MRI Makes Prostate Screening More Precise

Prostate cancer screening isn’t a guideline-directed screening test yet, but this could change with the use of MRI and other tools. A series of papers published in several JAMA journals late last week indicates the progress that’s being made. 

As we’ve discussed in previous issues, prostate screening with PSA tests hasn’t met the threshold for clinical benefit achieved by other population-based screening exams.

  • PSA-based screening has been characterized by lower mortality benefits and relatively high rates of overdiagnosis and complications from follow-up procedures. 

But some researchers believe that PSA screening could be made more effective by using additional diagnostic tools like imaging and blood tests to focus on potentially high-risk disease for biopsy while active surveillance is used for less threatening prostate lesions. 

In the ProScreen trial in Finland, researchers tested the combination of PSA, a kallikrein four-panel blood test, and MRI in selecting patients for biopsy. 

  • Patients were sent to MRI if they had PSA scores of 3.0 ng/mL or higher and kallikrein scores of 7.5% or higher; those with abnormal MRI scans got targeted biopsy. 

The researchers tested the ProScreen protocol in a study of 61.2k men, with 15.3k invited to screening and 7.7k getting screened. Over a preliminary three-year follow-up period, researchers found …

  • 9.7% of men met the PSA threshold for a suspicious lesion; this fell to 6.8% after the kallikrein test and 2.7% after MRI, illustrating the protocol’s ability to reduce biopsies
  • Biopsy yield for high-grade cancer was 1.7%, which an editorial called a “remarkably high yield”
  • Overdetection of low-grade disease was 0.4%, compared to 3.2% in a comparable previous study

In a second study, this one in JAMA Oncology, researchers performed a meta-analysis of 80.1k men from 12 studies in which MRI was used to direct patients to prostate biopsy after PSA testing, finding that MRI-directed protocols had …

  • Higher odds of detecting clinically significant prostate cancer (OR=4.15) compared to PSA screening alone
  • Lower odds ratio for biopsy (OR=0.28)
  • Lower odds ratio for detecting clinically insignificant cancer (OR=0.34)

Finally, a secondary analysis in JAMA of a large UK trial illustrates the challenges of prostate screening without MRI guidance. Researchers reviewed 15-year outcomes of the Cluster Randomized Trial of PSA Testing for Prostate Cancer (CAP), a study of 415k men,196k of whom were screened from 2002 to 2009 without the use of MRI, finding … 

  • PSA screening increased detection of low-grade cancer (2.2% vs. 1.6%) but not intermediate or high-grade disease
  • Screening reduced prostate cancer mortality by a small amount (0.69% vs. 0.78%)

The Takeaway

Taken together, new studies offer a roadmap toward making MRI an integral part of prostate screening, such that perhaps in years to come it can join other cancer tests as a population-based screening tool.

AI Speeds Up MRI Scans

In our last issue, we reported on a new study underscoring the positive return on investment when deploying radiology AI at the hospital level. This week, we’re bringing you additional research that confirms AI’s economic value, this time when used to speed up MRI data reconstruction. 

While AI for medical image analysis has garnered the lion’s share of attention, AI algorithms are also being developed for behind-the-scenes applications like facilitating staff workflow or reconstructing image data. 

  • For example, software developers have created solutions that enable scans to be acquired faster and with less input data (such as radiation dose) and then upscaled to resemble full-resolution images. 

In the new study in European Journal of Radiology, researchers from Finland focused on whether accelerated data reconstruction could help their hospital avoid the need to buy a new MRI scanner. 

  • Six MRI scanners currently serve their hospital, but the radiology department will be losing access to one of them by the end of the year, leaving them with five. 

They calculated that a 20% increase in capacity per remaining scanner could help them achieve the same MRI throughput at a lower cost; to test that hypothesis they evaluated Siemens Healthineers’ Deep Resolve Boost algorithm. 

  • Deep Resolve Boost uses raw-data-to-image deep learning reconstruction to denoise images and enable rapid acceleration of scan times; a total knee MRI exam can be performed in just two minutes. 

Deep Resolve Boost was applied to 3T MRI scans of 78 patients acquired in fall of 2023, with the researchers finding that deep learning reconstruction… 

  • Reduced annual exam costs by 399k euros compared to acquiring a new scanner
  • Enabled an overall increase in scanner capacity of 20-32%
  • Had an acquisition cost 10% of the price of a new MRI scanner, leading to a cost reduction of 19 euros per scan
  • Was a lower-cost option than operating five scanners and adding a Saturday shift

The Takeaway

As with last week’s study, the new research demonstrates that AI’s real value comes from helping radiologists work more efficiently and do more with less, rather than from direct reimbursement for AI use. It’s the same argument that was made to promote the adoption of PACS some 30 years ago – and we all know how that turned out.

MRI’s Value for Prostate Screening

Among cancer screening tests, prostate screening could be the most problematic. But a new study published this week in JAMA Network Open offers guidance on the role that MRI can play in making prostate screening more effective – and opening the door to population-based screening.

The problem with prostate screening is that PSA tests often discover disease that’s either indolent or slow-growing. 

  • This can lead to a cascade of interventions that are expensive and have harms of their own. 

But prostate cancer remains a common – and deadly – cancer, with 1.5M cases globally in 2022, and it’s the second most commonly occurring cancer in men after lung cancer.

  • Given these statistics, there has to be a way to perform prostate screening more effectively.

MRI offers one such alternative, and a clinical consensus has emerged that performing a single MRI scan after a positive PSA result can help stratify men before biopsy. 

  • In this scenario, men might not be referred to biopsy if their MRI scan is negative, and adoption of this protocol has helped reduce prostate biopsies in PSA-positive men while still detecting clinically significant cancer.   

But if one MRI scan is good, are repeat MRI scans even better? In the new study, Swedish researchers investigated this question in a secondary analysis of the STHLM3-MRI trial, which involved repeat screening of 1.5k men 2-3 years after an original prostate screening.

Of the group who got repeat PSA and MRI screening, 667 men had PSA levels of 3 ng/mL or higher, the threshold for MRI testing, with the repeat scans finding … 

  • 51 men (7.6%) had equivocal lesions (PI-RADS score of 3)
  • 33 men (4.9%) had suspicious lesions (PI-RADS score of 4)
  • Only 10 men (1.5%) had lesions with PI-RADS scores of 4 or greater

The findings led the authors to conclude that cancer detection was “limited” in the second round of PSA and MRI prostate screening, and detection of low-grade tumors was low.

The Takeaway

At first blush, STHLM3-MRI may seem like a negative study, but it actually helps frame the debate over prostate cancer screening and MRI’s role by omitting the need for multiple repeat scans. The results also give clinicians confidence that it’s safe to omit prostate biopsies in men who have a single negative MRI result – a key finding in reducing the downstream costs of any population-based screening program.

Can AI Direct Breast MRI?

A deep learning algorithm trained to analyze mammography images did a better job than traditional risk models in predicting breast cancer risk. The study shows the AI model could direct the use of supplemental screening breast MRI for women who need it most. 

Breast MRI has emerged (along with ultrasound) as one of the most effective imaging modalities to supplement conventional X-ray-based mammography. Breast MRI performs well regardless of breast tissue density, and can even be used for screening younger high-risk women for whom radiation is a concern. 

But there are also disadvantages to breast MRI. It’s expensive and time-consuming, and clinicians aren’t always sure which women should get it. As a result, breast MRI is used too often in women at average risk and not often enough in those at high risk. 

In the current study in Radiology, researchers from MGH compared the Mirai deep learning algorithm to conventional risk-prediction models. Mirai was developed at MIT to predict five-year breast cancer risk, and the first papers on the model emerged in 2019; previous studies have already demonstrated the algorithm’s prowess for risk prediction

Mirai was used to analyze mammograms and develop risk scores for 2.2k women who also received 4.2k screening breast MRI exams from 2017-2020 at four facilities. Researchers then compared the performance of the algorithm to traditional risk tools like Tyrer-Cuzick and NCI’s Breast Cancer Risk Assessment (BCRAT), finding that … 

  • In women Mirai identified as high risk, the cancer detection rate per 1k on breast MRI was far higher compared to those classified as high risk by Tyrer-Cuzick and BCRAT (20.6 vs. 6.0 & 6.8)
  • Mirai had a higher PPV for predicting abnormal findings on breast MRI screening (14.6% vs. 5.0% & 5.5%)
  • Mirai scored higher in PPV of biopsies recommended (32.4% vs. 12.7% & 11.1%) and PPV for biopsies performed (36.4% vs. 13.5% & 12.5%)

The Takeaway
Breast imaging has become one of the AI use cases with the most potential, based on recent studies like PERFORMS and MASAI, and the new study shows Mirai could be useful in directing women to breast MRI screening. Like the previous studies, the current research is pointing to a near-term future in which AI and deep learning can make breast screening more accurate and cost-effective than it’s ever been before. 

MRI Findings Linked to Psychosis

Over one-quarter of patients presenting with a first episode of psychosis had some kind of abnormality on brain MRI scans, and about 6% of all findings were clinically relevant and required a change in patient management. Writing in JAMA Psychiatry, researchers from the UK and Germany say their study suggests that MRI should be used in the clinical workup of all patients presenting with psychosis. 

Psychosis caused by another medical condition – called secondary psychosis – can have causes that produce brain abnormalities visible on MRI scans. These are findings like white-matter hyperintensities that – while not themselves a form of pathology – are sometimes associated with more serious conditions like cognitive decline. 

MRI scans of people experiencing their first psychotic episode could detect some of these abnormalities before subsequent episodes occur. But at present there is no consensus as to whether MRI should be used in the evaluation of patients presenting with first-episode psychosis. 

In a meta-analysis, researchers wanted to investigate the prevalence of intracranial radiological abnormalities on MRI scans of patients with first-episode psychosis. They reviewed 12 independent studies that covered a total of 1,613 patients. Findings across all the studies included:

  • A prevalence rate of 26.4% for all radiological abnormalities 
  • A prevalence rate of 5.9% for clinically relevant abnormalities 
  • One in 18 patients had a change in management after an MRI scan
  • White-matter hyperintensities were the most common abnormality, with a prevalence of 7.9% for all abnormalities and 0.9% among clinically relevant abnormalities

Given the impact of MRI on patient management, the authors suggested that performing routine scans on people after their first psychotic episode could have both clinical and economic benefits. This could be especially true due to the financial costs of failing to identify a clinically relevant abnormality that could lead to a later episode if not treated.

The Takeaway 

These findings may break the logjam over whether MRI should be routinely used in the evaluation of patients with first-episode psychosis. The authors note that while many of the abnormalities found on MRI in the studies they reviewed did not require a change in patient management, abnormalities could be harbingers of poorer patient outcomes, even if they don’t eventually lead to a diagnosis of secondary psychosis.

GE HealthCare’s MRI Contrast Play

GE HealthCare has expanded its MRI contrast portfolio with the European debut of Pixxoscan. The gadolinium-based contrast agent gives GE another macrocyclic gadolinium-based contrast agent to sell in Europe, in addition to its Clariscan GBCA.

MRI contrast developers have been working to address one of the most persistent problems in MRI: their reliance on gadolinium. Gadolinium works great for lighting up MR images, but it’s a toxic metal that has to be bonded with a chelate – a sort of molecular cage – in order to be used safely in humans. 

Pixxoscan is a macrocyclic GBCA that’s based on gadobutrol, a formulation already used in Bayer’s Gadovist GBCA and that’s now available generically. Macrocyclic GBCAs are considered more stable and less likely to release gadolinium than linear agents. 

Most linear GBCAs have been barred from the European market since 2017. The FDA never took a similar approach, but the US market has largely shifted from linear GBCAs to macrocyclic agents due to safety concerns. 

GE HealthCare highlighted that Pixxoscan is formulated at twice the concentration of gadolinium ions, which reportedly enables it to be used at half the injection volume of other GBCAs. The company also said that the agent’s cage-like macrocyclic chelate provides high kinetic stability. 

Pixxoscan will start shipping initially in Austria, and GE HealthCare expects to expand it across Europe. A spokesperson didn’t confirm plans for a US rollout.   

Pixxoscan’s launch comes as two of GE HealthCare’s competitors, Guerbet and Bracco, are rolling out their formulations of gadopiclenol, a high-relaxivity agent that can be used at half the dose of conventional GBCAs. The companies collaborated on the development of the agent, which Guerbet is selling as Elucirem and Bracco as Vueway. 

The Takeaway

GE HealthCare’s launch of Pixxoscan gives the company another macrocyclic agent to sell in Europe in addition to Clariscan. The question is how the agent will compete with gadopiclenol from Bracco and Guerbet, which are already touting its dose and relaxivity advantages.

Siemens Healthineers Targets MRI at Shape 2023

Siemens Healthineers kicked-off RSNA announcements season with its Shape 23 event, highlighted by a pair of forthcoming MRIs that should serve as the cornerstones of its high-end lineup for years to come.

Magnetom Cima.X – Siemens reinforced its already-solid 3T MR lineup with its new Magnetom Cima.X, calling it the company’s “strongest 3T MRI system ever.”

The Magnetom Cima.X owes that “strongest 3T” title to its new Gemini Gradients, which achieve 200 mT/m amplitude and 200 T/m/s slew rate performance. That’s a 2.5x increase from Siemens’ previous 3T MRIs and it’s higher than any other clinically released whole-body MRI. 

The Magnetom Cima.X also features Siemens Healthineers’ …

  • Benchmark 3T magnet
  • Deep Resolve AI image reconstruction for up to 50% faster scans
  • Open Recon for integrating custom reconstruction and post-processing solutions
  • BioMatrix Technology to automatically adjust exams based on patient biovariability
  • myExam Companion for streamlining technologist workflows

Magnetom Terra.X – Siemens’ new Magnetom Terra.X 7T MR is the long-awaited successor to the Magnetom Terra (the first FDA-cleared 7T MR), bringing improved clinical and research performance. The Magnetom Terra.X leverages Siemens’ new Ultra IQ Technology to achieve even greater image quality and visualization of small structures, Deep Resolve for image reconstruction-based speed and image enhancements, and Open Recon to support custom reconstructions.

The Takeaway

Although both MRIs are still under development, their starring role in Siemens Healthineers’ big RSNA event underscores their significance to Siemens’ high-end MRI lineup, and gives a glimpse of features to expect in future 1.5T and 3T MR launches. That’s especially notable given that Siemens’ last two RSNA announcements focused on its new low-field 0.55T MRIs, and it hasn’t launched any high-field systems in over three years.

MRI Accessibility Advantage

Memorial MRI and Diagnostic’s COO Todd Greene starred in a recent Aunt Minnie webinar, detailing the role MRI accessibility plays in the Texas imaging group’s strategy, and sharing some very relevant takeaways for imaging providers and vendors.

Founded in 2001, Memorial MRI and Diagnostic (MMD) operates 16 imaging centers across Texas, including eight in greater Houston and eight Dallas-area locations added through its 2021 acquisition of Prime Diagnostic Imaging. 

  • MMD’s strategy focuses on integrating its imaging centers within their local communities, making patient access and referring physician relationships particularly important.

In addition to proximity to patients, MMD’s MRI accessibility strategy historically focused on maintaining a fleet of open bore 1.5T MRI scanners to accommodate larger and claustrophobic patients. 

  • This is especially important given that many of MMD’s patients are “Texas sized” or don’t realize they’re claustrophobic until the scan begins. 

That strategy started to change when MMD installed United Imaging’s 3T uMR OMEGA ultra-wide-bore (75 cm), allowing it to scan larger and claustrophobia-prone patients (plus all other patients) without open MRIs’ scan speed and image quality tradeoffs. 

  • The uMR OMEGA was MMD’s first 3T MRI at any of MMD’s imaging centers, although Greene expects its patient and referrer-friendly advantages to drive a continued shift towards wide-bore 3T MRI systems.

Greene also detailed Memorial MRI’s alliance with United Imaging (the webinar’s sponsor), specifically highlighting the scalability of UIH’s “Software for Life” (scanners automatically updated with future software) and “All-In” (scanners include all possible features/packages) policies.

As the webinar wrapped up, Greene warned imaging centers not to blindly rely on what has worked in the past, predicting that “ease of access is what is going to shape the future of healthcare.” 

The Takeaway

We get plenty of insights from the medical center side of radiology, but it’s still rare to hear from imaging center chains. That makes MDD’s insights particularly useful for the many regional imaging providers who’d like to improve MRI accessibility (without open MRI’s tradeoffs) and for MRI OEMs looking to drive 3T MRI adoption in an imaging provider segment that historically favored 1.5T systems.

RSNA 2021 Reflections

The first in-person RSNA since COVID is officially a wrap. Hope you had a blast if you made it to Chicago and a productive week if you stayed home. We also hope you enjoy The Imaging Wire’s big takeaways from what might have been both the most special and most subdued RSNA ever.

Crowds & Conversations – We were already expecting 50% lower attendance than RSNA 2019, but the exhibit hall and cab lines looked more like 70% below 2019’s crowds (even less on Sunday & Wednesday). That said, most of the stronger companies had steady booth traffic and nearly every exhibitor emphasized that the attendees who did show up were ready to have high-quality conversations.

Focus on Productivity – Just about every product message at RSNA focused on productivity and efficiency, often with greater emphasis than clinical effectiveness. The modality-based efficiency enhancements seemed to be the most impactful, which is good news for technologist bandwidth and patient throughput, but might be bad news for rad burnout unless informatics/AI efficiency can catch up (it doesn’t seem like that happened this year).

Modality Milestones – The major OEMs did a good job making modalities cool again, debuting milestone innovations across both their MR (low-helium, low-field, reconstruction, coils) and CT (photon-counting, spectral, upgradability) lineups. We also saw the latest scanners take big strides in operator efficiency and patient experience. There weren’t many breakthroughs with X-ray or ultrasound, and most point-of-care ultrasound OEMs stayed home (rads aren’t their market anyway), but attendees seemed okay with that.

AI Showcase – The RSNA AI Showcase had solid traffic and high energy (especially on Mon & Tues), helped by continued AI buzz and the fact that RSNA finally let AI vendors out of the basement. The AI Showcase highlighted many of the trends we’ve been seeing all year, including larger vendors transitioning to AI platform strategies, an increased focus on workflow integration and care coordination, and a greater emphasis on radiologist efficiency. There were also far fewer brand-new AI tools than previous years, as many vendors focused on improving their current products and/or expanding their portfolio via partnerships. 

PACS Cloud Focus – PACS vendors continued to place a major emphasis on their respective cloud advantages, and there was a widespread consensus that cloud is on every imaging IT roadmap. The PACS vendors seemed to talk less about multi-ology enterprise imaging than previous years, and expanding EI beyond radiology/cardiology still seemed pretty futuristic for most players. It was also quite clear that most of the PACS players’ AI marketplaces/platforms haven’t been as prioritized as earlier announcements might have suggested.

Best RSNA Since… 2019 – We’ve heard some folks saying this was the “best RSNA ever” because it was easy to get around and it was great to see everyone, but those seem more like pandemic silver linings than “best ever” qualifications. Still, the imaging industry made the most of RSNA 2021, and everyone seemed truly happy to be together again after two long years of working from home. As long as COVID cooperates, we should be set up for an excellent RSNA 2022.

GE’s Productive RSNA

GE Healthcare had another busy RSNA, highlighted by several major modality launches and an overarching focus on helping imaging teams be more productive. 

Return to MR Hardware – After focusing on AIR Recon DL during the last two RSNAs, GE Healthcare’s MR team made sure to roll-out new hardware at this year’s show. 

  • GE’s MR section was headlined by its new SIGNA Hero 3T MR, which brings a wide range of improvements (image quality, workflows, productivity, comfort, reconstruction, helium & energy), and a major focus on operator efficiency.  
  • GE also unveiled the SIGNA Artist Evo, which allows health systems / imaging centers to upgrade their existing 1.5T 60cm-bore MRs with 70cm bore systems (w/ AIR Recon DL & AIR Coils), without the construction and downtime typically required when upgrading to a net new MR system.

GE’s Scalable CT Platform – GE unveiled the unique Revolution Apex platform, which offers the modularity and scalability to cover a wide range of current and future needs, and represents GE’s biggest CT launch since 2014. 

  • The FDA-cleared Revolution Apex CT is available with multiple detector coverage configurations (40mm, 80mm, 160mm, upgradable w/o replacing gantry) and is offered with GE’s new Smart Subscription service (allows software upgrades/downgrades, plus auto updates). 
  • True to GE’s productivity focus, the Revolution Apex also includes a range of features to improve technologist efficiency and/or expand clinical applications (e.g. “Effortless Workflow,” patient positioning camera, TrueFidelity DLIR, motion correction for cardiac).

Much More – GE Healthcare has been busy throughout 2021, so although the other products in its RSNA booth were still quite new, they’ve already been detailed in previous Imaging Wire issues. Some of these other highlights include its in-development Photon Counting CT, it’s now FDA-approved Endotracheal Tube X-ray AI tool, its StarGuide SPECT/CT scanner, and its recent alliance with Optellum.

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