Accuracy of 4-Dimensional Computed Tomography for Localization in Primary Hyperparathyroidism

Background: The etiology of primary hyperparathyroidism (PHP) is single-gland adenoma in most patients. Imaging localization of single-gland disease allows for a focused operation. We sought to determine the accuracy of imaging for localizing a solitary parathyroid adenoma. Methods: A single-institution retrospective review was performed of adult patients with PHP undergoing parathyroidectomy from January 2017 through December 2018. Surgeon-performed ultrasound (US), four-dimensional computed tomography (4DCT), and sestamibi were assessed for localization of a parathyroid adenoma yielding a single-gland parathyroidectomy. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for each imaging modality. Results: One hundred fifty-four patients underwent parathyroidectomy for PHP during the study period, with 100 patients meeting inclusion criteria with a mean age of 61.1 (SD 10) y and 80% women. Mean calcium was 11.1 mg/dL (SD 0.7) and mean PTH was 116 pg/mL (SD 66). All 100 patients had surgeon-performed US with 17 localized, 51 patients had 4DCT with 41 (80%) localized, and 69 patients had sestamibi with 53 (77%) localized. Eighty-two patients underwent successful unilateral parathyroidectomy, 18 required bilateral neck exploration. US was the most specific imaging modality at 94%. Accuracy of imaging localization was 32% for US, 70% for sestamibi, and 86% for 4DCT. Conclusions: Surgeon-performed US is a highly specific imaging modality for preoperative localization of solitary parathyroid adenoma in patients with PHP. 4DCT is the most accurate imaging localization study and should be considered for patients with a nonlocalized US.