Pre-operative localisation of parathyroid adenomas in primary hyperparathyroidism – comparative accuracy at a single centre — ASN Events
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Pre-operative localisation of parathyroid adenomas in primary hyperparathyroidism – comparative accuracy at a single centre (#333)

Christopher Chan 1 2 , Alethea LT Chong 1 3 , Shaun McGrath 1 4 , Christopher W Rowe 1 3 4
  1. Department of Diabetes and Endocrinology, Hunter New England Local Health District, Newcastle, NSW, Australia
  2. School of Medicine, The University of Sydney, Sydney, NSW, Australia
  3. School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia
  4. Newcastle Endocrinology, Charlestown, NSW, Australia

Accurate localisation of parathyroid adenomas in primary hyperparathyroidism is necessary for selection of patients for minimally invasive parathyroidectomy [1]. Imaging practices have evolved over the past decade. The audit aimed to evaluate contemporary localisation at a single centre, with comparison to previous data.

A retrospective audit included adults with biochemically-confirmed hyperparathyroidism with pre-operative ultrasound localisation at a specialist centre and subsequent surgery between 2020 and 2023. Patients with MEN1, eGFR <30ml/min or re-operative parathyroid surgery were excluded. High-frequency neck ultrasound with a linear transducer, dual-isotope subtraction scintigraphy and 4D-CT localisation were compared with operative findings as the reference standard.

There were 203 cases, with 175 (86%) having single-gland disease confirmed intraoperatively and on histopathology. All patients had pre-operative ultrasound, 200/203 had scintigraphy and 89/203 underwent 4D-CT. Most patients (58%) had moderate hypercalcaemia (calcium 2.70-2.99mmol/L) and 7.4% had severe hypercalcaemia. 80% had focussed parathyroidectomy.  Post-operative cure rate (normocalcaemia) was 97%.  For single gland disease, ultrasound demonstrated 84.6% sensitivity and positive predictive value (PPV) 96.7% for “possibly consistent” localisation and 75.4% sensitivity and PPV 99.2% for “highly likely” localisation. Scintigraphy demonstrated 84.4% sensitivity and PPV 94.2% for “possibly consistent” localisation and 68.8% sensitivity and PPV 96.0% for “highly likely” localisation. 4D-CT demonstrated 78.3% sensitivity and PPV 84.4% for “possibly consistent” localisation and 65.2% sensitivity and PPV 83.3% for “highly likely” localisation. Inter-modality concordance between ultrasound and scintigraphy was 85% (PPV 91.8%), 59.4% between ultrasound and 4D-CT (PPV 92.7%) and 62.7% between scintigraphy and 4D-CT (PPV 88.1%). Compared with previous audit data, ultrasound and scintigraphy concordance increased from 69% to 85%, with a decrease in PPV from 100% to 91.8%. For cases of ultrasound and scintigraphy discordance (n=25), 4D-CT correctly localised 80%.

Specialist parathyroid ultrasound and scintigraphy are complementary modalities providing high concordance and diagnostic accuracy. 4D-CT can help resolve discordant cases. 

  1. 1. Bilezikian JP, Khan AA, Silverberg SJ, Fuleihan GE, Marcocci C, Minisola S, Perrier N, Sitges-Serra A, Thakker RV, Guyatt G, Mannstadt M, Potts JT, Clarke BL, Brandi ML; International Workshop on Primary Hyperparathyroidism. Evaluation and Management of Primary Hyperparathyroidism: Summary Statement and Guidelines