Advancing Ultrasound Technology
Contributed by Amanda Fraraccio
As we continue our focus on advancements in technology let’s take a look at our field of ultrasound and where we are heading. For many years CT and MRI were the preferred diagnostic tools in many disciplines, however, advancements in imaging quality and workflow, as well as the rising awareness of radiation exposure with other imaging modalities, have driven the interest of manufacturers and scientists toward ultrasound (De, 2012). Sarah Fawcett, BB Imaging Regional Supervisor, has this to say about the evolution of ultrasound over the course of her 17-year career, “CT and MRI were the gold standards for diagnosing most disease and ultrasound was considered not as reliable. When I first started scanning in 2001 and would find significant disease in the lower extremity arterial system the radiologist would then recommend a lower extremity fluoroscopy arteriogram to confirm. This procedure would give the patient a high dose of radiation. Image quality has improved so much in ultrasound that ultrasound imaging has now become the gold standard for diagnosing peripheral vascular disease.”
There are many reasons that ultrasound has come so far. The speed, efficacy, cost-effectiveness and noninvasive nature of ultrasound imaging are some of the key attributes that have given this technology an edge over other imaging modalities. In addition, ultrasound equipment is economical; even the most advanced ultrasound systems cost about one-fifth of the price for a low-end magnetic resonance imaging (MRI) system (De, 2012).
Another area of advancement in recent years is the use of ultrasound elastography. This is a technology that has taken the centuries-old diagnostic tool of physical palpation and extended that method to organs located beyond the reach of physical touch, providing new opportunities for diagnosis and noninvasive assessment of disease. This technology could lead to a great reduction in the need for biopsies in diagnosing many conditions. Elastography is being used to diagnose and stage liver disease, evaluate breast lesions, and examine the prostate. There are two methods, strain and shear wave ultrasound elastography. Achieving the same results with both methods can lead to higher confidence in the diagnosis. It has been reported in some practices that up to 70% of unnecessary breast biopsies have been eliminated based on the results of the two ultrasound elastography tests (Massat, 2016).
For more information on this transformative tool see this article
http://appliedradiology.com/articles/ultrasound-elastography-gaining-clinical-use
As with most emerging technologies, there are some stumbling blocks to address. The newest diagnostics available such as 3D and 4D ultrasound, fusion imaging, and strain and shear wave elastography are not reimbursed in many healthcare plans. Historically technology is several years ahead of the adaptation of health care plans (De, 2012). Another issue being spotlighted is lack of diversity in study samples. Many norms and guidelines in medicine are set based on studies including mostly male Caucasian participants. For example, a very detailed study on cardiac ultrasound diagnostics from the American Society of Echocardiography (ASE) and the European Association of Cardiac Imagery based their guidelines for diagnostics on a study sample of Caucasian men, Caucasian women, and a small percentage of Black men (Lang, et al., 2015).
Children are another understudied group. Elastography has the potential to be very useful in evaluating liver stiffness in pediatric liver disease for diagnosis. Following its progression in pediatric patients, including children with liver transplants, metabolic disorders, and cystic fibrosis could be key; however, all of the current data is based on adults (Massat, 2016). The good news is there are medical professionals who see this gap and are working to address the issue. Currently, there are pediatricians gathering data on elastography in small studies but hopefully, as the technology becomes more widespread the studies will grow (Massat, 2016).
There are also organizations who are addressing norms in cardiovascular ultrasound. The clinical usefulness of echocardiography is based on the detection of abnormalities, which relies on the accurate definition of “normality” across different countries or races. Currently, available echocardiographic “reference values” that define “normality” are mostly based on cross-sectional observations of Caucasians from the U.S. and Europe (Imaging Technology News, 2018). ASE who has the most recent data from 2015 is working on a study with its International Alliance Partners and the World Alliance of Societies of Echocardiography (WASE) to conduct a new Normal Values Study. This study is bringing together the scientific cardiovascular ultrasound community from around the world to better understand if the current recommended normal values for heart dimensions and function in subjects from different races and countries are similar or different. In addition, normal values for novel echocardiography modalities such as 3-D and strain will be established. They have currently enrolled a landmark number of 1,000 subjects. People from six continents have been enrolled and final results are expected to be available in 2019 (Imaging Technology News, 2018). Ms. Fawcett observes “.this study is very valuable. For example, I personally find that there is left atrial enlargement on a majority of the echo studies that I perform. I have often questioned the "normal" accepted values for the left atrium. It could be that the previous method for coming up with the normal values used too small of a group of people that were non-diverse.” Fawcett currently scans in a facility that serves predominately Native Americans. The future of more expansive research groups could bring with it answers that lead to better diagnosis for a wider range of patients.
For more on this study visit:
References
De, D. (2012, October 25). https://www.itnonline.com/article/emerging-trends-ultrasound-imaging. Retrieved from Itn Online: https://www.itnonline.com/article/emerging-trends-ultrasound-imaging
Imaging Technology News. (2018, February 26). https://www.itnonline.com/content/ase-participating-global-study-establish-new-standardization-cardiovascular-ultrasound. Retrieved from itnonline: https://www.itnonline.com/content/ase-participating-global-study-establish-new-standardization-cardiovascular-ultrasound
Lang, R. M., Badano, L. P., Mori-Avi, V., Afilalo, J., Armstrong, A., & Ernande, L. J.-U. (2015). Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Morrisville: American Society of Echocardiography.
Massat, M. B. (2016, March 2). ultrasound elastography is extending palpation to organs located beyond the reach of physical touch, providing new opportunities for diagnosis and the noninvasive assessment of disease. Retrieved from Radiology the Journal of Practical Medical Imaging and Management: ultrasound elastography is extending palpation to organs located beyond the reach of physical touch, providing new opportunities for diagnosis and the noninvasive assessment of disease.