Factors related to a non-localising technetium 99m sestamibi scan result during parathyroid adenoma imaging in primary hyperparathyroidism.

Objectives: The aim of this study is to investigate factors that are associated with having a non-localising Tc-sestamibi scan.

Design: A retrospective study was performed on patients that underwent parathyroid surgery performed within a single institution between 2001 and 2018.

Setting: Single tertiary centre for parathyroid surgery.

Participants: 230 patients underwent surgery for primary hyperparathyroidism due to a solitary parathyroid adenoma and had preoperative Tc-sestamibi imaging.

Main Outcome Measures: Variables including age, gender, intra-operative location of parathyroid adenoma, adenoma weight and pre- and postoperative calcium and parathyroid hormone levels were investigated through univariate and multivariate analysis to identify any association with having a non-localising (negative) Tc-sestamibi scan result.

Results: Multivariate analysis identified that right-sided adenomas (P = .038), superior adenomas (P = .042) and a lower preoperative PTH level (P = .034) were all individual factors associated with having a negative Tc-sestamibi scan result. Although the weight of the adenoma was significant on univariate analysis (P = .029), this was not demonstrated on multivariate analysis (P = .422).

Conclusion: Factors that were associated with having non-localising Tc-sestamibi scan were right-sided adenomas, superior adenomas and lower preoperative PTH level. Further large prospective multicentre studies are needed to further evaluate these initial findings.