Musculoskeletal complications,
such as osteoporosis or the delayed union of fractures, are major
societal problem. Early diagnosis of these skeletal disorders leads
to prompt treatment and will dramatically reduce the risk of complication.
Current principal diagnostic method for osteoporosis is the test
of bone mineral density (BMD) using dual-energy X-ray absorptionmetry
(DEXA). Because of its radiation affects, high costs, variable results
and non-repeatable, DEXA has limitations as a reliable and routine
diagnostic method.
Ultrasonic techniques provide an intriguing method
for characterizing the material properties of bone in a manner which
is non-invasive, non-destructive, repeatable, safe and relatively
accurate. Using plane wave ultrasound with larger wave-length, we
have demonstrated that ultrasonic velocity and attenuation can reliably
reflect BMD and bulk modulus of bone as validated with CT number,
micro-CT, and contact mechanical testing. The objective of this
proposal is to further develop a scanning confocal acoustic diagnostic
(SCAD) system capable of generating noninvasive, high-resolution
US attenuation and velocity maps of trabecular and cortical bones,
for predicting the risk of osteoporosis and fracture. This objective
will be achieved by a series of four specific aims: 1) Develop a
SCAD system for non-invasively mapping of wave velocity and attenuation
in bone; 2) Correlate SCAD determined velocity and attenuation to
micro-CT identified BMD and architecture, and using fractal analysis
in trabecular bone; 3) Determine the ultrasonic attenuation and
velocity of cortical and trabecular bones and their interface; and
4) As a pilot step, mapping ultrasonic attenuation and velocity
to predict BMD and structural modulus in an ex-vivo model using
SCAD. |
