Quantification of organ motion based on an adaptive image‐based scale invariant feature method. Issue 11 (2nd October 2013)

• Record Type: Journal Article
• Authors: Paganelli, Chiara; Peroni, Marta; Baroni, Guido; Riboldi, Marco
• Is Part Of: Medical physics. Volume 40:Issue 11(2013)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2013-10-02
• Subjects: Computed tomography -- Computed radiography -- Pneumodyamics, respiration -- Registration; computerised tomography -- feature extraction -- image motion analysis -- image registration -- invariance -- lung -- medical image processing -- motion measurement -- phantoms -- pneumodynamics; feature extraction -- image‐guided treatment -- deformable image registration -- motion quantification and analysis; Computerised tomographs -- Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Analysis of motion; Medical imaging -- Medical image contrast -- Lungs -- Computed tomography -- Vector fields -- Anatomy -- Image guided radiation therapy -- Image sensors -- Medical image quality -- Radiation treatment; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4822486
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: : The availability of corresponding landmarks in IGRT image series allows quantifying the inter and intrafractional motion of internal organs. In this study, an approach for the automatic localization of anatomical landmarks is presented, with the aim of describing the nonrigid motion of anatomo‐pathological structures in radiotherapy treatments according to local image contrast. Methods: : An adaptive scale invariant feature transform (SIFT) was developed from the integration of a standard 3D SIFT approach with a local image‐based contrast definition. The robustness and invariance of the proposed method to shape‐preserving and deformable transforms were analyzed in a CT phantom study. The application of contrast transforms to the phantom images was also tested, in order to verify the variation of the local adaptive measure in relation to the modification of image contrast. The method was also applied to a lung 4D CT dataset, relying on manual feature identification by an expert user as ground truth. The 3D residual distance between matches obtained in adaptive‐SIFT was then computed to verify the internal motion quantification with respect to the expert user. Extracted corresponding features in the lungs were used as regularization landmarks in a multistage deformable image registration (DIR) mapping the inhale vs exhale phase. The residual distances between the warped manual landmarks and their reference position in the inhale phase were evaluated, in order to provide a quantitative indication of the registration performed with the three different point sets. Results: : The phantom study confirmed the method invariance and robustness properties to shape‐preserving and deformable transforms, showing residual matching errors below the voxel dimension. The adapted SIFT algorithm on the 4D CT dataset provided automated and accurate motion detection of peak to peak breathing motion. The proposed method resulted in reduced residual errors with respect to standard SIFT, providing a motion description comparable to expert manual identification, as confirmed by DIR. Conclusions: : The application of the method to a 4D lung CT patient dataset demonstrated adaptive‐SIFT potential as an automatic tool to detect landmarks for DIR regularization and internal motion quantification. Future works should include the optimization of the computational cost and the application of the method to other anatomical sites and image modalities.