image shows a mouse ear after a successful cosmetic filler
injection. The filler, in green, rests in the tissue without
blocking the blood vessels and veins. Click to expand
Siavash Yousefi, U of Washington
Jan. 27, 2014 - Millions of seniors each year
remove wrinkles, soften creases or plump up their lips by injecting a
gel-like material into their facial tissue. These cosmetic procedures
are sometimes called “liquid facelifts.” They are said to be minimally
invasive, but sometimes things go wrong. In a matter of minutes,
patients’ skin can turn red or blotchy white and the injected area
becomes painful. Vital blood supply to the face is restricted and if
untreated, parts of the tissue will die. That scenario is irreversible
and can leave deep scars.
Physicians haven’t been able to pinpoint why this
happens because until now it was difficult to see how the injected
fluid, or filler, behaves in facial tissue.
New imaging technology from University of
Washington engineers allows scientists to analyze what happens within
the smallest blood vessels during an injection. This finding could be
used to prevent accidents during procedures and help clinicians reverse
the ill effects if an injection doesn’t go as planned.
“Filler-induced tissue death can be a really
devastating complication for the patient and provider,” said
Chang, a UW assistant professor of ophthalmology specializing
in plastic and reconstructive surgery. “This noninvasive imaging
technique provides far better detail than I’ve ever seen before and
helped us figure out why this is happening.”
Using this technology, Chang and her team saw that
complications arose when filler was inadvertently injected into the
bloodstream rather than in the intended soft tissues of the face. The
gel builds up in a vessel, blocking blood movement and oxygen exchange.
The team tested this in the ears of mice, which offer a model of what
can happen in the blood vessels of a human face, Chang said.
In this image the cosmetic filler (green) is shown
blocking a major vein in a mouse ear. This scenario can happen in human
faces during facelift procedures.
a UW professor of bioengineering, and his lab pioneered this
fine-resolution imaging, called optical microangiography. It can turn
out 3-D images of the body’s vascular network by shining a light onto
the tissue without touching it or adding any fluorescent dyes.
“We can visualize how blood responds to the
cosmetic filler gel, even looking at the responses of each individual
vessel. No other technique can provide this level of scrutiny,” Wang
The optical imaging technique operates on the same
concept as ultrasound, which leverages changes in sound to detect
structures. This technique instead uses light to repeatedly scan tissue
cross-sections, delineating unmoving pieces (surrounding tissues) from
moving segments (blood cells in vessels). Researchers compare image
frames and piece together the complex visual web.
High-resolution microvasculature of a mouse ear are
shown using the UW’s optical imaging technique called microangiography.
This technology can see blood vessels as small as 5
microns in diameter. Capillaries, the smallest vessels in our bodies,
are about 7 microns in diameter and a red blood cell is usually 3 to 5
“Our niche is imaging the microvascular system,”
said team member
a UW graduate student in bioengineering. Other applications of the
technology include analyzing how wounds heal, tracking what happens
during strokes and traumatic brain injuries, and imaging human eyes to
study diseases such as glaucoma and macular degeneration.
Cosmetic filler procedures have surged worldwide in
recent years, particularly in Europe and Asia. In 2012 in the U.S. about
2 million procedures were performed. Up to 800 patients reportedly
suffered serious complications, including potentially permanent
During the procedure, a practitioner injects the
gel-like solution, often a natural substance called hyaluronic acid,
multiple times into a person’s face. Restriction of blood to the
tissues, called ischemia, often doesn’t show up until later, when the
patient develops pain and sees changes on the surface of the skin,
meaning the tissue is dying.
Some practitioners suggest using massage and warm
compresses to treat the area, while others tell patients to take
aspirin, but the field doesn’t have a standard course of action for
treating these complications, Chang said. She has been called in for
several emergencies to treat other practitioners’ patients who show
signs of a failed procedure. This can lead to tissue death and even
blindness if the affected area is near the eyes.
With this new understanding, practitioners can try
to reverse the effect of vascular blockage by injecting an enzyme that
dissolves hyaluronic acid fillers. The research team is now testing all
types of available cosmetic fillers to see if their results hold on each
brand and evaluating new treatments for reversing procedure
“Our lab is trying to develop novel and clinically
useful biomedical imaging techniques for early diagnosis, treatment and
management of human diseases. Using this technology to better understand
facelift complications is a perfect example that fulfills this mission,”
The research was funded in part by the organization
Research to Prevent Blindness and a Latham Vision Research Innovation
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