# Ultrasound and Scintigraphy for Preoperative Localization in Primary Hyperparathyroidism: A Single-Center Experience

## TL;DR

This study evaluates the effectiveness of ultrasound and sestamibi scans in locating abnormal parathyroid glands before surgery for hyperparathyroidism.

## Contribution

The study provides a single-center analysis of the diagnostic accuracy and clinical impact of combining ultrasound and scintigraphy for preoperative localization in primary hyperparathyroidism.

## Key findings

- Ultrasound had higher predictive value for surgical cure compared to scintigraphy.
- Combined ultrasound and scintigraphy did not significantly improve cure rates over ultrasound alone.
- Reoperations and patients with negative imaging results had lower cure rates.

## Abstract

Introduction

Primary hyperparathyroidism is an endocrine condition characterized by elevated parathyroid hormone, often with high calcium levels, though calcium may remain normal in some cases. The condition is most frequently caused by a single parathyroid adenoma. Surgical removal of the affected gland is generally recommended for symptomatic patients, and modern surgical approaches, including minimally invasive techniques, are guided by preoperative imaging. Ultrasound (US) is commonly used, and an additional scan, such as a sestamibi scan, may be employed to aid surgical planning. This study reviewed cases of parathyroid surgery over nine years at a single center to evaluate the utility of US and sestamibi parathyroid scintigraphy (PS) for preoperative localization.

Methods

In this retrospective study, we examined cases of parathyroid surgery for primary hyperparathyroidism at the Department of Otolaryngology, York District Hospital, York, United Kingdom, over a nine-year period. A total of 316 patients underwent parathyroid surgery during the study period. Nineteen cases were excluded: 17 had tertiary hyperparathyroidism, and two had a preoperative diagnosis of multiple endocrine neoplasia type 1 and underwent four-gland excision. The remaining 297 cases, in which a likely candidate lesion for primary hyperparathyroidism was identified prior to surgery, were included.

Results

The average age was 61.3 ± 12.7 years, with 235 (78.6%) females. US demonstrated a sensitivity of 79.4%, a specificity of 64.3%, a positive predictive value (PPV) of 95.3%, and a negative predictive value (NPV) of 25.7%. Scintigraphy had a sensitivity of 76.2%, a specificity of 48.3%, a PPV of 91.6%, and an NPV of 21.5%. Combined US and scintigraphy showed a sensitivity of 59.4%, specificity of 77.8%, PPV of 95.5%, and NPV of 19.6%. The OR of cure for revision versus first operation was 0.20 (p = 0.001, 95% CI: 0.072-0.528). The OR of cure in positive versus negative US cases, controlling for scintigraphy status, was 5.233 (95% CI: 2.14-12.775, p < 0.0001). Scintigraphy alone was not a significant predictor of cure (OR 2.169, 95% CI: 0.904-5.204, p = 0.083). In an analysis of US as a predictor of cure, controlling for scintigraphy status and whether the operation was a revision or first operation, only US status remained a significant predictor (OR 4.47, p = 0.001, 95% CI: 1.77-11.251).

Conclusions

Image-guided focused parathyroidectomy results in superior cure rates in patients with primary hyperparathyroidism. In our practice, US predicted a high rate of all-cause cure and cure when histology corresponded with US findings. We were unable to show that PS, as an adjunct to US, significantly improved cure rates. Patient groups at high risk of operative failure include those undergoing reoperation, those without positive US or scintigraphy findings, and those with concomitant thyroid pathology. In these patients, further imaging, such as 4D CT, could be considered to delineate candidate lesions in greater detail for preoperative planning.