Cramer Justin A, Huff Trevor, Kelly Sean, Welch Daniel, DeLuna Devin, Beyersdorf Conner, High Robin, White Matthew
Mayo Clinic Arizona, 5711 E Mayo Blvd, Phoenix, AZ, 85054, USA.
University of Arizona, 1501 N. Campbell, Tucson, AZ, 85724, USA.
Neuroimage Rep. 2025 Apr 4;5(2):100260. doi: 10.1016/j.ynirp.2025.100260. eCollection 2025 Jun.
Symmetry and standard alignment are crucial in both clinical interpretation and research on head CT studies. Registration to a standard template is the traditional method for alignment, yet registration does not guarantee precise alignment of any given structure. This study introduces a method for aligning skull base structures while still achieving a standard anterior commissure-posterior commissure (AC-PC)-like orientation on head CT studies using landmarks, specifically the cochleas and nasal bridge.
A retrospective study was conducted using head CTs from various General Electric scanners. Landmarks were manually annotated, and a 3D U-Net was trained for landmark identification. Landmark-based alignment was then performed on a test dataset and assessed in two different ways: whole head and skull base alignment. Whole head alignment was assessed quantitatively by expert review. Skull base alignment was then assessed at the cochleas, comparing their alignment between this landmark-based technique and registration to a template.
This landmark-based technique significantly improved whole head and skull base alignment of head CT studies. Whole head alignment reduced average deviations of 5, 11, and 4° in the axial, sagittal, and coronal planes to 1, 5, and 2° respectively. Meanwhile, skull base alignment assessed via the cochlea was also improved relative to traditional registration. For the landmark technique, the cochleas were deviated from perfect by a mean of 0.552 and 0.511 mm along the y and z axes compared to 2.110 and 2.506 mm with registration.
This study demonstrates a simple landmark-based technique for aligning the cochleas on head CT studies while approximating whole head AC-PC orientation, which has applications in both clinical and research settings, particularly for studies focused on the skull base.
对称性和标准对齐在头部CT研究的临床解读和研究中都至关重要。与标准模板配准是传统的对齐方法，但配准并不能保证任何给定结构的精确对齐。本研究介绍了一种在头部CT研究中对齐颅底结构的方法，同时仍能通过地标（特别是耳蜗和鼻梁）实现类似前连合-后连合（AC-PC）的标准方向。
使用来自各种通用电气扫描仪的头部CT进行回顾性研究。手动标注地标，并训练一个3D U-Net用于地标识别。然后在测试数据集上进行基于地标的对齐，并通过两种不同方式进行评估：全脑对齐和颅底对齐。全脑对齐通过专家评审进行定量评估。然后在耳蜗处评估颅底对齐，比较这种基于地标的技术与模板配准之间的对齐情况。
这种基于地标的技术显著改善了头部CT研究的全脑和颅底对齐。全脑对齐将轴向、矢状面和冠状面的平均偏差分别从5°、11°和4°降低到1°、5°和2°。同时，通过耳蜗评估的颅底对齐相对于传统配准也有所改善。对于地标技术，耳蜗沿y轴和z轴与完美对齐的平均偏差为0.552和0.511毫米，而配准的偏差为2.110和2.506毫米。
本研究展示了一种简单的基于地标的技术，用于在头部CT研究中对齐耳蜗，同时近似全脑AC-PC方向，该技术在临床和研究环境中都有应用，特别是对于专注于颅底的研究。
