POCUS Cuts DVT Stays

Using POCUS in the emergency department (ED) to scan patients with suspected deep vein thrombosis (DVT) cut their length of stay in the ED in half. 

Reducing hospital length of stay is one of the holy grails of healthcare quality improvement. 

  • It’s not only more expensive to keep patients in the hospital longer, but it can expose them to morbidities like hospital-acquired infections.

Patients admitted with suspected DVT often receive ultrasound scans performed by radiologists or sonographers to determine whether the blood clot is at risk of breaking off – a possibly fatal result. 

  • But this requires a referral to the radiology department. What if emergency physicians performed the scans themselves with POCUS?

To answer this question, researchers at this week’s European Emergency Medicine Conference presented results from a study of 93 patients at two hospitals in Finland.

  • From October 2017 to October 2019, patients presenting at the ED received POCUS scans from emergency doctors trained on the devices. 

Results were compared to 135 control patients who got usual care and were sent directly to radiology departments for ultrasound. 

  • Researchers found that POCUS reduced ED length of stay from 4.5 hours to 2.3 hours, a drop of 52%.

Researchers described the findings as “convincing,” especially as they occurred at two different facilities. The results also answer a recent study that found POCUS only affected length of stay when performed on the night shift. 

The Takeaway
Radiology might not be so happy to see patient referrals diverted from their department, but the results are yet another feather in the cap for POCUS, which continues to show that – when in the right hands – it can have a big impact on healthcare quality.

Breast Ultrasound Gets Wearable

Wearable devices are all the rage in personal fitness – could wearable breast ultrasound be next? MIT researchers have developed a patch-sized wearable breast ultrasound device that’s small enough to be incorporated into a bra for early cancer detection. They described their work in a new paper in Science Advances.

This isn’t the first use of wearable ultrasound. In fact, earlier this year UCSD researchers revealed their work on a wearable cardiac ultrasound device that obtains real-time data on cardiac function. 

The MIT team’s concept expands the idea into cancer detection. They took advantage of previous work on conformable piezoelectric ultrasound transducer materials to develop cUSBr-Patch, a one-dimensional phased-array probe integrated into a honeycomb-shaped patch that can be inserted into a soft fabric bra. 

The array covers the entire breast surface and can acquire images from multiple angles and views using 64 elements at a 7MHz frequency. The honeycomb design means that the array can be rotated and moved into different imaging positions, and the bra can even be reversed to acquire images from the other breast. 

The researchers tested cUSBr-Patch on phantoms and a human subject, and compared it to a conventional ultrasound scanner. They found that cUSBr-Patch:

  • Had a field of view up to 100mm wide and an imaging depth up to 80mm
  • Achieved resolution comparable to conventional ultrasound
  • Detected cysts as small as 30mm in the human volunteer, a 71-year-old woman with a history of breast cysts
  • The same cysts were detected with the array in different positions, an important capability for long-term monitoring

The MIT researchers believe that wearable breast ultrasound could detect early-stage breast cancer, in cases such as high-risk people in between routine screening mammograms. 

The researchers ultimately hope to develop a version of the device that’s about the size of a smartphone (right now the array has to be hooked up to a conventional ultrasound scanner to view images). They also want to investigate the use of AI to analyze images.

The Takeaway

It’s still early days for wearable breast ultrasound, but the new results are an exciting development that hints of future advances to come. Wearable breast ultrasound could even have an advantage over other wearable use cases like cardiac monitoring, as it doesn’t require continuous imaging during the user’s activities. Stay tuned.

Taking Ultrasound Beyond Breast Density

When should breast ultrasound be used as part of mammography screening? It’s often used in cases of dense breast tissue, but other factors should also come into play, say researchers in a new study in Cancer

Conventional X-ray mammography has difficulties when used for screening women with dense breast tissue, so supplemental modalities like ultrasound and MRI are called into play. But focusing too much on breast density alone could mean that many women who are at high risk of breast cancer don’t get the additional imaging they need.

To study this issue, researchers analyzed the risk of mammography screening failures (defined as interval invasive cancer or advanced cancer) in ~825k screening mammograms in ~377k women, and more than ~38k screening ultrasound studies in ~29k women. All exams were acquired from 2014 to 2020 at 32 healthcare facilities across the US.

Researchers then compared the mammography failure rate in women who got ultrasound and mammography to those who got mammography alone. Their findings included: 

  • Ultrasound was appropriately targeted at women with heterogeneously or extremely dense breasts, with 95.3% getting scans
  • However, based on their complete risk factor profile, women with dense breasts who got ultrasound had only a modestly higher risk of interval breast cancer compared to women who only got mammography (23.7% vs. 18.5%) 
  • More than half of women undergoing ultrasound screening had low or average risk of an interval breast cancer based on their risk factor profile, despite having dense breasts
  • The risk of advanced cancer was very close between the two groups (32.0% vs. 30.5%), suggesting that a large fraction of women at risk of advanced cancer are getting only mammography screening with no supplemental imaging

The Takeaway 

On the positive side, ultrasound is being widely used in women with dense breast tissue, indicating success in identifying these women and getting them the supplemental imaging they need. But the high rate of advanced cancer in women who only received mammography indicates that consideration of other risk factors – such as family history of breast cancer and body mass index – is necessary beyond just breast tissue density to identify women in need of supplemental imaging. 

Ultrasound Spots Breech Pregnancies

Performing routine third-trimester ultrasound scans on pregnant women could help identify breech pregnancies, giving women the opportunity to consider alternative birth options. UK researchers in PLOS Medicine said the impact was found with both conventional and POCUS ultrasound scanners. 

While the incidence of breech presentation at full term is only 3-4%, when breech births do occur they can result in higher morbidity and mortality for both babies and mothers. 

In the UK, third-trimester ultrasound scans aren’t routinely performed for low-risk women, missing a chance to give them other options like Cesarean birth.

  • Therefore, researchers investigated the effectiveness and impact of these scans at two hospitals, one that used conventional ultrasound scanners and the other employing POCUS units (GE HealthCare’s Vscan Air).
  • At the POCUS facility, scans were typically performed by trained midwives. Women were scanned between 2016 to 2021 at both hospitals.

Performing routine ultrasound scans at 36 weeks reduced the incidence of undiagnosed breech presentation by 71% at the hospital using conventional ultrasound and 69% at the POCUS hospital.

  • The rate of undiagnosed breech presentation dropped from 14.2% to 2.8% with conventional ultrasound and from 16.2% to 3.5% with POCUS.
  • The scans also had an impact on babies’ health. Infants born at either facility had less likelihood of a lower Apgar score (<7) five minutes after birth, and babies were less likely to be sent to the neonatal care unit.

The researchers believe their findings suggest a revision of the UK’s clinical guidelines, which don’t currently call for routine third-trimester ultrasound scans for low-risk women. With respect to POCUS, they said their research was the first to investigate the technology for diagnosing fetal presentation, and their findings support wider use of POCUS in areas where conventional ultrasound isn’t available. 

The Takeaway

What’s really exciting about this study are the findings about POCUS. Maternal-fetal complications are a huge problem in developing countries and places with less access to imaging technology. POCUS scanners could be used by trained personnel like midwives – perhaps with AI assistance –  to identify problems before birth.

Creating A Novice Echo Screening Pathway

We hear a lot about AI’s potential to expand ultrasound to far more users and clinical settings, and a new study out of Singapore suggests that ultrasound’s AI-driven expansion might go far beyond what many of us had in mind.

The PANES-HF trial set up a home-based echo heart failure screening program that equipped a team of complete novices (no experience with echo, or in healthcare) with EchoNous’s AI-guided handheld ultrasound system and Us2.ai’s AI-automated echo analysis and reporting solution.

After just two weeks of training, the novices performed at-home echocardiography exams on 100 patients with suspected heart failure, completing the studies in an average of 11.5 minutes per patient.

When compared to the same 100 patients’ NT-proBNP blood test results and reference standard echo exams (expert sonographers, cart-based echo systems, and cardiologist interpretations), the novice echo AI pathway…

  • Yielded interpretable results in 96 patients 
  • Improved risk prediction accuracy versus NT-proBNP by 30% 
  • Detected abnormal LVEF <50% scans with an 0.880 AUC (vs. NT-proBNP’s 0.651-0.690 AUCs)
  • Achieved good agreement with expert clinicians for LVEF<50% detection (k=0.742)

These findings were strong enough for the authors to suggest that emerging ultrasound and AI technologies will enable healthcare organizations to create completely new heart failure pathways. That might start with task-shifting from cardiologists to primary care, but could extend to novice-performed exams and home-based care.

The Takeaway

Considering the rising prevalence of heart failure, the recent advances in HF treatments, and the continued sonographer shortage, there’s clearly a need for more accessible and efficient echo pathways — and this study is arguably the strongest evidence that AI might be at the center of those new pathways.

GE Acquires BK Medical

GE Healthcare’s ultrasound portfolio became a lot more diverse last week with its acquisition of surgical ultrasound company BK Medical. Here’s some details and perspectives:

The Acquisition – GE Healthcare will acquire BK Medical from Altaris Capital Partners for $1.45b, separating BK Medical from Analogic. That’s a pretty big investment considering that GE’s ultrasound unit brings in $3b a year.

GE’s Surgical Expansion – With BK Medical, GE’s ultrasound unit expands from diagnostics to intraoperative imaging and surgical navigation, which is reportedly a fast-growing and high-margin business for BK Medical. 

The BK Portfolio – BK Medical got its start in urology ultrasound, and more recently expanded to ultrasound systems used to guide minimally invasive and robotic surgeries and to visualize deep tissue during neuro and abdominal surgeries. That adds up to five unique ultrasound systems.

GE Impact – GE sees a lot of value in BK Medical. BK gives GE an ultrasound portfolio that the other OEMs can’t match (diagnostic, surgical, post-operative), “accelerates” GE’s precision health strategy, and will reportedly deliver “high-single-digit” ROI within five years.

GE Acquisition Trend – While GE Healthcare spent 2018 and 2019 selling major non-imaging businesses (value-based care to Veritas Capital, life sciences to Danaher), GE’s 2020 and 2021 acquisitions have focused on expanding its capabilities within imaging (Zionexa for radiopharmaceuticals, Prismatic Sensors for CT detectors, and now BK Medical for ultrasound). That says a lot about GE Healthcare’s imaging focus, and is quite different from Philips and Siemens, which have increasingly targeted M&A outside of imaging.

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