INTRODUCTION: The normal pituitary gland’s anterior and posterior parts are distinct on MRI. The anterior part is isointense on both T1 and T2 weighted images. The posterior pituitary has intrinsic high T1 signal, and is of hypointense signal on T2 weighted images. Pituitary stalk shows normal top-to-bottom tapering on sagittal and coronal images.
We present a case wherein the absence of normal signal of posterior pituitary gland helped us to attain the diagnosis of central diabetes insipidus. Roughly half the cases of central DI are caused by trauma (surgery or head trauma), tumors (lung cancer, leukemia or lymphoma) or infiltrative diseases (Langerhans cell histiocytosis, sarcoidosis, Wegener’s granulomatosis). The other half are due to idiopathic DI, where an autoimmune process is the most common culprit, especially in young adults. Among patients with idiopathic central DI, the most common finding on brain imaging is loss of the posterior pituitary hyperintense signal and pituitary stalk thickening.