THE IMAGING PERFORMANCE OF PREOPERATIVE CERVICAL ULTRASONOGRAPHY AND 99MTC=SESTAMIBI SCINTIGRAPHY IN PRIMARY HYPERPARATHYROIDISM

A SINGLE CENTRE EXPERIENCE

Abstract

INTRODUCTION
Primary hyperparathyroidism is the third commonest endocrine disorder globally. Parathyroidectomy provides the only curative treatment in the management of primary hyperparathyroidism (PHPT). Therefore, accurate preoperative localisation by cervical ultrasonography (US) or 99mTc-sestamibi scintigraphy study (Sestamibi) of enlarged pathological parathyroid gland is crucial.

METHODOLOGY
All PHPT cases who underwent parathyroidectomy and had preoperative localisation by either cervical US, Sestamibi scan or a combination of both in Queen Elizabeth II Hospital from year 2012 to 2018 were retrospectively analysed. The imaging findings were compared to intraoperative findings and histopathological examination correlation of parathyroid lesions.

RESULTS
40 patients had parathyroidectomy and intraoperatively, 92.5% (37/40) were single-gland and 7.5% (3/40) were multiple-gland diseases. 80% (32/40) were parathyroid adenomas and 20% (8/40) were parathyroid hyperplasias. All patients had US scan performed and 77.5% (31/40) of patients had Sestamibi scan. Cervical US detected enlarged parathyroid glands in 55% (22/40) and Sestamibi in 100% (31/31) of the cases. US demonstrated a sensitivity of 53.8% and positive predictive value of 95.5% while Sestamibi alone or in combination with US demonstrated a sensitivity of 100% and positive predictive value of 71%. 73.3% (11/15) of patients who had Sestamibi following negative US findings correctly identified abnormal parathyroid gland intraoperatively. 5% (2/40) of the cases did not achieve remission postoperatively.

CONCLUSION
Combination of both US and Sestamibi scan may increase the success of localizing abnormal parathyroid gland. However, in our centre selective use of Sestamibi following negative US findings may be more cost effective.