Segmentation of cancellous bone from high-resolution computed tomography images: influence on trabecular bone measurements.

The quantification of cancellous bone network from computed tomography (CT) images requires a segmentation step which is crucial and difficult because of the partial volume effect in CT images. In this paper, we present and evaluate a new approach for segmenting cancellous bone network from high-resolution CT (HRCT) slices. The idea is first to detect a skeleton from the crest lines of the structure and then to thicken it to extract the whole bone structure by satisfying local neighborhood constraints.

Distribution of intracortical porosity in human midfemoral cortex by age and gender.

The purpose of this study was to describe the age-specific distribution of midfemoral intracortical porosity throughout the cortical width in males and females. Microradiography and an automated image analysis system were used to study midfemoral cortical bone specimens from 163 white people, including 77 males and 86 females, in a recent anthropological collection covering a broad age range. In each specimen, porosity (percentage of the cortical bone area occupied by pores), pore number, and pore size were measured throughout the entire cortex and in three cortical subregions of equal width labeled the periosteal, midcortical, and endosteal subregions.

A method of radio-frequency inhomogeneity correction for brain tissue segmentation in MRI.

An automatic method of correcting radio-frequency (RF) inhomogeneity in magnetic resonance images is presented. The method considers that image intensity variation due to radio-frequency inhomogeneity contains not only low frequency components, but also high frequency components. The variation is regarded as a multiplication of low frequency (capacity variation of coil) and the frequency of object (true image).

A comparison of spinal quantitative computed tomography with dual energy X-ray absorptiometry in European women with vertebral and nonvertebral fractures.

Quantitative computed tomography (QCT) was compared to dual X-ray absorptiometry (DXA) measured in the lumbar spine of 508 European women defined as normal without fracture (NoF), or osteoporotic (OP), with either vertebral fracture (VF), or peripheral fracture (PF). The correlations between QCT and DXA BMD measurements were significantly different in normal and in osteoporotic patients, indicating that the two exams do not measure the same bone aspects. According to ROC curves results, QCT Z-scores separate OP from NoF with better sensitivity than all other measurements.

CT of the middiaphyseal femur: cortical bone mineral density and relation to porosity.

Purpose: To determine whether computed tomography (CT) can be used to quantify age- and site-related changes in cortical bone mineral density (cBMD) at the middiaphyseal femur and whether cBMD differences are related to intracortical porosity.

Materials And Methods: Cortical bone specimens from 163 femurs were studied with CT and microradiography. Femurs were from 77 males and 86 females in a white anthropologic collection covering a broad age spectrum.