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  • Look Ahead: The Future of Ultrasound in Radiology

    Ultrasound expert Deborah Levine, MD, discusses how radiologists can continue to be leaders in the field. By Deborah Levine, MD

    October 1, 2017

    The Future of Ultrasound in Radiology

    As I am sure the radiology community is aware, the use of ultrasound (US) has exploded around the world and across medical subspecialties. Changes in hardware and software have allowed for smaller, less expensive machines, and thus many healthcare providers now utilize US in their daily practice. Despite concerns that this will lead to the demise of US as practiced by radiologists, my anecdotal experience, i.e., talking to radiologists around the United States and Canada, has shown me that US volumes are still robust. However, there is growing concern in the ultrasound community that if our expertise in the subspecialty dwindles, other subspecialists will fill the void.

    Image Optimization and Ultrasound Education

    Over the past two decades, US machines have decreased in size and increased in performance, so much so that it has become easier to obtain diagnostic-quality images. Many machines have image optimization buttons that allow for a variety of machine-controlled variables that automatically adjust to improve image quality. While I lament the fact that many imagers do not understand the physics behind the varied US parameters that can be manipulated on a US machine, how can I complain when the vast majority of the images I see are of good-to-excellent quality? Nonetheless, it behooves the imaging community to ensure that our trainees understand US physics, and have the opportunity to develop skills in real-time scanning so that we can maintain our role as US experts. Hands-on training of US is variable across radiology residency programs. While many of our residency and fellowship programs continue to have strong scanning requirements in our US rotations, there is increased demand for trainee time in other imaging subspecialty areas, especially considering that the U.S. radiology residency curricula are condensed into the first three years of residency. Training in US will allow radiologists to continue to offer this safe and inexpensive modality for the benefit of our patients.

    Keeping the Focus on Patient Care

    It was 30 years ago that Roy Filly lamented in a Radiology editorial (Radiology 1988;167:400) that US would be the stethoscope of the future. Today we continue to see the proliferation of US in many medical subspecialties given the advances in technology that allow for smaller, less expensive machines and imaging at the bedside. While small laptop and handheld US machines can be disruptive and pervasive technologies and can be a threat to the practice of US by radiologists, they can also benefit patient care if appropriate diagnoses can be obtained in a more timely fashion. We need to work with our referring clinicians to ensure that appropriate training and standards for quality exist in their US practices; that quality metrics are met; and that images are available outside of their departments for review and/or re-interpretation when needed. This is our opportunity to continue to contribute as imaging experts.

    Bedside US examinations are often targeted exams to answer a specific clinical question. These differ from the complete diagnostic US examinations performed in radiology departments. As in any imaging examination, we need to ensure that our image quality is excellent, that images are available for review outside of our imaging departments, that reports are available in the information system in a timely fashion, that our conclusions address the clinical indication for the examination, and that we have excellent communication of critical results with our referring providers. We should feel comfortable making sonographic diagnoses and not always rely on referral to CT or MR for additional information when that information can be provided by US. We should feel comfortable talking face-to-face with our patients about their sonographic diagnoses.

    Volumes and Cine Clips — More Than Pretty Pictures

    There is no doubt that parents love the 3-D images of the fetus that are obtained during obstetric imaging. However, I find 3-D imaging most useful for intrauterine device (IUD) position, where the coronal view is most important and can be easily reconstructed. With the rapidly decreasing cost of storage of medical images and with faster internet connections, we can review, reconstruct and store 3-D volumes outside of the examination room, potentially allowing for more rapid examinations.

    We can also review cine clips that allow for interpretation by specialists at remote locations and for reassessment of images after the patient has left the US suite. While I much prefer onsite US scanning and talking to the patient personally, I realize that practice patterns vary according to regional and local needs. Having the ability to obtain large quantities of US data and optimize display for later interpretation are advances in US and information technology that should allow us to improve our US practices.

    Elastography — Taking US Beyond Anatomy

    Elastography allows for non-invasive assessment of tissue mechanical properties. Much has been written about liver elastography for assessment of liver fibrosis (and monitoring of treatment of viral hepatitis), but there are many other uses of elastography, including assessment of tumors in a variety of organs and assessment of muscular diseases. The wide availability of US-based elastography, including its use at the bedside and relatively low cost, ensures that this technique will have increasing use in the future.

    Contrast — Beyond Screening and Lesion Characterization

    Ultrasound contrast allows for improved screening for metastatic disease and improved characterization of lesions (for example in the liver and kidney), compared to non-contrast imaging, providing tumor imaging at a lower cost (compared to MRI) and with no radiation exposure (compared to CT). These issues of cost, lack of radiation exposure, and also paucity of contra-indications are particularly important in patients who need multiple examinations or at-risk populations, such as children. Ultrasound contrast can also be used for studies such as voiding cystourethrogram, allowing for a non-radiation, non-iodine contrast method for examining the urinary tract. Looking to the future, US contrast will enjoy increased use for the above-mentioned vascular and other intra-cavitary indications.

    Ultrasound Therapeutics and Procedures

    Imagine combining a therapeutic agent into US contrast microbubbles. We could inject the contrast and burst the bubbles right when they arrive at the tissue of interest to provide targeted therapy. Other methods of drug delivery with US include binding ligands that are over-expressed in tumors to microbubbles to enhance local delivery or using US to disrupt the blood brain barrier to allow medications into the brain. These therapies are already in select use for enhancing the delivery of chemotherapy and genetic material, but are not yet mainstream. Additionally, high-intensity focused ultrasound (HIFU) can be used to treat fibroids and even prostate cancer. Many other uses for HIFU are on the horizon. Finally, fusion imaging is a welcome technology that allows for US-guided biopsies of lesions initially visualized on other modalities such as CT and MRI.

    Expanding Opportunities

    I see the future of US as one of expanding opportunities for improvements in patient care. However, it is up to radiologists whether or not we will continue to be the physician experts who are the leaders in the field.

    Deborah Levine, MD is director of Obstetric & Gynecologic Ultrasound (US) at Beth Israel Deaconess Medical Center, Boston, and a professor of radiology at Harvard Medical School. Dr. Levine focuses her clinical work in US and her research on obstetric and gynecologic US. For the past decade, Dr. Levine has devoted much of her academic time to working as senior deputy editor of Radiology. Dr. Levine is president of the Society of Radiologists in Ultrasound. She is a member of the RSNA Public Information Advisors Network.

    A 66-year-old man with an elbow mass. Grayscale image shows a solid heterogeneous mass (arrows) in the lateral elbow soft tissues. A two-dimensional tissue stiffness color map obtained using shear wave elastography (above) demonstrates high intra-lesional stiffness and permits quantitative measurement of tissue stiffness, expressed in kilopascals. Biopsy confirmed pleomorphic leiomyosarcoma. Case courtesy of Colm McMahon, MD

    A two-year-old girl with a history of UTI. Sagittal images of the right kidney during ultrasound contrast enhanced voiding cystourethrogram (VCUG) shows reflux into the collecting system, which had not been noted on prior x-ray VCUG. Images courtesy of Harriet Paltiel, MD

    Ultrasound in a patient with elevated liver function tests. Liver stiffness mean from 10 measurements (one shown here) was 2.98m/s, which is in the range of cirrhosis. Image courtesy of Richard Barr, MD