Volume averaging limitations of computed tomography.
Volume averaging limitations of computed tomography.
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计算机断层扫描的体积平均局限性。
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
S. LaFalce
中科院分区：
文献类型：
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作者：
David J. Goodenough;K. Weaver;David O. Davis;S. LaFalce
一个简单的体积平均模型不足以预测骨或空气与软组织混合物的有效CT衰减值。理论和实验表明，从扫描分层亚层厚物体得到的计算层析值与相对分数含量具有非线性相关性，并且与分层物质的空间范围具有惊人的大相关性。该模式被应用于薄而平的结构中的计算机断层摄影值的问题，例如蛛网膜下腔的血池。结果表明，对于血液和软组织等低对比度物质层，与简单的体积平均理论的偏差很小，而对于骨、空气和组织等对比度较高的物质层，可能会有很大的偏差。这一现象解释了某些伪影，并展示了分析重建技术的准确性中相当基本的问题。这可能证明后处理校正或迭代方法是合理的。
A simple volume averaging model was shown to be inadequate for predicting effective computed tomographic attenuation values of mixtures of bone or air with soft tissue. Computed tomographic values derived from scanning stratified sub-slice thickness objects were shown theoretically and experimentally to have a non-linear dependency on relative fractional content and a surprisingly large dependency on spatial extent of the stratified substances. The mode was applied to the problem of computed tomographic values in thin, flat structures such as pools of blood in the subarachnoid space. The results show only small deviations from simple volume averaging theory for layers of low contrast substances such as blood and soft tissue, but potentially large deviations for layers of substances with high contrast differences such as bone, air, and tissue. This phenomenon explains certain artifacts and demonstrates rather fundamental problems in the accuracy of analytic reconstruction techniques. It may justify postprocessing correction or iterative approaches.