Impact of errors in experimental parameters on reconstructed breast images using diffuse optical tomography.
Impact of errors in experimental parameters on reconstructed breast images using diffuse optical tomography.
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DOI：
10.1364/boe.9.001130
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发表时间：
2018-03
影响因子：
3.4
通讯作者：
Bin Deng;M. Lundqvist;Q. Fang;S. Carp
中科院分区：
文献类型：
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作者：
Bin Deng;M. Lundqvist;Q. Fang;S. Carp
近红外扩散光学断层扫描（NIR-DOT）是一种新兴技术，可为乳腺癌管理提供基于血红蛋白的功能性成像肿瘤生物标志物。最有前途的临床翻译机会是在恶性病变与良性病变的鉴别诊断，以及新辅助化疗的早期反应评估和指导。在整个视野内组织氧合血红蛋白和脱氧血红蛋白浓度的准确定量以及在治疗指导背景下纵向成像期间的可重复性对于NIR-DOT成功转化为临床实践至关重要。DOT逆问题的不适定和病态性质使得该技术特别容易受到可能发生的模型误差的影响，例如，当实验条件不完全匹配图像重建过程中内置的假设时。为了评估DOT图像对平行板NIR-DOT系统在实践中可能遇到的实验误差的敏感性，我们模拟了7种不同类型的误差，每种误差都有一定的幅度范围。我们通过使用来自健康女性志愿者的五个实际乳房X线照片的数字乳房模型来生成模拟数据，其中我们添加了一个1厘米的肿瘤。在将每种实验误差类型和幅度应用于模拟测量后，我们在有和没有结构事先指导的情况下重建光学图像，并评估总血红蛋白浓度（HbT）和病变与周围区域之间的HbT对比度与最佳情况的总体误差。研究发现，轻微的平面内探头未对准和板旋转不会导致大的量化误差。然而，任何平面外探头倾斜都可能导致病变对比度显著恶化。在这项工作中调查的错误类型中，光学图像最不可能受到乳房形状不准确的影响，但由于信号通道之间的串扰，光学图像的恶化程度最大。然而，光学图像中的误差可以有效地控制时，适当地估计实验参数在数据采集和图像处理过程中占。最后，使用结构先验恢复的光学图像，在一般情况下，不太容易受到实验误差，但是，病变对比度更敏感的错误时，肿瘤位置被用作先验信息。本模拟研究的结果可为光学乳房成像研究中的系统设计和操作提供指导。
Near-infrared diffuse optical tomography (NIR-DOT) is an emerging technology that offers hemoglobin based, functional imaging tumor biomarkers for breast cancer management. The most promising clinical translation opportunities are in the differential diagnosis of malignant vs. benign lesions, and in early response assessment and guidance for neoadjuvant chemotherapy. Accurate quantification of the tissue oxy- and deoxy-hemoglobin concentration across the field of view, as well as repeatability during longitudinal imaging in the context of therapy guidance, are essential for the successful translation of NIR-DOT to clinical practice. The ill-posed and ill-condition nature of the DOT inverse problem makes this technique particularly susceptible to model errors that may occur, for example, when the experimental conditions do not fully match the assumptions built into the image reconstruction process. To evaluate the susceptibility of DOT images to experimental errors that might be encountered in practice for a parallel-plate NIR-DOT system, we simulated 7 different types of errors, each with a range of magnitudes. We generated simulated data by using digital breast phantoms derived from five actual mammograms of healthy female volunteers, to which we added a 1-cm tumor. After applying each of the experimental error types and magnitudes to the simulated measurements, we reconstructed optical images with and without structural prior guidance and assessed the overall error in the total hemoglobin concentrations (HbT) and in the HbT contrast between the lesion and surrounding area vs. the best-case scenarios. It is found that slight in-plane probe misalignment and plate rotation did not result in large quantification errors. However, any out-of-plane probe tilting could result in significant deterioration in lesion contrast. Among the error types investigated in this work, optical images were the least likely to be impacted by breast shape inaccuracies but suffered the largest deterioration due to cross-talk between signal channels. However, errors in optical images could be effectively controlled when experimental parameters were properly estimated during data acquisition and accounted for in the image processing procedure. Finally, optical images recovered using structural priors were, in general, less susceptible to experimental errors; however, lesion contrasts were more sensitive to errors when tumor locations were used as a priori info. Findings in this simulation study can provide guidelines for system design and operation in optical breast imaging studies.