Accurate quantification of width and density of bone structures by computed tomography

Hangartner, Thomas N.; Short, David F.

doi:10.1118/1.2769102

Cited by 31 publications

(26 citation statements)

References 27 publications

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“…An algorithm was developed to identify the density maxima of both the inner and outer cortical layers and the intervening lower density values of the diploë. The outer boundaries of the cortical layers were defined as the points where the density values were equal to or greater than half of the associated cortical maximum, consistent with published recommendations [16][17][18]. The inner cortical boundaries were defined as the points where the density values were half of the difference between the cortical maximum and diploë minimum.…”

Section: Measurements Of Skull Layersmentioning

confidence: 99%

Parametric mapping and quantitative analysis of the human calvarium

Voie¹,

Dirnbacher²,

Fisher³

et al. 2014

Computerized Medical Imaging and Graphics

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Section: Measurements Of Skull Layersmentioning

confidence: 99%

Parametric mapping and quantitative analysis of the human calvarium

Voie¹,

Dirnbacher²,

Fisher³

et al. 2014

Computerized Medical Imaging and Graphics

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“…When the energy of the incident beam is 60 keV and the FS and BS scattering angles are 15 and 165 , the energy difference between the forward and backward scattered components is about 11 keV. Different penetration abilities and possible differences in the thicknesses of the surrounding tissues can result in varying amounts of attenuation among the FS and BS beams.…”

Section: Iia Theorymentioning

confidence: 99%

“…3. Incident, forward scattered at 15 , and backscattered at 165 spectra recorded from a test object containing a mineral concentration of 166.7 mg=cm 3 using a maximum voltage of 76.5 kV are shown. The endpoint energy of the incident beam appears to be slightly higher due to the summing effect as a consequence of high count rates.…”

Section: Iiia (Fs-bs) Ratiomentioning

confidence: 99%

“…For example, QCT scanners are relatively expensive and are constantly in use for procedures that are more urgent than routine bone assessment. In addition, Table I indicates that QCT for bone density measurements 15 has a high dosage of 50 lSv or more 16,17 and is relatively imprecise with systematic errors that are about 7% or higher because of its reliance on multiple spectra from different thin slices. It is notable that the scattering methods described in this study when used with a ring detector might be able to achieve a comparable dosage to the 50 lSv of QCT, which could be as low as 50 lSv and thus within a factor of 50 of DXA and much closer in some estimates and cases (Table I).…”

Section: Introductionmentioning

confidence: 99%

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How to improve x‐ray scattering techniques to quantify bone mineral density using spectroscopy

Krmar

Ganezer

2012

Medical Physics

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Purpose: The purpose of this study was to develop a new diagnostic technique for measuring bone mineral density (BMD) for the assessment of osteoporosis, which improves upon the coherent to Compton scattering ratio (CCSR) method, which was first developed in the 1980s. To help the authors achieve these goals, they have identified and studied two new indices for CCSR, the forward scattered to backward scattered (FS-BS) and the forward scattered to transmitted (FS-T) ratios. They believe that, at small angles, these two parameters can offer a practical in vivo determination of BMD that can be used to overcome the limitations of past CCSR systems, including high radiation dosages, costs, and examination durations. Methods: In previous CCSR studies, a high-activity radioactive source with a long half-live (usually 241 Am) and an expensive and bulky cryogenic HPGe detector were applied to both in vivo and in vitro measurements. To make this technique more suitable for clinical applications, the possibility of using a standard diagnostic x-ray tube generating a continuous spectrum was investigated in this paper. Scattered radiation from trabecular bone-simulating phantoms containing various mineral densities that span the normal range of in vivo BMD was collected in this study using relatively inexpensive noncryogenic CdTe or NaI detectors. Results: The initial results demonstrate that a modified version of CCSR can be successfully applied to trabecular bone assessment using a diagnostic x-ray tube with a continuous spectrum in two variations, the FS-BS and the FS-T ratio. When FS-BS is measured, intensity spectra in the forward and backward directions must be collected while FS-T requires only the integral intensity of the scattered and transmitted (T) spectra in the energy region above 40 keV. For both of these methods, forward scattering angles less than or equal to 15 and backward scattering angles greater than or equal to (165 = 180 À 15 ) are needed. Conclusions: The authors determined that FS-T is more sensitive to changes in BMD than transmission or absorption alone and that the FS-BS method can yield an absolute measurement of the mean atomic number of the scattering medium, after a correction for path-dependent attenuation. Since this study determined that the FS-T ratio is independent of the incident energy over a broad energy region, it will be possible to apply FS-T to bone densitometry using inexpensive integral photon detectors. The authors believe that, by replacing the radionuclide source with an x-ray tube and the cryogenically cooled HPGe detector with a single solid state CdTe, NaI, or silicon detector or an annular array of detectors, as suggested in this study, the past difficulties of CCSR concerning high radiation exposure, costs, and durations as well as lack of convenience can be overcome and that CCSR could eventually become popular in clinical settings. V C 2012 American Association of Physicists in Medicine. [http://dx

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“…34 A few algorithms have been dedicated for cortical bone segmentation at femur using 3-D QCT imaging. 33,[35][36][37][38] Recent advancements in multirow-detector CT (MD-CT) imaging technologies have enabled a resolution that allows in vivo segmentation of individual trabeculae and their microarchitectural analysis at peripheral anatomic sites, e.g., distal tibia. 39 A major advantage of bone CT imaging at a peripheral site as compared to a central site, e.g., proximal femur is that a peripheral bone CT requires significantly lower radiation dose as compared to a femur CT-a few days of background radiation for a peripheral bone CT versus two or three years of background radiation for a bone CT at a central site.…”

Section: Introductionmentioning

confidence: 99%

Automated cortical bone segmentation for multirow‐detector CT imaging with validation and application to human studies

et al. 2015

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Purpose: Cortical bone supports and protects human skeletal functions and plays an important role in determining bone strength and fracture risk. Cortical bone segmentation at a peripheral site using multirow-detector CT (MD-CT) imaging is useful for in vivo assessment of bone strength and fracture risk. Major challenges for the task emerge from limited spatial resolution, low signal-to-noise ratio, presence of cortical pores, and structural complexity over the transition between trabecular and cortical bones. An automated algorithm for cortical bone segmentation at the distal tibia from in vivo MD-CT imaging is presented and its performance and application are examined. Methods: The algorithm is completed in two major steps-(1) bone filling, alignment, and regionof-interest computation and (2) segmentation of cortical bone. After the first step, the following sequence of tasks is performed to accomplish cortical bone segmentation-(1) detection of marrow space and possible pores, (2) computation of cortical bone thickness, detection of recession points, and confirmation and filling of true pores, and (3) detection of endosteal boundary and delineation of cortical bone. Effective generalizations of several digital topologic and geometric techniques are introduced and a fully automated algorithm is presented for cortical bone segmentation. Results: An accuracy of 95.1% in terms of volume of agreement with manual outlining of cortical bone was observed in human MD-CT scans, while an accuracy of 88.5% was achieved when compared with manual outlining on postregistered high resolution micro-CT imaging. An intraclass correlation coefficient of 0.98 was obtained in cadaveric repeat scans. A pilot study was conducted to describe gender differences in cortical bone properties. This study involved 51 female and 46 male participants (age: 19-20 yr) from the Iowa Bone Development Study. Results from this pilot study suggest that, on average after adjustment for height and weight differences, males have thicker cortex (mean difference 0.33 mm and effect size 0.92 at the anterior region) with lower bone mineral density (mean difference −28.73 mg/cm 3 and effect size 1.35 at the posterior region) as compared to females. Conclusions: The algorithm presented is suitable for fully automated segmentation of cortical bone in MD-CT imaging of the distal tibia with high accuracy and reproducibility. Analysis of data from a pilot study demonstrated that the cortical bone indices allow quantification of gender differences in cortical bone from MD-CT imaging. Application to larger population groups, including those with compromised bone, is needed. C 2015 American Association of Physicists in Medicine.

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Accurate quantification of width and density of bone structures by computed tomography

Cited by 31 publications

References 27 publications

Parametric mapping and quantitative analysis of the human calvarium

Parametric mapping and quantitative analysis of the human calvarium

How to improve x‐ray scattering techniques to quantify bone mineral density using spectroscopy

Automated cortical bone segmentation for multirow‐detector CT imaging with validation and application to human studies

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