Distortion in magnetic resonance images needs to be taken into account for the purposes of radiotherapy treatment planning (RTP). A commercial MRI grid phantom was scanned on four different MRI scanners with multiple sequences to assess variations in the geometric distortion. The distortions present across the field of view were then determined. The effect of varying bandwidth on image distortion and signal to noise was also investigated. Distortion maps were created and these were compared to the location of patient anatomy within the scanner bore to estimate the magnitude and distribution of distortions located within specific clinical regions. Distortion magnitude and patterns varied between MRI sequence protocols and scanners. The magnitude of the distortions increased with increasing distance from the isocentre of the scanner within a 2D imaging plane. Average distortion across the phantom generally remained below 2.0 mm, although towards the edge of the phantom for a turbo spin echo sequence, the distortion increased to a maximum value of 4.1 mm. Application of correction algorithms supplied by each vendor reduced but did not completely remove distortions. Increasing the bandwidth of the acquisition sequence decreased the amount of distortion at the expense of a reduction in signal-to-noise ratio of 13.5 across measured bandwidths. Imaging protocol parameters including bandwidth, slice thickness and phase encoding direction, should be noted for distortion investigations in RTP since each can influence the distortion. The magnitude of distortion varies across different clinical sites.
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Khoo VS, Dearnaley DP, Finnigan DJ, Padhani A, Tanner SF, Leach MO (1997) Magnetic resonance imaging (MRI): considerations and applications in radiotherapy treatment planning. Radiother Oncol 42(1):1–15. doi:10.1016/s0167-8140(96)01866-x
Chen L, Price JRA, Wang L, Li J, Qin L, McNeeley S, Ma CMC, Freedman GM, Pollack A (2004) MRI-based treatment planning for radiotherapy: dosimetric verification for prostate IMRT. Int J Radiat Oncol Biol Phys 60(2):636–647. doi:10.1016/j.ijrobp.2004.05.068
Prabhakar R, Julka PK, Ganesh T, Munshi A, Joshi RC, Rath GK (2007) Feasibility of using MRI alone for 3D radiation treatment planning in brain tumors. Jpn J Clin Oncol 37(6):405–411
Baldwin LN, Wachowicz K, Thomas SD, Rivest R, Fallone BG (2007) Characterization, prediction, and correction of geometric distortion in 3 T MR images. Med Phys 34(2):388–399. doi:10.1118/1.2402331
Jezzard P (2009) The physical basis of spatial distortions in magnetic resonance images. In: Bankman IN (ed) Handbook of medical image processing and analysis, 2nd edn. Elsevier, Amsterdam, pp 499–514
Chang H, Fitzpatrick JM (1992) A technique for accurate magnetic resonance imaging in the presence of field inhomogeneities. IEEE Trans Med Imaging 11(3):319–329
Doran SJ, Charles-Edwards L, Reinsberg SA, Leach MO (2005) A complete distortion correction for MR images: I. Gradient warp correction. Phys Med Biol 50(7):1343
Crijns SPM, Raaymakers BW, Lagendijk JJW (2011) Real-time correction of magnetic field inhomogeneity-induced image distortions for MRI-guided conventional and proton radiotherapy. Phys Med Biol 56(1):289–297
Wang D, Doddrell DM, Cowin G (2004) A novel phantom and method for comprehensive 3-dimensional measurement and correction of geometric distortion in magnetic resonance imaging. Magn Reson Imaging 22(4):529–542. doi:10.1016/j.mri.2004.01.008
Mizowaki T, Nagata Y, Okajima K, Kokubo M, Negoro Y, Araki N, Hiraoka M (2000) Reproducibility of geometric distortion in magnetic resonance imaging based on phantom studies. Radiother Oncol 57(2):237–242. doi:10.1016/s0167-8140(00)00234-6
Karger CP, Höss A, Bendl R, Canda V, Schad L (2006) Accuracy of device-specific 2D and 3D image distortion correction algorithms for magnetic resonance imaging of the head provided by a manufacturer. Phys Med Biol 51(12):N253
Antolak JA, Rosen II (1999) Planning target volumes for radiotherapy: how much margin is needed? Int J Radiat Oncol Biol Phys 44(5):1165–1170
Janke A, Zhao H, Cowin GJ, Galloway GJ, Doddrell DM (2004) Use of spherical harmonic deconvolution methods to compensate for nonlinear gradient effects on MRI images. Magn Reson Med 52(1):115–122. doi:10.1002/mrm.20122
Baldwin LN, Wachowicz K, Fallone BG (2009) A two-step scheme for distortion rectification of magnetic resonance images. Med Phys 36(9):3917–3926
Bakker CJG, Moerland MA, Bhawandien R, Beersma R (1992) Analysis of machine-dependent and object-induced geometric distortion in 2DFT MR imaging. Magn Reson Imaging 10(4):597–608. doi:10.1016/0730-725x(92)90011-n
Petersch B, Bogner J, Fransson A, Lorang T, Pötter R (2004) Effects of geometric distortion in 0.2 T MRI on radiotherapy treatment planning of prostate cancer. Radiother Oncol 71(1):55–64. doi:10.1016/j.radonc.2003.12.012
Stanescu T, Jans HS, Wachowicz K, Fallone BG (2010) Investigation of a 3D system distortion correction method for MR images. J Appl Clin Med Phys 11(1):2961
Stanescu T, Hans-Sonke J, Stavrev P, Fallone BG (2006) 3T MR-based treatment planning for radiotherapy of brain lesions. Radiol Oncol 40(2):125–132
Crijns SPM, Bakker CJG, Seevinck PR, de Leeuw H, Lagendijk JJW, Raaymakers BW (2012) Towards inherently distortion-free MR images for image-guided radiotherapy on an MRI accelerator. Phys Med Biol 57(5):1349
Zhang B, MacFadden D, Damyanovich AZ, Rieker M, Stainsby J, Bernstein M, Jaffray DA, Mikulis D, Menard C (2010) Development of a geometrically accurate imaging protocol at 3 Tesla MRI for stereotactic radiosurgery treatment planning. Phys Med Biol 55(1):6601–6615. doi:10.1088/0031-9155/55/22/002
Chen H–H, Boykin RD, Clarke GD, Gao JHT, Roby JW III (2006) Routine testing of magnetic field homogeneity on clinical MRI systems. Med Phys 33(11):4299–4306
AAPM (1990) Quality assurance methods and phantoms for magnetic resonance imaging: report of AAPM nuclear magnetic resonance Task Group No 1. Med Phys 17(2):287–295. doi:10.1118/1.596566
Moerland MA (1996) Magnetic resonance imaging in radiotherapy treatment planning. University Utrecht, Utrecht
Devic S (2012) MRI simulation for radiotherapy treatment planning. Med Phys 39(11):6701–6711. doi:10.1118/1.4758068
The authors would like to thank Michael Jameson from Liverpool Cancer Therapy Centre for useful discussions and access to some in-house code utilised in part of this project, as well as Peter Greer from the Calvary Mater Hospital Newcastle for access to the phantom. Special thanks to Matthew Hundy (Wollongong hospital), Joseph Turner (Campbelltown hospital) and Michael Serratore (Liverpool hospital) for their time in allowing access to the clinical MRI scanners to conduct this study.
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Walker, A., Liney, G., Metcalfe, P. et al. MRI distortion: considerations for MRI based radiotherapy treatment planning. Australas Phys Eng Sci Med 37, 103–113 (2014). https://doi.org/10.1007/s13246-014-0252-2
- Geometric distortion
- Radiotherapy treatment planning