The Role of 4D-CT for Pre-Operative Localization in Patients with Primary Hyperparathyroidism with Negative Ultrasonography and/or Sestamibi SPECT/CT.

Objectives: The major cause of primary hyperparathyroidism (pHPT) is parathyroid adenoma. Today, minimally invasive parathyroidectomy (MIP) has become the standard treatment for patients in whom the pathological gland can be localized with pre-operative imaging methods. In this study, we aimed to evaluate the role of 4D-CT in pre-operative localization in patients with pHPT who are negative for ultrasonography (USG) and/or sestamibi single-photon emission computed tomography/CT (SPECT/CT) and will undergo primary surgery. Methods: Patients whom were operated between 2018 and 2023 were included to this study. 4D-CT results of patients with one- or two-negative USG and SPECT/CT results were evaluated retrospectively. Results: In this study, 19 patients (5 men and 14 women) with a mean age of 57.1±8.5 years were evaluated. Pathology results were consistent with parathyroid adenoma in 18 patients (94.7%) and parathyroid hyperplasia in 1 patient (5.3%). USG was negative in six patients, SPECT/CT was negative in 14 patients, and both were negative in four patients. In 4D-CT, positive images were detected in 15 patients and these results were finalized as true positive in 14 patients and false positive in 1 patient. The sensitivity of 4D-CT was 82.4% (95% CI: 60.4-95.3%), positive predictive value was 93.3% (95% CI: 73.8-99.6%), accuracy was 78.9%, and localization rate was 73.7%. In 14 (73.7%) patients, the pathological glands were removed by MIP. Conclusion: In approximately 75% of patients with negative USG and/or SPECT/CT, the pathological gland can be localized with 4D-CT and MIP can be applied in these patients.