Endocrine Abstracts

Parathyroidectomy is the only definitive cure for primary hyperparathyroidism (PHPT). The standard for pre-operative localisation of parathyroid pathology at our institution is both a (99m)Tc-sestamibi SPECT/CT (sestamibi) and neck ultrasound scan (USS). The aim of this audit was to assess the accuracy of this standard pre-operative imaging.

Methods: Retrospective data was gathered from all parathyroidectomies performed at St Thomas’ Hospital between 2008 and 2011.

Results: 164 parathyroid operations were identified with complete data available for 140 patients (included in this report). Of these, 72.9% were female, age 17–87 years (mean 56). Histology identified 111 (79.3%) adenomas, 21 (15%) hyperplasia, 2 (1.4%) adenoma plus hyperplasia and 6 (5%) ‘other pathology’.

Sestamibi scans were performed in 134 patients (95.7%) with accurate localisation in 98 (73.1%). USS were performed in 115 patients (82.1%) with accurate localisation in 63 (54.8%). Of the 109 patients (77.9%) who had both sestamibi and USS; both scans correctly identified an adenoma in 51 (48.8%) cases: in 25 cases (22.9%) only the sestamibi correctly identified the lesion, in 10 (9.2%) cases only the USS correctly identified the lesion. Neither scan correctly identified the lesion in 23 (21.1%) cases.

In 140 patients, sestamibi and/or USS correctly identified the location of parathyroid pathology in 108 patients (77.1%). Therefore, pre-operative imaging was not helpful in 22.9% of patients.

Discussion: Pre-operative sestamibi and/or USS accurately located parathyroid pathology in over 75% of cases. Sestamibi was requested more often and was more accurate at pre-operative localisation vs USS. USS identified parathyroid pathology in 10 (9.2%) of patients in whom the sestamibi was non-diagnostic. USS should be reserved for those patients with negative sestamibi rather than used routinely in pre-operative localisation of parathyroid pathology.