Characterization of 3D geometric distortion of magnetic resonance imaging scanners commissioned for radiation therapy planning

Torfeh, Tarraf; Hammoud, R.; Perkins, G.; McGarry, M.; Aouadi, Souha; Çelik, Azim; Hwang, Ken Pin; Stancanello, Joseph; Petric, Primoz; Al-Hammadi, Noora

doi:10.1016/j.mri.2016.01.001

Cited by 58 publications

(105 citation statements)

References 17 publications

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“…For example, a recent study using an MR phantom found that 3D correction was superior to 2D-only correction. The authors also made the important observation that 3D correction actually also improves the in-plane slice accuracy over 2D-only algorithms because the 2D algorithms depend on the estimated 3D distance from isocenter to calculate distortion effect [25]. Another phantom study found that 2D-only correction merely reduced maximal distortion in their experimental conditions from 3.4 mm to 3.2 mm, numbers that are quite similar to those reported in the present work [9].…”

Section: Discussionsupporting

confidence: 80%

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Distortion inherent to magnetic resonance imaging can lead to geometric miss in radiosurgery planning

Seibert

White

Kim

et al. 2016

Practical Radiation Oncology

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Purpose Anatomic distortion is present in all MRI data due to non-linearity of gradient fields and measures up to several millimeters. We evaluate the potential for uncorrected MRI to lead to geometric miss of the target volume in stereotactic radiosurgery (SRS). Methods and Materials Twenty-eight SRS cases were studied retrospectively. MRIs were corrected for gradient non-linearity distortion in three dimensions, and gross tumor volumes (GTVs) were contoured. The manufacturer-specified distortion field was then re-applied to GTV masks to allow measurement of GTV displacement in uncorrected images. The uncorrected GTV was used for SRS planning, and the dose received by the true (corrected) GTV was measured. Results Median displacement of the GTV due to gradient distortion was 1.2 mm (interquartile range 0.1 mm – 2.3 mm), with a minimum of 0 mm and a maximum of 3.9 mm. Eight of the twenty-eight cases met a priori criteria for “geometric miss.” Conclusions While MRI distortion is often subtle on visual inspection, there is a significant clinical impact of this distortion on SRS planning. Distortion-corrected MRI should uniformly be used for intracranial radiosurgery planning because uncorrected MRI can lead to potential geometric miss.

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Section: Discussionsupporting

confidence: 80%

“…Gradient non-linearity distortion has been reported to increase with distance from the center of the magnetic field [9, 12, 13, 22, 25]. To investigate this effect in our own data, we calculated the Euclidean distance (in 3D) of the center of mass of the true, corrected GTV from the magnet isocenter.…”

Section: Methodsmentioning

confidence: 99%

Distortion inherent to magnetic resonance imaging can lead to geometric miss in radiosurgery planning

Seibert

White

Kim

et al. 2016

Practical Radiation Oncology

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“…Some new large geometric phantoms are being developed to simulate and evaluate distortion with large FOV 21, 22. The magnitude of the distortions increases with increasing distance from the isocenter of the scanner 23, 24. Similar to our results, within a distance of 200 mm, the mean distortion in the axial plane can be controlled in an acceptable range for radiotherapy.…”

Section: Discussionsupporting

confidence: 81%

Quantitative analysis of image quality for acceptance and commissioning of an MRI simulator with a semiautomatic method

Chen

Dai

2018

J Applied Clin Med Phys

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Magnetic Resonance Imaging (MRI) simulation differs from diagnostic MRI in purpose, technical requirements, and implementation. We propose a semiautomatic method for image acceptance and commissioning for the scanner, the radiofrequency (RF) coils, and pulse sequences for an MRI simulator. The ACR MRI accreditation large phantom was used for image quality analysis with seven parameters. Standard ACR sequences with a split head coil were adopted to examine the scanner's basic performance. The performance of simulation RF coils were measured and compared using the standard sequence with different clinical diagnostic coils. We used simulation sequences with simulation coils to test the quality of image and advanced performance of the scanner. Codes and procedures were developed for semiautomatic image quality analysis. When using standard ACR sequences with a split head coil, image quality passed all ACR recommended criteria. The image intensity uniformity with a simulation RF coil decreased about 34% compared with the eight‐channel diagnostic head coil, while the other six image quality parameters were acceptable. Those two image quality parameters could be improved to more than 85% by built‐in intensity calibration methods. In the simulation sequences test, the contrast resolution was sensitive to the FOV and matrix settings. The geometric distortion of simulation sequences such as T1‐weighted and T2‐weighted images was well‐controlled in the isocenter and 10 cm off‐center within a range of ±1% (2 mm). We developed a semiautomatic image quality analysis method for quantitative evaluation of images and commissioning of an MRI simulator. The baseline performances of simulation RF coils and pulse sequences have been established for routine QA.

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“…An in‐house Java‐based software module described in our previous work18 was used for automating the assessment of the geometric distortion. This module calculates the coordinates of each control point by measuring the center of mass (COM), then the algorithm corrects for gross phantom misalignment errors (translational and rotational errors), and finally establishes a one‐to‐one correspondence between the corrected control points in the MRI datasets and known positions obtained from the CT gold standard control points (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, tests conducted in order to evaluate 3D geometric accuracy as well as blurring artifact of balanced steady‐state gradient echo Cine MR Pulse sequence used with respiratory motion are described. This evaluation is performed using a point‐based phantom covering a 300 × 200 × 400 mm 3 Field Of View (FOV) 18. The geometric accuracy and the blurring artifact were evaluated for sequences acquired in the axial, sagittal, and coronal planes.…”

Section: Introductionmentioning

confidence: 99%

Geometric accuracy of the MR imaging techniques in the presence of motion

Torfeh

Hammoud

Kaissi

et al. 2018

J Applied Clin Med Phys

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Magnetic Resonance Imaging (MRI) is increasingly being used for improving tumor delineation and tumor tracking in the presence of respiratory motion. The purpose of this work is to design and build an MR compatible motion platform and to use it for evaluating the geometric accuracy of MR imaging techniques during respiratory motion. The motion platform presented in this work is composed of a mobile base made up of a flat plate and four wheels. The mobile base is attached from one end and through a rigid rod to a synchrony motion table by Accuray® placed at the end of the MRI table and from the other end to an elastic rod. The geometric accuracy was measured by placing a control point‐based phantom on top of the mobile base.In‐house software module was used to automatically assess the geometric distortion. The blurring artifact was also assessed by measuring the Full Width Half Maximum (FWHM) of each control point. Our results were assessed for 50, 100, and 150 mm radial distances, with a mean geometric distortion during the superior–inferior motion of 0.27, 0.41, and 0.55 mm, respectively. Adding the anterior–posterior motion, the mean geometric distortions increased to 0.4, 0.6, and 0.8 mm. Blurring was observed during motion causing an increase in the FWHM of ≈30%. The platform presented in this work provides a valuable tool for the assessment of the geometric accuracy and blurring artifact for MR during motion. Although the main objective was to test the spatial accuracy of an MR system during motion, the modular aspect of the presented platform enables the use of any commercially available phantom for a full quality control of the MR system during motion.

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Characterization of 3D geometric distortion of magnetic resonance imaging scanners commissioned for radiation therapy planning

Cited by 58 publications

References 17 publications

Distortion inherent to magnetic resonance imaging can lead to geometric miss in radiosurgery planning

Distortion inherent to magnetic resonance imaging can lead to geometric miss in radiosurgery planning

Quantitative analysis of image quality for acceptance and commissioning of an MRI simulator with a semiautomatic method

Geometric accuracy of the MR imaging techniques in the presence of motion

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