At this week's First Pan American/Iberian Meeting on Acoustics in
Cancun, researchers presented results on acoustic microscopy, a burgeoning
technique that could provide new kinds of medically useful information
on biological tissue.
Unlike many other microscopy techniques, acoustical microscopy can
be performed on living tissue and even inside the body, with the use
of small ultrasound probes. And unlike optical microscopy of biological
specimens, acoustic microscopy does not require tissue staining.
In the technique, an ultrasound probe makes contact with a tissue sample,
then yields an image based on how the tissue responds to the ultrasound.
Although the resolution of acoustical microscopy is ultimately limited
to about the cell level, rather than the molecular level (its maximum
resolution is about 0.1 microns, about a hundredth of the width of a
red blood cell), it can provide unique information on a biological tissue's
mechanical properties. For many materials, the mechanical properties
have a wider range of values than the optical properties, so the technique
could come in handy for characterizing Alzheimer's plaques, to name
one example.
In principle, an acoustic microscope could also yield quick assessments
on the pathology of skin lesions, without a biopsy and long before other
techniques could provide information.
At the meeting, researchers described how acoustic microscopy is already
advancing cardiology, specifically in the area of intravascular ultrasound
(IVUS), in which a small ultrasound camera is threaded into the body
to detect artery blockage.
Using a scanning acoustic microscope to gather basic data on artery
plaque, Yoshifumi Saijo of Tohoku University (saijo@idac.tohoku.ac.jp)
and his colleagues are helping clinicians better interpret IVUS images.
Employing knowledge from acoustical microscopy, Ton van der Steen (vandersteen@tch.fgg.eur.nl)
of the Erasmus Medical Center in the Netherlands and colleagues have
developed a clinical technique called IVUS elasticity imaging, which
can detect vulnerable artery plaques, a hard-to-catch condition which
kills up to 250,000 people every year in the US alone.
(Session 1pBB at the meeting; Background information at http://www.acoustics.org/press/144th/Jones.htm
and http://www.eur.nl/fgg/thorax/elasto/;
see session abstracts here)
