Diagnostic accuracy of ultrasonography and 99m-Technetium Sestamibi scintigraphy for the preoperative localization of Parathyroid Adenoma keeping histopathological findings as reference standard

Objective: To determine the diagnostic accuracy of Ultrasound (US) and 99m-Tc Sestamibi scan in patients with primary hyperparathyroidism (PHPT) for the localization of parathyroid adenoma before surgery keeping Parathyroid histopathology as reference standard.

Method: This three years retrospective study was performed in the Department of Endocrinology, Hayatabad Medical Complex, Peshawar. Patients with PHPT who underwent parathyroidectomy from July 2019 to June 2022 were included in the study. Information relating to localization studies prior to surgical management like US and 99m-Tc Sestamibi scan was documented. These imaging findings were subsequently compared with the findings of parathyroid surgery and histopathology results which were taken as reference standard.

Results: The sensitivity, positive predictive value (PPV) and overall accuracy of US for the preoperative localization of parathyroid adenoma was 77%, 95.7% and 75%, respectively. Whereas the sensitivity, PPV and accuracy of 99m-Tc Sestamibi scintigraphy was 89.5%, 95% and 86% respectively.

Conclusion: Ultrasound despite its cost effectiveness has a lower sensitivity compared to 99m-Tc Sestamibi scintigraphy. Similarly, the sensitivity and overall accuracy of US and 99m-Tc Sestamibi scan when taken in combination is higher compared to either modality. It is thus recommended that the combination of these modalities should be employed to localize the adenomas accurately for surgery of the parathyroid gland for a better outcome.