Several studies suggested that preoperative localization of abnormal parathyroid (PT) glands may be useful in reducing operative time facilitating parathyroidectomy, especially in patients with ectopic PT glands. At present, noninvasive techniques used to evaluate patients with primary HPT include (1) 99mTc-sestamibi scintigraphy, (2) high-resolu tion neck ultrasonography, (3) CT scanning, and (4) magnetic resonance imaging (MRI). The sensitivity and posi tive predictive value of each technique range from 70% to 90%, and a combination of two of more tests may signi ficantly improve the results. In the minimally-invasive era both radioguided and videoassisted parathyroidectomy requi re an accurate preoperative localization of the abnormal PT glands, and PT imaging should be obtained before surgery in all patients with primary hyperparathyroidism, with the aim of reducing operative time and hospital stay.