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The role of contrast-enhancend ultrasonography (CEUS) in comparison with 99mTechnetium-sestamibi scintigraphy for localization diagnostic of primary hyperparathyroidism.

INTRODUCTION
Correct preoperative detection of parathyroid gland adenoma (PA) in the case of primary hyperparathyroidism (pHPT) is the requirement for unilateral cervical exploration associated with lower morbidity. We present our experience with contrast-enhanced ultrasonography (CEUS) as diagnostic tool for the preoperative localization of PA in pHPT in comparison to the (99m)Technetium-sestamibi scintigraphy.


METHODS
Between 8/2009-5/2013 143 patients with pHPT received surgical interventions in the Department of Surgery at the University Hospital of Regensburg. In all patients contrast-enhanced ultrasonography (CEUS) was performed as diagnostic tool for the localization of pathological parathyroid glands. By one experienced examiner CEUS was performed after bolus injection of 1-2.4 ml contrast agent with storage of digital cine loops from the arterial phase (15-45 s) to the late phase (3 Min). Criteria for a parathyroid adenoma were marginal hypervascularisation in the arterial phase and wash out in the late phase. 74 patients received (99m)Technetium-sestamibi scintigraphy. The sensitivity of both diagnostic tools was analyzed in comparison to the intraoperative and histological findings.


RESULTS
CEUS revealed a sensitivity of 95.9% for the detection of pathological parathyroid glands and even of 97.1% for patients without scintigrapy in comparison to 60.8% for (99m)Technetium-sestamibi scintigraphy. Sensitivity of CEUS in patients with negative scintigraphy was 96.3%. In multivariate regression analysis detection of small PA compared to scintigraphy was better by trend but did not reach significance (p = 0.019). Follow-up with a minimum of 8 weeks showed normal serum levels of calcium and parathyroid hormone in all patients except one.


CONCLUSIONS
CEUS represents a new diagnostic method for the localization of parathyroid gland adenomas independent on findings in scintigraphy. In the present of appropriate expertise in CEUS no further diagnostic procedures are required.