The pituitary gland exhibits enlargement on T1WI and a reduced enhancement signal in the posterior pituitary lobe.[80,81] In cases where the pituitary stalk is affected, both thickening of the stalk and enlargement of the pituitary funnel may be noted.[80,84] Biopsy rates for GPA are low, with only 28% of patients undergoing diagnostic biopsy in the study by Vega-Beyhart et al.[80] This low rate could be associated with c-ANCA positivity, which might enhance the accuracy of GPA diagnosis to some extent. This evidence concerns the gene PRTN3 and granulomatosis with polyangiitis.