Multiparametric MRI Imaging
Prostate MRI and PI-RADS Scores Explained
Written and reviewed by Shervin Badkhshan, MD · Last reviewed
November 2026
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PI-RADS is a score from 1 to 5 that radiologists use on prostate MRI reports. It describes how likely an area in the prostate is to be a cancer that may need treatment. A PI-RADS score is an estimate of risk, not a diagnosis. An MRI cannot diagnose prostate cancer by itself. Only a biopsy can.
1. What the test is and why I ordered it
A prostate MRI uses a magnet, not radiation, to show the inside of the prostate in detail. I order it when PSA or an exam raises concern, to decide whether a biopsy is needed and where to aim it, or to follow men on active surveillance.
2. What the numbers usually mean
Each area of concern gets a PI-RADS score from 1 to 5, describing how likely it is to be a clinically significant cancer:
- PI-RADS 1: very low
- PI-RADS 2: low
- PI-RADS 3: intermediate; the MRI can't call it either way
- PI-RADS 4: high
- PI-RADS 5: very high
The report also lists prostate volume (used to calculate PSA density), the size and location of any lesion, and whether anything appears to extend beyond the prostate. Most benign enlargement happens in the central (transition) zone; most cancers start in the outer (peripheral) zone.
3. What usually happens next
- PI-RADS 1 to 2: usually continued PSA monitoring rather than biopsy, especially when PSA density is low.
- PI-RADS 3: the decision depends on PSA density, other markers, and your preferences.
- PI-RADS 4 to 5: a targeted (MRI fusion) biopsy is usually recommended.
MRI is very good but not perfect. It can miss some cancers and flag areas that turn out to be benign.
4. When to call right away
- You cannot urinate
- After a biopsy: fever, chills, heavy bleeding, or clots
5. Where to see your result and ask about it
Your actual result, and any note from your care team, is in your patient portal, the same one you use to book visits and send messages. Send questions about your result through the portal, or call the office at (516) 535-1900. If something feels urgent, call the office or go to the nearest emergency room. This page explains what results usually mean; it can't interpret yours.
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