Prostate MRI

Panorama general

Prostate magnetic resonance imaging (MRI) is a test that creates detailed pictures of the prostate.

MRI uses a magnetic field and radio waves to create pictures of the inside of the body. When it's used to make pictures of the prostate, MRI can look for signs of prostate cancer and other conditions that affect the prostate.

For prostate cancer, a healthcare team might use prostate MRI to help decide whether to do a prostate biopsy. A biopsy removes samples of prostate tissue for testing. MRI images also may help with planning the biopsy. If the prostate MRI shows areas of concern, the biopsy can focus on those areas. After a prostate cancer diagnosis, MRI might give information that helps the healthcare team decide on the treatment.

Prostate MRI is done in different ways. Some techniques use a thin wire in the rectum to improve image quality. Others use contrast material to show blood flow. Multiparametric MRI (mpMRI), which uses contrast, combines several MRI techniques to highlight differences between healthy prostate tissue and prostate cancer. The healthcare team chooses the method based on the reason for the test.

Por qué se hace

Prostate MRI is an imaging test that creates detailed pictures of the prostate. This test is done to look for signs of prostate cancer and other prostate conditions. A healthcare team may order prostate MRI to gather information that other tests can't get.

Prostate cancer

The healthcare team might use prostate MRI at different times before and after prostate cancer diagnosis.

• After a PSA test. If a prostate-specific antigen (PSA) test finds a high level of PSA in the blood, a healthcare professional might recommend prostate MRI to look for signs of cancer. The results of your MRI scan might help the health professional decide whether a biopsy is needed. A prostate biopsy removes tissue samples from the prostate for testing.
• Before a prostate biopsy. MRI may help identify areas in the prostate that raise concern for cancer. Then the healthcare team can target those areas during a prostate biopsy. A biopsy done in this way is sometimes called a fusion biopsy.
• After a prostate cancer diagnosis. After confirming a prostate cancer diagnosis, the healthcare team might use MRI to see whether the cancer has grown beyond the prostate. This information helps the healthcare team plan treatment.
• Before starting active surveillance. Some people choose close monitoring instead of treatment for prostate cancer. This approach is called active surveillance. A prostate MRI scan can help check for areas of cancer that may have been missed on other tests before starting active surveillance.
• When prostate cancer comes back. If the healthcare team thinks the prostate cancer has come back, a prostate MRI scan can look for signs of cancer in the prostate area. When prostate cancer comes back it's called prostate cancer recurrence.

Some people wonder whether prostate MRI is better than a prostate biopsy. Prostate MRI can detect areas of concern and say whether they are likely or not likely to be cancer. But prostate MRI can't tell for sure whether or not you have cancer. A prostate biopsy removes tissue samples for testing. It's the only way to be sure about the diagnosis. MRI and biopsy have different uses, although they can be used together to diagnose prostate cancer.

Other prostate conditions

A prostate MRI scan also may help the healthcare team check prostate symptoms or other concerns. Prostate MRI images may show conditions that are not cancer.

• Enlarged prostate. Prostate MRI sometimes shows an enlarged prostate, called benign prostatic hyperplasia (BPH).
• Prostatitis. Prostate MRI sometimes finds signs of swelling and irritation in the prostate. This condition, called prostatitis, can be caused by infection. Prostatitis sometimes looks similar to prostate cancer on MRI scans.
• Conditions present at birth. Prostate MRI may show prostate conditions that someone is born with, such as differences in the way the prostate developed before birth. Conditions that are present at birth are called congenital conditions.

Riesgos

Prostate MRI is a safe procedure. There are no known harmful effects from exposure to the magnetic fields or radio waves used to make the images. While other tests use radiation to make images, MRI doesn't use radiation.

As with all tests, prostate MRI has some side effects and risks.

Side effects of contrast material

Some prostate MRIs use a contrast material with gadolinium to make clearer pictures. The contrast material is safe for most people.

A healthcare professional puts the contrast into a vein in your arm or hand. You might get a bruise from the injection. Sometimes the contrast causes nausea. It also is possible to have an allergic reaction.

Some types of gadolinium can cause side effects in people with kidney disease. If your healthcare team is concerned about this, they might test your kidney function to help choose the contrast that is safe for you.

Risks caused by metal objects

MRI uses strong magnets to make pictures. These magnets can affect metal in and around the MRI machine, creating a risk of serious injury. Metal on or in the body also can cause problems with the MRI images.

Do not wear anything made of metal to your appointment. Remove anything metal that you can, such as body piercings, jewelry, hearing aids and removable dental devices.

Tell your healthcare team about any metal that can't be removed. This includes pacemakers, defibrillators, nerve stimulators, hearing implants, and metal coils and clips. Some implanted devices are safe to have in the MRI machine, but some aren't. Your healthcare team makes sure any metal that's in your body is safe before your MRI.

Incorrect results

A prostate MRI scan is an accurate test, but it's possible for the test to miss an area of cancer. This is called a false-negative.

It's also possible for the test to detect something that looks like cancer but is later shown by a biopsy to not be cancer. This is called a false-positive. Some conditions that aren't cancer can look similar to prostate cancer on an MRI scan. This includes bleeding from a prostate biopsy and swelling and irritation of the prostate, called prostatitis.

Healthcare teams use prostate MRI results along with the results of other tests and procedures to get an accurate diagnosis and select the right treatment for you.

Cómo prepararte

If your healthcare team gives you instructions to help you prepare for prostate MRI, follow them carefully. Your team may ask you to stop eating and drinking for a period of time before the test. Often you can take your medicines as usual unless you are told something different by your care team. If your MRI uses a device that goes into the rectum, your healthcare team may ask you to use an enema at home before your appointment. An enema flushes waste from the rectum with water or a solution.

Before your prostate MRI scan, tell your healthcare team:

• About any medicines you take, including medicines that you can buy without a prescription, as well as any vitamins or supplements that you take.
• About any allergies or bad reactions you've had to any medicines, foods, iodine or latex.
• About any metal or devices in your body. Examples include implanted medical devices, such as pacemakers and glucose monitors, and foreign metal objects, such as bullet fragments and body piercings.
• Whether you've ever felt afraid of being in small spaces, also called claustrophobia. Some people feel this way during imaging tests. Medicine may help you feel more at ease during the test.

If you drive, you should be able to drive yourself to and from your appointment. If you receive medicine to help you feel at ease during the test, you will need someone to drive you to and from your appointment. Ask a care team member about this before the day of your scan.

Qué esperar

During a prostate MRI scan, you lie on a table that goes into an imaging machine. If the test involves using contrast material, it typically takes about 45 minutes. A prostate MRI scan that doesn't use contrast often takes less time.

After the test, you can go about your day as usual unless you receive medicine to help you relax during the test. If you receive this medicine, you should not drive or return to work that day.

Before prostate MRI

Before prostate MRI, you change into a gown. Your care team may ask you to use the bathroom. Having an empty bladder and rectum helps make the images clearer.

Sometimes prostate MRI uses contrast material. If your MRI scan uses contrast, a member of the healthcare team puts a thin tube into a vein in your hand or arm. You might feel a pinch when it goes into your skin. The healthcare team gives the contrast through the tube.

For some prostate MRI scans, the healthcare professional puts a device into your rectum. The device, called an endorectal coil, only goes a short way into the rectum. The coil contains wires that send signals to the MRI machine. The coil is covered by a condom and has a small balloon on one end. You may feel pressure in the rectum as the healthcare professional inserts the device and inflates the balloon to hold the device in place.

During prostate MRI

During prostate MRI, a healthcare professional asks you to lie on a table that can slide into the MRI machine. Often, the MRI machine looks like a long narrow tube that is open on both ends. Some machines are open on the sides.

Once you're in the right position, the healthcare professional goes to another room where the care team monitors you. The table slowly slides through the MRI machine. The table might go in and come out of the machine a few times during the test.

The MRI machine creates a strong magnetic field around you. The machine directs radio waves at your body. You don't feel the magnetic field or radio waves, and there are no moving parts around you.

You shouldn't feel pain during a prostate MRI scan. It's possible to feel some discomfort from lying still during the test. If this becomes too much, tell your care team. The team uses monitors so that they can see and hear you during the test.

During the MRI scan, the internal part of the magnet produces repetitive tapping, thumping and other noises. Your care team may offer you earplugs or play music to help block the noise.

After prostate MRI

After the prostate MRI is done, you rest for a few minutes while your healthcare team checks the images. The team reviews the images to ensure no more scans are needed. Once your healthcare team decides you are done, you can leave and go about your day. Follow any instructions you receive from your care team.

Resultados

Ask your healthcare team when you can expect to learn the results of your prostate MRI scan. The healthcare professionals who run the imaging machine can't tell you the results. You likely will get the results from the healthcare professional who ordered the test. Sometimes the results appear in an online patient portal before you meet with your healthcare professional to talk about the results.

A radiologist looks at the prostate MRI scans to determine the results. A radiologist is a doctor who specializes in using imaging tests to diagnose diseases. The radiologist usually writes the results for other healthcare professionals, so the report can be hard to understand.

What prostate cancer looks like on MRI scans

On prostate MRI scans, areas of concern that are likely to be cancer often look darker than the tissue around them. The MRI results might describe a dark area in the images as a lesion or an area of signal change. If the test used contrast, areas of prostate cancer may take up the contrast sooner than healthy tissue does.

The radiologist who looks at the images checks for patterns that are commonly found in images that show prostate cancer.

A prostate MRI scan can't tell whether cancer is present or not. Instead, the results tell whether it's likely or not likely that something found on the images may be cancer.

What the PI-RADS score means

The prostate MRI report may contain a score based on the Prostate Imaging-Reporting and Data System (PI-RADS). The score, which goes from 1 to 5, describes how likely it is that something concerning detected on MRI is a clinically significant prostate cancer.

A clinically significant prostate cancer is one that may need treatment. PI-RADS defines a clinically significant cancer as one that has a Gleason score of 7 or higher or a grade group of 2 or higher.

• PI-RADS 1 is a very low score. It means that it's highly unlikely that the area of concern detected on the images is a clinically significant prostate cancer.
• PI-RADS 2 is a low score. It means that it's unlikely that the area of concern is a clinically significant prostate cancer.
• PI-RADS 3 is an intermediate score. It means it's not clear whether the area of concern is a clinically significant prostate cancer.
• PI-RADS 4 is a high score. It means that it's likely that the area of concern is a clinically significant prostate cancer.
• PI-RADS 5 is a very high score. It means that it's highly likely that the area of concern is a clinically significant prostate cancer.

If there is more than one area of concern in the images, your results may have more than one PI-RADS score.

PI-RADS scores are based on MRI scans. They don't include blood test results, biopsy results or symptoms. Your healthcare team uses the MRI results along with other information to decide on next steps.

Common terms in prostate MRI results

The radiologist often describes what the MRI results look like using technical terms. Here are some terms that you may see.

• Lesion. A lesion is an area that looks different from surrounding prostate tissue. It doesn't always mean cancer. A lesion also could be an area of scarring or irritation.
• Restricted diffusion. Diffusion-weighted imaging is a type of MRI that looks at the movement of water molecules in the prostate tissue. When the results say there is restricted diffusion in a certain area, this means the water molecules aren't moving as freely as they do in other areas. Prostate cancer often shows restricted diffusion. Other conditions also can cause this, so this term doesn't always mean cancer.
• Low T2 signal. T2-weighted imaging is a type of MRI that looks at the amount of water in the tissue. Areas of tissue that have a lot of water appear brighter. Areas with less water appear darker. The results might say the darker areas have a low T2 signal. Prostate cancer can cause a low T2 signal, but so can prostatitis and benign prostatic hyperplasia (BPH).
• DCE positive. Dynamic contrast-enhanced (DCE) imaging is a type of MRI that looks at how tissue takes up contrast. DCE positive means that an area of concern takes up the contrast more quickly than the tissue around it. It doesn't always mean cancer, but it can raise the chances that prostate cancer is present.

What your prostate MRI results mean

What your prostate MRI results mean for you depends on the reason for your test. Your healthcare team considers these results with those from other tests. Together, this information helps the team decide what action to take next.

Next steps depend on the results and the overall situation. Some people may not need more testing right away. Others may have more imaging tests or a prostate biopsy.