Successful minimally invasive parathyroidectomy for primary hyperparathyroidism depends on accuracy of pre-operative localisation studies. Ultrasound (US) and sestimibi (SM) scanning remain the imaging modalities of choice reserving MRI, CT and PET for patients who have not been cured by previous explorations or for whom other localization techniques are uninformative or discordant. The aim of this study was to review the accuracy of US and SM in the pre-operative localisation of parathyroid adenomas.
We performed a retrospective review of 51 consecutive patients with a biochemical diagnosis of primary hyperparathyroidism who underwent surgery by one of two Endocrine Surgeons. We compared findings on ultrasound and 99mTc-sestamibi scintigraphy to histology results.
Of the 51 patients who underwent parathyroid surgery from January 2012 June 2013, complete data was available for 47 (M:F 12:35; median age 64 years, range 1581). Primary hyperparathyroidism was confirmed biochemically with pre-operative calcium 2.85±0.17 mmol/l and parathyroid hormone concentration 126.0± 113.0 pg/ml. Thirty six patients had a solitary parathyroid adenoma, six had parathyroid hyperplasia, one had multiple adenomas and four had inconclusive histological findings. Ultrasound was positive in 29 of 36 (80.6%) adenomas with precise anatomical position found in 22 of the 29 giving a sensitivity, specificity and positive predictive value of 81, 64 and 88%, respectively. Pre-operative 99mTc-sestamibi scintigraphy correctly identified 21 of 36 (58.3%) adenomas with 58.3% sensitivity, 81.8% specificity and 91.3%. positive predictive value. US findings correlated with SM in 20 patients and were 85% accurate giving sensitivity 81.2%, specificity 100% and positive predictive value 100%.
US and SM scanning show good concordance with histology following parathyroid surgery and when combined provide accurate pre-operative localisation. They should remain the first line to guide minimally invasive parathyroidectomy while other techniques should be reserved for when results are discordant or for those who need re-exploration following failed surgery.