Dual-phase 99mTc-MIBI scintigraphy to assess calcimimetic effect in patients on haemodialysis with secondary hyperparathyroidism

Objective To evaluate the effect of calcimimetics with Tc-99m-methoxy-isobutyl-isonitrile (MIBI) parathyroid scintigraphy in secondary hyperparathyroidism. Methods This prospective study included 30 consecutive haemodialysis patients with inadequately controlled secondary hyperparathyroidism despite standard medical treatment. Patients were given a single daily oral dose of 30 mg of cinacalcet. A baseline and 1-year follow-up dual-phase Tc-99m-MIBI scintigraphy were performed. Tc-99m-MIBI uptake in each parathyroid gland was graded on a semiquantitative scale (scoring 0-3). Results Twenty-one of the 30 patients responded to cinacalcet (70%). Abnormal positive glands were identified by Tc-99m-MIBI scintigraphy in 27 out of 30 patients (53 glands). The sensitivity and specificity of Tc-99m-MIBI in detecting cinacalcet response were 90 and 89%, respectively. The mean baseline and posttreatment grades of Tc-99m-MIBI uptake were 2.9 +/- 1.8 and 1.1 +/- 1.2 (P<0.0001) in the responder group and 3.1 +/- 2.1 and 3.9 +/- 2.2 (P=ns) in the nonresponder group. Conclusion Tc-99m-MIBI scintigraphy is useful in monitoring the response to calcimimetics in secondary hyperparathyroidism. Nucl Med Commun 30:890-894 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.