# Comparison of Ultrasonography and Scintigraphy as Localization Techniques in the Preoperative Evaluation of Primary Hyperparathyroidism

## TL;DR

This study compares ultrasonography and scintigraphy for locating affected parathyroid glands in patients with primary hyperparathyroidism before surgery.

## Contribution

The study provides a direct comparison of diagnostic accuracy metrics for ultrasonography and scintigraphy in preoperative localization of pHPT.

## Key findings

- Scintigraphy showed 100% sensitivity and 100% NPV, while ultrasonography had 60% sensitivity and 25.93% NPV.
- Ultrasonography demonstrated higher specificity (87.5%) and PPV (93.2%) compared to scintigraphy.
- A significant difference was observed in non-localization of affected glands between the two techniques.

## Abstract

Primary hyperparathyroidism (pHPT) is the most common endocrine disorder responsible for hypercalcemia in non-hospitalized patients. When indicated for parathyroidectomy for pHPT, preoperative imaging is recommended to localize the affected parathyroid glands, including neck ultrasonography and 99m-Tc-sestaMIBI scintigraphy. The aim of this study was to investigate and compare the findings obtained by ultrasonography and scintigraphy in the preoperative evaluation. A retrospective review was conducted on all patients who underwent partial parathyroidectomy for a diagnosis of pHPT between January 2022 and December 2024 in a specialized center in Mexico. The locations according to scintigraphy and ultrasound were compared using the McNemar test, and specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV) were determined. A significant difference was observed only in the case of non-localization of affected glands (p<0.0001).

For scintigraphy, sensitivity was 100%, specificity 60.70%, PPV 73.7%, and NPV 100%. For ultrasonography, sensitivity was 60%, specificity 87.5%, PPV 93.2%, and NPV 25.93%. The concordance observed between the preoperative localization findings obtained by 99m-Tc-sestaMIBI scintigraphy and ultrasonography in patients with pHPT highlights the enduring value of ultrasonography as a preoperative tool, due to its accessibility and cost-effectiveness.