A 55-year-old man presents with hypercalcaemia (serum calcium 2.9 mmol/L), elevated intact PTH, and a low 24-hour urinary calcium. DEXA scan shows osteoporosis of the lumbar spine. He meets surgical criteria for parathyroidectomy. Which imaging modality is the first-line for pre-operative parathyroid localisation?

• A 4D-CT parathyroid protocol
• B MRI neck with gadolinium
• C Selective venous sampling for PTH
• D 99mTc-sestamibi scintigraphy with SPECT ✓

Explanation

For primary hyperparathyroidism requiring parathyroid localisation before minimally invasive parathyroidectomy, 99mTc-sestamibi scintigraphy (with SPECT for 3D localisation) is the standard first-line investigation as it identifies hyperfunctioning parathyroid adenomas with sensitivity of 80–90%. 4D-CT is used when sestamibi is negative or discordant. MRI is reserved for failed sestamibi and CT cases. Selective venous sampling is invasive and reserved for persistent/recurrent disease after failed exploration.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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