MRI Imaging for Prostate Cancer
Magnetic resonance imaging (MRI) is an important tool in diagnosing and treating prostate cancer. It uses magnetism and radiowaves to create a picture of what’s inside your body. A positive biopsy is required to definitively diagnose prostate cancer.
MRI imaging aids the precise targeting of areas for focal therapy. Recent developments in MRI technology have allowed radiographers to create more accurate scans. This includes the development of multiparametric MRI scans (mpMRI).
What is a Multiparametric MRI (mpMRI) scan for prostate cancer?
A multiparametric MRI (mpMRI) is a detailed prostate scan that combines several imaging sequences to locate and grade cancer before any biopsy. Used first in the pathway, it reduces unnecessary biopsies and improves accuracy — MRI-targeted biopsy detects 36.3% of clinically significant cancers versus 27.6% with standard TRUS biopsy (VISION, European Urology, 2024). Dr Aqua Asif of The Focal Therapy Clinic is a named co-author of this study.
An mpMRI (multi-parametric MRI) is a highly detailed imaging test that helps identify clinically significant prostate cancer more accurately than a biopsy alone. It also reduces unnecessary biopsies — in the VISION analysis, 32.2% of men were able to avoid a biopsy altogether — and improves biopsy sample accuracy.
At The Focal Therapy Clinic, we use your mpMRI results to determine if you're suitable for focal therapy. During the scan, a contrast agent is used to make images clearer, helping us see if cancer is confined to the prostate or has spread.
focal therapy eligibility →
Prostate MRI builds on a proud British legacy: Professor John Mallard's medical physics team at the University of Aberdeen developed the world's first whole-body MRI scanner, which scanned its first patient in 1980. That pioneering work laid the foundation for the MRI-first diagnostic pathway that protects men from unnecessary biopsies today.
What to expect when getting your MRI scan
- You may be asked to change into a hospital gown or keep your clothes if they don’t have metal (zips, clips).
- Remove jewellery, body piercings, and your watch.
- Empty pockets of coins and keys.
- You can bring a friend or relative, but they must also remove any metal.
- You'll lie on your back on a couch that slides into the MRI machine.
- A contrast dye may be injected into your arm to enhance images of the prostate.
- Possible mild side effects from the dye: nausea, headache, warmth, metallic taste, dizziness.
- Stay as still as possible (scan takes about 10 minutes).
- The radiographer will monitor you throughout, and you can communicate via an intercom.
- You may be asked to hold your breath at times.
- The MRI machine makes a loud clanging sound—headphones will be provided for hearing protection.
Getting the results
After your mpMRI, a specialist prostate radiologist assigns a PI-RADS or Likert score from 1 to 5: 1–2 means cancer needing treatment is unlikely; 3 is uncertain; 4–5 means it is likely to very likely. At The Focal Therapy Clinic your scan is reported by a consultant radiologist to recognised quality standards (PI-QUAL).
A radiologist will review your MRI images and assign a score from 1 to 5, known as your PI-RADS or Likert score. This score indicates the likelihood of cancer in your prostate, with 1 being low risk and 5 being high risk.
| PI-RADS or Likert score | What it means |
|---|---|
| Score 1 | It's very unlikely that you have prostate cancer that needs to be treated |
| Score 2 | It's unlikely that you have prostate cancer that needs to be treated |
| Score 3 | It isn't possible to tell from the scan whether you have prostate cancer that needs to be treated - you may hear this called a borderline result. |
| Score 4 | It's likely that you have prostate cancer that needs to be treated |
| Score 5 | It's very likely that you have prostate cancer that needs to be treated. |
The PI-QUAL scoring system used to assess prostate MRI reporting quality was developed by Dr Francesco Giganti (first author), with Dr Clare Allen and Dr Aqua Asif of The Focal Therapy Clinic among its co-authors (Radiology, 2023).
Why MRI quality matters — and what a first-class report includes
Focal therapy is only as good as the map it follows — put simply, you can't treat what you can't see. Your treatment plan relies on the biopsy, the biopsy relies on the radiologist's reading of your MRI, and that reading relies on the scan being done well in the first place. A weakness anywhere in that chain narrows your treatment options at the end of it: without good imaging, there is no focal therapy.
A clear, expert mpMRI also spares men unnecessary procedures: 30–40% of men can avoid a biopsy altogether when imaging is done and read to a high standard — a range the published trials support (VISION found 32.2% of men could avoid biopsy; PROMIS, 27%).
Not every scan and report meets the same standard.
Mr Alan Doherty, Consultant at The Focal Therapy Clinic, expects five things in every prostate MRI report:
One quality marker worth asking any centre about is how often it reports PI-RADS 3 ("uncertain"). Expert centres commit to a clear answer wherever the imaging allows and keep equivocal reports low; frequent fence-sitting pushes almost every patient towards a biopsy — which defeats the purpose of scanning first.
Mr Doherty also puts a number on what a decisive report means in practice: "If it's PI-RADS 4, I know that's a 70 per cent likelihood of hitting a cancer." Our own audit bears this out — across 426 PI-RADS 4 patients, 69.7% had clinically significant cancer confirmed on biopsy.
Reporting standards are improving nationally — and The Focal Therapy Clinic's radiologists have been at the centre of that work. Dr Clare Allen, this page's reviewing radiologist, has been instrumental in establishing standards for prostate MRI reporting over the last 15 years. She was lead radiologist on the landmark PROMIS trial (The Lancet, 2017), which established that mpMRI detects 93% of clinically significant prostate cancers compared with just 48% for standard TRUS biopsy, and she recently led a study across 14 London hospitals showing that targeted regional intervention improves the diagnostic quality of prostate MRI protocols. Prof Francesco Giganti, her fellow FTC radiologist, is first author of the PI-QUAL quality standard (versions 1 and 2) and a developer of the PRECISE and PI-FAB scoring systems now used worldwide. At The Focal Therapy Clinic, every scan is reported by a consultant uro-radiologist to the PI-QUAL standard our own team helped create.
What does such a report actually look like? The structured format shown below — a per-zone scoring grid, precise volume measurements, annotated images and a schematic map of every lesion — was pioneered by Dr Allen and is the standard to which every Focal Therapy Clinic patient's scan is reported.
What our own audit shows
The Focal Therapy Clinic audits its diagnostic pathway. In an internal audit of MRI-ultrasound fusion targeted biopsies over 36 months (881 patients, 2,235 targeted lesions, all with complete histology), detection rates rose step-by-step with the PI-RADS score — exactly as the scoring system intends:
| PI-RADS score | Patients | Significant cancer found (GG2+) |
|---|---|---|
| PI-RADS 3 ("uncertain") | 218 | 60.6% |
| PI-RADS 4 | 426 | 69.7% |
| PI-RADS 5 | 223 | 88.3% |
Before any biopsy, every MRI in this series was second-read and contoured by Dr Clare Allen, Consultant Radiologist — the specialist review this page describes. The audit measured what that second review adds:
| Second-review outcome | Result |
|---|---|
| Patients with areas of concern identified on MRI review (not in the original report) | 40.4% |
| Patients whose PI-RADS score was upgraded | 10.3% |
| Patients with clinically significant cancer found in a previously unreported location | 1 in 6 (16.0%) |
| Patients spared a false-negative ("no cancer") result | 16 of 881 |
Source: FTC internal audit of biopsies over 36 months to March 2026. Read the full audit summary (PDF)
Fusion MRI
An MRI-ultrasound fusion biopsy overlays your mpMRI onto live ultrasound so the needle targets the exact suspicious area, rather than sampling the prostate at random. This targeted approach — established by the PRECISION and VISION trials — finds more significant cancers and misses fewer, while sparing men with low-risk findings an unnecessary biopsy.
Fusion MRI is an advanced technique that combines MRI scans with live ultrasound to guide prostate cancer treatments.
In a fusion MRI, our expert radiographer marks your prostate, your tumour and lesions, your seminal vesicles and your urethra on your scan results. In a fusion biopsy, a grid is also added. During your biopsy, your MRI scan is overlayed onto your live ultrasound, and a grid-shaped needle guide is used to accurately sample the target area. With a transperineal fusion MRI-guided biopsy, there is very little downtime or soreness afterwards, and it’s much more accurate in confirming a suspected diagnosis of prostate cancer.
During fusion focal therapy, the MRI scan is overlayed onto your live ultrasound and this is used to guide your treatment; for HIFU, this is an ultrasound probe, and for NanoKnife, it is needles. This allows your surgeon to target your tumour very accurately, increasing the effectiveness of your treatment and reducing the risk of damaging any other tissue.
If your MRI and biopsy confirm you're suitable, focal therapy (HIFU or NanoKnife) can treat the cancer while sparing healthy tissue — see focal therapy treatment options.
- Improved Tumour Detection – More accurate than ultrasound alone
- Greater Targeting Precision – Helps specialists precisely pinpoint tumours
- Reduces Risk of Missing Cancerous Tissue – Ensures comprehensive tumour destruction
How Is an Ultrasound-MRI Fusion Prostate Biopsy Done?
You first receive a prostate MRI. The radiologist reviews the images for areas that are suspicious for prostate cancer.
Next, doctors perform an ultrasound test. Your doctor provides local anaesthesia for your comfort and inserts a small ultrasound probe into the rectum.
The fusion biopsy technology combines your MRI images with the ultrasound image in real time. This fusion (blending) of images creates a clearer picture to pinpoint any suspicious areas in the prostate.
Your doctor uses the ultrasound and prostate MRI images to collect the prostate biopsy (tissue sample) with a needle. Only urologists with special training and knowledge of prostate cancer perform this procedure.
“I didn’t have a multi parametric [MRI]. It was a conventional imaging, and that didn't show anything on the normal MRI…..it was from the biopsy how I was diagnosed.The biopsy showed that I had prostate cancer, and fortunately, because I caught it early, it was Gleason six, which is the early stages.”
Alphonso Archer
The Focal Therapy Clinic patient
Questions to ask your doctor or nurse
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Frequently asked questions
Learn more about focal therapy for prostate cancer
Survey of Prostate Cancer Patients Reveals Severe Knowledge Gaps Among Men
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Is Testosterone Replacement Therapy Safe After Prostate Cancer Treatment?
Sources
Medically reviewed by Dr Clare Allen, Consultant Radiologist (mpMRI pioneer; PROMIS lead radiologist).
Evidence: Kasivisvanathan V, … Asif A, … Moore CM. VISION: MRI-targeted vs standard biopsy. European Urology 2024;87(5):512–523 (doi:10.1016/j.eururo.2024.08.022) — co-authored by FTC's Dr Aqua Asif. Giganti F, Ng A, Asif A et al. PI-QUAL. Radiology 2023 (doi:10.1148/radiol.231130) — co-authored by FTC's Dr Aqua Asif and Dr Francesco Giganti. Ahmed HU et al. PROMIS. Lancet 2017. Kasivisvanathan V et al. PRECISION. NEJM 2018.
Guideline: NICE NG131.
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