<prompt> A 32-year-old woman is evaluated in the clinic for symptoms of polyuria and polydipsia. She has no significant past medical history and her only medication is the oral contraceptive pill.Her physical examination is entirely normal. Urine and serum biochemistry investigations are suggestive of central diabetes insipidus DI. Which of the following is the most likely finding on magnetic resonance imaging MRT of the brain?hypothalamic tumorhyperintense signals in the cerebral cortexagenesis of the corpus callosumlack of hyperintense signals from the posterior pituitary  <response>: Because DI is usually caused by destruction, or agenesis, of the posterior pituitary, its normal signaling is lost. Pituitary DI can also result from trauma, tumors both primary and secondary, granulomas, infections, inflammatory diseases, chemical toxins, congenital malformations, and genetic disorders.Depending on the cause, the MRI may demonstrate other associated findings. 