High specifity of preoperative ultrasound in primary HPT

Objective: For preoperative localization of biochemically defined primary HPT high resolution ultrasonography (US) and technetium-99m sestamibi-scintigraphy (Tc-Mibi) is performed. Aim of this study was to evaluate the sensitivity and usefulness of US alone.

Design: Between January 2004 and May 2007 we operated 77 patients with primary HPT. The diagnosis was determined by elevated serum-calcium and -PTH. To determine localisation preoperatively US was performed in 77 cases. Tc-Mibi was performed in 27 cases. All patients underwent bilateral cervical exploration.

Results: US and Tc-Mibi were analysed and compared to surgical and histopathologic findings. At surgery 82 parathyroid lesions were found in 77 patients (one four-adenoma-desease and two two-adenom-desease). 43 patients had concomitant thyroid disease. The overall sensitivity of US was 84%, with concomitant thyroid disease (CTD) 79% and without CTD 91% respectively. The overall sensitivity of Tc-Mibi was 85% with CTD 80% and without CTD 92% respectively. In patients with both diagnostic procedures the sensitivity increases up to 94%.

Conclusion: In experienced hands US is a high sensitive technique to find and localize parathyroid adenomas. Sensitivity is reduced with concomitant thyroid diseases. Only when US is negative we think that Tc-Mibi is indicated.