Value of 123 I/ 99m Tc-sestamibi parathyroid scintigraphy with subtraction SPECT/CT in primary hyperparathyroidism for directing minimally invasive parathyroidectomy.

BACKGROUND: Primary hyperparathyroidism/(PHPT) is one of the most common endocrinological conditions. Surgery remains the only curative option. We have evaluated the performance of double isotope 123 I/99m Tc-sestamibi parathyroid scintigraphy/(PS) with subtraction SPECT/CT in PHP for identifying uniglandular disease.

METHODS: Ninety PHPT patients undergoing parathyroidectomy (December 2015-August 2016) were included. All patients were evaluated with neck ultrasound/(US), PS and SPECT/CT with a new protocol. Outcomes from imaging modalities were reported as: uniglandular disease/(UGD), multiglandular disease/(MGD), or negative, and were compared to post-operative diagnoses.

RESULTS: Post-operatively, 72 and 18 patients had true UGD and MGD, respectively. Sensitivities and specificities of US, pinhole scintigraphy with subtraction, pinhole and SPECT/CT with subtraction, and all modalities combined were 91.7%/38.9%, 88.9%/72.2%, 93%/66.7% and 84.72%/77.78%, respectively: specificity of US + PS superior to US alone, p = 0.074. SPECT/CT enables reclassification of doubtful uptake foci.

CONCLUSIONS: Combination of neck US and PS with subtraction SPECT/CT offers a higher specificity for guiding towards minimally invasive parathyroidectomy.