Visualisation Technique for Trabecular Architecture of Bone Using Ultrasound Signals
We have proposed a new technique for visualising trabecular architecture of spongy bone using ultrasound A-mode signals from a transducer of medical ultrasound system. The technique can be established by finding a method to distinguish between bone and bone marrow. Firstly, the A-mode signal intensity was fitted by the form, A=A0exp(-ax), where A, A0, a, and x represent echo intensity, initial value of echo, attenuation factor, and distance, respectively. Then the curve was moved slightly downward or upward by multiplying with the coefficient k (0.9~1.2), and it was used as an index line to distinguish between bone and bone marrow. To clarify the validity of the proposed technique, we examined bovine bone specimen and a spongy-shaped specimen made by ceramics. The pixel size for creating architecture was 0.2 (width) × 0.15 (depth) mm for bone marrow and 0.2 × 0.3 mm for bone substance, and the pixel size differs due to the difference in wave speeds. The visualisation technique was capable to create an image size of ~10 mm depths from the surface of cortical bone. We also tried to visualise the heel bone.
F. Nogata, "Visualisation Technique for Trabecular Architecture of Bone Using Ultrasound Signals ", Applied Mechanics and Materials, Vols. 1-2, pp. 99-106, 2004