Photon-Counting Detector 4D CT for Preoperative Localization in Primary Hyperparathyroidism

BACKGROUND AND PURPOSE: Accurate preoperative localization of abnormal parathyroid tissue is essential for successful minimally invasive parathyroidectomy. Conventional imaging with ultrasound and Tc-99m sestamibi scintigraphy can be limited, particularly in ectopic disease. This study evaluated the performance of photon-counting detector CT (PCD-CT) for 4D parathyroid imaging in patients with primary hyperparathyroidism. MATERIALS AND METHODS: In this IRB-approved ambispective study, 36 patients with primary hyperparathyroidism underwent preoperative 4D PCD-CT followed by parathyroidectomy. Ultrasound and sestamibi scintigraphy were available in 34 and 33 patients, respectively. Three blinded fellowship-trained radiologists independently reviewed imaging studies, with each reader assigned to a single modality. Imaging findings were compared with operative and histopathologic results, which served as the reference standard. Patient-level localization rates were summarized with two-sided 95% exact binomial confidence intervals; comparisons among modalities were descriptive. RESULTS: PCD-CT correctly localized abnormal parathyroid tissue in 36/36 patients (100%; 95% CI, 90.3%-100%). Ultrasound demonstrated surgically confirmed definite lesions in 12/34 patients (35%; 95% CI, 19.7%-53.5%), increasing to 16/34 (47%; 95% CI, 29.8%-64.9%) when confirmed equivocal findings were included. Sestamibi scintigraphy demonstrated definite surgically confirmed lesions in 19/33 patients (57%; 95% CI, 39.2%-74.5%); confirmed localization increased to 23/33 (70%; 95% CI, 51.3%-84.4%) when equivocal findings were included. PCD-CT localized lesions in 8 patients not identified by ultrasound or scintigraphy, most of which were inferior or ectopic. All 7 ectopic adenomas were localized by PCD-CT, compared with 3/7 by ultrasound and 4/7 by scintigraphy. CONCLUSIONS: Photon-counting 4D CT demonstrated promising high localization rate for preoperative localization of abnormal parathyroid glands in primary hyperparathyroidism, particularly with ectopic adenomas.