Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Penn Memory Center, Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Cereb Cortex. 2017 Nov 1;27(11):5185-5196. doi: 10.1093/cercor/bhw299.
Multiple techniques for quantification of hippocampal subfields from in vivo MRI have been proposed. Linking in vivo MRI to the underlying histology can help validate and improve these techniques. High-resolution ex vivo MRI can provide an intermediate modality to map information between these very different imaging modalities. This article evaluates the ability to match information between in vivo and ex vivo MRI in the same subjects. We perform rigid and deformable registration on 10 pairs of in vivo (3 T, 0.4 × 0.4 × 2.6 mm3) and ex vivo (9.4 T, 0.2 × 0.2 × 0.2 mm3) scans, and describe differences in MRI appearance between these modalities qualitatively and quantitatively. The feasibility of using this dataset to validate in vivo segmentation is evaluated by applying an automatic hippocampal subfield segmentation technique (ASHS) to in vivo scans and comparing SRLM (stratum/radiatum/lacunosum/moleculare) surface to manual tracing on corresponding ex vivo scans (and in 2 cases, histology). Regional increases in thickness are detected in ex vivo scans adjacent to the ventricles and were not related to scanner, resolution differences, or susceptibility artefacts. Satisfactory in vivo/ex vivo registration and subvoxel accuracy of ASHS segmentation of hippocampal SRLM demonstrate the feasibility of using this dataset for validation, and potentially, improvement of in vivo segmentation methods.
已经提出了多种从活体 MRI 量化海马亚区的技术。将活体 MRI 与基础组织学联系起来可以帮助验证和改进这些技术。高分辨率离体 MRI 可以提供一种中间模态，以在这些非常不同的成像模态之间映射信息。本文评估了在相同受试者中匹配活体和离体 MRI 信息的能力。我们对 10 对活体（3 T，0.4×0.4×2.6 mm3）和离体（9.4 T，0.2×0.2×0.2 mm3）扫描进行了刚性和变形配准，并定性和定量描述了这些模态之间的 MRI 外观差异。通过将自动海马亚区分割技术（ASHS）应用于活体扫描，并将 SRLM（层/放射状/腔隙/分子层）表面与相应的离体扫描上的手动追踪（在 2 个案例中，还有组织学）进行比较，评估了使用该数据集验证活体分割的可行性。在离体扫描中靠近脑室的区域厚度增加，与扫描仪、分辨率差异或磁化率伪影无关。海马 SRLM 的 ASHS 分割的活体/离体配准和亚体素精度令人满意，证明了使用该数据集进行验证的可行性，并且可能改进了活体分割方法。
