15 September, 2018

What is Prostate MRI?

Prostate MRI is a non-invasive imaging technique that uses magnetic fields, radio waves, and high-powered computers to create detailed pictures of the prostate gland. Since 2009, it has played an increasingly important role in the detection, diagnosis, and management of prostate cancer. It allows radiologists to determine the size, extent, and nature of a tumor, while simultaneously helping men avoid overtreatment and manage their cancer without sacrificing their quality of life.

Benefits of Prostate MRI

Before prostate MRI, radiologists diagnosed prostate cancer using ultrasound-guided biopsy. A systematic biopsy requires up to 12 needles inserted into the prostate. Due to the limitations of ultrasound, the needles were inserted randomly, in the hopes of discovering a malignant tumor. This type of testing – informally labeled “poke and hope” by physicians – often missed significant cancers, resulting in repeated biopsies and the risk that an undiscovered cancer could grow and become life-threatening.

Prostate MRI eliminates the need for this type of procedure. It maps the interior of the prostate – something impossible with ultrasound – and provides detailed pictures of abnormal growths. It can also measure the metabolic activity of abnormal cells. (Cancer cells restrict the movement of water and have unusual blood flow, both of which are visible on an MRI.) As a result, its detection of intermediate and high-risk cancers is 17 percent higher compared to systemic biopsy.

Additionally, when biopsy is required, level one data from two randomized clinical control studies called “Promis and Presision” has proven the benefit of performing MRI beforehand. In some cases, this makes it possible to identify benign tumors without biopsy. In others, MRI is a guide, allowing physicians to target specific growths with a single needle, resulting in less discomfort and few missed cancers.

Effect on Treatment

Using prostate MRI, physicians can locate the exact position of a cancer, measure its volume, estimate its Gleason score – which indicates how aggressive it is – and determine its stage. It can even tell whether the cancer has spread to organs outside the prostate. Using this data, physicians can make better recommendations and patients can make better decisions regarding treatment.

Active Surveillance

Because prostate MRI can differentiate between high-grade and low-grade cancers, it opens the door to an approach known as “active surveillance.” During active surveillance, the patient’s condition is monitored with regular MRIs, PSA evaluations, and clinical evaluation, but no surgery or radiation is given until the cancer becomes threatening or produces major symptoms. According to the Prostate Cancer Foundation, roughly 30 percent of prostate cancers will never grow large enough to become life-threatening and can be safely managed with active surveillance.1

Candidates for Prostate MRI

Men who are worried about their health should discuss prostate MRI with their doctor to see whether they might benefit from the procedure. Prostate MRI is recommended for men who meet the following criteria:

  • Have elevated PSA levels

  • Have received a positive digital rectal exam

  • Have a known cancer that needs to be staged

  • Are part of an active surveillance program

  • Who suspect they may have a recurrent prostate cancer

PSA (prostate-specific antigen) is an enzyme secreted by the prostate gland. High levels of PSA are strongly associated with prostate cancer. A digital rectal exam is a physical examination where a doctor examines a patient’s prostate with their finger, looking for abnormal bumps or growths.

RadNet Prostate MRI Program

RadNet was one of the first radiology practices in America to establish a dedicated prostate MRI program. Our prostate MRI team performs more prostate MRIs than any group in the country and outcome audits have shown our accuracy meets or exceeds the top academic centers in the world. This level of knowledge and insight result in accurate, relevant, and clinically significant reports for patients and their doctors and allows them to triage men at risk and stratify men who would benefit from biopsy.


  1. Prostate Cancer Foundation: Active Surveillance

15 September, 2018


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