Now that contrast-enhanced ultrasound (CEUS) has been approved in the United States for several abdominal applications in adults and pediatrics, I decided to take a deeper look into the sonographer’s role in CEUS. Traditionally, sonographers perform ultrasound examinations based on a protocol, construct a preliminary ultrasound findings worksheet, and perhaps discuss the findings with a radiologist. And now CEUS has transformed traditional ultrasound and gives physicians and sonographers additional diagnostic information related to the presence and patterns of contrast enhancement.
Based on sonographers’ traditional scope of practice, some questions came to mind. What is the training process for sonographers to learn CEUS? How should CEUS images be obtained and stored? How should CEUS findings be communicated?
I envision CEUS training for sonographers broken down into stages, where they begin by learning the basics and eventually transition to where they can perform and record the studies independently. The first stage for sonographers is the ‘CEUS learning curve.’ In this stage, sonographers become familiar with basic CEUS concepts, eg, understanding physics of contrast agents and contrast-specific image acquisition modes, CEUS protocols, and typical patterns of contrast enhancement seen in various organs. In addition, an important part of the training is recognizing contrast reactions, and learning IV placement, documentation and billing related to CEUS.
The next stage involves sonographers performing more patient care and gaining scanning responsibilities. Sonographers place the IV and prepare the contrast agent. The scope of sonographer responsibilities does not generally include contrast injection (although it is reasonable since CT, MR, nuclear medicine, and echocardiography technologists routinely place IV lines and inject contrast). It should be noted that CEUS examination usually requires an additional person (physician, nurse, or another sonographer) to assist with contrast injection while the sonographer performs the ultrasound examination. In the beginning of sonographer training, it is very beneficial to have a radiologist present in the room to guide scanning and appropriate image recording.
In the third stage, a well-trained sonographer is more independent. At the completion of the examination, the sonographer will either send clips or still images to a physician to document the CEUS findings and discuss the procedure. Ideally a worksheet is filled out, comparable to what is done today with “regular” ultrasound.
The majority of CEUS examinations are performed based on pre-determined protocols, usually requiring a 30–60-sec cineloop to document contrast wash-in and arterial phase enhancement. After that continuous scanning should be terminated and replaced with intermittent acquisition of short 5–10-sec cineloops obtained every 30–60 sec to document late phase contrast enhancement. These short clips have the advantage of limiting stored data while providing the interpreting physician with real-time imaging information. Detailed information on liver imaging CEUS protocols could be found in the recently published technical guidelines of the ACR CEUS LI-RADS committee.[i] Some new users might acquire long 2–3-minute cineloops instead, producing massive amounts of CEUS data. As a result, studies can slow down a PACS system if departments are not equipped to deal with large amounts of data. In addition, prolonged continuous insonation of large areas of vascular tissue could result in significant ultrasound contrast agent degradation limiting our ability to detect late wash-out, a critical diagnostic parameter required to diagnose well differentiated HCC. Any solution requires identifying and capturing critical moments, which will be determined by a sonographer’s expertise. Exactly how sonographers can ensure CEUS will successfully capture the most important images is a critical question that must be answered and standardized.
Ideally, leading academic institutions should provide CEUS training for physicians and sonographers. I have seen and attended CEUS continuing medical education courses and they are a great way for physicians and sonographers to learn CEUS imaging. CEUS is a step forward for sonographers and will potentially transform our scope of practice. The technology will advance the importance of sonographers and diagnostic ultrasound, and importantly it will improve the care of our patients.
Dr. Laurence Needleman, MD
Dr. Andrej Lyshchik, MD
Dr. John Eisenbrey, PhD
Joanna Imle, RDMS, RVT
[i] Lyshchik A, Kono Y, Dietrich CF, Jang HJ, Kim TK, Piscaglia F, Vezeridis A, Willmann JK, Wilson SR. Contrast-enhanced ultrasound of the liver: technical and lexicon recommendations from the ACR CEUS LI-RADS working group. Abdom Radiol (NY). 2017 Nov 18. doi: 10.1007/s00261-017-1392-0. [Epub ahead of print]
Has CEUS helped your sonography career? How do you envision CEUS being incorporated in your work? Comment below or let us know on Twitter: @AIUM_Ultrasound.
Corinne Wessner BS, RDMS, RVT is the Research Sonographer for Thomas Jefferson University Hospital in Philadelphia, Pennsylvania. Corinne has an interest in contrast-enhanced ultrasound, ultrasound research, medical education, and sonographer advocacy.