Mount Sinai uses a neuroendovascular procedure called petrosal sinus sampling to diagnose and treat patients who have an abnormally high level of the steroid cortisol in their bloodstream (Cushing’s syndrome). This much cortisol can produce life-threatening complications, such as uncontrolled blood pressure or diabetes.
In order to treat Cushing’s syndrome, it is important to establish the source of excessive hormone production. Diagnosing the cause of elevated cortisol levels can be difficult because in many cases nothing shows up in radiographic tests. A benign pituitary tumor (Cushing’s disease), however, is a common cause.
If your doctor suspects Cushing’s disease but no tumor is visible on a high quality MRI, petrosal sinus sampling can help confirm the tumor’s presence and determine on which side of the pituitary gland the tumor resides.
Petrosal sinus sampling entails threading a small catheter from the femoral vein in the groin to the main veins draining from the pituitary gland. The procedure allows direct sampling of the blood from either side of the pituitary gland before it mixes with blood from other parts of the body. The results will determine whether the pituitary gland is, in fact, the source of the Cushing’s, and therefore, whether pituitary surgery will be helpful. The study takes about two hours, and patients can go home the same day.