1 3 ORIGINAL ARTICLE Ann Nucl Med (2008) 22:123–131 DOI 10.1007/s12149-007-0086-z A. Sukan (*) · M. Reyhan · M. Aydin · A.F. Yapar · A. Aktas Department of Nuclear Medicine, Adana Teaching and Medical Research Center, Baskent University Faculty of Medicine, Dadaloglu Mah, 39 Sokak, No. 6, Yuregir, 01250 Adana, Turkey e-mail: aysunsukan@yahoo.com Y. Sert Department of Biostatistics, Cukurova University, Adana, Turkey T. Canpolat Department of Pathology, Baskent University Faculty of Medicine, Ankara, Turkey Preoperative evaluation of hyperparathyroidism: the role of dual-phase parathyroid scintigraphy and ultrasound imaging Aysun Sukan · Mehmet Reyhan · Mehmet Aydin Ali F. Yapar · Yasar Sert · Tuba Canpolat Ayse Aktas US was 87% and 91%; positive predictive value (PPV) was 94% and 92%, respectively. MIBI and US identified the parathyroid pathology in 92% and 85% of patients in the non-concomitant thyroid disease group, and in 53% and 47% of patients in the concomitant thyroid disease group, respectively. The weight of the gland between primary and secondary hyperparathyroidism did not reveal a significant difference (P = 0.4). Signifi- cant differences were found with respect to age, PTH, Ca, and P levels between the pHPT and sHPT (P < 0.001). Intact PTH levels showed significant differences between MIBI positive and negative patients (P = 0.013), and also US positive and negative patients (P = 0.012). A significant negative correlation was found between iPTH and Ca at sHPT (P < 0.001). Conclusions The concomitancy of thyroid disease greatly influences scintigraphic and ultrasonographic detection of parathyroid pathology in pHPT and sHPT. The combination of MIBI and US appears promising for localizing parathyroid pathology in patients with both primary and secondary hyperparathyroidism. The con- cordance rate is high together with a lower chance of missing concomitant thyroid pathology, which might alter the surgical approach. Keywords Hyperparathyroidism · 99m Tc-MIBI · Ultrasound · Thyroid nodules Introduction Primary hyperparathyroidism is a generalized disorder of calcium (Ca), phosphate (P), and bone metabolism caused by an increased secretion of parathyroid hormone (PTH). Solitary adenoma is the leading cause of primary Received: 20 August 2007 / Accepted: 16 October 2007 © The Japanese Society of Nuclear Medicine 2008 Abstract Objective The aim of this study was to evaluate the efficacy of dual-phase 99mTc-methoxyisobutylnitrile (MIBI) parathyroid scintigraphy (PS) and ultrasound (US) in primary (pHPT) and secondary (sHPT) hyperparathyroidism. Methods A total of 69 patients (mean age 47 ± 16; age range 14–79 years), including 19 patients with sHPT were enrolled in this study. Preoperative serum intact parathyroid hormone (iPTH) levels, calcium (Ca), phos- phate (P), alkaline phosphatase, and 24-h urinary-free Ca measurements were obtained. Concomitant thyroid pathology was also recorded. Results Histopathology revealed 30 solitary adenomas and 71 hyperplastic glands in 55 patients. The remaining patients’ histopathology revealed normal parathyroid, thyroid, or lymph nodes. The sensitivities of MIBI and US in pHPT were 70% and 60%, respectively. It was 60% for both procedures in sHPT. The overall sensitivity of combined US + MIBI in pHPT and sHPT was 81% and 71%, respectively. The overall specificity of MIBI and