Clinical effectiveness ofPureWave technology inimaging obese patientsResults of a six-site study
The World Health Organization reportsthat more than one in ten of the world’s
adult population is obese.1 Obese patients
present special challenges for ultrasoundimaging, because it is difficult to achieve
the penetration required for high quality,diagnostic images. As a result, pathology may
be missed, or patients may require additional
imaging studies that can increase the cost ofdiagnosis and expose patients to unnecessary
radiation. In addition, the inability to obtain
diagnostic images disrupts imaging providers’workflow and may lead to lost revenue.
Obese patients impact sonographers as well,
who must push harder to get quality images,
increasing strain that may lead to injuries,
which may result in long exams.

In addition, its tissue aberration correction
technology “senses” above-average amountsof adipose tissue and adjusts accordingly.
Six clinical sites tested the C5-1 PureWave
transducer with tissue aberration correction
and coded beamforming technologies andrecorded their observations. Each site wasasked to complete 50 to 75 technicallydifficult patient ultrasound exams using theC5-1 PureWave transducer on the iU22
ultrasound system, and compare results basedon previous experience with conventional
technologies. They then completed aquestionnaire about their experiences.

Philips C5-1 PureWave transducer isdesigned to make imaging obese patientseasier. It employs Philips-exclusive
PureWave technology, for acoustic
efficiency in transducer tuning and system
optimization that facilitates imaging of awide range of patient types with fewer
artifacts and better penetration.

1

http://www.who.int/mediacentre/factsheets/fs311/en/index.html

Clinical sites conducting the study
The clinical sites participating in thestudy were:• University of Alabama Hospital and theKirklin Clinic; Birmingham, Alabama, USA• University of Texas M.D. Anderson Cancer
Center; Houston, Texas, USA• Cliniques Universitaires Saint Luc UCL;
Brussels, Belgium• University of Colorado; Denver, Colorado,USA• St. Paul’s Hospital; Vancouver, British
Columbia, Canada• Freeman Hospital; Newcastle Upon Tyne, UK

Summary of results
Below are the combined summary results from the participating sites. Individual resultsfrom each site can be found in the following pages.
• Exam times reduced by 2% to 38%• A reduction in pain and fatigue from scanning in 29% to 85% of the cases• Sonographers felt that they had to push less in 48% to 93% of the cases in orderto achieve penetration of an organ or structure• Marked improvement in color sensitivity in 31% to 86% of the cases• Using the C5-1 transducer prevented a recommendation for additional studies with
CT and/or MR due to an inadequate ultrasound study in 8% to 69% of the cases

Sophisticated technologies for difficult exams
The C5-1 PureWave transducer employs sophisticated technology to support excellent
image quality and reduced operator strain, even when imaging obese patients.

C5-1 transducer design
Extraordinary design efforts have resulted in a powerful transducer
that is both lightweight and easy to hold, for reduced fatigue during
scanning. The C5-1 features a highly flexible cable and optimaltransducer balance that contributes to scanning comfort duringextended or difficult exams. In addition, minimized elevation dimension
improves intercostal access when imaging challenging patients with
reduced rib spaces.
PureWave crystal technology
The C5-1 uses Philips-exclusive PureWave crystal technology.
PureWave crystals are the result of a manufacturing technique thatcreates a near-perfect atomic level arrangement. The uniformity andlack of grain boundaries help transfer energy with up to 85% greater
precision and efficiency over conventional materials. Their extended
bandwidth covers the frequency range of two transducers, withimproved Doppler performance and highly sensitive harmonic imaging.
Tissue aberration correction technology
A main cause of ultrasound image degradation arises from the improperassumption of speed of sound characteristics when scanning patientswith significant adipose layers. The resulting beam aberrations accountfor the loss of detail resolution seen on obese patients. The C5-1
PureWave transducer works in conjunction with the iU22 xMATRIX,
CX50, and HD15 ultrasound systems to accommodate for the alteredspeed of high-frequency sound waves through adipose layers versus
other tissue. In this unique mode, the ultrasound system becomes“aware” of increased adipose content and applies aberration correction
algorithms. The result is increased sharpness and clarity in image quality
throughout the entire beam length.

2Conventional PZTPureWave crystal

material (800x)

material (800x)

Correction for superficial
adipose layers

University of Alabama Hospitaland the Kirklin Clinic
Birmingham, Alabama
Michelle L. Robbin, MD
Franklin Tessler, MD

Describe the technically difficult patients thatyou encounter in your lab.
We have a large proportion of obese patients whoselivers and other abdominal organs are more than four
to five centimeters deep, representing a significant
diagnostic challenge. Additionally, we have large
numbers of people with hepatic steatosis, diagnosed
as an echogenic liver of varying severity. A significant
proportion of our patient’s livers are so fatty that wecan only say they have a liver, but cannot characterize
it further.
What happens when you encounter a technicallydifficult patient?
It definitely takes longer to perform an ultrasound ona technically difficult patient. Image optimization is moredifficult, and the sonographer has to work harder tocreate acceptable images. The sonographer may haveto try several different transducers before settling on
the transducer that provides adequate penetration yetyields diagnostic images. We perform a large numberof challenging abdominal Doppler studies on cirrhotic
patients, patients with suspected renal artery stenosis,
and immediately postoperative liver transplant patients.
Acquiring images and Doppler waveforms quickly has
been a challenge before the iU22, especially in the small
cirrhotic liver. The patient has to be sent to CT or MR
when we are unable to confidently exclude liver lesions,which is often impossible in a cirrhotic patient, or one
with severe steatosis.

Summarize the results of your technicallydifficult patient study using the C5-1.
At least one of my sonographers typically has finger
and hand numbness during a long renal artery Doppler
study. When she used the C5-1 transducer, she did nothave finger and hand numbness because of the superiortransducer ergonomics. In another study, we were able
to get diagnostic images of the renal artery stenosis wesuspected was present but were unable to demonstrate
without the abdominal penetration mode.
• Exam time reduced 19%• A reduction in pain and fatigue from scanningin 77% of the cases• Sonographers felt that they had to push lessin 77% of the cases in order to achieve penetrationof an organ or structure• Marked improvement in color sensitivity
in 79% of the cases• The C5-1 prevented a recommendation for
CT or MR, due to inadequate ultrasound study,in 43% of cases.

“We sonologists loved the images – ‘What a great image’ was a frequent comment.”“Good penetration of fatty liver.”“We clearly showed innumerable liver lesions in a patient in whom an ultrasoundpreviously from another vendor only showed a heterogenous liver. Similarly, we
showed many more liver lesions in another patient with the (C5-1) on the iU22.”
3

University of Texas M.D.
Anderson Cancer Center
Houston, Texas
Deepak Bedi, MD

Describe the technically difficult patients thatyou encounter in your lab.
Large patients, fatty liver, liver/renal/abdominal
pathology, large fibroids, gassy patients, ICU patients.
What happens when you encounter a technicallydifficult patient?
It takes more time to do the ultrasound exam. There isgreater strain on the sonographer. It takes more of theradiologist’s time.

Summarize the results of your technicallydifficult patient study using the C5-1.
Found it easier to see deep organs on large patients.
Did not have to “reach” and strain to find an acousticwindow.
• Exam time reduced by 16%• A reduction in pain and fatigue from scanningin 30% of the cases• Sonographers felt that they had to push lessin 48% of the cases in order to achieve penetrationof an organ or structure• Marked improvement in color sensitivity
in 61% of the cases• The C5-1 prevented a recommendation for
CT or MR, due to inadequate ultrasound study,
in 9% of cases.

“Useful for critically ill patients, with multiple lines, tubes, etc., where theC5-1 allows you penetration without looking for the ideal acoustic window.”“Particularly suitable for imaging deep-seated kidneys and liver, without sweatingover the anterior approach.”“Sonographers did not have to rearrange equipment, reposition themselves
or dig hard to get images.”

4Cliniques Universitaires
Saint Luc UCLBrussels, BelgiumEtienne Danse, MD, PhD
Mohamed Kichouh, Sonographer

Describe the technically difficult patients thatyou encounter in your lab.
Obesity and fatty liver, modification of the liver texture
related to chemotherapy, large amounts of bowel gas,
non-cooperative patients, post-operative evaluation(in critical care units) with a large amount of color
Doppler studies of the liver and the kidneys, large
amount of color Doppler studies of the kidneys inpatients with hypertension, diabetes mellitus, andrenal function impairment.
What happens when you encounter a technicallydifficult patient?
Increased time for the examination (sometimes with adoubling time), increased pressure on the skin; in someof these cases the ultrasound results are not enough forgiving an optimal answer and the patients are referredto MR or CT.

Summarize the results of your technicallydifficult patient study using the C5-1.
• Exam time reduced by 38%• A reduction in pain and fatigue from scanningin 85% of the cases• Sonographers felt that they has to push lessin 86% of the cases in order to achieve penetrationof an organ or structure• Marked improvement in color sensitivity
in 86% of the cases• The C5-1 prevented a recommendation for
CT or MR, due to inadequate ultrasound study,in 69% of the cases.

“The increased performance of color mode reduces the time to insonate themajority of the patients, particularly in cases of color Doppler of the kidneys.”“The C5-1 is more ergonomic and pleasant to use resulting in a reductionof fatigue at the end of the day.”“The sites of treated lesions were clearly better delineated with the C5-1.”

5University of Colorado Hospital
Denver, Colorado
Julia A. Drose, BA, RDMS, RDCS, RVT

Describe the technically difficult patients thatyou encounter in your lab.
Obesity, large amount of subcutaneous fat (notnecessarily an obese person), cirrhotic livers, fatty livers,
massive ascites, abdominal scars, thin-kyphotic patients,
twin pregnancy, pregnant with polyhydramnios.
What happens when you encounter a technicallydifficult patient?
Technically difficult patients often take longer toexamine and their exams are usually less diagnostic.
An additional test, such as a CT, is often recommended
secondary to the diagnostic limitations of theultrasound exam. Sonographers do have to pushharder or scan in awkward positions in some cases.
This causes pain at the time of the exam and probably
contributes to long-term injury or disability. The mostimportant consequence of imaging a technically difficult
patient is that we often cannot provide a diagnostic
answer to the clinical question.

Summarize the results of your technicallydifficult patient study using the C5-1.
The C5-1 PureWave transducer was considered an
asset to all of our sonographers. It did improve imagingin difficult patients. In 47 out of 63 cases (75%), thesonographers felt the C5-1 improved their diagnostic
confidence in the exam.
• Exam time reduced 2% to 3%• A reduction in pain and fatigue from scanningin 29% of the cases• Sonographers felt that they had to push lessin 52% of the cases in order to achieve penetrationof an organ or structure• Marked improvement in color sensitivity
in 78% of the cases• The C5-1 prevented a recommendation for
CT or MR, due to inadequate ultrasound study,
in 8% of cases.

“Great improved penetration – visualization of structures.”“Improved penetration of fatty liver.”“Didn’t press hard, patient in pain – still got good image.”

6St. Paul’s Hospital
Vancouver, British Columbia
Cathy Fix, RDMS, Ultrasound Supervisor

Describe the technically difficult patients thatyou encounter in your lab.
Obese patients, fatty and cirrhotic livers, technicallychallenging patients with poor acoustic windows.
What happens when you encounter a technicallydifficult patient?
This has a significant impact to our lab in having to spend
more time on each patient, making fewer exams possible,and decreasing diagnostic confidence. This increasein difficulty also places more physical strain on oursonographers, which can lead to injury as well as creating
the need for further diagnostic imaging tests when theultrasound examination does not give optimal results.

Summarize the results of your technicallydifficult patient study using the C5-1.
We increased our diagnostic confidence for all of ourobstetrical exams. We also increased confidence in liver
exams including technically difficult patients and thosewith fatty infiltration or cirrhosis.
• Exam time reduced 4%• A reduction in pain and fatigue from scanningin 54% of the cases• Sonographers felt that they had to push lessin 64% of the cases in order to achieve penetrationof an organ or structure• Marked improvement in color sensitivity
in 31% of the cases• The C5-1 prevented a recommendation for
CT or MR, due to a suboptimal ultrasoundexamination, in 29% of cases.

“Didn’t have to work so hard to get diagnostic images.”“Increase in diagnostic confidence especially with fetal heads and fetal hearts.”“We need penetration and good spatial and contrast resolution and the C5-1
has those.”“Lack of artifacts helping increase our diagnostic confidence.”

7

Freeman Hospital
Newcastle Upon Tyne, UKDr. Simon T. Elliott and team

Describe the technically difficult patients thatyou encounter in your lab.
Mostly obese patients and fatty livers; a lot of requests
for retroperitoneal pathology and Doppler studies.
What happens when you encounter a technicallydifficult patient?
In difficult patients, the main problem is reduced
diagnostic confidence, due to limited access or sensitivity.

Summarize the results of your technicallydifficult patient study using the C5-1.
The C5-1 definitely improves diagnostic confidence
through better penetration and color Doppler
sensitivity. It also increases the speed of the exam andhelps in uncooperative patients.
• Exam time reduced by 34%• A reduction in pain and fatigue from scanningin 87% of the cases• Sonographers felt that they had to push lessin 93% of the cases in order to achieve penetrationof an organ structure• Marked improvement in color Doppler
in 71% of the cases• Without the C5-1, 19% of the cases would havebeen referred to MR or CT“Good penetration of fatty liver.”“Excellent in difficult, scarred abdomen.”“Increases speed and confidence for gallbladder and bile ducts.”

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