75Se Selenocholesterol adrenocortical imaging in Conn's syndrome and Cushing's syndrome.
Image (a) is a posterior view of the abdomen in a patient with Conn's syndrome (primary aldosteronism). It reveals high uptake of 75Se selenocholesterol in the right adrenal cortex, shown in red and yellow, as compared to the normal uptake in the left adrenal cortex, shown in blue. Production of aldosterone by a Conn's adenoma does not suppress the uptake of 75Se selenocholesterol by the normal adrenal. The purpose of adrenal cortical imaging is to localise an adenoma or demonstrate bilateral hyperplasia once a positive diagnosis has been made of Conn's or Cushing's syndrome, clinically and biochemically. A second use is to demonstrate whether an adrenal mass, seen incidentally during CT imaging of the abdomen, has a functionally significant abnormality. Image (b) is a posterior view of the abdomen in a patient with Cushing's syndrome due to a solitary cortisol secreting adenoma. A high uptake of 75Se selenocholesterol is seen in the cortisol producing adenoma. In this case, the left adrenal is not visualised because of suppression of ACTH by the high cortisol level, thereby reducing the normal uptake of 75Se selenocholesterol.
