Medical Design Briefs - September 2021 - 34

mode, the transducers can be
programmed to transmit out of
sync, which produces ultrasound
beams that can be
steered to different angles.
" With the phased array technology,
we can manipulate the
ultrasound beam in the way
that we want, " says Muyang Lin,
a nanoengineering PhD student
at UC San Diego, who is
also a co-first author of the
study. " This gives our device
multiple capabilities: monitoring
central organs as well as
blood flow, with high resolution.
This would not be possible
using just one transducer. "
The phased array consists of a
12 × 12 grid of ultrasound transducers.
When electricity flows
through the transducers, they
vibrate and emit ultrasound
waves that travel through the skin and
deep into the body. When the ultrasound
waves penetrate through a major blood
vessel, they encounter movement from
red blood cells flowing inside. This movement
changes or shifts how the ultrasound
waves echo back to the patch -
an effect known as Doppler frequency
shift. This shift in the reflected signals
gets picked up by the patch and is used
to create a visual recording of the blood
flow. This same mechanism can also be
used to create moving images of the
heart's walls.
■ A Potential Game Changer in the
Clinic
For many people, blood flow is not
something that is measured during a
regular visit to the physician. It is usually
assessed after a patient shows some signs
to do point of care or continuous
at-home monitoring. "
In tests, the patch performed
as well as a commercial ultrasound
probe used in the clinic.
It accurately recorded blood
flow in major blood vessels such
as the carotid artery, which is an
artery in the neck that supplies
blood to the brain. Having the
ability to monitor changes in
this flow could, for example,
help identify if a person is at
risk for stroke well before the
onset of symptoms.
Ultrasound patch wired to its full experimental setup. (Credit: Nature
Biomedical Engineering)
of cardiovascular problems, or if a
patient is at high risk.
The standard blood flow exam itself
can be time consuming and labor intensive.
A trained technician presses a
handheld ultrasound probe against a
patient's skin and moves it from one
area to another until it's directly above a
major blood vessel. This may sound
straightforward, but results can vary
between tests and technicians.
Since the patch is simple to use, it
could solve these problems, says Sai
Zhou, a materials science and engineering
PhD student at UC San Diego and coauthor
of the study. " Just stick it on the
skin, then read the signals. It's not operator
dependent, and it poses no extra
work or burden to the technicians, clinicians
or patients, " he says. " In the future,
patients could wear something like this
The researchers point out
that the patch still has a long way
to go before it is ready for the
clinic. Currently, it needs to be
connected to a power source
and benchtop machine in order
to work. Xu's team is working on
integrating all the electronics on
the patch to make it wireless.
The paper is titled, " Continuous monitoring
of deep-tissue haemodynamics
with stretchable ultrasonic phased
arrays. " Co-authors include Baiyan Qi,
Zhuorui Zhang, Mitsutoshi Makihata,
Boyu Liu, Yi-hsi Huang, Hongjie Hu,
Yue Gu, Yimu Chen, Yusheng Lei, Shu
Chien and Erik Kistler, UC San Diego;
Taeyoon Lee, Yonsei University and
Korea Institute of Science and
Technology; and Kyung-In Jang, Daegu
Gyeonbuk Institute of Science and
Technology, Republic of Korea.
This work was supported by the
National Institutes of Health (grant
1R21EB027303-01A1) and the Center
for Wearable Sensors at the UC San
Diego Jacobs School of Engineering.
For more information, visit https://
ucsdnews.ucsd.edu.
Mastering the UKCA Compliance Challenge
Deadlines are approaching
for compliance.
RQM+
Monroeville, PA
January 1, 2021, ushered in significant
change for the UK but also for medical
device manufacturers worldwide wishing
to continue to sell their products in this
market. Although it is merely the start of
a transition period toward a new regulatory
regime, businesses would do well to
34
Intro
Cov
take note of a series of deadlines and
dates, culminating with the June 30,
2023, the date by which their devices
must have obtained UKCA marking to
continue to be present in this market. In
addition to working toward achieving
compliance for the EU's Medical Device
Regulation (MDR) and In Vitro Diag -
nostic Regulation (IVDR), medical de -
vice businesses with products on the UK
market will need to plan ahead to
ensure that they achieve UK compliance
in time.
www.medicaldesignbriefs.com
ToC
+
-
A
The UK's exit
from the European
for
Union (EU) has also created a divergence
between the requirements
Great Britain (England, Scotland, and
Wales) and Northern Ireland. The ongoing
pressures and increase in compliance
requirements in the UK and EU markets
are putting a strain on medical device
manufacturers and regulatory authorities
alike, but there may well be some
overlap that businesses would do well to
identify and leverage to their advantage
throughout the transition phase.
Medical Design Briefs, September 2021
µ
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https://ucsdnews.ucsd.edu http://www.medicaldesignbriefs.com
Medical Design Briefs - September 2021

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