Preoperative Localization in Primary Hyperparathyroidism with Combined 4DCT-MIBI SPECT/CT

Primary hyperparathyroidism (PHPT) requires precise preoperative localization for minimally invasive parathyroidectomy. This study evaluates the efficacy of combined four-dimensional computed tomography (4DCT) and technetium-99m sestamibi (MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) at our center over 5 years. We conducted a retrospective search for patients with biochemically proven PHPT who underwent combined 4DCT-MIBI SPECT/CT from October 2018 to September 2023. Images were reviewed by two radiologists for lesion presence and location. Enhancement patterns of the parathyroid lesions were classified in relation to the thyroid. Data were analyzed for sensitivity, interobserver agreement, and statistical difference between modalities. Demographic and histopathological results were also retrieved. Of 122 parathyroid lesions, 4 were intrathyroidal and 1 was ectopic. One parathyroid carcinoma was found, with others being either adenoma or hyperplasia. There was one false-positive case of thymoma in the anterior mediastinum. Combined 4DCT-MIBI SPECT/CT achieved 87.7% sensitivity (95% confidence interval [CI]: 81.9–93.5%), outperforming 4DCT (77.0%, 95% CI: 69.6–84.5%), and MIBI scan (71.3%, 95% CI: 63.3–79.3%) alone. Interobserver agreement was near-perfect (kappa: 0.91–0.98). On 4DCT, 48% of lesions showed type A enhancement, 47% type B, and 5% type C. The combined 4DCT-MIBI SPECT/CT protocol offers high sensitivity and excellent interobserver reliability for preoperative lesion localization in patients with PHPT, outperforming standalone 4DCT or MIBI studies. These findings underscore the potential of this integrated imaging approach to enhance targeted surgical treatment and patient outcomes.