Trabecular thickness measurement in cancellous bones: postmortem rat studies with the zoom-in micro-tomography technique.

Using the cross-sectional images taken with the zoom-in micro-tomography technique, we measured trabecular thicknesses of femur bones in postmortem rats. Since the zoom-in micro-tomography technique is capable of high resolution imaging of a small local region inside a large subject, we were able to measure the trabecular thickness without extracting bone samples from the rats. For the zoom-in micro-tomography, we used a micro-tomography system consisting of a micro-focus x-ray source, a 1248 x 1248 flat-panel x-ray detector and a precision scan mechanism. To compensate for the limited spatial resolution in the zoom-in micro-tomography images, we used the fuzzy distance transform for the calculation of the trabecular thickness. To validate the trabecular thickness measurement with the zoom-in micro-tomography images, we compared the measurement results with those obtained from the conventional micro-tomography images of the extracted bone samples. The difference between the two types of measurement results was less than 2.5%.