17th September 2020

A 54-year-old lady has recently undergone pituitary surgery

A 54-year-old lady has recently undergone pituitary surgery to remove an intracranial tumour. She presents several weeks later, complaining of polydipsia and polyuria. Initial investigations show a raised serum osmolality and low urine osmolality. A diagnosis of cranial diabetes insipidus is suggested. Which of the following investigations is most commonly used to confirm the diagnosis of cranial diabetes insipidus? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.