Automated landmark-based symmetric and standard alignment of skull base structures on CT

Area of Science:

• Medical Imaging
• Radiology
• Neuroscience

Background:

• Standard alignment of head CT scans is crucial for accurate clinical interpretation and research.
• Traditional template registration methods do not guarantee precise alignment of specific anatomical structures.
• A need exists for improved alignment techniques, especially for skull base research.

Purpose of the Study:

• To introduce and evaluate a novel landmark-based technique for aligning head CT studies.
• To achieve standard anterior commissure-posterior commissure (AC-PC)-like orientation using specific anatomical landmarks.
• To improve the alignment of skull base structures in head CT scans.

Main Methods:

• A retrospective study using head CTs from General Electric scanners.
• Manual annotation of landmarks (cochleas, nasal bridge) and training a 3D U-Net for identification.
• Assessment of landmark-based alignment against template registration for both whole head and skull base structures.

Main Results:

• Significant improvement in whole head alignment, reducing angular deviations in axial, sagittal, and coronal planes.
• Enhanced skull base alignment, with cochlear deviations reduced from 2.110/2.506 mm to 0.552/0.511 mm.
• Landmark-based technique demonstrated superior precision compared to traditional registration.

Conclusions:

• A simple, effective landmark-based technique for aligning head CTs, particularly focusing on the skull base.
• The method approximates AC-PC orientation, enhancing utility in clinical and research applications.
• This approach offers improved accuracy for studies involving the skull base.