Greater Boston Urology Blog

What is 3D MRI/Ultrasound Fusion Biopsy?

Today, we have a Q&A with Greater Boston Urology's Dr. Michael J. Curran regarding 3D MRI/ultrasound fusion biopsy.

As with all content on Greater Boston Urology's blog, the following information is educational in nature, not medical advice. Always talk to your physician about your specific health care questions and conditions.

[Editor's note: This article was reviewed and updated on 7/21/21 with additional links.]

Q: First, let's discuss biopsies in general. When does a patient need a biopsy of the prostate?

DR. CURRAN: If a patient has an elevated PSA (prostate-specific antigen) and/or a palpable abnormality on their prostate gland, these patients will have the option to have a biopsy of the prostate. But let's back up a moment and talk about biopsies in general.

In almost all cancers, with the exception of prostate, when we do biopsies with the purpose of diagnosing cancer, we target the lesion. So if you have a thyroid nodule, we target that nodule and biopsy that. If you have a breast nodule, we target the nodule and biopsy that. If you have liver cancer, we'll get a CAT scan or MRI and target the lesion and biopsy that. If you have kidney cancer, we'll see a tumor on the kidney and biopsy that.

Up until recently, when someone met the criteria to have a biopsy of the prostate, the typical process involved performing an ultrasound study of the prostate and inspecting the prostate to see if we could spot anything to target. The prostate gland's location and the limits of the technology make it difficult to get a precise view, however. We'll see a targetable lesion by ultrasound probably less than 10 percent of the time. And when we target that, it still might be 50-50 whether we find cancer in that lesion or not. So 90 percent of the time, we will need to "randomly" biopsy the prostate to see if cancer is there.

Historically, the only cancer that has been "blindly biopsied" has been the prostate. And that was the best we could do, given the technology. But this has since changed, thanks to 3D MRI fusion biopsy.

Q: Simply put, what is 3D MRI/ultrasound fusion biopsy?

DR. CURRAN: In the last several years, we have seen increased interest in using MRI to evaluate the prostate. We've also seen advances in MRI technology that give us clearer pictures of the prostate gland. As such, we've created criteria that the radiologist can use to find specific lesions in the prostate that we should be targeting for biopsy.

But MRIs still pose challenges. The biggest issue is that it's very difficult to do a targeted biopsy on an MRI machine. The equipment alone would need to be highly specialized since we'd be performing the biopsy while in a magnetic field.

So the goal was to find a way to localize the lesions that we see on an MRI, but use something in an office environment that's readily available, like ultrasound, to do the targeting. So the idea was to "fuse" the MRI images (which are taken ahead of time) with an ultrasound that is done live in the office. If you can fuse those, then you can target a lesion for biopsy.

That's how the 3D MRI/ultrasound fusion biopsy came to be.

Today when we get an MRI, the radiologists provide us a scale that's rated 1 through 5, known as the PIRAD score. This is based on the radiologist's visual interpretation of the MRI as well as objective criteria (e.g. water density, blood flow parameters, etc.) that differentiate tumor cells from normal cells. As the PIRAD score increases, the likelihood that you'll find cancer in that lesion will increase.

So when we see patients with a PIRAD 1 or 2 lesion, the likelihood of finding cancer in that lesion is pretty low, less than 30 percent. With a PIRAD 4 or 5 lesion, the likelihood of finding cancer in that lesion rises up around 80-90 percent and in some cases, even higher.

Remember, if we're doing an initial biopsy guided by ultrasound alone, we're going to find cancer in about 35-40 percent of those patients. If we're doing a 3D MRI fusion biopsy, we find cancer in over 80 percent of those patients.

Q: In addition to the increased accuracy, what are some of the other benefits of 3D MRI fusion biopsy?

DR. CURRAN: The benefits are many and include the following:

  • There's no increase in side effects over conventional biopsy. The most commons side effect is some blood in the urine and blood in the semen. Infection is a possibility, but our infection rate at Greater Boston Urology is less than 1%, which is better than national averages.
  • There's no increase in down time over conventional biopsy.
  • Most patients can have a normal day a day or two after the biopsy.

Typically, our patients are very happy with the technology because we can show them on the screen what their prostate looks like and what appears suspicious. We can give them a picture that shows us taking a biopsy of the suspicious area. The patient then knows that they got the best care possible.

In addition, 3D MRI fusion biopsy allows us to decrease the number of overall biopsies since we can now better determine who, in fact, would truly benefit from a biopsy. At Greater Boston Urology, we've adopted criteria to decide who should have a 3D MRI fusion biopsy.

Q: Can you tell us more about the criteria?

DR. CURRAN: First, let's quickly review the indications to do a prostate biopsy: either an elevated PSA or a palpable nodule on the prostate. Now, here are our criteria for determining who should get a 3D MRI fusion biopsy:

1. Patients who've never had a biopsy, but who have a palpable nodule on the prostate. This could be somebody who has an elevated PSA or a normal PSA.

2. Patients who had prior negative biopsies (so the blinded ultrasound biopsy came back with no sign of cancer), but the patient's PSA is still rising. Their risk of harboring cancer is increasing based on the fact that they have a rising PSA. Some of these patients might have cancer that the first biopsy missed, and some patients do not have cancer. We use the MRI to decide who needs the biopsy and who doesn't. So if we don't see a lesion on the MRI, we may decide not to repeat the biopsy in that patient. We may just follow their PSA or follow them by MRI, or follow them by a combination of PSA and MRI. If we do see a lesion on the MRI, then we can do a targeted biopsy.

3. Patients who've been diagnosed with low and very low risk prostate cancer who are in active surveillance protocols. When these patients have their first repeat biopsy, which is usually one year after the initial diagnosis, we're getting an MRI, and if there's a lesion, then we perform the 3D MRI/ultrasound fusion biopsy.

We are finding a significant number of patients were under-staged at the time of their initial biopsy and that they're in need of moving from active surveillance to a treatment pathway. (Nationally, one third of all patients on active surveillance will eventually need to seek therapeutic intervention.)

4. Patients with very large prostates. When we do a blind ultrasound biopsy of the prostate, we're really hoping to find the cancer if it exists. The larger the prostate, however, the less likely we are to "hit" the cancer.

A normal prostate is between 20-30 grams. If someone has a prostate that's 80 grams or bigger—and the patient has never had a biopsy—we believe that patient would benefit from having an MRI first to see if there's something to target while that person undergoes a biopsy.

Q: Are there any downsides to 3D MRI fusion biopsy?

DR. CURRAN: MRIs are not one hundred percent perfect, which means we still find cancers in areas that look normal on MRI. In other words, a patient could have a clean MRI where we do not see a targetable lesion. The patient thinks he's OK, but he might not be. He might simply have a cancer that's still invisible to the MRI. This is why we don't use 3D fusion biopsy on everybody—it's not one hundred percent perfect.

Another important point: not all urologists are trained in 3D MRI fusion biopsy. At Greater Boston Urology, we have designated three specific physicians who have done additional training and have spent hundreds of hours gaining expertise in utilizing this technology. We have been very fortunate to be in an integrated urology group that allows us to make sure all of our patients, regardless of which of our offices they go to, can have access to this type of technology and the expertise our doctors have gained in doing the biopsies.

Q: Does insurance typically cover 3D MRI fusion biopsy?

DR CURRAN: The biggest challenge we face with insurance companies is that they are making it harder for us to get MRIs. I have heard countless stories from urologists having a hard time getting MRIs approved by insurance companies, which ends up being a roadblock to using the technology.

At GBU, we have good success at getting approval for our patients' MRIs. When we explain to insurance companies that this is not a random request, we have the guidelines discussed above, and we're using this technology in an effort to reduce the number of people having biopsies overall, then they typically will approve the MRI.

Again, it's because of our integrated group practice of urology that has allowed us to have these conversations with insurance companies and to provide this service to our patients.

Q: How long has GBU been offering 3D MRI fusion biopsy?

DR. CURRAN: We were the first group in New England to perform 3D MRI fusion biopsy with a system called Artemis. This was approximately four years ago. Last year, we upgraded to the Invivo UroNav system.

We have three physicians trained and certified in 3D MRI fusion biopsy: Dr. Geffin, Dr. Lin, and myself. We also have an ultrasound manager, Shane Kolton. He's a true equipment specialist who supports the doctor in every procedure. It's an incredibly strong team.

Q: What else would you like readers to know about 3D MRI fusion biopsy?

DR. CURRAN: Thanks to this technology, our understanding of prostate cancer has changed in two specific areas. Historically, the anterior part of the prostate gland was very difficult to sample, and, thus, under-sampled when doing a blind ultrasound-guided biopsy. We used to believe very few cancers were located in this anterior region. With 3D fusion biopsy, we're finding that we just weren't diagnosing those cancers and that they occur in much greater number than we believed existed before. So it's changing our understanding of where cancer is in the prostate gland, which is a significant benefit.

The other area involves the issue of under-staging, which I mentioned earlier. For patients who have been told they can go on active surveillance, we're finding that some of them had cancers that were under-staged. The reason for the under-staging is related to the Gleason score.

The Gleason score is a number from 2-10 that the pathologist gives us that tells us how aggressive the cancer is. If it's 6 or less, it's not very aggressive. If it's 8 or higher, it's an extremely aggressive disease. And if it's 7, it's intermediate.

We're finding that many patients who we tell have a Gleason 6 disease may actually have a Gleason 7. What we're finding, thanks to 3D fusion biopsy, is that as you get more central to the tumor itself, the Gleason score increases. So when you're at the exact center of a tumor, you're going to find the highest Gleason score that's in that tumor. As you move out into the periphery, the Gleason scoring may actually change.

So the ability to not only target that tumor, but also target the center of the tumor may have an impact on what we recommend to the patient for treatment. The 3D MRI fusion biopsy gives us the ability to better target the center of the tumor, resulting in a more precise Gleason score.

Q: If a reader is interested in going through Greater Boston Urology for a 3D MRI fusion biopsy, how would that work?

DR CURRAN: If you're currently a Greater Boston Urology patient, we'll definitely discuss the criteria with you. If you are a patient outside of GBU, we're more than happy to work with your urologist to provide the technology and then return you to your doctor once the biopsy is done. Bottom line: we can provide the technology to anybody who wants it, provided he fits the criteria.

If someone would like a consult, he is free to go to our website and contact one of our doctors. From there, we'd be happy to talk to him about the technology.

From a billing perspective, if you're in a closed-network system, it depends on whether you have any out-of-network benefits or not. Some closed networks have no out-of-network benefits. We can still see you, but you'd have to pay cash.

If you're in a narrow network that has out-of-network benefits, you can come to see us with a referral, and your co-pay and deductible may be slightly higher than if you were "in network."

And if you have Medicare, Medicaid, or a PPO, you can come see us.

Thanks for your time, Dr. Curran.



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