In Vivo MRI of Rat Thyroid Glands for Non-Invasive Virtual Histopathology

Background Thyroid and parathyroid are two endocrine glands implicated in regulation of growth and metabolism as well as calcium homeostasis. Thyroid hypertrophy, hyperplasia and neoplasia are spontaneous findings often observed in rats in non-clinical safety studies. Such findings, however, can also be induced by investigational compounds. In order to understand the time of onset, progression and potential regression of these abnormalities longitudinal (i.e., time course) assessment are required. In humans, MRI is a well established non-invasive imaging modality to examine thyroid glands for neoplasias . In contrast, in vivo MRI of thyroids in rodents is not established and current literature is very scant . The purpose of the present study was to back-translate this modality to the rodent model. Rat thyroid and parathyroid glands were assessed non-invasively by in vivo MRI and subsequently by conventional histology for comparison.