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

Basil Knnecke¹, Barbara Lenz¹, Markus Stephan-Gldner¹, Anna Maria Brndli-Baiocco¹, Jrgen Funk¹, Thomas Pfister¹, Markus von Kienlin¹

Thyroid hypertrophy, hyperplasia and neoplasia are spontaneous but also drug-induced findings observed in non-clinical safety studies in rats. 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 commonly used to non-invasively diagnose thyroid neoplasia. The purpose of this study was to back-translate these modalities to the rodent situation. MRI yielded excellent tissue contrast in rat thyroid glands, thus providing the prerequisite for virtual histology in situ. Comparison of MR images to histopathological sections revealed good correlation for lesions larger than approximately 500um.