What is MRI of the Prostate?

Magnetic resonance imaging (MRI) is a noninvasive test doctors use to diagnose medical conditions.

MRI uses a powerful magnetic field, radiofrequency pulses, and a computer to produce detailed pictures of internal body structures. MRI does not use radiation (x-rays).

Detailed MR images allow doctors to examine the body and detect disease.

Multiparametric (Mp-MRI) is an advanced form of imaging. It uses three MRI techniques to provide anatomical pictures and information on the function of the prostate gland.

Mp-MRI assesses water molecule motion (called water diffusion) and blood flow (called perfusion imaging) within the prostate. This helps your doctor tell the difference between diseased and normal prostate tissue.

The prostate is part of the male reproductive system. It sits in front of the rectum, above the base of the penis, and below the bladder. The prostate surrounds the first part of the urethra. It helps make the milky fluid called semen. Semen carries sperm out of the body when a man ejaculates. Your doctor will most commonly use ultrasound or MRI to image the prostate. See the Prostate Ultrasound page for more information.

What are some common uses of the procedure?

Your doctor uses MRI to evaluate prostate cancer and see if it is limited to the prostate. Mp-MRI provides information on how water molecules and blood flow through the prostate. This helps determine whether cancer is present and, if so, whether it is aggressive and if it has spread.

Occasionally, MRI of the prostate is used to evaluate other prostate problems, including:

• infection (prostatitis) or prostate abscess.
• an enlarged prostate, called benign prostatic hyperplasia (BPH).
• abnormal conditions present at birth.
• complications after pelvic surgery.

Who interprets the results and how do I get them?

A radiologist, a doctor trained to supervise and interpret radiology exams, will analyze the images. The radiologist will send a signed report to your primary care or referring physician, who will share the results with you.

You may need a follow-up exam. If so, your doctor will explain why. Sometimes a follow-up exam further evaluates a potential issue with more views or a special imaging technique. It may also see if there has been any change in an issue over time. Follow-up exams are often the best way to see if treatment is working or if a problem needs attention.

What are the benefits vs. risks?

Benefits

• MRI is a noninvasive imaging technique that does not involve exposure to radiation.
• MR images of the body's soft-tissue structures are clearer and more detailed than those of other imaging methods. This detail makes MRI a valuable tool in early diagnosis and evaluation of the extent of tumors, such as prostate cancer.
• MRI has proven valuable in diagnosing a broad range of conditions, including cancer. It is also useful in diagnosing benign conditions such as an enlarged prostate and infection.
• Mp-MRI helps distinguish between low-risk/slow-growing and high-risk/aggressive prostate cancers. It also helps determine if cancer has spread beyond the prostate.
• MRI can detect abnormalities that might be obscured by bone with other imaging methods.
• The MRI gadolinium contrast material is less likely to cause an allergic reaction than the iodine-based contrast materials used for x-rays and CT scanning.

Risks

• The MRI exam poses almost no risk to the average patient when appropriate safety guidelines are followed.
• If sedation is used, there is a risk of using too much. However, your vital signs will be monitored to minimize this risk.
• The strong magnetic field is not harmful to you. However, it may cause implanted medical devices to malfunction or distort the images.
• Nephrogenic systemic fibrosis is a recognized complication related to injection of gadolinium contrast. It is exceptionally rare with the use of newer gadolinium contrast agents. It usually occurs in patients with serious kidney disease. Your doctor will carefully assess your kidney function before considering a contrast injection.
• There is a very slight risk of an allergic reaction if your exam uses contrast material. Such reactions are usually mild and controlled by medication. If you have an allergic reaction, a doctor will be available for immediate assistance.
• Although there are no known health effects, evidence has shown that very small amounts of gadolinium can remain in the body, particularly the brain, after multiple MRI exams. This is most likely to occur in patients receiving multiple MRI exams over their lifetime for monitoring chronic or high-risk health conditions. The contrast agent is mostly eliminated from the body through the kidneys. If you are a patient in this category, consult with your doctor about the possibility of gadolinium retention, as this effect varies from patient to patient.

What are the limitations of MRI of the Prostate?

High-quality images depend on your ability to remain perfectly still and follow breath-holding instructions while the images are being recorded. If you are anxious, confused or in severe pain, you may find it difficult to lie still during imaging.

A person who is very large may not fit into certain types of MRI machines. There are weight limits on the scanners.

Implants and other metallic objects can make it difficult to obtain clear images. Patient movement can have the same effect.

A very irregular heartbeat may affect the quality of images. This is because some techniques time the imaging based on the electrical activity of the heart.

MRI cannot always distinguish between cancer and inflammation or the presence of blood products within the prostate. Blood may sometimes appear due to a prostate biopsy. To avoid confusing any bleeding with cancer, your doctor may wait six to eight weeks after prostate biopsy to perform prostate MRI. This will allow any remnants of bleeding to resolve.

A prostate MRI can detect if a cancer is growing outside the walls of the prostate gland or into nearby structures, such as the seminal vesicles or bladder. This is a sign of possible metastatic disease. However, the exam cannot tell if a cancer has spread distantly into other organs outside the pelvis. If you are a high-risk patient or a patient with biochemical recurrence, your doctor may perform PSMA PET/CT, a test that can accurately detect the spread of prostate cancer to anywhere else in the body.

An MRI exam typically costs more and may take more time than other imaging exams. Talk to your insurance provider if you have concerns about the cost of MRI.