High-resolution Computed Tomography for Clinical Imaging of Bone Microarchitecture

Abstract

BackgroundThe role of bone structure, one component of bone quality, has emerged as a contributor to bone strength. The application of high-resolution imaging in evaluating bone structure has evolved from an in vitro technology for small specimens to an emerging clinical research tool for in vivo studies in humans. However, many technical and practical challenges remain to translate these techniques into established clinical outcomes.Questions/purposesWe reviewed use of high-resolution CT for evaluating trabecular microarchitecture and cortical ultrastructure of bone specimens ex vivo, extension of these techniques to in vivo human imaging studies, and recent studies involving application of high-resolution CT to characterize bone structure in the context of skeletal disease.MethodsWe performed the literature review using PubMed and Google Scholar. Keywords included CT, MDCT, micro-CT, high-resolution peripheral CT, bone microarchitecture, and bone quality.ResultsSpecimens can be imaged by micro-CT at a resolution starting at 1 μm, but in vivo human imaging is restricted to a voxel size of 82 μm (with actual spatial resolution of ~ 130 μm) due to technical limitations and radiation dose considerations. Presently, this mode is limited to peripheral skeletal regions, such as the wrist and tibia. In contrast, multidetector CT can assess the central skeleton but incurs a higher radiation burden on the subject and provides lower resolution (200–500 μm).ConclusionsCT currently provides quantitative measures of bone structure and may be used for estimating bone strength mathematically. The techniques may provide clinically relevant information by enhancing our understanding of fracture risk and establishing the efficacy of antifracture for osteoporosis and other bone metabolic disorders.

Application of quantitative computed tomography for assessment of trabecular bone mineral density, microarchitecture and mechanical property

“…With a small field of view of 10 centimeters, the in plane and through plane spatial resolution can close to 200-500 um, is larger, but close to the trabecular size (100-150 μm) [12].…”

“…The high resolution pQCT (HR-pQCT) is primarily installed at major research centers and clinical radiology departments [111][112][113][114]. Using the high spatial resolution image (100 μm or less in pixel size), the resolution obtained is close to or smaller than the average trabecular thickness (100-150 μm) [12]. It can separate the periosteal boundary and segment the cortical and trabecular compartments.…”

“…This scanner uses polychromatic X-ray source, which produces highest spatial resolution images of less 10 μm [12,122]. μQCT can effectively quantify the volumetric BMD and the microarchitecture of cortical and trabecular bone.…”

“…A certain number of new technologies have been developed for assessing bone mineral density until now, including peripheral QCT (pQCT) [7], μCT (microCT) [8], magnetic resonance imaging (MRI) [9,10] and quantitative ultrasound (QUS) [11]. Compared to DXA, QCT offers superior sensitivity in diagnosing osteoporosis, monitoring the bone density changes, and evaluating the bone trabecular microarchitectural and mechanical property simultaneously, but still considered a supplemental method due to its high radiation [12]. Two-dimensional QCT BMD measurement of the spine tended to show a lower precision, which lead to limited employment [13].…”

The Possibility of Determining Osteoporosis by Analysing the Medical Images of the Cortical Bone

“…Medical image analysis is a very topical issue; recently many new methods have been developed for various medical objects and tasks [7]- [9], as well as methods that are intended specifically for a bone structure analysis and osteoporosis [10]- [12]. Most existing medical image processing algorithms are manual or semi-automatic algorithms.…”