Validation of a deformable MRI to CT registration algorithm employing same day planning MRI for surrogate analysis.
Validation of a deformable MRI to CT registration algorithm employing same day planning MRI for surrogate analysis.
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DOI：
10.1002/acm2.12296
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发表时间：
2018-03
影响因子：
2.1
通讯作者：
Pollack A
中科院分区：
文献类型：
--
作者：
Padgett KR;Stoyanova R;Pirozzi S;Johnson P;Piper J;Dogan N;Pollack A
由于信号特征及其空间强度分布的内在差异，验证可变形多模态图像配准具有挑战性。使用这些空间强度分布来评估多模态配准也是复杂的，因为这些度量经常被用在配准优化过程中。这项工作通过在基准标记放置后使用计划MRI作为替代，评价了诊断MRI和放射治疗计划CT之间前列腺的刚性和可变形图像配准。替代品允许直接定量分析，这在多模态领域可能是困难的。对于13例前列腺患者，在两个不同的时间点采集T2图像，第一个时间点是计划前几周（诊断-MRI），第二个时间点是计划-CT的同一天（计划-MRI）。利用市售算法将诊断MRI变形为计划CT，该算法从局部刚性配准合成了可变形图像配准（DEG）算法。计划MRI为计划CT提供了独立的替代品，用于使用图像相似性指标（包括Pearson相关性和标准化互信息（NMI））评估配准准确性。通过仅观察前列腺、近端精囊、阴茎球和组合区域进行局部分析。计划-MRI为计划-CT提供了一个很好的替代，两个数据集之间基准对准的残余误差为亚毫米，0.78 mm。在13例病例中，11例病例的MRI上级刚性配准，表明前列腺和相关关键器官周围区域内的NMI改善了27.37%（P < 0.009）。Pearson相关分析显示相似的结果，显示13.02%的改善（P < 0.013）。通过使用计划-MRI作为计划-CT的替代，可以对配准准确性进行独立评价。这一人群为MRI到CT的对比提供了理想的测试基础，避免了固有的更具挑战性的多模态比较。
Validating deformable multimodality image registrations is challenging due to intrinsic differences in signal characteristics and their spatial intensity distributions. Evaluating multimodality registrations using these spatial intensity distributions is also complicated by the fact that these metrics are often employed in the registration optimization process. This work evaluates rigid and deformable image registrations of the prostate in between diagnostic‐MRI and radiation treatment planning‐CT by utilizing a planning‐MRI after fiducial marker placement as a surrogate. The surrogate allows for the direct quantitative analysis that can be difficult in the multimodality domain. For thirteen prostate patients, T2 images were acquired at two different time points, the first several weeks prior to planning (diagnostic‐MRI) and the second on the same day as the planning‐CT (planning‐MRI). The diagnostic‐MRI was deformed to the planning‐CT utilizing a commercially available algorithm which synthesizes a deformable image registration (DIR) algorithm from local rigid registrations. The planning‐MRI provided an independent surrogate for the planning‐CT for assessing registration accuracy using image similarity metrics, including Pearson correlation and normalized mutual information (NMI). A local analysis was performed by looking only within the prostate, proximal seminal vesicles, penile bulb, and combined areas. The planning‐MRI provided an excellent surrogate for the planning‐CT with residual error in fiducial alignment between the two datasets being submillimeter, 0.78 mm. DIR was superior to the rigid registration in 11 of 13 cases demonstrating a 27.37% improvement in NMI (P < 0.009) within a regional area surrounding the prostate and associated critical organs. Pearson correlations showed similar results, demonstrating a 13.02% improvement (P < 0.013). By utilizing the planning‐MRI as a surrogate for the planning‐CT, an independent evaluation of registration accuracy is possible. This population provides an ideal testing ground for MRI to CT DIR by obviating the need for multimodality comparisons which are inherently more challenging.
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影响因子：
7.3
作者：
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通讯作者：
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DOI：
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发表时间：
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影响因子：
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