Multi-modality parathyroid imaging: A shifting paradigm

Abstract

The goal of parathyroid imaging in hyperparathyroidism is not diagnosis, rather it is the localization of the cause of hyperparathyroidism for planning the best therapeutic approach. Hence, the role of imaging to accurately and precisely localize the abnormal parathyroid tissue is more important than ever to facilitate minimally invasive parathyroidectomy over bilateral neck exploration. The common causes include solitary parathyroid adenoma, multiple parathyroid adenomas, parathyroid hyperplasia and parathyroid carcinoma. It is highly imperative for the radiologist to be cautious of the mimics of parathyroid lesions like thyroid nodules and lymph nodes and be able to differentiate them on imaging. The various imaging modalities available include high resolution ultrasound of the neck, nuclear imaging studies, four-dimensional computed tomography (4D CT) and magnetic resonance imaging. Contrast enhanced ultrasound is a novel technique which has been recently added to the armamentarium to differentiate between parathyroid adenomas and its mimics. Through this review article we wish to review the imaging features of parathyroid lesions on various imaging modalities and present an algorithm to guide their radiological differentiation from mimics.

Keywords: Parathyroid adenoma; Ultrasound; Four-dimensional computed tomography; Magnetic resonance imaging; Nuclear Imaging; Contrast enhanced ultrasound

Core Tip: Parathyroid adenoma is the commonest cause of primary hyperparathyroidism, the management of which lies in definitive surgery. Accurate preoperative imaging is of prime importance to facilitate surgery. Imaging modalities include radiological investigations like ultrasound, four-dimensional computed tomography and magnetic resonance imaging which provide anatomical localization and nuclear scans like MIBI, single photon emission computed tomography and Fluoro-choline positron emission tomography which provide functional imaging details. Contrast-enhanced ultrasound is a novel modality which is being explored in the evaluation of parathyroid adenomas.