Abstract
Purpose: The accuracy of 4D-CT registration is limited by inconsistent Hounsfield unit (HU) values in the 4D-CT data from one respiratory phase to another and lower image contrast for lung substructures. This paper presents an optical flow and thin-plate spline (TPS)-based 4D-CT registration method to account for these limitations.
Methods: The use of unified HU values on multiple anatomy levels (e.g., the lung contour, blood vessels, and parenchyma) accounts for registration errors by inconsistent landmark HU value. While 3D multi-resolution optical flow analysis registers each anatomical level, TPS is employed for propagating the results from one anatomical level to another ultimately leading to the 4D-CT registration. 4D-CT registration was validated using target registration error (TRE), inverse consistency error (ICE) metrics, and a statistical image comparison using Gamma criteria of 1 % intensity difference in 2 mm3window range.
Results: Validation results showed that the proposed method was able to register CT lung datasets with TRE and ICE values <3 mm. In addition, the average number of voxel that failed the Gamma criteria was <3 %, which supports the clinical applicability of the propose registration mechanism.
Conclusion: The proposed 4D-CT registration computes the volumetric lung deformations within clinically viable accuracy.
Original language | English (US) |
---|---|
Pages (from-to) | 875-889 |
Number of pages | 15 |
Journal | International Journal of Computer Assisted Radiology and Surgery |
Volume | 9 |
Issue number | 5 |
DOIs | |
State | Published - Sep 28 2014 |
Externally published | Yes |
Keywords
- Lung registration
- Optical flow
- Radiotherapy
ASJC Scopus subject areas
- Surgery
- Biomedical Engineering
- Radiology Nuclear Medicine and imaging
- Computer Vision and Pattern Recognition
- Computer Science Applications
- Health Informatics
- Computer Graphics and Computer-Aided Design