Imaging Tests for Cushing's Disease
Remember, this website is not meant to diagnose you - it is for informational use only.
MRI stands for Magnetic Resonance Imaging. It is a form of radiology that uses a magnetic field combined with pulsating radio waves to make pictures of structures within the body.
In some cases, you may have an IV inserted into your arm for the administration of a contrast (radioactive dye) prior to the scan. This dye enhances the quality of the image that will appear on the MRI scan. This contrast gives a warm (flushing) sensation to most people.
For a pituitary MRI, you will lie flat on a platform and your head will be placed inside the magnetic portion of the imagine machine. You may be given headphones or earplugs to protect your hearing during this test, as the sound of the machine can be quite loud. The machine does take several minutes to process images, and you should plan on this test taking up to a half hour.
As with the image above, normal glandular tissue appears white; whereas gray or black anomalies appearing where normal tissue would be is indicative of a tumor.
IPSS stands for Inferior Petrosal Sinus Sampling. It is a form of imaging that is used to detect pituitary abnormalities in the case of a normal or inconclusive MRI with confirmed Cushing's Disease cases.
For this imaging test, the patient lies on an x-ray table under an x-ray machine. Sedation and pain medications are administered through an IV. A small incision is made in the groin area of the legs, and a catheter is inserted into the femoral veins. A medication called heparin is also administered intravenously to prevent blood clots from forming in the brain. Catheters are advanced through the large veins of the legs, torso, and neck, eventually stopping at the base of the skull. Here is where micro-catheters are further advanced to the inferior petrosal sinuses. These sinuses are a series of vessels and channels that surround the pituitary gland and empty blood into the internal jugular vein. Contrast (radioactive dye) is now administered through the IV to help the radiologist view the position of the micro-catheters.
Once the micro-catheter has reached its destination, blood samples are taken from the inferior petrosal sinuses, as well as the peripheral veins (for comparison). After these baseline samples are collected, synthetic CRH is administered, followed by the drawing of time-sequenced samples.
Ratios between the petrosal sinus sampling and peripheral vein samples are compared to determine the results. Higher ratios are indicative of pituitary Cushing's; whereas lower ratios would be indicative of ectopic Cushing's. If ectopic Cushing's is the culprit, your treating doctor will most likely order an abdominal CT Scan.
CT stands for Computed Tomography. This form of radiology uses a computer to scan an object from several different angles, producing cross-sectional images that allow medical professionals to non-invasively look inside glands, organs or other objects within the body.
In some cases, you may be asked to drink a liquid contrast (radioactive dye diluted with water) prior to the scan, in addition to having an IV inserted into your arm for the administration of additional contrast. The dyes enhances the quality of the image that will appear on the CT scan. This contrast gives a warm (flushing) sensation to most people.
For an abdominal CT Scan, you will lie flat on a platform and the radiology technician will slowly slide the platform through the CT Scanner (which is donut-shaped, as noted in the picture above), and center your abdomen under the machine. The scanner will take a preliminary image; then you will be asked to hold your breath while the scanner rotates and the platform slowly slides you back to the starting position.
As with the MRI, normal tissue appears white; whereas gray or black anomalies appearing where normal tissue would be is indicative of a tumor. However, there are many different angles and details with a CT Scan, making it easier for your treating doctor to detect and diagnose a tumor.
Typically, with an abdominal CT Scan, your treating doctor is looking for an adrenal or ectopic tumor that is causing Cushing's Syndrome.
Now that a source has been confirmed through imaging, the next step is treatment for Cushing's!