Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

About the Study

Protocol Investigator

Karel Pacak, M.D., Ph.D., D.Sc.
Section on Medical Neuroendocrinology
Reproductive Biology and Medicine Branch
National Institute of Child Health and Human Development
National Institutes of Health

What is this study about?

The goal of this study is to develop better methods of diagnosis and treatment for pheochromocytomas. These tumors, which usually arise from the adrenal glands, are often difficult to detect with current methods. Pheochromocytomas release chemicals called catecholamines, causing high blood pressure. Undetected, the tumors can lead to severe medical consequences, including stroke, heart attack and sudden death, in situations that would normally pose little or no risk, such as surgery, general anesthesia or childbirth.

Patients with pheochromocytoma may be eligible for this study. Candidates will be screened with a medical history and physical examination, electrocardiogram, and blood and urine tests. Study participants will undergo blood, urine, and imaging tests, described below, to detect pheochromocytoma. If a tumor is found, the patient will be offered surgery. If surgery is not feasible (for example, if there are multiple tumors that cannot be removed), evaluations will continue in follow-up visits. If the tumor cannot be found, the patient will be offered medical treatment and efforts to detect the tumor will continue. Diagnostic tests may include the following:

  • Blood tests - Two blood tests-glucagon stimulation and clonidine suppression - are done that require insertion of intravenous (i.v.) catheters (thin flexible tubes) into arm veins. While the patient rests lying down, a drug (glucagon or clonidine) is given through the i.v. line. Blood pressure and heart rate are monitored frequently, and blood is collected from the i.v. line to measure levels of catecholamines and their breakdown products, metanephrines.
  • Standard imaging tests - Non-investigational imaging tests include computed tomography (CT), magnetic resonance imaging (MRI), sonography, and 123I-MIBG scanning. These scans may be done before and after surgical removal of pheochromocytoma.
  • PET imaging - Positron emission tomography (PET) scanning is done using an injection of radioactive agents called fluorodopamine and fluoroDOPA. These agents enter pheochromocytoma cells, making the tumor radioactive and visible on the PET scan. The scans take up to about 2 hours.
  • Urine - A 24-hour urine collection is collected for analysis.
  • Genetic testing - A small blood sample is collected for DNA analysis.

What kind of commitment is involved?

Patients are required to provide complete information

How can I ask questions or ask for help?

Email us at adamskt@mail.nih.gov (or click on Contact). We will respond in 5 business days.