Jody Dascalu | June 17, 2023
Ultrasound is a vital medical imaging technology that uses high-frequency sound waves to visualize structures within the body. Its potential applications in diagnosing and treating diverse conditions have broadened with emerging research, which is providing valuable insights into newer, more accurate diagnostic methodologies and unique therapeutic applications. These advancements increase the capacity to combat diseases more effectively and improve patient outcomes.
Innovations in ultrasound imaging: From 2D to 4D scans
Ultrasound imaging, initially introduced as a diagnostic tool, has expanded its function through technological advancements. Traditional ultrasound is often synonymous with pregnancy, as it is commonly used to monitor fetal development. However, its usage spans beyond obstetrics, reaching into areas such as cardiology, gastroenterology and urology. Ultrasound is non-invasive, safe and provides real-time imaging, making it an invaluable tool in modern medicine.
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Two-dimensional grayscale images have evolved into three and four-dimensional scans, adding depth and time to the observations. Moreover, the development of Doppler ultrasound enables physicians to observe blood flow and identify blockages or abnormalities using sound waves.
A collaborative effort from scientists at the University of Sheffield, Harvard University, Tsinghua University and the University of Galway has led to a breakthrough in ultrasound technology.
Their technique allows ultrasound machines to measure human tissue’s tension level, a critical determinant of tissue health. This advancement could greatly improve the diagnosis of abnormal tissue, scarring and cancer.
Ultrasound used to measure tissue tension
Conventional ultrasound machines use sound waves to create images of internal organs, but these often fall short in distinguishing normal from abnormal tissues. This newly developed technique bridges this diagnostic gap by measuring tissue tension, a universal property in living tissue disrupted by disease.
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The research team adapted a method used to measure tension along railway lines, applying it to medical ultrasound. This breakthrough ultrasound method uses shear waves to measure tension in tissue. By using two sound waves moving in opposite directions, they could determine the speed at which sound travels through tissue, which varies with the tension level. This pioneering technique can measure tension in any soft tissue, significantly enhancing ultrasound scans’ diagnostic potential.
Ultrasound-targeted drug delivery
With these diagnostic improvements, ultrasound has also found applications in treatment. Ultrasound-targeted drug delivery (UTDD) is a promising approach to overcome the limitations of traditional drug delivery systems, which often fail to maintain high therapeutic concentrations for long durations. UTDD leverages the sophistication of ultrasound technology to achieve spatiotemporal control over drug delivery, increasing the efficiency and therapeutic efficacy of various drugs, from chemotherapeutics to antibiotics.
It enables real-time control of drug release during insonation, and its high spatial resolution allows for precise targeting. The noninvasive, non-ionizing and relatively inexpensive nature of ultrasound also increases its clinical applicability. It addresses the need for externally controlled, responsive drug delivery systems, improving on prior techniques that were often constrained by the transition from in vitro to complex in vivo environments.
Microbubble cavitation in drug delivery
Microbubble cavitation, a key component of UTDD, utilizes microbubbles as drug delivery agents. The microbubbles respond to acoustic waves, leading to small ruptures in local cell membranes, increasing drug delivery. This precise targeting ensures the effects are localized to the tissue intended for treatment, vital for cancer treatments, and the blood-brain barrier opening.
Despite the potential of UTDD, the amount of drug that can be incorporated into a microbubble shell is limited, and adding or incorporating a drug into the microbubble shell might alter the drug’s biological activity or the acoustic capabilities of the ultrasound contrast agent (UCA). As a result, ongoing research is investigating the development of synthetic microbubbles that enhance acoustic energy absorption and decrease the cavitation threshold.
Promising strategies for cancer therapy
Microbubbles, when paired with UTDD and sonoporation techniques, offer promising strategies for cancer therapy. They enhance the delivery of therapeutic agents such as curcumin and doxorubicin (DOX) to cancer cells, causing tumor inhibition.
Microbubbles can also transport genes and gases to further improve cancer treatment. For instance, oxygen-loaded microbubbles have been used to boost tumor radiosensitivity by increasing local tumor oxygenation. Sonoporation has shown potential in treating pancreatic ductal adenocarcinoma (PDAC), a notoriously lethal cancer.
Microbubbles have also been utilized for infection-related delivery, demonstrating increased delivery of antimicrobials and anti-rejection drugs in urinary tract infections and acute transplant rejections respectively. These novel approaches underline the potential of UTDD and microbubbles in medical applications.
Ultrasound in brain activity modulation
Beyond drug delivery, ultrasound has found use in modulating brain activity. Transcranial focused ultrasound (tFUS) is a non-invasive brain stimulation technique that can modulate neuronal activity.
A study on tFUS’s effects on the medial prefrontal cortex (mPFC), a key region for cognitive control and emotional regulation, revealed that tFUS can modulate brain activity. However, the mPFC’s depth within the brain meant that precise local effects were not confirmed.
Future research incorporating functional neuroimaging could provide a clearer picture. The results hint that tFUS could modify neuronal activity in neuropsychiatric diseases, such as depression and sleep disorders. Nevertheless, further studies are needed to refine parameters and assess therapeutic effects.
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Ultrasound’s new horizons in healthcare
In conclusion, the advancements in ultrasound technology are revolutionizing its role in healthcare, both in diagnosis and treatment. From pioneering methods for measuring tissue tension to innovative drug delivery systems leveraging microbubble cavitation, the potential applications of ultrasound are broad and transformative. The technique’s ability to modulate deep-seated brain structures non-invasively signals a promising avenue in neuropsychiatric treatment. As the field of ultrasound continues to evolve, its potential for improving patient outcomes and transforming medical practice is undeniably significant. Future research promises even more exciting breakthroughs in this rapidly advancing field.
About the author
Jody Dascalu is a freelance writer in the technology and engineering niche. She studied in Canada and earned a Bachelor of Engineering. As an avid reader, she enjoys researching upcoming technologies and is an expert on a variety of topics.
