Preoperative localization of single gland disease in primary hyperparathyroidism: a comparative study for preoperative localization with four-dimensional computed tomography, ultrasonography, and technetium-99m-sestamibi single-photon emission computed tomography.

Background: Treatment guidelines for primary hyperparathyroidism (PHPT) recommend high-resolution neck ultrasonography (US), technetium-99m-sestamibi single-photon emission computed tomography (^99mTc-sestamibi SPECT), and contrast-enhanced four-dimensional computed tomography (4D CT) as image evaluation methods. This study aimed to compare the sensitivity and accuracy of the three image evaluation methods recommended in the guidelines for patients with PHPT and evaluate the utility of 4D CT for preoperative localization in single gland disease.

Methods: A retrospective medical chart review was performed on 41 patients who underwent surgery for single gland disease at the Department of Otorhinolaryngology, Pusan National University Hospital, between January 2021 and March 2023. All the patients underwent preoperative US, ^99mTc-sestamibi SPECT, and 4D CT. The location of the abnormal parathyroid lesion, removed during surgery and confirmed by postoperative pathological examination, was used as the reference standard. The sensitivity, specificity, and accuracy of the three imaging evaluations were assessed and compared to the reference standard location.

Results: The sensitivity, specificity, and accuracy of the imaging modalities were as follows: 4D CT, 95.1%, 98.4%, and 97.6%; US, 82.9%, 95.1%, and 92.1%; and ^99mTc-sestamibi SPECT, 78.0%, 97.6%, and 92.7%, respectively. Furthermore, a total of nine cases were identified where accurate localization could not be achieved through US and ^99mTc-sestamibi SPECT. The presence of coexisting thyroid lesions was significantly correlated with incorrect localization in preoperative US (P<0.05). The small volume of the parathyroid tumor was significantly associated with an increased rate of false-negatives using ^99mTc-sestamibi SPECT (P<0.05).

Conclusions: In the preoperative localization of abnormal parathyroid lesions, 4D CT demonstrated higher sensitivity and specificity than US and ^99mTc-sestamibi SPECT. 4D CT can accurately localize abnormal parathyroid lesions, even in cases in which both US and ^99mTc-sestamibi SPECT yielded incorrect localizations.