultrasound (US), radionuclide scanning, magnetic resonance imaging, and computed tomography, often used in combination. Currently, US-guided blue dyes, especially methylene blue (MB) injection, are used to identify parathyroid tumours.

Material and methods
This was a retrospective study of 228 patients. Preoperative ultrasound, scintigraphy, and bio­chemistry were performed on all patients, and fine-needle aspiration procedures were performed on suspected patients. Using preoperative US-G injection with MB dye, target tumours were injected in all cases.

Results
A total of 163 patients were female and 65 were male. The mean age was 42.5 years. US was positive in 203 (89%) cases, 25 (11%) were negative, and all had a positive sestamibi scan (100%). US-G needle injections with MB dye of target tumours were successful in all cases. The average diameter of the lesions was 18 mm. All had positive intraoperative identification of parathyroid adenoma and MB staining (100% accuracy, 100% sensitivity, and 100% specificity). Operating time (min ± SD) was 22.7 ± 11.5 minutes, and the success rate was 100%. All were parathyroid adenomas histologically. Intraoperative parathormone hormone decreased in all patients. In postoperative follow-up, all were normocalcaemic with no local or systemic complications.

Conclusions
Localisation of small parathyroid adenomas by US-guided blue dye injection is a safe, simple, and useful tool when performing parathyroidectomy with no complications.