Parathyroid Imaging and Localization Using SPECT/CT: Initial Results

Abstract

Primary hyperparathyroidism is caused by a single parathyroid adenoma in up to 90% of clinical cases. Selective surgical excision of the hyperfunctioning parathyroid gland is the treatment of choice for this condition, and parathyroid scintigraphy is one of the primary and standard methods used for preoperative localization. SPECT/CT is advantageous over planar imaging because SPECT/CT provides useful anatomic information, improving overall diagnostic confidence. This paper evaluates the initial findings of a hybrid parathyroid imaging technique that was put into effect after the installation of a SPECT/CT system in the nuclear medicine department at Torbay Hospital, Torquay, United Kingdom. The key findings from 3 of the initial sets of patient studies are discussed, along with the key learning points after the introduction of this new clinical service. From January 2009 until December 2009, 9 patients underwent a parathyroid study at Torbay Hospital (8 women [87.5%] and 1 man [12.5%]; mean age [±SD], 61 ± 10.12 y). All patients were referred from the endocrinology department because they had clinical signs of parathyroid adenoma (67%) or required preoperative localization of parathyroid adenoma (33%). For parathyroid scintigraphy, 640-990 MBq of (99m)Tc-sestamibi were administrated intravenously. A SPECT/CT system was used to acquire images from the level of the submandibular glands through the basal third of the heart. Three sets of images were acquired, and the processed images were reviewed for quality, attenuation correction, and registration. Two (22%) of the 9 studies were negative for possible adenoma, and 7 (78%) were positive. Of the positive studies, 6 (86%) showed an adenoma on the left inferior gland and only 1 (14%) showed an adenoma in an eccentric position. The introduction of parathyroid SPECT/CT has resulted in the development of new imaging and processing protocols within our nuclear medicine department. Introducing any new technique requires knowledge, understanding, and practical skills. The additional information gained from the parathyroid SPECT/CT technique has provided new skills for practitioners and increased reporting confidence for physicians.