Measuring geometric accuracy in magnetic resonance imaging with 3D-printed phantom and nonrigid image registration

Abstract Objective We aimed to develop a vendor-neutral and interaction-free quality assurance protocol for measuring geometric accuracy of head and brain magnetic resonance (MR) images. We investigated the usability of nonrigid image registration in the analysis and looked for the optimal registration parameters. Materials and methods We constructed a 3D-printed phantom and imaged it with 12 MR scanners using clinical sequences. We registered a geometric-ground-truth computed tomography (CT) acquisition to the MR images using an open-source nonrigid-registration-toolbox with varying parameters. We applied the transforms to a set of control points in the CT image and compared their locations to the corresponding visually verified reference points in the MR images. Results With optimized registration parameters, the mean difference (and standard deviation) of control point locations when compared to the reference method was (0.17 ± 0.02) mm for the 12 studied scanners. The maximum displacements varied from 0.50 to 1.35 mm or 0.89 to 2.30 mm, with vendors’ distortion correction on or off, respectively. Discussion Using nonrigid CT–MR registration can provide a robust and relatively test-object-agnostic method for estimating the intra- and inter-scanner variations of the geometric distortions.

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Comparison of radiographer interobserver image registration variability using cone beam CT and MR for cervix radiotherapy

British Journal of Radiology ◽

10.1259/bjr.20200169 ◽

2020 ◽

Vol 93 (1112) ◽

pp. 20200169

Author(s):

John Rodgers ◽

Rosie Hales ◽

Lee Whiteside ◽

Jacqui Parker ◽

Louise McHugh ◽

...

Keyword(s):

Magnetic Resonance ◽

Image Registration ◽

Image Guidance ◽

Cone Beam Ct ◽

Cone Beam ◽

Mr Images ◽

Mr Image ◽

Image Guided Radiotherapy ◽

Multimodality Image ◽

Planning Ct

Objectives: The aim of this study was to assess the consistency of therapy radiographers performing image registration using cone beam computed tomography (CBCT)-CT, magnetic resonance (MR)-CT, and MR-MR image guidance for cervix cancer radiotherapy and to assess that MR-based image guidance is not inferior to CBCT standard practice. Methods: 10 patients receiving cervix radiation therapy underwent daily CBCT guidance and magnetic resonance (MR) imaging weekly during treatment. Offline registration of each MR image, and corresponding CBCT, to planning CT was performed by five radiographers. MR images were also registered to the earliest MR interobserver variation was assessed using modified Bland–Altman analysis with clinically acceptable 95% limits of agreement (LoA) defined as ±5.0 mm. Results: 30 CBCT-CT, 30 MR-CT and 20 MR–MR registrations were performed by each observer. Registration variations between CBCT-CT and MR-CT were minor and both strategies resulted in 95% LoA over the clinical threshold in the anteroposterior direction (CBCT-CT ±5.8 mm, MR-CT ±5.4 mm). MR–MR registrations achieved a significantly improved 95% LoA in the anteroposterior direction (±4.3 mm). All strategies demonstrated similar results in lateral and longitudinal directions. Conclusion: The magnitude of interobserver variations between CBCT-CT and MR-CT were similar, confirming that MR-CT radiotherapy workflows are comparable to CBCT-CT image-guided radiotherapy. Our results suggest MR–MR radiotherapy workflows may be a superior registration strategy. Advances in knowledge: This is the first publication quantifying interobserver registration of multimodality image registration strategies for cervix radical radiotherapy patients.

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Nonrigid Image Registration of Brain MR Images Using Normalized Mutual Information

Advances in Intelligent Systems and Computing - Proceedings of the Second International Conference on Soft Computing for Problem Solving (SocProS 2012), December 28-30, 2012 ◽

10.1007/978-81-322-1602-5_112 ◽

2014 ◽

pp. 1069-1077 ◽

Cited By ~ 1

Author(s):

Smita Pradhan ◽

Dipti Patra

Keyword(s):

Image Registration ◽

Mutual Information ◽

Mr Images ◽

Nonrigid Image Registration ◽

Normalized Mutual Information ◽

Brain Mr Images

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Diffusion-weighted breast magnetic resonance imaging with distortion correction using non-rigid image registration: a clinical study

Radiological Physics and Technology ◽

10.1007/s12194-020-00568-1 ◽

2020 ◽

Vol 13 (2) ◽

pp. 210-218

Author(s):

Yasuo Takatsu ◽

Hajime Sagawa ◽

Masafumi Nakamura ◽

Yuichi Suzuki ◽

Tosiaki Miyati

Keyword(s):

Magnetic Resonance Imaging ◽

Clinical Study ◽

Magnetic Resonance ◽

Image Registration ◽

Breast Magnetic Resonance Imaging ◽

Distortion Correction ◽

Resonance Imaging ◽

Diffusion Weighted ◽

Breast Magnetic Resonance

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Simultaneous Reconstruction of 4-D Myocardial Motion from Both Tagged and Untagged MR Images Using Nonrigid Image Registration

Lecture Notes in Computer Science - Medical Imaging and Augmented Reality ◽

10.1007/978-3-642-15699-1_11 ◽

2010 ◽

pp. 98-107 ◽

Cited By ~ 2

Author(s):

Wenzhe Shi ◽

Maria Murgasova ◽

Philip Edwards ◽

Daniel Rueckert

Keyword(s):

Image Registration ◽

Mr Images ◽

Myocardial Motion ◽

Nonrigid Image Registration ◽

Simultaneous Reconstruction

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Geometrical accuracy of a 3-tesla magnetic resonance imaging unit in Gamma Knife surgery

Journal of Neurosurgery ◽

10.3171/sup.2006.105.7.190 ◽

2006 ◽

Vol 105 (Supplement) ◽

pp. 190-193 ◽

Cited By ~ 16

Author(s):

Yoichi Watanabe ◽

Chung K. Lee ◽

Bruce J. Gerbi

Keyword(s):

Magnetic Resonance ◽

Mr Imaging ◽

Gamma Knife ◽

Pulse Sequence ◽

Distortion Correction ◽

Gamma Knife Surgery ◽

3 Tesla ◽

Mr Images ◽

Geometrical Accuracy ◽

Rapid Acquisition

ObjectThe authors sought to evaluate and improve the geometrical accuracy of a 3-tesla magnetic resonance (MR) imaging unit used for Gamma Knife surgery (GKS).MethodsTo evaluate the geometrical accuracy of a Siemens Magnetom Trio 3-tesla MR imaging unit, two phantoms were used. Both phantoms were imaged with computed tomography (CT), a 1.5-tesla MR imaging unit (Siemens Avanto), and the 3-tesla MR imaging unit. A pair of orthogonal films was obtained with a radiotherapy simulator to validate the spatial coordinates of the marker positions determined with CT. The coordinates of the markers were measured using the GammaPlan treatment planning software. Magnetic resonance imaing was performed using three-dimensional (3D) magnetization-prepared rapid acquisition gradient echo (MPRAGE) and fast low-angle shot sequence (FLASH) pulse sequences. The voxel size was 1 × 1 × 1 mm3.Conclusions The root-mean-square error of MR images was 2 ± 0.73 mm for 3D MPRAGE. The error was reduced to 1.5 ± 0.64 mm for FLASH. The errors were decreased further by applying an image distortion correction method (the field-of-view filter) to the images acquired with FLASH. The mean errors were 1.3 ± 0.39 mm and 1.5 ± 0.77 mm for the two phantoms. The errors increased from 1 mm to 3.1 mm as the measurement points approached the caudal edge of the head coil (larger z value). Proper selection of a pulse sequence together with a geometrical distortion correction improved the geometrical accuracy of MR images. However, further study is needed to increase the geometrical accuracy of 3-tesla MR imaging units for radiosurgical applications.

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