The utility of 4-dimensional computed tomography for preoperative localization of primary hyperparathyroidism in patients not localized by sestamibi or ultrasonography

Background. To determine the sensitivity and clinical application of 4-dimensional computed tomography (4D CT) for the localization of patients with primary hyperparathyroidism when ultrasonography (US) and sestamibi scans (STS) are negative. Methods. We compiled a database of 872 patients with primary hyperparathyroidism who underwent parathyroid operation by a single surgeon from January 2003 to September 2013. Seventy-three patients who failed to have positive localization by US or STS were identified. Thirty-six underwent operation without a preoperative 4D CT, and 37 underwent operation after 4D CT. Results. In patients not localized by US or STS, 4D CT was 89% sensitive in localizing an abnormal parathyroid gland when reviewed blindly by a radiologist specializing in endocrine localization studies, yielding a positive likelihood ratio of 0.89 and positive predictive value of 74%. Sensitivity, positive likelihood ratio, and positive predictive value for correct gland lateralization were 93%, 0.93, and 80%. The average size of parathyroid glands removed after preoperative localization by 4D CT was 404 mg and 0.57 cm(3) (SD = 280, 0.64), compared with 259 mg and 0.39 cm(3) (SD = 166, 0.21) in patients not localized by 4D CT A focused, unilateral exploration was performed in 38% of patients with preoperative localization by 4D CT compared with 19% of patients without 4D CT (x(2) = 3.0, P = .041). Conclusion. 4D CT provided a positive localization in a clinically substantial number of patients not able to be localized by US or STS, which enabled an increased rate of successful, focused, unilateral operations compared with patients who did not undergo a 4D CT