ICUS Weekly News Monitor 12-21-2017


  1. ICUS,  Dec 15, 2017,  GE Healthcare - Imagination at Work: A powerful innovation in liver imaging (Extract)
  2. Journal of the American Society of Echocardiography,  Oct 17, 2017,  Right Ventricular Size and Function; Quantification of Right Ventricular Size and Function from Contrast-Enhanced by Three-Dimensional Echocardiographic Images

Authors:  Diego Medvedofsky, MD, et al.

GE Healthcare - Imagination at Work: A powerful innovation in liver imaging

Dec 15, 2017

(Extract. Courtesy of GE Healthcare. Reproduced with permission.)

Contrast-enhanced ultrasound is a valuable and affordable diagnostic tool for assessing liver lesions. It is also easy to adopt as a service with minimal investment in equipment and training. Clinician education and more clarity around procedure reimbursement are keys to its wider adoption for patients’ benefit.

Advantages of CEUS

Microbubble contrast agents have greatly expanded the utility of ultrasound in the liver, especially for evaluating liver lesions. Contrast-enhanced ultrasound (CEUS) is emerging as a quick and low-risk technique that in a variety of cases can provide a lower-cost, more immediately available alternative to CT and MR contrast exams.

CEUS exams are fast and often definitive. They may also have significant value for patients who are at risk from nephrotoxic contrast agents.

Furthermore, CEUS is relatively simple to add as a service – it requires no substantial capital investment and only a minimum of staff training. The basic steps to CEUS adoption are simple and straightforward as outlined below.

Clinician education is a key to the technique’s growth: many specialists are unaware of it or do not appreciate its full range of capabilities. It is also important to resolve issues surrounding reimbursement for the contrast portion of the procedure and to ensure that CEUS is included in decision-support software tools that help clinicians gauge the appropriateness of imaging studies.

CEUS has the built-in advantage of enabling clinicians to assess contrast enhancement patterns in real time, with better temporal resolution than other modalities. Ultrasound microbubble contrast agents allow lesion enhancement to be observed in all vascular phases in real-time imaging. Side effects from  these agents are very rare. They can be given without first assessing liver or kidney function and, if need be, multiple doses can be given repeatedly in the same imaging session.1

Among the compelling clinical benefits, a CEUS exam:

  • Costs less than MR and CT scans.
  • Avoids the radiation exposure of a CT study.
  • Saves time: A CEUS study takes approximately 10 minutes after the IV is placed and contrast given, versus 45 minutes or more inside an MR scanner bore.
  • Eliminates the challenge inherent in MR scans for claustrophobic patients, and for those who are otherwise unable to tolerate a lengthy exam and may require sedation.

In the liver, CEUS can be used to define and characterize lesions. It can help definitively distinguish benign from malignant lesions; no confirmation with CT or MR is needed. In patients at risk for hepatocellular carcinoma (HCC), liver monitoring via ultrasound is performed at intervals, such as every six months. If a lesion is observed, CEUS can be arranged on the spot and the patient can receive a diagnosis before leaving the clinic.

After treatment of a tumor, CEUS can be used to determine whether any viable malignant tissue remains. Patients can be monitored over time to ensure against recurrence. In these cases, CT or MR follow-ups may be necessary to look for new tum or elsewhere in the liver.

In view of these benefits, many care centers are exploring the addition of CEUS. Here is an overview of the basic steps involved:

Step 1: Adding ultrasound contrast agents to the formulary

CEUS procedures have been simplified by the emergence of a contrast agent FDA-approved in April 2016 for characterization of focal liver lesions in adult and pediatric patients. This agent was previously FDA-approved for use in adults with suboptimal echocardiograms to opacify the left ventricular chamber and improve delineation of the left ventricular endocardial border.

Lumason is now FDA-approved for use in liver imaging to improve the sensitivity and specificity of ultrasonography in differentiating between malignant and benign focal hepatic lesions. It is the first ultrasound contrast agent approved for use in pediatric patients.

There are generally no major issues in getting a contrast agent added to the formulary. While approval procedures differ among hospitals, here are a few essential steps to follow:

  • Work with your institution’s pharmacy committee to identify the steps to add a new drug to the formulary. If a CEUS contrast agent is already present, you may need to provide justification for a second one.
  • Complete an application for decision-makers that emphasizes:
    • The agent’s clinical value and patient safety profile.
    • The agent’s workflow benefits and FDA approval.
  • If there are issues, consult with external sources, including the contrast agent manufacturer, to identify the appropriate approval channels.

Step 2: Training the staff

An essential component of CEUS is training staff to perform the procedure and having access to personnel qualified to start the necessary IV.

The level of sonographers’ involvement in CEUS studies will vary by institution. Some physicians prefer to conduct the actual scans themselves; in those cases the sonographers may perform pre-injection images and position the patients for the exams.

Others train sonographers in the scanning procedure. As CEUS gains acceptance and procedure volumes grow, there are different options for managing IV cannulation. In some centers, nurses start the IVs. In other cases, MR or CT technologists do so. Institutions with higher CEUS volumes train sonographers for this role. The question is which model works best given the patient load and availability of qualified staff.

Step 3: Scheduling CEUS cases

Ease of scheduling adds to the benefits of CEUS. Typically, the exams are scheduled as outpatient procedures, on relatively short lead times. Referring physicians should be instructed to specify  ultrasound contrast on their orders. Where this does not occur, the radiologist needs to call the referring physician back and have the contrast instruction added.

There are two basic models for scheduling cases. The first is to pre-schedule patients, reserving a day or an afternoon for contrast cases. This has the advantage of ensuring that CEUS champions and IV placement personnel are available on site. On the other hand, it may forfeit the opportunity to perform  cases on the spot where warranted.

In the second model, the department allows add-on CEUS studies. For example, when a suspicious liver lesion is detected in a new patient, a physician can order and perform a CEUS exam on the same day, instead of waiting days or weeks for a CT or MRI appointment. An advantage of the same-day “add-on” CEUS study is that it avoids the risk of the patient failing to show up for a second appointment. More important, CEUS can immediately rule out malignancies, or confirm them so that the referring physicians can be notified and the patients’ care expedited.

Generally speaking, CEUS practices start with pre-scheduled exams and move up to performing add-on cases as volume grows and the staff becomes comfortable with the procedure.

Step 4: Educating clinicians

Education about CEUS and its clinical value is vital to its wider acceptance. For example, some radiologists may need to be shown evidence that CEUS has clinical value, poses minimal risk to patients, and will not consume more of their limited time. In addition, before embarking on a CEUS practice, it is essential to make presentations to the clinical teams that comprise the main sources of referrals: hepatologists for patients with liver masses, oncologists for patients with cancer. Presentations need to demonstrate the benefits of CEUS to clinical practice.

Remember to educate your Department leaders who should not  be overlooked in education; the better they understand the benefits of CEUS, the more likely they will be to approve its use. Practitioners should seek hands-on clinical experience. Ways to do so include visiting an existing center with a CEUS practice to observe cases, identifying and consulting with a few goto experts, and working with ultrasound vendors to evaluate imaging systems and view technology demonstrations.

Billing and reimbursement

While a CPT code exists for the contrast agent itself, no such code yet exists for the professional component of the contrast portion of the ultrasound exam. For hospitals serving indigent patients, CEUS enables savings because the exams cost significantly less than CT or MRI. Otherwise, uncertainty about reimbursement gives some physicians pause.

With wider adoption, CEUS promises to bring new excitement and potentially game-changing benefits to a long standing, tried-and-true liver imaging technology. It can reinforce ultrasound as a robust imaging modality.

Adding CEUS: Tips to smooth the process

It is not difficult to add contrast-enhanced ultrasound as a technique for evaluating liver lesions. Here are a few ideas for helping the process ramp up smoothly.

  • Identify current IV placement resources and utilize their expertise when possible.
  • Identify a few enthusiastic sonographers to train in the CEUS technique. They are likely to find it invigorating to learn about a new and powerful ultrasound procedure.
  • Identify one or two radiologists to champion CEUS and drive implementation.
  • Educate referring physicians on the clinical benefits of CEUS for evaluating liver lesions and instruct them to add it as an option on their orders.

Reference:

  1. Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver – update 2012 AWFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS AND ICUS. Ultrasound in Med. & Biol., Vol. 39, No. 2, pp. 187–210, 2013. ©2013 World Federation for Ultrasound in Medicine & Biology.

Imagination at work

www.gehealthcare.com.Product may not be available in all countries and regions. Contact a GE Healthcare Representative for more information.

Data subject to change.

© 2017 General Electric Company . February 2017/JB46265US

GE, the GE Monogram and imagination at work are trademarks of General Electric Company.

Reproduction in any form is forbidden without prior written permission from GE. Nothing in this material should be used to diagnose or treat any disease or condition. Readers must consult a healthcare professional.

 
 
 
 
 
 

Journal of the American Society of Echocardiography

J Am Soc Echocardiogr 2017;30:1193-202

 http://dx.doi.org/10.1016/j.echo.2017.08.003

Oct 17, 2017

Right ventricular Size and Function

Quantification of Right Ventricular Size and Function from Contrast-Enhanced Three-Dimensional Echocardiographic Images

Authors:  Diego Medvedofsky, MD, Victor Mor-Avi, PhD, Eric Kruse, RDCS, Brittney Guile, RDCS Boguslawa Ciszek, RDCS, Lynn Weinert, RDCS, Megan Yamat, RDCS, Valentina Volpato, MD, Karima Addetia, MD, Amit R. Patel, MD, and Roberto M. Lang, MD, Chicago, Illinois

Highlights

  • We hypothesized that contrast enhancement during 3D echocardiographic imaging would improve the accuracy of RV volume and function analysis.
  • This hypothesis was tested by comparing measurements obtained from nonenhanced and contrast-enhanced images against cardiac magnetic resonance reference images.
  • Contrast enhancement improved the visualization of RV endocardial borders, resulting in more accurate and more reproducible measurements.
  • This approach may be particularly useful in patients with suboptimal image quality.

Background

Three-dimensional (3D) echocardiography directly assesses right ventricular (RV) volumes without geometric assumptions, despite the complex shape of the right ventricle, and accordingly is more accurate and reproducible than the two-dimensional methodology, which is able to measure only surrogate parameters of RV function. Volumetric analysis has been hampered by frequent inability to clearly visualize RV endocardium, especially the RV free wall, in 3D echocardiographic images. The aim of this study was to test the hypothesis that RV contrast enhancement during 3D echocardiographic imaging would improve the accuracy of RV volume and function analysis.

Methods

Thirty patients with a wide range of RV size and function and image quality underwent transthoracic 3D echocardiography with and without contrast enhancement and cardiovascular magnetic resonance imaging on the same day. RV end-diastolic and end-systolic volumes and ejection fraction were measured from contrast-enhanced and nonenhanced 3D echocardiographic images and compared with cardiovascular magnetic resonance reference values using linear regression and Bland-Altman analyses. Blinded repeated measurements were performed to assess measurement variability.

Results

RV contrast enhancement was feasible in all patients. RV volumes obtained both with and without contrast enhancement correlated highly with cardiovascular magnetic resonance (end-diastolic volume, r = 0.90 and r = 0.92; end-systolic volume, r = 0.92 and r = 0.94, respectively), but the correlation for ejection fraction was better with contrast (r = 0.87 vs r = 0.70). Biases were smaller with contrast for all three parameters (end-diastolic volume, −16 ± 23 vs −36 ± 25 mL; end-systolic volume, −10 ± 16 vs −23 ± 18 mL; ejection fraction, −0.7 ± 5.5% vs −2.7 ± 8.1% of the mean measured values), reflecting improved accuracy. Also, measurement reproducibility was improved by contrast enhancement.

Conclusions

Contrast enhancement improves the visualization of RV endocardial borders, resulting in more accurate and reproducible 3D echocardiographic measurements of RV size and function. This approach may be particularly useful in patients with suboptimal image quality.

ICUS Sponsors

ICUS gratefully acknowledges its 2017 sponsors:

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