Sponsored Content | Case Study | Ultrasound Imaging | July 01, 2019

Ultrasound is Transforming Care Delivery for the Bariatric Patient

The Acuson Sequoia with Deep Abdominal Transducer (DAX) scanning a 600 pound patient.

The Acuson Sequoia with Deep Abdominal Transducer (DAX) scanning a 600 pound patient.

The DAX employs an advanced form of Multi-D beam formation to enable high quality imaging up to 40 cm for the technically difficult patient.

The DAX employs an advanced form of Multi-D beam formation to enable high quality imaging up to 40 cm for the technically difficult patient.

“With our present technology, we often struggle with large patients,” said Richard G. Barr, M.D., Ph.D., at Southwoods Imaging. “With the new ACUSON Sequoia ultrasound system, we have the availability of the Deep Abdominal Transducer (DAX). This new technology allows us to get much deeper into the abdomen in those challenging patients. This is important because if we are looking for multiple lesions, we need to be able to scan the entire liver.” A radiologist for more than 25 years, Dr. Barr is president of Radiology Consultants, Inc. and a diagnostic radiology specialist at Southwoods Imaging, both in Youngstown, Ohio. With the new DAX technology, Dr. Barr can obtain diagnostic information on high BMI patients where traditional technology, such as B-mode, color, pulsed wave doppler, elastography and contrast enhanced ultrasound (CEUS) exams, fails.

The DAX transducer is available on the ACUSON Sequoia ultrasound system, which was designed with a new BioAcoustic Imaging architecture able to compensate for energy loss and adapt the signal to each patient’s bioacoustic characteristics. A unique and patented imaging transducer, the DAX leverages the power of BioAcoustic Imaging technology and penetrates up to 40 cm deep in the abdomen. DAX was also designed to work in advanced modes, including shear wave elastography, contrast enhanced ultrasound, and multimodality fusion imaging.


The Population Challenge

Obesity is a growing problem in the United States. In 2016 alone, obesity affected 107 million people in the country. Of those, 39.8 percent were adults and 18.5 percent were youth.1

For all patients, accurate and timely diagnosis is vital. Yet, a recent study found that obese patients are 1.65 times more likely to have significant undiagnosed conditions.2 With obesity linked to more than 60 chronic diseases and associated with almost 50 percent of all cancers in patients younger than 65, this is a critical population to address.3

At an estimated $190 billion, obesity-related medical costs are high.4 If the obesity incidence continues to increase, these costs will likely rise, particularly as the obese youth of today become the obese adults of tomorrow.


The Technical Challenge

In obese patients, it can be challenging to get reliable and diagnostic ultrasound images both from a technical aspect due to ultrasound physics, and ergonomically as the operator is often required to increase the pressure of the transducer on the body.

Due to the increased subcutaneous fat and adipose tissue, the ultrasound beam can be significantly attenuated due to ultrasound wave absorption and scattering that occurs with increasing depth.

The impact of obesity on image quality is highlighted in a 15-year longitudinal study.5 This study analyzed more than 5 million radiology reports and determined that abdominal ultrasonography was the modality most commonly associated with habitus-limited reports. “If a patient has a habitus-limited report on an abdominal ultrasound, it is likely that the next step would be additional imaging with CT or MRI … likely with contrast. If we could confidently answer those tough clinical questions right away in ultrasound, we could help to reduce these types of follow-up exams, associated costs, and unnecessary patient anxiety,” said Dr. Barr.


A Novel Approach

The Deep Abdominal Transducer (DAX) on the ACUSON Sequoia employs an advanced form of Multi-D beam formation that controls the beam thickness and beam formation, enabling unprecedented imaging throughout a 40 cm depth. This novel approach may allow the DAX to obtain clinically relevant information when conventional technology fails. “What we are finding is that the ACUSON Sequoia with DAX transducer is providing us with clinical advantages in a few specific areas compared to conventional technology. First, we are noticing that we are able to get color and Doppler information much deeper and easier in the abdomen, which is critical for evaluating abdominal vasculature. Second, we are also seeing increased penetration and improved accuracy and reliability in our liver elastography exams on high BMI patients when assessing chronic liver disease. Third, the DAX allows us to perform contrast enhanced
ultrasound exams much deeper with a high sensitivity for evaluating focal liver lesions. CEUS exams are traditionally limited in depth of penetration so this expands our clinical capabilities in CEUS,” said
Dr. Barr.


A New Level of Confidence

Case: 61 yo with BMI of 41.8, generalized abdominal pain

A 61-year-old female with a BMI of 41.8 (extremely obese) presented for an abdominal ultrasound with liver elastography for generalized abdominal pain and a history of non-alcoholic fatty liver disease (NAFLD).

To assess liver stiffness, an abdominal ultrasound with liver elastography was conducted on a conventional ultrasound system at the imaging center. Liver elastography shear waves are known to attenuate quickly; the attenuation increases with increased subcutaneous tissue. This makes obese patients a challenge for liver elastography exams. Most patient-related confounding factors increase the stiffness value; therefore, a normal value of elastography can be accepted as normal, whereas an increased value must be taken in clinical context.

When conducting the liver elastography exam on the conventional ultrasound system, there were some challenges in acquiring the elastography values due to drop out and limited areas of good quality in the acquisition. The shear wave values that were obtained were extremely elevated and consistent with that of a cirrhotic patient with a median stiffness of 2.05 m/s (13.05 kPa). The patient’s previous lab work and clinical history presented with a normal but fatty liver. For this patient, Dr. Barr brought in the ACUSON Sequoia with DAX to correlate the liver elastography results. Using the DAX, the values obtained were a median stiffness of 0.88 (2.35 kPa) indicating no clinically significant liver stiffness. The liver elastography results on the ACUSON Sequoia with DAX were consistent with the patient’s labs and other clinical considerations. For confirmation, a FibroSure blood test was performed, which came back as normal, confirming the data acquired with the DAX.

“Obesity is a patient factor known as a source of variability in liver elastography exams on conventional technology,” said Dr. Barr. “The pulse generating the shear wave attenuates as it traverses the patient and reaches a point where adequate shear waves are not generated for accurate measurements on conventional technology. What we experienced on this patient was that the ACUSON Sequoia with DAX was able to provide quick, accurate, and reliable elastography measurements even in an extremely obese patient. Now she can continue her routine yearly follow-up for NAFLD.”


Case: 87 yo male with BMI of 27, abdominal pain/liver function tests

An 87-year-old male with a BMI of 27 (overweight) came in for an abdominal ultrasound for abdominal pain and increased liver function tests. The patient stated that he was told over 25 years ago that he had a liver infection but hasn’t had any additional follow-up. No previous imaging was conducted.

Performed on a conventional ultrasound system, the ultrasound exam demonstrated multiple liver masses as well as a potential portal vein thrombosis. As the exam was technically challenging and required sensitive color Doppler at depth, the ACUSON Sequoia with DAX was brought in for additional
patient assessment.

“The portal vein was relatively deep, and we wanted to see if the DAX could provide any additional useful information. Since the DAX can penetrate much deeper in CEUS mode, we decided to inject ultrasound contrast agents to confirm a portal vein thrombosis,” said Dr. Barr. Upon injection of the ultrasound contrast agents, the main portal vein demonstrated arterial flow. Typical presentation of non-malignant portal vein thrombosis on CEUS is no arterial flow is seen. Further analysis on the ACUSON Sequoia using Pulsed Wave Doppler confirmed pulsatile flow not seen on the conventional ultrasound system. The pulsatile flow within the main portal vein is an indication of tumor in the vessel. The diagnosis for this patient was advanced hepatocellular carcinoma (HCC) with tumor in vessel. Due to several factors, including tumor in vessel, this patient is not a candidate for liver transplant.

“With deeper penetration in CEUS and the deep Doppler capabilities of the DAX, we were able to make a confident diagnosis and distinguish between portal vein thrombosis and portal vein tumor thrombosis, which is a critical finding for transplant candidates, as it precludes transplantation,” said Dr. Barr.



As precision medicine expands and the delivery of healthcare evolves, there is a need for specialized technology that addresses all patient variations and body types. The increased incidence of obesity makes imaging the high-BMI patient a critical population to address with ultrasound.

However, obesity is shown to have a negative impact on image quality. As patients get larger, the number of inconclusive results proportionally increases. Ultrasound is the modality most highly impacted by this trend. The new ACUSON Sequoia was designed to address many of the key challenges in ultrasound, which includes obtaining high-quality, reliable images on the high-BMI patient in an ergonomic and economic way. “On the ACUSON Sequoia and with DAX technology, I feel confident when scanning patients ranging from the pediatric patient, all the way to the bariatric patient,” said Dr. Barr.


Case study supplied by Siemens Healthineers.



1. Adult Obesity Facts [Internet]. Centers for Disease Control and Prevention; 2018 Aug [cited 2019 May]. Available from: https://www.cdc.gov/obesity/data/adult.html.

2. “Fat-shaming” Patients Can Cause Real Harm [Internet]. WebMD, HealthDay Reporter; 2017 Aug [cited 2019 May]. Available from: https://www.webmd.com/diet/obesity/news/20170803/fat-shaming-patients-can-cause-real-harm.

3. Execessive Weight Gain, Obesity, and Cancer. Opportunities for Clinical Intervention [Internet]. JAMA; 2017 Nov 28 [cited 2019 May]. Available from: https://jamanetwork.com/journals/jama/article-abstract/2656710.

4. Economic Costs [Internet]. Harvard T.N. Chan, Obesity Prevention Source; 2019 [cited 2019 May]. Available from: https://www.hsph.harvard.edu/obesity-prevention-source/obesity-consequences/economic/

5. Uppot R, Sahani D, Hahn P, Kalra M, Saini S, Mueller P. Effect of obesity on image quality: fifteen-year longitudinal study for evaluation of dictated radiology reports. Radiological Society of North America. Radiology. 2006 Aug; 240(2): 435-9.

Related Content

Lung and respiratory health pioneer paves way for more precise care of complex respiratory conditions
News | Artificial Intelligence | September 25, 2020
September 25, 2020 — VIDA Diagnostics, Inc. announced that it has received 510(k) clearance from the Food and Drug Ad
EchoGo Pro automates cardiac ultrasound measurements for heart functions, but also empower physicians to predict the occurrence of coronary artery disease (CAD).

EchoGo Pro automates cardiac ultrasound measurements for heart functions, but also empower physicians to predict the occurrence of coronary artery disease (CAD).

News | Cardiovascular Ultrasound | September 25, 2020
September 25, 2020 — Based on its recent analysis of the global...
RADLogics AI-Powered solution in use: chest X-ray of COVID-19 positive case with heatmap key image.

RADLogics AI-Powered solution in use: chest X-ray of COVID-19 positive case with heatmap key image.

News | Artificial Intelligence | September 23, 2020
September 23, 2020 — RADLogics
The cartilage in this MRI scan of a knee is colorized to show greater contrast between shades of gray.

The cartilage in this MRI scan of a knee is colorized to show greater contrast between shades of gray. Image courtesy of Kundu et al. (2020) PNAS

News | Artificial Intelligence | September 22, 2020
September 22, 2020 — Researchers at the University of Pitts...
New research from King's College London has found that COVID-19 may be diagnosed on the same emergency scans intended to diagnose stroke.

Canon Medical Systems

News | Cardiac Imaging | September 22, 2020
September 22, 2020 — New research from King's College London has
Philips Azurion Lung Edition supports high precision diagnosis and minimally invasive therapy in one room
News | Lung Imaging | September 21, 2020
September 21, 2020 — Philips introduced...
According to a new report published by P&S Intelligence, the global radiotherapy market is expected to expand from $7.2M in 2019 to $17M by 2030.

Image courtesy of Accuray

Feature | Radiation Therapy | September 21, 2020 | By Melinda Taschetta-Millane
According to a...
A new report, Magnetic Resonance Imaging Equipment Market Size, Share & Industry Analysis, conducted by Fortune Business Insights, states that the magnetic resonance imaging (MRI) equipment market reached $7.24 billion in 2019 and is projected to reach $11.36 billion by 2027

Image courtesy of Siemens Healthineers

Feature | Magnetic Resonance Imaging (MRI) | September 21, 2020 | By Melinda Taschetta-Millane
A new report,...