open access

Vol 24, No 6 (2019)
Original research articles
Published online: 2019-11-01
Submitted: 2019-03-18
Get Citation

Evaluating the accuracy of geometrical distortion correction of magnetic resonance images for use in intracranial brain tumor radiotherapy

Seyed Mehdi Bagherimofidi, Claus Chunli Yang, Roberto Rey-Dios, Madhava R. Kanakamedala, Ali Fatemi
DOI: 10.1016/j.rpor.2019.09.011
·
Rep Pract Oncol Radiother 2019;24(6):606-613.

open access

Vol 24, No 6 (2019)
Original research articles
Published online: 2019-11-01
Submitted: 2019-03-18

Abstract

Aim

Determine the 1) effectiveness of correction for gradient-non-linearity and susceptibility effects on both QUASAR GRID3D and CIRS phantoms; and 2) the magnitude and location of regions of residual distortion before and after correction.

Background

Using magnetic resonance imaging (MRI) as a primary dataset for radiotherapy planning requires correction for geometrical distortion and non-uniform intensity.

Materials and Methods

Phantom Study: MRI, computed tomography (CT) and cone beam CT images of QUASAR GRID3D and CIRS head phantoms were acquired. Patient Study: Ten patients were MRI-scanned for stereotactic radiosurgery treatment. Correction algorithm: Two magnitude and one phase difference image were acquired to create a field map. A MATLAB program was used to calculate geometrical distortion in the frequency encoding direction, and 3D interpolation was applied to resize it to match 3D T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE) images. MPRAGE images were warped according to the interpolated field map in the frequency encoding direction. The corrected and uncorrected MRI images were fused, deformable registered, and a difference distortion map generated.

Results

Maximum deviation improvements: GRID3D, 0.27mm y-direction, 0.07mm z-direction, 0.23mm x-direction. CIRS, 0.34mm, 0.1mm and 0.09mm at 20-, 40- and 60-mm diameters from the isocenter. Patient data show corrections from 0.2 to 1.2mm, based on location. The most-distorted areas are around air cavities, e.g. sinuses.

Conclusions

The phantom data show the validity of our fast distortion correction algorithm. Patient-specific data are acquired in <2min and analyzed and available for planning in less than a minute.

Abstract

Aim

Determine the 1) effectiveness of correction for gradient-non-linearity and susceptibility effects on both QUASAR GRID3D and CIRS phantoms; and 2) the magnitude and location of regions of residual distortion before and after correction.

Background

Using magnetic resonance imaging (MRI) as a primary dataset for radiotherapy planning requires correction for geometrical distortion and non-uniform intensity.

Materials and Methods

Phantom Study: MRI, computed tomography (CT) and cone beam CT images of QUASAR GRID3D and CIRS head phantoms were acquired. Patient Study: Ten patients were MRI-scanned for stereotactic radiosurgery treatment. Correction algorithm: Two magnitude and one phase difference image were acquired to create a field map. A MATLAB program was used to calculate geometrical distortion in the frequency encoding direction, and 3D interpolation was applied to resize it to match 3D T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE) images. MPRAGE images were warped according to the interpolated field map in the frequency encoding direction. The corrected and uncorrected MRI images were fused, deformable registered, and a difference distortion map generated.

Results

Maximum deviation improvements: GRID3D, 0.27mm y-direction, 0.07mm z-direction, 0.23mm x-direction. CIRS, 0.34mm, 0.1mm and 0.09mm at 20-, 40- and 60-mm diameters from the isocenter. Patient data show corrections from 0.2 to 1.2mm, based on location. The most-distorted areas are around air cavities, e.g. sinuses.

Conclusions

The phantom data show the validity of our fast distortion correction algorithm. Patient-specific data are acquired in <2min and analyzed and available for planning in less than a minute.

Get Citation

Keywords

MRI guided radiotherapy; MRI image geometric distortion correction; Radiotherapy; Magnetic resonance imaging; Intracranial brain tumor radiotherapy

About this article
Title

Evaluating the accuracy of geometrical distortion correction of magnetic resonance images for use in intracranial brain tumor radiotherapy

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 24, No 6 (2019)

Pages

606-613

Published online

2019-11-01

DOI

10.1016/j.rpor.2019.09.011

Bibliographic record

Rep Pract Oncol Radiother 2019;24(6):606-613.

Keywords

MRI guided radiotherapy
MRI image geometric distortion correction
Radiotherapy
Magnetic resonance imaging
Intracranial brain tumor radiotherapy

Authors

Seyed Mehdi Bagherimofidi
Claus Chunli Yang
Roberto Rey-Dios
Madhava R. Kanakamedala
Ali Fatemi

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By "Via Medica sp. z o.o." sp.k., ul. Świętokrzyska 73, 80–180 Gdańsk, Poland
tel.:+48 58 320 94 94, fax:+48 58 320 94 60, e-mail: journals@viamedica.pl