Author: Brian Casey

ABUS Flies Solo for Breast Screening

Posted on by Brian Casey

Is breast ultrasound ready for use as a primary breast screening modality – without mammography? Maybe not in developed countries, but researchers in China gave automated breast ultrasound a try, with results that are worth checking out in a new study in AJR. 

Mammography is unquestionably the primary imaging modality for first-line breast screening, with other technologies like ultrasound and MRI taking a supplemental role, such as for working up questionable cases or for women with dense breast tissue.

  • But the standard mammography-dominated paradigm might not be suitable for some resource-challenged countries that have yet to build an installed base of X-ray-based mammography systems. 

One of these countries is China, which not only has fewer mammography systems in rural areas but also has a population of women who have denser breast tissue, which can cause problems with conventional mammography. 

  • As a result, the Chinese National Breast Cancer Screening Program has adopted ultrasound as its primary screening modality, with women ages 35-69 eligible for screening breast ultrasound every 2-3 years. Mammography is reserved for additional workup. 

But handheld ultrasound has challenges of its own. It’s operator-dependent, and image interpretation requires experienced radiologists – also in short supply in some Chinese regions.

  • So the AJR researchers performed a study of 6k women who were screened with GE HealthCare’s Invenia ABUS 2.0 scanner, which uses ultrasound to scan women lying in the supine position. Images were sent via teleradiology to expert radiologists at a remote institution.

How did ABUS perform as a primary screening modality? The researchers found that after a single round of screening …

  • ABUS had a cancer detection rate of 4.0 cancers per 1k women (4.4 for women 40-69).
  • Sensitivity was 92% and specificity was 88%.
  • Abnormal interpretation rate was 12%.
  • 96% of detected cancers were invasive, and 74% were node-negative.
  • Two interval cancers were detected (rate of 0.33 per 1k).

How do the numbers compare to mammography? 

  • The cancer detection rate in the Breast Cancer Surveillance Consortium study was 5.1 cancers per 1k women, so not far off. 

The Takeaway

The results offer an interesting look at an alternative to the mammography-first breast screening paradigm used in developed countries, where ABUS is mostly used as a supplemental technology. For resource-challenged areas around the world, ABUS with teleradiology could solve multiple problems at once.

PSMA-PET Reduces Prostate Deaths

Posted on by Brian Casey

Using PSMA-PET instead of conventional imaging to stage patients with recurrent prostate cancer could reduce deaths by 13% and lead to improved quality of life. The new paper in JAMA Network Open confirms the value of PSMA imaging compared to traditional imaging approaches. 

Recurrent prostate cancer is one of the trickiest cancers to manage, especially as biochemical recurrence can occur in up to half of patients getting local treatment. 

  • PSA tests work well for detecting rising prostate antigen levels that could signify recurrence, but it can be difficult to locate recurrent cancer with existing imaging tools like CT and bone scans.

PET using a new generation of PSMA tracers offers a better solution thanks to tracers that target the PSMA protein that builds up on the surface of prostate cancer cells.

  • Previous studies have shown that PSMA-PET is more sensitive and specific for detecting recurrent prostate cancer, especially at lower PSA levels – but the modality’s long-term effects haven’t been explored. 

In the new study, researchers wanted to investigate the impact of switching to PSMA-PET on mortality and quality of life using statistical modeling to predict outcomes from three imaging approaches …

  • Conventional imaging with CT and bone scan.
  • CT and bone scan followed by PSMA-PET for negative or equivocal cases.
  • PSMA-PET alone.

They then projected outcomes for a hypothetical population of 1k patients with biochemically recurrent prostate cancer, defined as a persistent or rising PSA of 0.20 ng/mL after prostatectomy or PSA 2.0 ng/mL or higher following radiation therapy. They found …

  • PSMA-PET had the lowest number of prostate cancer deaths at 512, compared to conventional imaging plus PSMA-PET (520) or just conventional imaging (587).
  • PSMA-PET diagnosed 611 patients with metastasis compared to 630 with conventional imaging plus PSMA-PET and 297 with only conventional imaging.
  • PSMA-PET yielded 824 more quality-adjusted life years per 1k patients than conventional imaging.

The Takeaway

The findings are not only good news for patients with recurrent prostate cancer, they are also a boon for developers of commercially available PSMA-PET radiotracers like Lantheus Medical Imaging’s Pylarify (approved in 2021), Telix Pharmaceuticals’ Illuccix (approved in 2021), and Blue Earth Diagnostics’ Posluma (approved in 2023). 

FFR-CT Reduces Invasive Angiography Rates

Posted on by Brian Casey

Performing automated CT-derived fractional flow reserve with Shukun Technology’s software reduced referrals to invasive coronary angiography by 19% in a new study in Radiology. The findings suggest that software-based FFR-CT can serve a gatekeeper role in managing workup of patients with suspected coronary artery disease. 

Cardiac CT has been a revolutionary tool for assessing people with heart problems, evolving rapidly into a first-line modality that’s eclipsed other more traditional imaging technologies. 

  • But CCTA’s prowess also has a downside – more referrals to invasive coronary angiography, in some cases for patients without obstructive disease.

Rising to this challenge is FFR-CT, which uses automated software to calculate maximum blood flow in the coronary arteries and detect dangerous coronary lesions that could be early signs of a cardiac event. 

  • The segment to date has been dominated by HeartFlow, thanks to its early start in the field: its FFRCT software got FDA clearance in 2014 and the company has used its dominance to build a massive cash position.

In the new China CT-FFR Study 3, researchers in China used another FFR-CT application, Shukun’s skCT-FFR, and compared angio referral rates for 5.3k patients with suspected coronary artery disease who were scanned with either CCTA alone or CCTA and FFR-CT. They found …

  • Referral rates were lower for those who got FFR-CT (10% vs. 12.4%), a 19% relative difference.
  • Fewer cardiac events occurred in the FFR-CT group at one year (0.5% vs. 1.1%).
  • There was no statistically significant difference in major adverse cardiac event rates at 90 days (0.5% vs. 0.8%, p=0.12) and one year (2.9% vs. 2.8%, p=0.9).

Shukun is not as well known in the West as other developers of FFR-CT software like HeartFlow, but the company has raised over $250M to date – enough to land it in the top echelon of AI developers. 

  • One advantage of Shukun that was evident with the new study is that image processing was performed on-site, rather than being shipped off-site as is the case with other applications. 

The Takeaway

The study shows that FFR-CT can make cardiac CT more precise while tamping down on referrals to invasive angiography that have come from growing CT use. The results should also help put Shukun on the radar of many industry observers in a segment that so far has been dominated by HeartFlow.

Do Imaging Costs Scare Patients?

Posted on by Brian Casey

A new study in JACR reveals an uncomfortable reality about medical imaging price transparency: Patients who knew how much they would have to pay for their imaging exam were less likely to complete their study. 

Price transparency has been touted as a patient-friendly tool that can get patients engaged with their care while also helping them avoid nasty billing surprises for out-of-pocket costs. 

  • Price transparency is considered to be so important that CMS in 2021 implemented rules requiring hospitals to disclose their standard charges online, as well as post a user-friendly list of their services that includes prices. 

But given that the rules were implemented relatively recently, not much is known about how they might affect patient behavior, such as compliance with recommended follow-up imaging exams.

  • Indeed, a recent study by some of the same authors found that patients are largely unaware of how much their imaging exams will cost them. 

So researchers analyzed data from two previously published studies of patients who either completed or were scheduled for outpatient imaging exams in Southern California. 

  • Patients were asked if they had been told how much their exam would cost them out-of-pocket when they scheduled it. 

Of the 532 patients who were surveyed, researchers found …

  • Only 15% said they knew about their out-of-pocket costs before their imaging exam. 
  • Fewer patients who completed their exams knew their costs compared to those who canceled (12% vs. 22%).
  • Patients who knew their costs were 67% less likely to complete their appointment than those who didn’t (OR=0.33).

So what’s the solution? The researchers suggested that healthcare providers may need to take a more proactive approach to disclosing price information to patients.

  • One possibility would be to integrate pricing discussions into patient-provider communications when ordering imaging exams, rather than relying on patients to seek pricing information on their own. 

The Takeaway

The findings show that medical imaging price transparency is more complicated than just posting a list of prices online and expecting patients to do the rest of the work. Imaging providers may need to get more involved in pricing discussions – the question is whether many of them are ready for it.

Did Malpractice Risk Kill V/Q Exams?

Posted on by Brian Casey

CT perfusion angiography exams have largely replaced nuclear medicine-based ventilation/perfusion (V/Q) studies for detecting pulmonary embolism. But a new article in Academic Radiology suggests that CT’s rise wasn’t entirely based on clinical efficacy – fears of malpractice risk may have played a role. 

V/Q studies can help diagnose PE by enabling clinicians to visualize lung perfusion, showing defects such as blockages in pulmonary vessels. The scans are typically performed in three phases … 

  1. An albumin injection to show pulmonary vasculature.
  2. A radiopharmaceutical that’s inhaled and imaged with a gamma camera.
  3. A chest radiograph to correlate findings. 

The scans dominated PE imaging in the 1980s, but the rise of CT saw radiology facilities begin to shift.

  • CTPA was seen as having higher spatial resolution and was easier to perform than nuclear medicine exams. 

But the new article suggests that there were other forces at work as well – in particular, fear of malpractice risk from PEs that weren’t adequately followed after inconclusive V/Q exams.

  • The problem originated with clinical guidelines for V/Q reporting that classified some 20% of V/Q studies as “low probability” for PE when they probably would have better been classified as “inconclusive” or “non-diagnostic.”

As a result, a number of “low probability” patients weren’t followed up adequately, with tragic results that later figured into medical malpractice cases …

  • A patient who was diagnosed with pneumonia after an inconclusive V/Q exam, sent home, and died one day later of a “massive” PE.
  • A patient with leg and chest pain who was given heparin after a negative V/Q scan and later suffered internal hemorrhage; fortunately she survived.
  • A patient with “vague symptoms” who had an inconclusive V/Q scan and later died of an undiagnosed PE that some claimed would have been detected on CTPA.

Indeed, the theme of PE malpractice cases began to shift over time, from failure to diagnose V/Q scans to failure to order CTPA exams – which were soon seen as the clinical gold standard.

The Takeaway

Given the fast pace of development in radiology, it’s inevitable that some technologies that were once clinical staples fall by the wayside. But the new article offers a fascinating look at how clinical language can lead to medico-legal concerns that influence physician behavior – often in ways that are impossible to detect as they happen.

Low-Dose CT Confounds CAD in Kids

Posted on by Brian Casey

When it comes to pediatric CT scans, clinicians should make every effort to reduce dose as much as possible. But a new study in AJR indicates that lower CT radiation dose can affect the performance of software tools like computer-aided detection. 

Initiatives like the Image Wisely and Image Gently projects have succeeded in raising awareness of radiation dose and have helped radiologists find ways to reduce it.

But every little bit counts in pediatric dose reduction, especially given that one CT exam can raise the risk of developing cancer by 0.35%. 

  • Imaging tools like AI and CAD could help, but there have been few studies examining the performance of pulmonary CAD software developed for adults in analyzing scans of children.

To address that gap, researchers including radiologists from Cincinnati Children’s Hospital Medical Center investigated the performance of two open-source CAD algorithms trained on adults for detecting lung nodules in 73 patients with a mean age of 14.7 years. 

  • The algorithms included FlyerScan, a CAD developed by the authors, and MONAI, an open-source project for deep learning in medical imaging. 

Scans were acquired at standard-dose (mean effective dose=1.77 mSv) and low-dose (mean effective dose=0.32 mSv) levels, with the results showing that both algorithms turned in lower performance at lower radiation dose for nodules 3-30 mm … 

  • FlyerScan saw its sensitivity decline (77% vs. 67%) and detected fewer 3mm lung nodules (33 vs. 24).
  • MONAI also saw lower sensitivity (68% vs. 62%) and detected fewer 3mm lung nodules (16 vs. 13).
  • Reduced sensitivity was more pronounced for nodules less than 5 mm.

The findings should be taken with a grain of salt, as the open-source algorithms were not originally trained on pediatric data.

  • But the results do underscore the challenge in developing image analysis software optimized for pediatric applications.

The Takeaway

With respect to low radiation dose and high AI accuracy in CT scans of kids, radiologists may not be able to have their cake and eat it too – yet. More work will be needed before AI solutions developed for adults can be used in children.

Mammography AI Predicts Cancer Before It’s Detected

Posted on by Brian Casey

A new study highlights the predictive power of AI for mammography screening – before cancers are even detected. Researchers in a study JAMA Network Open found that risk scores generated by Lunit’s Insight MMG algorithm predicted which women would develop breast cancer – years before radiologists found it on mammograms. 

Mammography image analysis has always been one of the most promising use cases for AI – even dating back to the days of computer-aided detection in the early 2000s. 

  • Most mammography AI developers have focused on helping radiologists identify suspicious lesions on mammograms, or triage low-risk studies so they don’t require extra review.

But a funny thing has happened during clinical use of these algorithms – radiologists found that AI-generated risk scores appeared to predict future breast cancers before they could be seen on mammograms. 

  • Insight MMG marks areas of concern and generates a risk score of 0-100 for the presence of breast cancer (higher numbers are worse). 

Researchers decided to investigate the risk scores’ predictive power by applying Insight MMG to screening mammography exams acquired in the BreastScreen Norway program over three biennial rounds of screening from 2004 to 2018. 

  • They then correlated AI risk scores to clinical outcomes in exams for 116k women for up to six years after the initial screening round.

Major findings of the study included … 

  • AI risk scores were higher for women who later developed cancer, 4-6 years before the cancer was detected.
  • The difference in risk scores increased over three screening rounds, from 21 points in the first round to 79 points in the third round.
  • Risk scores had very high accuracy by the third round (AUC=0.93).
  • AI scores were more accurate than existing risk tools like the Tyrer-Cuzick model.

How could AI risk scores be used in clinical practice? 

  • Women without detectable cancer but with high scores could be directed to shorter screening intervals or screening with supplemental modalities like ultrasound or MRI.

The Takeaway
It’s hard to overstate the significance of the new results. While AI for direct mammography image interpretation still seems to be having trouble catching on (just like CAD did), risk prediction is a use case that could direct more effective breast screening. The study is also a major coup for Lunit, continuing a string of impressive clinical results with the company’s technology.

Breast Cancer Mortality Falls Again

Posted on by Brian Casey

New data from the American Cancer Society highlight the remarkable strides that have been made against breast cancer, with the U.S. death rate falling 44% over the last 33 years – saving over half a million lives. But the statistics also underscore the work that remains to be done, particularly with minority women. 

The fight against breast cancer has been one of public health’s major success stories.

  • High mammography screening uptake has led to early detection of cancers that can then be treated with revolutionary new therapies. 

Much of the credit for this success goes to the women’s health movement, which has conducted effective advocacy campaigns that have led to …

But breast cancer remains the third most common killer of women after heart disease and lung cancer, and there have been disturbing trends even as the overall death rate falls. 

  • Breast cancer incidence has been rising especially in younger women, and major disparities continue to be seen, particularly with survival in Black women.

The American Cancer Society’s new report represents the group’s biennial review of breast cancer statistics, finding … 

  • In 2024 there will be 311k new cases of invasive breast cancer, 56.5k cases of DCIS, and 42.3k deaths. 
  • The breast cancer mortality rate has fallen 44% from 1989 to 2022, from 33 deaths per 100k women to 19 deaths.
  • Some 518k breast cancer deaths have been averted.
  • The mortality rate ranges from 39% higher than average for Black women to 38% lower for Asian American Pacific Islander women. 
  • The mortality rate is slightly higher than average (0.5%) for White women.
  • The average breast cancer incidence rate is 132 per 100k women, but ranges from 5% higher for White women to 21% lower for Hispanic women.
  • Women 50 years and older will account for most invasive cases (84%) and deaths (91%).

The Takeaway

As Breast Cancer Awareness Month begins, women’s health advocates should be heartened by the progress that’s been made overall. But battles remain, from eliminating patient out-of-pocket payments for follow-up studies to addressing race-based disparities in breast cancer mortality. In many ways, the fight is just beginning. 

The Cost of Extra Cancer Detection

Posted on by Brian Casey

It’s well known that using additional screening modalities beyond traditional 2D mammography can detect more cancers in women with dense breast tissue. But at what cost? A new study in Clinical Breast Cancer documents both the clinical value and the economic cost of supplemental breast imaging technologies. 

2D mammography is the basis for any breast cancer screening program, but the modality’s shortcomings are well known, especially in women with dense breasts. 

  • In fact, the FDA earlier this month began requiring breast imaging providers to notify women of their density status and explain how higher density is a breast cancer risk factor. 

Imaging vendors and clinicians have developed a range of technologies to supplement 2D mammography when needed, ranging from DBT to molecular breast imaging to breast MRI.

  • Each has its own advantages and disadvantages, which can leave many breast imaging providers confused about the best technology to use.

To shed some light, Matthew Covington, MD, of the University of Utah compared detection rates for various supplemental imaging modalities; he then estimated costs for each if it was the only modality used for supplemental imaging with 2D mammography in a U.S. population with 469k detectable breast cancers. 

  • The study assumed that 2D mammography would detect only 41% of cancers – leaving the majority undetected. 

Adding a supplemental modality boosted cancer detection rates, but also screening’s cost …

  • DBT detected 47% of all cancers at a cost of $933M
  • Ultrasound detected 51% at a cost of $1.84B
  • MBI detected 71% at a cost of $4.16B
  • Contrast-enhanced mammography detected 80% at a cost of $3.87B
  • MRI detected 100% at a cost of $6.36B

As the data indicate, MRI is clearly the most effective supplemental modality, but at a cost that’s almost 7X that of DBT. 

The Takeaway

The new data are a fascinating – if sobering – look at the intersection of clinical value and economic cost. They also highlight healthcare’s inconvenient truth: The resources needed to provide the highest-quality care are finite, regardless of whether you’re in a single-payor or fee-for-service system.

MRI Reduces Prostate Biopsies

Posted on by Brian Casey

New research provides additional support for MRI’s role in making prostate screening more effective. In a new study in NEJM, researchers found that MRI can help reduce unnecessary biopsies more than 50%, with a very low chance of missing high-risk disease. 

As we’ve discussed in previous newsletters, prostate cancer screening based on PSA levels is an imprecise test. 

  • Many men with suspiciously high PSA (typically 3-4 ng/mL or higher) undergo biopsies that detect clinically insignificant disease that would never present a health risk during their lifetimes – the classic definition of overdiagnosis. 

Adding MRI can help make prostate screening more precise by directing biopsy-based workup to only those men with clinically significant cancer – but questions still abound about exactly when it should be used. 

In new results from the GÖTEBORG-2 trial in Sweden, researchers compared prostate screening protocols in men with PSA levels 3 ng/mL and higher who got MRI scans:

  • One group automatically got systemic biopsy and then MRI-targeted biopsy based on MRI results.
  • The other group only got MRI-targeted biopsy if they had a suspicious MRI scan.

In 13.2k men who were followed up for a median of four years, researchers found that those in whom systemic biopsy was omitted …

  • Had 57% lower risk of clinically insignificant cancers.
  • Had lower relative risk of clinically insignificant cancers in subsequent screening rounds (RR=0.25 vs. 0.49).
  • Had 16% lower risk of detecting clinically significant cancers.
  • Had 35% lower risk of advanced or high-risk cancers.

On the down side, the protocol eliminating systemic biopsy could lead to later diagnoses for higher-risk disease for 3 in 1k men – but given the slow-growing nature of prostate cancer it’s not clear how significant this is. 

  • Also, the data indicate that “most prostate cancers become visible on MRI” before they are incurable, which increases the likelihood that they would at least be detected on subsequent screening rounds and could be treated effectively.

The Takeaway

The new findings should help clinicians hone in on the best prostate screening protocols for maximizing detection of clinically significant cancer while minimizing unnecessary workup. Hopefully, the addition of new technologies like AI can move this process along.

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