Cardiovascular magnetic resonance virtual tagging with B-spline-based free-form deformation

2021 ◽  
Author(s):  
Hajime Sagawa ◽  
Tosiaki Miyati
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Free Form ◽  
B Spline ◽  
Free Form Deformation

Comparison of B-Spline Surface and Free-Form Deformation Geometry Control for Aerodynamic Optimization

AIAA Journal ◽  
2017 ◽  
Vol 55 (1) ◽  
pp. 228-240 ◽  
Author(s):  
Christopher Lee ◽  
David Koo ◽  
David W. Zingg
Keyword(s):  
Free Form ◽  
Aerodynamic Optimization ◽  
B Spline ◽  
Spline Surface ◽  
Free Form Deformation

scholarly journals Rotation and torsion of the left ventricle with cardiovascular magnetic resonance tagging: comparison of two analysis software

2020 ◽  
Author(s):  
Lauri Lehmonen ◽  
Mikko Jalanko ◽  
Mika Tarkiainen ◽  
Touko Kaasalainen ◽  
Johanna Kuusisto ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Left Ventricle ◽  
Spatial Modulation ◽  
Free Form ◽  
Specific Reference ◽  
Gabor Filtering ◽  
Rigid Registration ◽  
Harmonic Phase ◽  
Apical Rotation

Abstract Background Left ventricle rotation and torsion are fundamental components of myocardial function, several software have been developed for the analysis of these components. Purpose of the study was to compare the suitability of two such software with different technical principles in analyzing rotation and torsion of the left ventricle during systole. Methods A group of hypertrophic cardiomyopathy (HCM) patients (N = 14, age 43 ± 11 years), mutation carriers without hypertrophy (N = 10, age 34 ± 13 years) and healthy controls (N = 12, age 43 ± 17 years) underwent a cardiovascular magnetic resonance examination including spatial modulation of magnetization tagging sequences in basal and apical levels of the left ventricle. The tagging images were analyzed offline using a harmonic phase image analysis method with Gabor filtering, and with non-rigid registration based free-form deformation technique. Left-ventricle rotation and torsion scores were obtained from end-diastole to end-systole with both software.Results Analysis was successful in all cases with both software. End-systolic torsion values between the study groups were not statistically different, with either software. End-systolic apical rotation, end-systolic basal rotation, and end-systolic torsion were consistently higher in Segment compared to HPF (p < 0.0001). End-systolic rotation and torsion values had statistically significant correlations between the two software (p < 0.0001), most significant in the apical plane. Conclusions When comparing absolute values of rotation and torsion between different individuals, software specific reference values are required. Harmonic phase flow with Gabor filtering, and non-rigid registration-based analysis methods can both be used reliably in the analysis of systolic rotation and torsion patterns of the left ventricle.

scholarly journals A Comparative Evaluation of 3 Different Free-Form Deformable Image Registration and Contour Propagation Methods for Head and Neck MRI: The Case of Parotid Changes During Radiotherapy

2017 ◽  
Vol 16 (3) ◽  
pp. 373-381 ◽  
Author(s):  
Sara Broggi ◽  
Elisa Scalco ◽  
Maria Luisa Belli ◽  
Gerlinde Logghe ◽  
Dirk Verellen ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Image Registration ◽  
Head And Neck ◽  
Deformable Image Registration ◽  
Similarity Coefficient ◽  
Free Form ◽  
Dice Similarity Coefficient ◽  
Contour Propagation ◽  
Free Form Deformation ◽  
Symmetric Distance

Purpose: To validate and compare the deformable image registration and parotid contour propagation process for head and neck magnetic resonance imaging in patients treated with radiotherapy using 3 different approaches—the commercial MIM, the open-source Elastix software, and an optimized version of it. Materials and Methods: Twelve patients with head and neck cancer previously treated with radiotherapy were considered. Deformable image registration and parotid contour propagation were evaluated by considering the magnetic resonance images acquired before and after the end of the treatment. Deformable image registration, based on free-form deformation method, and contour propagation available on MIM were compared to Elastix. Two different contour propagation approaches were implemented for Elastix software, a conventional one (DIR_Trx) and an optimized homemade version, based on mesh deformation (DIR_Mesh). The accuracy of these 3 approaches was estimated by comparing propagated to manual contours in terms of average symmetric distance, maximum symmetric distance, Dice similarity coefficient, sensitivity, and inclusiveness. Results: A good agreement was generally found between the manual contours and the propagated ones, without differences among the 3 methods; in few critical cases with complex deformations, DIR_Mesh proved to be more accurate, having the lowest values of average symmetric distance and maximum symmetric distance and the highest value of Dice similarity coefficient, although nonsignificant. The average propagation errors with respect to the reference contours are lower than the voxel diagonal (2 mm), and Dice similarity coefficient is around 0.8 for all 3 methods. Conclusion: The 3 free-form deformation approaches were not significantly different in terms of deformable image registration accuracy and can be safely adopted for the registration and parotid contour propagation during radiotherapy on magnetic resonance imaging. More optimized approaches (as DIR_Mesh) could be preferable for critical deformations.

Accurate B-spline Free-Form Deformation of Polygonal Objects

1998 ◽  
Vol 3 (3) ◽  
pp. 11-27 ◽  
Author(s):  
Jieqing Feng ◽  
Pheng-Ann Heng ◽  
Tien-Tsin Wong
Keyword(s):  
Free Form ◽  
B Spline ◽  
Free Form Deformation

Reproducing Existing Nacelle Geometries With the Free-Form Deformation Parametrization

2018 ◽  
Author(s):  
Konstantin Rusch ◽  
Martin Siggel ◽  
Richard-Gregor Becker
Keyword(s):  
Inverse Problem ◽  
Spline Approximation ◽  
Aircraft Design ◽  
Free Form ◽  
Design Phase ◽  
B Spline ◽  
Preliminary Aircraft Design ◽  
Least Squares Fit ◽  
Free Form Deformation ◽  
Grid Points

In the conceptual and preliminary aircraft design phase the Free-Form Deformation (FFD) is one of various parametrization schemes to define the geometry of an engine’s nacelle. This paper presents a method that is able to create a C2 continuous periodic approximation of existing reference nacelles with the B-spline based FFD, which is a generalization of the classical FFD. The basic principle of this method is to start with a rotational symmetric B-spline approximation of the reference nacelle, which is subsequently deformed with a FFD grid that is placed around the initial geometry. A method is derived that computes the displacement of the FFD grid points, such that the deformed nacelle approximates the reference nacelle with minimal deviations. As this turns out to be a linear inverse problem, it can be solved with a linear least squares fit. To avoid overfitting effects — like degenerative FFD grids which imply excessive local deformations — the inverse problem is regularized with the Tikhonov approach. The NASA CRM model and the IAE V2500 engine have been selected as reference geometries. Both resemble nacelles that are typically found on common aircraft models and both deviate sufficiently from the rotational symmetry. It is demonstrated that the mean error of the approximation decreases with an increase of the number of FFD grid points and how the regularization affects these results. Finally, the B-spline based FFD with the classical Bernstein based FFD are compared for both models. The results conceptually prove the usability of the FFD approach for the construction of nacelle geometries in the preliminary aircraft design phase.

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