Image-Based Assessment of Spinal Trabecular Bone Structure from High-Resolution CT Images

Abstract

The goal of this study was to assess whether a high-resolution CT measure of trabecular bone structure can enhance the discrimination between subjects with or without a vertebral fracture and having overall low hip or spine bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Sixty-one women with low BMD by DXA (T-score < -2.5 at hip or spine) were examined. Twenty women had sustained a vertebral fracture. Quantitative CT (QCT) BMD and high-resolution CT spinal scans were performed on a whole-body CT scanner. For the high-resolution images (0.31 mm pixel, 1.5 mm thick slice), trabecular bone was segmented from marrow using an adaptive threshold, region growth and skeletonization step. From the processed image we measured the apparent trabecular bone fraction (BV/TV), apparent trabecular thickness (I.Th) and apparent trabecular spacing (I.Sp). We also assessed the connectivity of the marrow space using region growing to derive a mean (HA) and maximum (HM) hole size. Despite the fact that the study population was preselected to have a low BMD by DXA, QCT BMD was highly associated with (p < 0.005) with fracture status. All structural parameters were correlated (r approximately 0.64 to 0.79) with BMD with p < 0.003 and showed significant differences between the fracture and non-fracture group. However, except for HA, this difference did not remain significant after adjustment for BMD. When BMD and then HA was entered into a paired linear regression model to predict fracture outcome, HA contributed with p = 0.03 and BMD with p = 0.86. ROC analysis was applied and showed that HA, BMD, I.Th and I.Sp discriminated the two groups with areas of 0.76, 0.75, 0.71 and 0.68, respectively. These findings suggest that an assessment of vertebral trabecular structure from high-resolution CT images is useful in discriminating subjects with vertebral fractures and potentially useful for predicting future fractures.

Alterations of Cortical and Trabecular Architecture Are Associated With Fractures in Postmenopausal Women, Partially Independent of Decreased BMD Measured by DXA: The OFELY Study

“…(13,14) In a study comparing 107 women with and 107 women without prevalent wrist fracture and using pQCT at the radius, the trabecular volumetric BMC and BMD data seemed to discriminate fractured and nonfractured cases better than cortical area and vBMC. (40) In another crosssectional study, 21 women with a recent wrist fracture were compared with a control group with no history of fracture and similar volumetric total BMD at the distal radius using pQCT.…”

“…CTbased evaluation of trabecular architecture has been performed in vivo both at peripheral sites, distal radius, and tibia, and, to some extent, at the lumbar spine. (13,14) At peripheral sites, improvements in spatial resolution have enabled 3D determination of trabecular bone architecture with sufficient accuracy. (15)(16)(17)(18) It has been shown that measures of bone structure obtained from conventional histological 2D sections and 3D CT data are highly correlated, indicating that 3D CT data sets can be used as a substitute for conventional histological sections for bone structure evaluation.…”

Association of larger holes in the trabecular bone at the distal radius in postmenopausal women with type 2 diabetes mellitus compared to controls

“…Briefly, BVTV was calculated as the area occupied by pixels corresponding to bone divided by the total area within the endosteal boundary. A region growing technique was utilized to determine hole size within the trabecular bone network and is defined as hole size ϭ ⌺A i Ϭ n (1) where A i denotes the area of the ith hole, and n denotes the number of holes present in the trabecular network (33). Within the skeletonized trabecular network, branches (single-pixel-wide line segments) and nodes (defined as points at which 3 or more branches join) were identified and used to compute nodal and branch density (34).…”

“…Hole size also appears to be a more powerful discriminator of vertebral fracture than Tb.Sp and Tb.Th, and can differentiate those with a fracture history with greater sensitivity and specificity than aBMD alone (33). Trabecular bone network hole size has also been shown to contribute to bone strength in an ex vivo study using radial bone specimens, where a strong association was demonstrated between average hole size and maximum hole area, as well as peak load at fracture (41).…”

Quantitative MRI for the assessment of bone structure and function

“…A further potential motivation is the study of the structural manifestations of metabolic bone disease such as renal osteodystropy (166). Evidence for these developments is the rapid growth of the clinical literature (8,83,84,127,145,165,(167)(168)(169)(170)(171)(172) and also, to a lesser extent, the increased use of CT to characterize TB (14)(15)(16)(173)(174)(175)(176)(177).…”