The numerical stability of transformation-based CT ventilation.
The numerical stability of transformation-based CT ventilation.
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DOI：
10.1007/s11548-016-1509-x
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发表时间：
2017-04
影响因子：
3
通讯作者：
Guerrero T
中科院分区：
文献类型：
--
作者：
Castillo E;Castillo R;Vinogradskiy Y;Guerrero T
计算机断层扫描(CT)衍生的通风成像利用可变形图像配准(DIR)从吸气/呼气4DCT阶段恢复呼吸引起的组织体积变化。虽然目前验证CT通气量的策略依赖于分析其与现有功能成像模式的相关性，但CT通气量计算的数值稳定性尚未得到表征。本研究的目的是研究DIR位移场的微小变化如何影响基于变换的CT通气量的计算。首先，我们推导了一个数学定理，该定理表明，由单个位移向量的扰动引起的通风度量的变化受扰动幅度的限制。其次，提出了一种新的计算用户自定义CT通风图像的雅可比约束最优化方法。利用雅可比约束方法，我们证明了对于相同的吸气/呼气CT对，可以计算具有相似空间精度的两个DIR变换，但生成的通风图像具有显著不同的物理特性。特别是，我们计算了一个与单光子发射CT灌注扫描完美相关的CT通风图像。分析和实验表明，虽然基于变换的CT通风是一种很有前途的方式，但DIR位移场的微小变化会导致通风图像的相对变化很大。因此，仍然需要改进CT通风的重复性的方法。
Computed tomography (CT)-derived ventilation imaging utilizes deformable image registration (DIR) to recover respiratory-induced tissue volume changes from inhale/exhale 4DCT phases. While current strategies for validating CT ventilation rely on analyzing its correlation with existing functional imaging modalities, the numerical stability of the CT ventilation calculation has not been characterized. The purpose of this study is to examine how small changes in the DIR displacement field can affect the calculation of transformation-based CT ventilation. First, we derive a mathematical theorem, which states that the change in ventilation metric induced by a perturbation to single displacement vector is bounded by the perturbation magnitude. Second, we introduce a novel Jacobian constrained optimization method for computing user-defined CT ventilation images. Using the Jacobian constrained method, we demonstrate that for the same inhale/exhale CT pair, it is possible to compute two DIR transformations that have similar spatial accuracies, but generate ventilation images with significantly different physical characteristics. In particular, we compute a CT ventilation image that perfectly correlates with a single-photon emission CT perfusion scan. The analysis and experiments indicate that while transformation-based CT ventilation is a promising modality, small changes in the DIR displacement field can result in large relative changes in the ventilation image. As such, approaches for improving the reproducibility of CT ventilation are still needed.
影响因子：
1.9
作者：
Liu S;Yuan Y;Castillo R;Guerrero T;Johnson VE
通讯作者：
Johnson VE