Continuation: With the support
of a one year ITG, an experimental Scanning Confocal Acoustic Diagnostic
(SCAD) system has been successfully developed which is capable of
generating non-invasive, high-resolution ultrasound (US) attenuation
and velocity maps of trabecular and cortical bones for predicting
the risk of osteoporosis and fracture. Ultrasonic attenuation and
velocity are measured and calculated, and can be converted to image,
e.g., gray scale. As an initial relational database between US measurements
and micro-CT parameters, SCAD determined US velocity and attenuation
are correlated with micro-CT identified BMD, porosity, trabecular
thickness and trabecular space, as well as previous determined bulk
material modulus in a total of 17 sheep distal femur samples. While
there are weak correlations of bone quality between single broad-band
US attenuation (BUA) and micro-CT, e.g., BMD (R=-0.53), porosity
(R=0.53), trabecular thickness (R=-0.20), trabecular space (13=015),
and averaged modulus (R=-0.63)' SCAD measurements significantly
improve these key correlations, i.e., BIVID (R=-0.78), porosity
(13=0.78), trabecular thickness (R=-0.5), trabecuiar space (R=0.88)'
and averaged modulus (R=-0.81). These results suggest that SCAD
can provide much detailed information than the single ultrasonic
measurement in determining osteoporosis related parameters. With
the SCAD concept has been demonstrated successful, it is now necessary
to use a larger number of samples measured by SCAD and correlated
with micro-CT to establish a reliable database and useful ultrasonic
index to evaluate bone quality. The US measurement of a well-controlled
different osteoporotic degree of porosity and/or BIVID of bone is
a major step forward toward the clinic use of this SCAD system.
Further, the SCAD system will be modified to work in vivo. Thus,
the objective of this project will expend and achieve through a
series of four specific aims: 1) Determine an interrelationship
between US parameters (using SCAD) and micro BMD (using micro-CT)
in a quantitative manner, in which the measurements will expand
to a large number of trabecular bone samples with correlation of
SCAD determined US attenuation and velocity to micro-CT identified
BMD, porosity trabecular space and trabecular width, as well as
modulus; 2) Develop a practical SCAD system for determining bone
quality properties in whole bone including combined cortical and
trabecular bones; 3) Correlate US velocity to micro stiffness of
trabecular bone using micro deformation testing. Thus, a well-established
SCAD system may provide a significant impact in diagnostic of osteoporosis
and bone quality. Early diagnosis of these skeletal disorders leads
to prompt treatment and will dramatically reduce the risk of complication |
