Koubar Khodor, Bekaert Virgile, Brasse David, Laquerriere Patrice
Université de Strasbourg, IPHC, Strasbourg, France.
CNRS, UMR7178, Strasbourg, France.
J Microsc. 2015 Jun;258(3):241-52. doi: 10.1111/jmi.12238. Epub 2015 Mar 25.
Bone mineral density plays an important role in the determination of bone strength and fracture risks. Consequently, it is very important to obtain accurate bone mineral density measurements. The microcomputerized tomography system provides 3D information about the architectural properties of bone. Quantitative analysis accuracy is decreased by the presence of artefacts in the reconstructed images, mainly due to beam hardening artefacts (such as cupping artefacts). In this paper, we introduced a new beam hardening correction method based on a postreconstruction technique performed with the use of off-line water and bone linearization curves experimentally calculated aiming to take into account the nonhomogeneity in the scanned animal. In order to evaluate the mass correction rate, calibration line has been carried out to convert the reconstructed linear attenuation coefficient into bone masses. The presented correction method was then applied on a multimaterial cylindrical phantom and on mouse skeleton images. Mass correction rate up to 18% between uncorrected and corrected images were obtained as well as a remarkable improvement of a calculated mouse femur mass has been noticed. Results were also compared to those obtained when using the simple water linearization technique which does not take into account the nonhomogeneity in the object.
骨密度在确定骨骼强度和骨折风险方面起着重要作用。因此，获得准确的骨密度测量值非常重要。微计算机断层扫描系统可提供有关骨骼结构特性的三维信息。重建图像中伪影的存在会降低定量分析的准确性，这主要是由于束硬化伪影（如杯状伪影）所致。在本文中，我们介绍了一种基于重建后技术的新型束硬化校正方法，该技术利用离线实验计算的水和骨线性化曲线，旨在考虑扫描动物体内的非均匀性。为了评估质量校正率，已进行校准线操作，以将重建的线性衰减系数转换为骨质量。然后将所提出的校正方法应用于多材料圆柱形模型和小鼠骨骼图像。未校正图像和校正图像之间的质量校正率高达18%，同时还注意到计算出的小鼠股骨质量有显著改善。还将结果与使用未考虑物体非均匀性的简单水线性化技术时获得的结果进行了比较。
