Parathyroid Imaging

Abstract

A colloquial saying described the best localization before parathyroid surgery was finding a good surgeon. While it is still important to have a high volume parathyroid surgeon, the trend away from bilateral neck exploration towards that of minimal invasive parathyroidectomy (MIP) has changed the perioperative management of parathyroid disease. The success of MIP depends heavily on the ability of preoperative imaging to localize the abnormal gland(s) and differentiate between single- and multigland disease. Most centers worldwide use a combination of ultrasound and sestamibiscintigraphy (sestamibi). When both are concordant for a single abnormal gland, high cure rates can be achieved. Sensitivity of both sestamibi (varying from 70% to 86%)and ultrasound (76%) are, however, limited. In these scenarios, several second-line imaging modalities have been employed, including Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). More recently, there has been increasing attention to the use of Positron Emitting Tomography (PET), of which the results using 18F-Fluorocholine (FCH) seem most promising. Interestingly, FCH was discovered to localize parathyroid adenomas by incident. It was first described in a patient with prostate cancer, who was found to have a focal hotspot in the neck. Biochemical testing revealed that this patient suffered from primary hyperparathyroidism (pHPT) and during surgery the adenoma was found at exactly the location that was indicated by FCH PET. The aim of this research was to investigate the performance of localization studies for abnormal parathyroid glands in patients with pHPT. Conventional imaging studies and the use of PET are discussed separately.