Magnetic Resonance Imaging (MRI) uses magnets and radio waves to form images of tissue inside the body. Stronger magnets produce higher-quality images. MRI machines range from weaker .5 Tesla (T) magnets to very strong 3.0 T machines.
MRI for Prostate Cancer Screening
In the United States, MRI is primarily used to assist with prostateThe prostate is a walnut-sized gland located between the bla... Full Definition cancerCancer is a group of diseases where cells grow abnormally an... Full Definition grading and staging. However, there is great interest in exploring MRI for initial prostate cancer screening as well. MRI for screening has proven popular in Europe, where more studies have been conducted to determine its accuracy in spotting tumors. According to a 2015 study, adding prostate MRI to prostate screening improves cancer detection and reduces unnecessary biopsies. This is an exciting possibility that could help many men avoid the discomfort and side effects of biopsyAn examination of tissue removed from the body to understand... Full Definition.
While there is a lot of evolving data, pre-biopsy MRI is not yet the diagnostic standard in the U.S., which means doctors are not likely to recommend it (and insurance may not cover it). This is one of those instances where you should ask your doctor if prostate MRI prior to biopsy might be helpful in your case. There may be clinical trials you can participate in or guidelines may change based on new research. It’s always okay to ask for different options.
MRI in prostate cancer care is becoming more common. In a 2014 study that surveyed academic medical centers, nearly 90% of the centers reported routine use of prostate MRI for cancer diagnosis and staging. Patients interested in a prostate MRI might consider visiting a major medical center if their local medical center does not offer prostate MRI.
MRI for Prostate Cancer Grading and Staging
Doctors can use prostate MRI tests to help stage prostate cancer. Urologists may refer men to radiology for a prostate MRI after a positive biopsy. The MRI test provides information that a biopsy might not, such as determining whether or not the cancer had spread beyond the prostate glandA gland is an organ that produces and secretes a chemical su... Full Definition.
This information, along with biopsy findings, PSA test results, and digital rectal exam results, can help the care team identify the best treatment options. For example:
- MRI images can determine with very good confidence whether or not the cancer has spread beyond the prostate gland. If it has, surgery may not be a good option, except in certain situations. BrachytherapyA form of radiotherapy where small radioactive implants are ... Full Definition may not be a good option either, unless combined with other types of radiationHigh-energy particles that cause ionization and tissue damag... Full Definition therapy.
- MRI images can show the location of a tumorA lump or swelling caused by abnormal growth of cells. Not a... Full Definition. A man’s tumor may be small but if it is close to the edge of the prostate, perhaps near the nerves important in erectile function or near the urethraThe duct urine (and semen for men) passes through on the way... Full Definition or rectal walls, doctors might encourage the man to pursue treatment rather than active surveillance.
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MRI also plays a valuable diagnostic role when used alongside biopsy. Even with a biopsy, cancer can be missed, especially if the tumor is close to the front of the body, where it is hard to feel during a digital rectal exam and hard to reach during a biopsy. The use of MRI to better target lesions during biopsy is also becoming more common.
A Versatile Tool in the Fight Against Prostate Cancer
To recap, MRI may currently be used in several ways:
- To provide staging information that guides therapy choice
- To determine if a biopsy is necessary
- To find cancer that might be missed in a biopsy
- To guide biopsies so that diseased tissue is sampled
- To guide radiation therapy so that diseased tissue gets a higher dose of radiation
- To assess a patient after treatment to determine if the treatment was successful
- To monitor a patient during active surveillance to see if the cancer is growing
- To monitor a patient after treatment to see if the cancer has come back
In some medical centers, the most recent advance in prostate MRI involves using an MRI scan to produce a 3D model of a patient’s prostate and surrounding tissue. Doctors can disassemble the resulting model, called a phantom, during a meeting with the patient and use it to explain where the cancer is and what different treatment options will do about it.
The phantoms are created using 3D printing using the MRI scan data as a 3D map. The phantom includes not only healthy prostate and tumor tissue but also the urethra, rectumThe final section of the large intestine, which ends at the ... Full Definition, nerve bundles, seminal vesiclesSmall glands that sit on top of the prostate that add nutrie... Full Definition, and penile bulbThe bottom portion, or base, of the penis, composed of a lar... Full Definition. The patient will be able to see just how big his tumor is and how close it is to other sensitive organs and tissues.
MRI Risks & Side Effects
MRI is a safe technique that does not expose the patient to radiation the way CT scans and X-rays do. Men who have metal objects in the body, including pacemakers, cochlear implants, or even shrapnel, should discuss them with their doctor. These objects could be life endangering during an MRI because the procedure involves use of a powerful magnet.
Some patients may find the MRI machine to be confining and uncomfortable. Open MRI machines that are open on all sides, or open-bore machines, meaning the tunnel is wider, are available at some imaging centers. If you have concerns about claustrophobia or any other aspect of the MRI procedure, discuss them with your doctor so you can find a solution together.