Bone-composition imaging using coherent-scatter computed tomography: Assessing bone health beyond bone mineral density
Bone-composition imaging using coherent-scatter computed tomography: Assessing bone health beyond bone mineral density
复制标题
DOI：
10.1118/1.2179151
复制
发表时间：
2006-04-01
期刊：
影响因子：
3.8
通讯作者：
Cunningham, IA
中科院分区：
文献类型：
--
作者：
Batchelar, DL;Davidson, MTM;Cunningham, IA
骨成分的定量分析对于代谢性骨疾病的准确诊断和监测是必要的。准确评估骨矿化状态是全面分析的首要要求。在诊断成像中，X射线相干散射取决于组织的分子结构。相干散射计算机断层扫描（CSCT）利用这一功能，以确定复合生物标本中的组织类型。我们使用CSCT绘制了骨组织模型和切除的尸体骨样本中与骨病相关的组织（脂肪、软组织、胶原和矿物质）的分布。使用专用扫描仪，我们测量了羟基磷灰石（骨矿物质）浓度的基础上相干散射模式从一系列样品具有不同的羟基磷灰石含量。测得的散射强度与矿物密度成正比，单位为真g/cm（3）。每个样品中羟基磷灰石浓度的重复测量彼此至多在2%以内，这表明在确定羟基磷灰石浓度方面具有优异的精度。所有的测量结果也被发现是准确的，在3%的已知值。通过混合已知质量的纯胶原蛋白和羟基磷灰石来创建模拟正常、过度矿化和矿化不足的骨的骨组织。对复合散射图案的分析给出了每种材料的密度。对于每种复合材料，密度在已知值的2%以内。胶原蛋白和羟基磷灰石浓度也在骨模拟体模中进行了检查，并结合其他骨成分（脂肪，软组织）。每个标本的相干散射特性的层析成像图进行重建，从该材料的特定图像生成。每个组织都被清楚地区分开，并且从该体模确定的胶原-矿物质比率也在已知值的2%以内。现有的骨分析技术不能确定完整标本中的胶原-矿物质比例。最后，为了证明该技术的原位潜力，检查了切除的正常尸体桡骨的矿化状态。从桡骨的材料特异性图像中获得的皮质骨的平均胶原-矿物质比率为0.53 +/- 0.04，这与健康骨骼的预期值0.55一致。(c)2006年美国医学物理学家协会。
Quantitative analysis of bone composition is necessary for the accurate diagnosis and monitoring of metabolic bone diseases. Accurate assessment of the bone mineralization state is the first requirement for a comprehensive analysis. In diagnostic imaging, x-ray coherent scatter depends upon the molecular structure of tissues. Coherent-scatter computed tomography (CSCT) exploits this feature to identify tissue types in composite biological specimens. We have used CSCT to map the distributions of tissues relevant to bone disease (fat, soft tissue, collagen, and mineral) within bone-tissue phantoms and an excised cadaveric bone sample. Using a purpose-built scanner, we have measured hydroxyapatite (bone mineral) concentrations based on coherent-scatter patterns from a series of samples with varying hydroxyapatite content. The measured scatter intensity is proportional to mineral density in true g/cm(3). Repeated measurements of the hydroxyapatite concentration in each sample were within, at most, 2% of each other, revealing an excellent precision in determining hydroxyapatite concentration. All measurements were also found to be accurate to within 3% of the known values. Phantoms simulating normal, over-, and under-mineralized bone were created by mixing known masses of pure collagen and hydroxyapatite. An analysis of the composite scatter patterns gave the density of each material. For each composite, the densities were within 2% of the known values. Collagen and hydroxyapatite concentrations were also examined in a bone-mimicking phantom, incorporating other bone constituents (fat, soft tissue). Tomographic maps of the coherent-scatter properties of each specimen were reconstructed, from which material-specific images were generated. Each tissue was clearly distinguished and the collagen-mineral ratio determined from this phantom was also within 2% of the known value. Existing bone analysis techniques cannot determine the collagen-mineral ratio in intact specimens. Finally, to demonstrate the in situ potential of this technique, the mineralization state of an excised normal cadaveric radius was examined. The average collagen-mineral ratio of the cortical bone derived from material-specific images of the radius was 0.53 +/- 0.04, which is in agreement with the expected value of 0.55 for healthy bones. (c) 2006 American Association of Physicists in Medicine.