Tag: ultrasound

Categories : Medical Research & TechnologyTags :

Low-frequency Ultrasound Improves Blood Oxygenation

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Research conducted by a team of scientists from Kaunas universities, Lithuania, revealed that low-frequency ultrasound influences blood parameters. The findings suggest that ultrasound’s effect on haemoglobin can improve oxygen’s transfer from the lungs to bodily tissues.

The research was undertaken on 300 blood samples collected from 42 pulmonary patients.

The samples were exposed to six different low-frequency ultrasound modes at the Institute of Mechatronics of Kaunas University of Technology (KTU). The calculations were made at the KTU Artificial Intelligence Centre.

Improved oxygen circulation and reduced blood pressure

KTU professors Vytautas Ostasevicius and Vytautas Jurenas say that the ongoing research papers are related to blood platelet aggregation.

The research of the KTU team revealed that the ultrasound affects not only platelet count but also red blood cells (RBC), which can result in better oxygen circulation and lowered blood pressure.

“During exposure to low-frequency ultrasound, aggregated RBCs are dissociated into single RBCs, whose haemoglobin molecules interact with oxygen over the entire surface area of RBCs, which is larger than that of aggregated RBCs and improves oxygen saturation in blood. The number of dissociated single RBCs per unit volume of blood decreases due to the spaces between them, compared to aggregates, which reduces blood viscosity and affects blood pressure,” explains Prof Ostasevicius, the Head of KTU Institute of Mechatronics.

The scientists claim that the effect of ultrasound on the haemoglobin in RBCs was higher than its impact on platelet aggregation, which is responsible for blood clotting.

Their findings have been supported by an additional analysis made at the LSMU Laboratory of Molecular Cardiology.

“This means that low-frequency ultrasound can be potentially used for improving oxygen saturation in lungs for pulmonary hypertension patients. Keeping in mind the recent COVID-19 pandemic, we see a huge potential in exploring the possibilities of our technology further,” says Prof Ostasevicius.

Partnership between medical and engineering scientists

In medicine, high-frequency ultrasound from 2 to 12MHz is used for both diagnostic and therapeutic purposes.

“Acoustic waves emitted by high-frequency ultrasound have a limited penetration depth into the body, so external tissues are more affected by high-frequency ultrasound than internal organs. Low-frequency ultrasound acoustic waves, penetrate deeper into the internal organs with a more uniform sound pressure distribution,” explains Prof Jurenas.

There are numerous applications for ultrasound in medical settings.

“For example, focused ultrasonic waves are used to break kidney stones, and to kill cancer cells. Maybe ultrasound can be used to activate certain medications. Or, to alleviate the delivery of antibiotics to the inflamed areas?” says Prof Jurenas.

The technology used in the above-described study is only one illustration of many successful working partnerships between engineers and physicians.

For example, just recently, the researchers of KTU Institute of Mechatronics have created the frame for immobilising the Gamma Knife radiosurgery patients at the Clinics of the Lithuanian University of Health Sciences.

“We believe, that using the know-how of different areas one can achieve greater results,” say KTU researchers about interinstitutional and interdisciplinary cooperation.

Source: Kaunas University of Technology

Categories : Lab Tests and ImagingTags :

New Technique Enhances Clarity of Photoacoustic Imaging in Dark Skin

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In photoacoustic imaging, laser light is pulsed through the skin into tissues, which release ultrasound signals with which the internal structure can be imaged. This works well for people with light skin but has trouble getting clear pictures from patients with darker skin. A Johns Hopkins University-led team found a way to deliver clear pictures of internal anatomy, regardless of skin tone. Their technique is described in the journal Photoacoustics.

In experiments the new imaging technique produced significantly sharper images for all people – and excelled with darker skin tones. It produced much clearer images of arteries running through the forearms of all participants, compared to standard imaging methods where it was nearly impossible to distinguish the arteries in darker-skinned individuals.

“When you’re imaging through skin with light, it’s kind of like the elephant in the room that there are important biases and challenges for people with darker skin compared to those with lighter skin tones,” said co-senior author Muyinatu “Bisi” Bell, Associate Professor at Johns Hopkins. “Our work demonstrates that equitable imaging technology is possible.”

“We show not only there is a problem with current methods but, more importantly, what we can do to reduce this bias,” Bell said.

The findings advance a 2020 report that showed pulse oximeters, which measure oxygen rates in the blood, have higher error rates in Black patients.

“There were patients with darker skin tones who were basically being sent home to die because the sensor wasn’t calibrated toward their skin tone,” Bell said.

Bell’s team created a new algorithm to process information from photoacoustic imaging, a method that combines ultrasound and light waves to render medical images. Body tissue absorbing this light expands, producing subtle sound waves that ultrasound devices turn into images of blood vessels, tumours, and other internal structures. But in people with darker skin tones, melanin absorbs more of this light, which yields cluttered or noisy signals for ultrasound machines.

The team was able to filter the unwanted signals from images of darker skin, in the way a camera filter sharpens a blurry picture, to provide more accurate details about the location and presence of internal biological structures.

The researchers are now working to apply the new findings to breast cancer imaging, since blood vessels can accumulate in and around tumours. Bell believes the work will improve surgical navigation as well as medical diagnostics.

“We’re aiming to mitigate, and ideally eliminate, bias in imaging technologies by considering a wider diversity of people, whether it’s skin tones, breast densities, body mass indexes – these are currently outliers for standard imaging techniques,” Bell said. “Our goal is to maximise the capabilities of our imaging systems for a wider range of our patient population.”

Source: John Hopkins University

Categories : CancerTags :

How Accurate is Supplemental Ultrasound in Breast Cancer Screening Failures?

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Dense breast tissue, which contains a higher proportion of fibrous tissue than fat, is a risk factor for breast cancer and also makes it more difficult to identify cancer on a mammogram. Many US states have enacted laws that require women with dense breasts to be notified after a mammogram, so that they can choose to undergo supplemental ultrasound screening to improve cancer detection. A recent study published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society, evaluated the results of such additional screening to determine its benefits and harms to patients.

Although supplemental ultrasound screening may detect breast cancers missed by mammography, it requires additional imaging and may lead to unnecessary breast biopsies among women who do not have breast cancer. Therefore, it is important to use supplemental ultrasound only in women at high risk of mammography screening failure – in other words, women who develop breast cancer after a mammogram shows no signs of malignancy.

Brian Sprague, PhD, of the University of Vermont Cancer Center, and his colleagues evaluated 38 166 supplemental ultrasounds and 825 360 screening mammograms without supplemental ultrasounds during 2014–2020 at 32 US imaging facilities within three regional registries of the Breast Cancer Surveillance Consortium.

The team found that 95.3% of supplemental ultrasounds were performed in women with dense breasts. In comparison, 41.8% of mammograms without additional screening were performed in women with dense breasts.

Among women with dense breasts, a high risk of interval invasive breast cancer was present in 23.7% of women who underwent ultrasounds, compared with 18.5% of women who had mammograms without additional imaging.

The findings indicate that ultrasound screening was highly targeted to women with dense breasts, but only a modest proportion of these women were at high risk of mammography screening failure. A similar proportion of women who received only mammograms were at high risk of mammography screening failure.

“Among women with dense breasts, there was very little targeting of ultrasound screening to women who were at the highest risk of a mammography screening failure. Rather, women with dense breasts undergoing ultrasound screening had similar risk profiles to women undergoing mammography screening alone,” said Dr Sprague. “In other words, many women at low risk of breast cancer despite having dense breasts underwent ultrasound screening, while many other women at high risk of breast cancer underwent mammography alone with no supplemental screening.”

Clinicians can consider other breast cancer risk factors beyond breast density to identify women who may be appropriate for supplemental ultrasound screening. Publicly available risk calculators from the Breast Cancer Surveillance Consortium are available that also consider age, family history, and other factors (https://www.bcsc-research.org/tools).

Source: Wiley

Categories : Injury & Trauma PaediatricsTags :

Portable Ultrasound Works Just as Well in Diagnosing Forearm Fractures in Kids

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Portable ultrasound devices could provide an alternative to x-ray machines for diagnosing forearm fractures in children, which could alleviate waiting times for families in hospital emergency departments (ED).

Griffith University researchers Professor Robert Ware and Senior Lecturer Peter Snelling compared functional outcomes in children given an ultrasound and those who received an x-ray on a suspected distal forearm fracture. Dr Snelling said the ultrasounds were performed by nurses, physiotherapists and emergency physicians at four south-east Queensland hospitals.

“They treated 270 children, aged between five and 15 years, during the randomised trial, which included a check-up 28 days later and another check-in at eight weeks,” Dr Snelling said. “The findings show the majority of children had similar recoveries and returned to full physical function.”

Less than one-third of children who were given an ultrasound needed a follow-up x-ray and care at an orthopaedic clinic. Those who didn’t have a buckle fracture or fractured arm were discharged from hospital without the need for further imaging.

Professor Ware said children who had an ultrasound initially had fewer x-rays, and shorter stays in the ED. “Families were also more satisfied with the treatment they received,” he said. “The results are promising and have wider implications beyond in hospital diagnosis and follow up care.

“By using a bedside ultrasound, this frees up the x-ray machine for patients who really need it and can potentially be a cost-cutting measure for hospitals as they reduce the number of x-rays without comprising the safety of patients.

“It also would be extremely beneficial in rural or remote areas eliminating the need for children and their families to travel to a larger hospital for an x-ray.”

Source: Griffith University

Categories : Lab Tests and ImagingTags :

Measuring Tissue Stiffness with Ultrasound Yields Sharper Images

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Researchers have developed a new ultrasound method that for the first time can measure the level of tension in human tissue – a key indicator of disease. The breakthrough, published in the journal Science Advances, could be used to build new ultrasound machines that are able to better discriminate between abnormal tissue, scarring, and cancer.

Images produced by the current techniques ultrasound used in healthcare aren’t usually enough to diagnose whether tissues are abnormal. To improve diagnosis, the researchers developed a way to measure forces such as tension by using an ultrasound machine. Tension is generated in all living tissue, so measuring it can indicate whether tissue is functioning properly or if it’s affected by disease.

The researchers harnessed a technique from a rail project at the University of Sheffield, which uses sound waves to measure tension along railway lines. The technique, used both for rail and medical ultrasound, relies on a simple principle: the greater the tension, the faster sound waves propagate. Using this principle, the researchers developed a method that sends two sound waves in different directions. The tension is then related to the speed of the waves by using mathematical theories developed by the researchers.

Previous ultrasound methods have struggled to show the difference between stiff tissue or tissue under tension. The developed technique is the first capable of measuring tension for any type of soft tissue, and without knowing anything about it. In this new paper, the researchers describe the new method and demonstrate how they used it to measure tension inside a muscle.

Study leader Dr Artur Gower, Lecturer in Dynamics at the University of Sheffield, said: “When you go to the hospital, a doctor might use an ultrasound device to create an image of an organ, such as your liver, or another part of your body, such as the gut, to help them explore what the cause of a problem might be. One of the limitations of ultrasounds used in healthcare now is that the image alone is not enough to diagnose whether any of your tissues are abnormal.

“What we’ve done in our research is develop a new way of using ultrasound to measure the level of tension in tissue. This level of detail can tell us whether tissues are abnormal or if they are affected by scarring or disease. This technique is the first time that ultrasound can be used to measure forces inside tissue, and it could now be used to build new ultrasound machines capable of diagnosing abnormal tissue and disease earlier.”

Source: University of Sheffield

Categories : Cardiovascular DiseaseTags :

Ultrasound to the Kidneys can Treat Resistant Hypertension

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A device that uses ultrasound to calm overactive nerves in the kidneys may be able to help some people get their blood pressure under control, according to successful test results published in JAMA Cardiology.

Led by researchers at Columbia University and Université de Paris, the study has found that the device consistently reduced daytime ambulatory blood pressure by an average of 8.5 points among middle-aged people with hypertension.

Lifestyle changes, such as cutting salt intake or losing weight, along with medications are often prescribed to lower blood pressure in patients with hypertension. Yet about one-third of hypertensive patients have resistant hypertension.

“Many patients in our clinical practice are just like the patients in our study, with uncontrolled blood pressure in the 150s despite some efforts,” says Ajay Kirtane, MD, professor of medicine at Columbia University Vagelos College of Physicians and Surgeons and co-leader of the study.

Leaving blood pressure uncontrolled for too long can lead to heart failure, strokes, heart attacks, and irreversible kidney damage.

“Renal ultrasound could be offered to patients who are unable to get their blood pressure under control after trying lifestyle changes and drug therapy, before these events occur,” says Kirtane, who is also an interventional cardiologist and director of cardiac catheterisation laboratories at NewYork-Presbyterian/Columbia University Irving Medical Center.

The study tested the device, which is used in an outpatient procedure called ultrasound renal denervation. The device is still investigational and has not yet been approved by the FDA for use outside of clinical trials.

Kidney nerves and hypertension

Hypertension in middle age is thought to be caused in part by overactive nerves in the kidneys, which trigger water and sodium retention and release hormones that can raise blood pressure. (In older people, hypertension often occurs as blood vessels stiffen). Antihypertensive drugs work in different ways to lower blood pressure, by dilating blood vessels, removing excess fluid, or blocking hormones that raise blood pressure. But none target the renal nerves directly.

Ultrasound therapy calms overactive nerves in the renal artery, disrupting signals that lead to hypertension. The therapy is delivered to the nerves via a thin catheter that is inserted into a vein in the leg or wrist and threaded to the kidney.

Study results

The new study pooled data from three randomised trials encompassing more than 500 middle-aged patients with varying degrees of hypertension and medication use.

Twice as many patients who received the ultrasound therapy reached their target daytime blood pressure (less than 135/85 mmHg) compared to patients in the sham groups.

“The result was almost identical across the different study groups, which definitively shows that the device can lower blood pressure in a broad range of patients,” Kirtane says.

The procedure was well-tolerated, and most patients were discharged from the hospital the same day. According to Kirtane, improvements in blood pressure were seen as soon as one month after the procedure.

The treatment will be evaluated by the FDA in the coming months.

Bottom line for patients with resistant hypertension

The investigators expect the treatment could be offered as an adjunct to medication therapy and lifestyle changes for patients with uncontrolled hypertension.

“Once the device is available, we envision recommending it to patients who have tried other therapies first. The hope is that by controlling blood pressure, we might be able to prevent kidney damage and other effects of uncontrolled blood pressure,” Kirtane adds.

Source: Columbia University Irving Medical Center

Categories : Cancer Medical Research & TechnologyTags :

Removing Tumours – Without the Scalpel

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A novel technology described in the journal Nanoscale enables targeted destruction of cancerous tumours, via a combination of ultrasound and the injection of nanobubbles into the bloodstream. Unlike invasive treatment methods or the injection of microbubbles into the tumour itself, this latest technology enables the destruction of the tumour in a non-invasive manner.

Dr Tali Ilovitsh at Tel Aviv University said: “Our new technology makes it possible, in a relatively simple way, to inject nanobubbles into the bloodstream, which then congregate around ​​the cancerous tumour. After that, using a low-frequency ultrasound, we explode the nanobubbles, and thereby the tumour.”

At present, the usual cancer treatment is surgical removal of the tumour, in combination with complementary treatments such as chemotherapy and immunotherapy.

Therapeutic ultrasound to destroy the cancerous tumour is a non-invasive alternative to surgery, a method which comes with advantages and disadvantages. On the one hand, it allows for localised and focused treatment; the use of high-intensity ultrasound can produce thermal or mechanical effects by delivering powerful acoustic energy to a focal point with high spatial-temporal precision. This method has been used to effectively treat solid tumours deep within in the body. Moreover, it makes it possible to treat patients who are unfit for tumour resection surgery. The disadvantage is that the heat and high intensity of the ultrasound waves could cause damage to neighbouring healthy tissues.

Reducing off-target damage

In the current study, Dr Ilovitsh and her team sought to overcome this problem. In the experiment, which used an animal model, the researchers were able to destroy the tumour by injecting nanobubbles into the bloodstream (as opposed to what has been until now, which is the local injection of microbubbles into the tumour itself), in combination with low-frequency ultrasound waves, with minimal off-target effects.

“The combination of nanobubbles and low frequency ultrasound waves provides a more specific targeting of the area of the tumour, and reduces off-target toxicity,” explains Dr Ilovitsh.

“Applying the low frequency to the nanobubbles causes their extreme swelling and explosion, even at low pressures. This makes it possible to perform the mechanical destruction of the tumours at low-pressure thresholds.”

“Our method has the advantages of ultrasound, in that it is safe, cost-effective, and clinically available, and in addition, the use of nanobubbles facilitates the targeting of tumours because they can be observed with the help of ultrasound imaging.”

Dr Ilovitsh adds that the use of low-frequency ultrasound also increases the depth of penetration, minimises distortion and attenuation, and enlarges the focal point. “This can help in the treatment of tumours that are located deep with the body, and in addition facilitate the treatment of larger tumour volumes. The experiment was conducted in a breast cancer tumour lab model, but it is likely that the treatment will also be effective with other types of tumours, and in the future, also in humans.”

Source: Tel Aviv University

Categories : Pain ManagementTags :

An Effective Short-term Therapy for Knee Osteoarthritis

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Knee pain
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With few solutions available, treatment of knee osteoarthritis is challenging, but a randomised control trial published in Arthritis and Rheumatology has found that, at least for short-term relief, ultrasound-guided genicular nerve block (GNB) was effective.

The global prevalence of knee osteoarthritis (OA) is ~22.9% of over-40s. Knee OA is a significant cause disability and potentially loss of independence. Treatment remains challenging, with nonsurgical management options such as education, weight loss, exercise therapy, and walking aids. Few recommended pharmacotherapeutic options exist for knee OA, with surgical joint replacement being a definitive treatment strategy for patients with severe disease who are unresponsive to conservative care. For many patients, such as people who are frail or elderly or people with complex comorbidities, surgical intervention may not be suitable.

In a 12-week parallel-group, placebo-controlled randomised trial of GNB, patients in the active arm received 3 injections of 5.7 mg celestone chronodose (1ml) and 0.5% bupivacaine (3ml) to the inferomedial, superomedial, and superolateral genicular nerves. Patients in the placebo arm received saline injections. An experienced radiologist or rheumatologist with the assistance of a senior sonographer used ultrasound to locate the nerves.

At baseline and at weeks 2, 4, 8, and 12, patients recorded their pain and disability on self-report scales. Patients in the active group reported improvements in pain scores at 2, 4, 8, and 12 weeks with a diminution of the effect over time. 

These results reflect comparator groups, which also reported an effect reduction at 12 weeks.

“This study demonstrates that genicular nerve block is an effective short-term therapy for pain management in people with knee osteoarthritis,” said corresponding author Ernst M. Shanahan, BMBS, MPH, MHPE, PhD, FAFOEM, FRACP, of Flinders University. “We think it may be a useful treatment option for this group of people, in particular those waiting for, or wishing to defer surgery.”

Categories : Surgeries & ProceduresTags :

NASA Technology Enables Nearly Painless Kidney Stone Removal

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Anatomic model of a kidney
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A new ultrasonic technique developed for emergency kidney stone treatments on Mars may offer an option to move kidney stones out of the ureter with minimal pain and no anaesthesia, according to a new feasibility study published in The Journal of Urology.

In the procedure, the physician uses a handheld transducer placed on the skin to direct ultrasound waves towards the stone. Using ultrasound propulsion, the stones can then moved and repositioned to promote their passage, while burst wave lithotripsy (BWL) can break up the stone.

Unlike with the standard technique of shock wave lithotripsy, there is minimal pain according to lead author Dr M. Kennedy Hall, a UW Medicine emergency medicine doctor. “It’s nearly painless, and you can do it while the patient is awake, and without sedation, which is critical.”

The researchers hope that one day the procedure of moving or breaking up the stones could eventually be performed in a clinic or emergency room setting with this technology, Dr Hall added.

Ureteral stones can cause severe pain and are a common reason for emergency department visits. Most patients with ureteral stones are advised to wait to see if the stone will pass on its own. However, this observation period can last for weeks, with nearly one-fourth of patients eventually requiring surgery, Dr Hall noted.

Dr Hall and colleagues evaluated the new technique to meet the need for a way to treat stones without surgery.

The study was designed to test the feasibility of using the ultrasonic propulsion or using BWL to break up stones in awake, unanaesthetised patients, Dr Hall said.

The study recruited 29 patients; 16 received propulsion and 13 received propulsion and BWL. In 19 patients, the stones moved. In two cases, the stones moved out of the ureter and into the bladder.

Burst wave lithotripsy fragmented the stones in seven of the cases. At a two-week follow up, 18 of 21 patients (86%) whose stones were located lower in the ureter, closer to the bladder, had passed their stones. In this group, the average time to stone passage was about four days, the study noted.

One of these patients felt “immediate relief” when the stone was dislodged from the ureter, the study stated.

The next step would a clinical trial with a control group, which would not receive either BWL bursts or ultrasound propulsion, to evaluate the degree to which this new technology potentially aids stone passage, Dr Hall said.

Development of this technology first started five years ago, when NASA funded a study to see if kidney stones could be moved or broken up, without anaesthesia, on long space flights, such as the Mars missions. The technology has worked so well that NASA has downgraded kidney stones as a key concern.

“We now have a potential solution for that problem,” Dr Hall said.

Source: University of Washington School of Medicine/UW Medicine

Categories : CancerTags :

Pump up the Volume: Killing Cancer with Ultrasound

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Sound waves
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University of Michigan scientists have developed an ultrasound technology that uses high-powered pulses to break down liver tumours in rats, kill cancer cells and stimulate the immune system to destroy the remaining tumour and prevent metastasis.

The researchers reported in Cancers that, by destroying just 50% to 75% of liver tumour volume, the rats’ immune systems were able to clear away the rest, with no evidence of recurrence or metastases in more than 80% of animals.

“Even if we don’t target the entire tumour, we can still cause the tumour to regress and also reduce the risk of future metastasis,” said Professor Zhen Xu, corresponding author of the study.

The treatment was also found to spur the rats’ immune responses, possibly contributing to the eventual regression of the untargeted portion of the tumour and preventing further spread of the cancer.

The noninvasive technique, called histotripsy, focuses ultrasound waves to mechanically destroy target tissue with high precision. The relatively new technique is currently being used in a human liver cancer trial in the US and Europe.

Often, a tumour cannot be directly targeted for certain treatments due to the mass’ size, location or stage. To investigate the effects of partially destroying tumours with sound, this latest study targeted only a portion of each mass, leaving behind a viable intact tumour. It also allowed the team to demonstrate the technique in less ideal conditions.

“Histotripsy is a promising option that can overcome the limitations of currently available ablation modalities and provide safe and effective noninvasive liver tumour ablation,” said Tejaswi Worlikar, a doctoral student in biomedical engineering.

Liver cancer ranks among the top 10 causes of cancer related deaths worldwide, with poor prognosis despite multiple treatment options. Tumour recurrence and metastasis after initial treatment is common, demanding improved treatments.

The ultrasound approach comes without the side effects from present treatments such as radiation and chemotherapy.

“Our transducer, designed and built at U-M, delivers high amplitude microsecond-length ultrasound pulses – acoustic cavitation – to focus on the tumour specifically to break it up,” Prof Xu said. “Traditional ultrasound devices use lower amplitude pulses for imaging.”

The microsecond pulses create microbubbles within targeted tissues that rapidly expand and collapse, tearing up cancer cells and disrupting the tumour’s structure.

Source: University of Michigan