CT and MRI of the Adrenal Gland

Most adrenal masses are detected when CT scans are performed for other reasons.  Often, a very specific method is used when performing a CT scan to examine abnormalities of the adrenal gland, which can mean repeating a scan in some cases.  CT scans are better than other types of imaging for the adrenal gland because they:

• Offer the best depiction of tissue characteristics
• Easily determine size of the abnormalities
• Can be done quickly
• Are available in many locations and at reasonable cost

Usually the density of the adrenal gland is best seen when a CT scan is performed without IV contrast (no dye is injected in the vein).  Density can often help differentiate benign from cancerous tumors of the adrenal gland.  However, IV contrast is useful in the two following scenarios:

• When the density falls between that of benign and malignant values, the speed at which the IV contrast exits the adrenal tumor can help distinguish between these two entities (adrenal washout study).
• Contrast can further define the surrounding anatomy (vasculature, lymph nodes).

In most cases, MRI of the adrenal gland does not yield any additional information beyond that of a properly performed CT scan.  Your physician will consider the following issues in determining the need for an MRI:

• The need to avoid radiation (pregnancy, children)
• An alternative for patient allergic to IV contrast
• Sometimes can reveal more tissue characteristics
• Confirmation (when not clear from symptoms and laboratory testing) of pheochromocytoma (adrenal tumor that produces dangerous amounts of adrenaline-type substances)
• Increased cost

Keep in mind, no radiographic test can reveal what is happening inside an adrenal tumor or how it is functioning.  Abnormal production of hormones is another very important factor when evaluating an adrenal mass.