Field-map correction in read-out segmented echo planar imaging for reduced spatial distortion in prostate DWI for MRI-guided radiotherapy applications

Bergen, Robert V.; Ryner, Lawrence; Essig, M.

doi:10.1016/j.mri.2019.12.005

Cited by 7 publications

(10 citation statements)

References 25 publications

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“…The presence of severe image distortion is common in diffusion MRI, due to the use of EPI with long readouts in the presence of substantial B 0 magnetic field heterogeneities as observed in the abdomen and pelvis. 7 For this reason,considerable research efforts have been devoted to obtaining diffusion MRI with reduced distortions, based on a variety of approaches: Correcting distortions via postprocessing, for example, based on a measured B 0 field map, 87,88 or based on two acquisitions obtained with reversed k-space acquisition order. 89 Shortening the EPI readout.…”

Section: Distortionmentioning

confidence: 99%

Quantitative diffusion MRI of the abdomen and pelvis

2021

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Diffusion MRI has enormous potential and utility in the evaluation of various abdominal and pelvic disease processes including cancer and noncancer imaging of the liver, prostate, and other organs. Quantitative diffusion MRI is based on acquisitions with multiple diffusion encodings followed by quantitative mapping of diffusion parameters that are sensitive to tissue microstructure. Compared to qualitative diffusion‐weighted MRI, quantitative diffusion MRI can improve standardization of tissue characterization as needed for disease detection, staging, and treatment monitoring. However, similar to many other quantitative MRI methods, diffusion MRI faces multiple challenges including acquisition artifacts, signal modeling limitations, and biological variability. In abdominal and pelvic diffusion MRI, technical acquisition challenges include physiologic motion (respiratory, peristaltic, and pulsatile), image distortions, and low signal‐to‐noise ratio. If unaddressed, these challenges lead to poor technical performance (bias and precision) and clinical outcomes of quantitative diffusion MRI. Emerging and novel technical developments seek to address these challenges and may enable reliable quantitative diffusion MRI of the abdomen and pelvis. Through systematic validation in phantoms, volunteers, and patients, including multicenter studies to assess reproducibility, these emerging techniques may finally demonstrate the potential of quantitative diffusion MRI for abdominal and pelvic imaging applications.

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Section: Distortionmentioning

confidence: 99%

Quantitative diffusion MRI of the abdomen and pelvis

2021

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“…Even though DWI could observe and quantify biological structures based on diffusion properties of water molecules and improve lesion conspicuity ( Prezzi et al, 2018 ), it has limited role for MR-guided planning in clinical practice mainly due to disadvantages in geometric integrity ( Liney and Moerland, 2014 ). Decreased geometric distortions and susceptibility artifacts of DWI are essential for radiotherapy (RT) in matching or image fusions with other anatomical images for external beam planning, because high degree of accuracy is needed in RT applications ( Bergen et al, 2020 ). Minimized geometric distortion is of critical importance to avoid excessive radiation dose to healthy tissues ( Bergen et al, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

“…Decreased geometric distortions and susceptibility artifacts of DWI are essential for radiotherapy (RT) in matching or image fusions with other anatomical images for external beam planning, because high degree of accuracy is needed in RT applications ( Bergen et al, 2020 ). Minimized geometric distortion is of critical importance to avoid excessive radiation dose to healthy tissues ( Bergen et al, 2020 ). According to several published literatures ( Chen et al, 2006 ; McPartlin et al, 2016 ; Studenski et al, 2016 ; Bergen et al, 2020 ), approximately 3 mm distortion would increase the doses in RT, and it would lead to significant dose errors if more than 1 cm and even affects the treatment outcomes.…”

Section: Discussionmentioning

confidence: 99%

“…Minimized geometric distortion is of critical importance to avoid excessive radiation dose to healthy tissues ( Bergen et al, 2020 ). According to several published literatures ( Chen et al, 2006 ; McPartlin et al, 2016 ; Studenski et al, 2016 ; Bergen et al, 2020 ), approximately 3 mm distortion would increase the doses in RT, and it would lead to significant dose errors if more than 1 cm and even affects the treatment outcomes. Results of the current study showed the superiority of TGSE-PROPELLER-DWI with minimized distortions and susceptibility artifacts, indicating the potential to be implemented in RT management.…”

Section: Discussionmentioning

confidence: 99%

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Turbo Gradient and Spin Echo PROPELLER-Diffusion Weighted Imaging for Orbital Tumors: A Comparative Study With Readout-Segmented Echo-Planar Imaging

Kong

Dingxi

et al. 2021

Front. Neurosci.

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Purpose: To qualitatively and quantitatively compare the image quality and diagnostic performance of turbo gradient and spin echo PROPELLER diffusion-weighted imaging (TGSE-PROPELLER-DWI) vs. readout-segmented echo-planar imaging (rs-EPI) in the evaluation of orbital tumors.Materials and Methods: A total of 43 patients with suspected orbital tumors were enrolled to perform the two DWIs with comparable spatial resolution on 3T. The overall image qualities, geometric distortions, susceptibility artifacts, and lesion conspicuities were scored by using a four-point scale (1, poor; 4, excellent). Quantitative measurements, including contrast-to-noise ratios (CNRs), apparent diffusion coefficients (ADCs), geometric distortion rates (GDRs), and lesion sizes, were calculated and compared. The two ADCs for differentiating malignant from benign orbital tumors were evaluated. Wilcoxon signed-rank test, Kappa statistic, and receiver operating characteristics (ROC) curves were used.Results: TGSE-PROPELLER-DWI performed superior in all subjective scores and quantitative GDR evaluation than rs-EPI (p < 0.001), and excellent interobserver agreement was obtained for Kappa value ranging from 0.876 to 1.000. ADClesion of TGSE-PROPELLER-DWI was significantly higher than those of rs-EPI (p < 0.001). Mean ADC of malignant tumors was significantly lower than that of benign tumors both in two DWIs. However, the AUC for differentiating malignant and benign tumors showed no significant difference in the two DWIs (0.860 vs. 0.854, p = 0.7448). Sensitivity and specificity could achieve 92.86% and 72.73% for TGSE-PROPELLER-DWI with a cutoff value of 1.23 × 10–3 mm2/s, and 85.71% and 81.82% for rs-EPI with a cutoff value of 0.99 × 10–3 mm2/s.Conclusion: Compared with rs-EPI, TGSE-PROPELLER-DWI showed minimized geometric distortion and susceptibility artifacts significantly improved the image quality for orbital tumors and achieved comparable diagnostic performance in differentiating malignant and benign orbital tumors.

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“…Although the measured T1 and T2 of the agar (T1 ∼1800 ms and T2 ∼60 ms) and kiwi regions (T1 ∼1600-1900 ms and T2 ∼200–400 ms) in the phantom (data not shown) was not very similar to the prostate (T1 ∼1400–1700 ms and T2 ∼80 ms) and its surrounding organs (T1 ∼900–1500 ms and T2 ∼27–44 ms) (Bojorquez et al 2017 ), we do not expect these values to affect the B 0 -field maps and distortions. This phantom is easy to create, similar to (Bergen et al 2020 ), and may be useful for testing implementations of new DW-MR sequences (Hutter et al 2017 , Kakkar et al 2017 ) on clinical scanners.…”

Section: Discussionmentioning

confidence: 99%

Characterization of B₀-field fluctuations in prostate MRI

et al. 2020

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Multi-parametric MRI is increasingly used for prostate cancer detection. Improving information from current sequences, such as T2-weighted and diffusionweighted (DW) imaging, and additional sequences, such as magnetic resonance spectroscopy (MRS) and chemical exchange saturation transfer (CEST), may enhance the performance of multi-parametric MRI. The majority of these techniques are sensitive to B 0 -field variations and may result in image distortions including signal pile-up and stretching (echo planar imaging (EPI) based DW-MRI) or unwanted shifts in the frequency spectrum (CEST and MRS). Our aim is to temporally and spatially characterize B 0 -field changes in the prostate. Ten male patients are imaged using dualecho gradient echo sequences with varying repetitions on a 3T scanner to evaluate the temporal B 0 -field changes within the prostate. A phantom is also imaged to consider no physiological motion. The spatial B 0 -field variations in the prostate are reported as B 0 -field values (Hz), their spatial gradients (Hz/mm) and the resultant distortions in EPI based DW-MRI images (b-value = 0 s/mm 2 and two oppositely phase encoded directions). Over a period of minutes, temporal changes in B -field values were ≤19 Hz for minimal bowel motion and ≥30 Hz for large motion. Spatially across the prostate, the B 0 -field values had an interquartile range of ≤18 Hz (minimal motion) and ≤44 Hz (large motion). The B 0 -field gradients were between -2 and 5 Hz/mm (minimal motion) and 2 to 12 Hz/mm (large motion). Overall, B 0 -field variations can affect DW, MRS and CEST imaging of the prostate.

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Field-map correction in read-out segmented echo planar imaging for reduced spatial distortion in prostate DWI for MRI-guided radiotherapy applications

Cited by 7 publications

References 25 publications

Quantitative diffusion MRI of the abdomen and pelvis

Quantitative diffusion MRI of the abdomen and pelvis

Turbo Gradient and Spin Echo PROPELLER-Diffusion Weighted Imaging for Orbital Tumors: A Comparative Study With Readout-Segmented Echo-Planar Imaging

Characterization of B₀-field fluctuations in prostate MRI

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Field-map correction in read-out segmented echo planar imaging for reduced spatial distortion in prostate DWI for MRI-guided radiotherapy applications

Cited by 7 publications

References 25 publications

Quantitative diffusion MRI of the abdomen and pelvis

Quantitative diffusion MRI of the abdomen and pelvis

Turbo Gradient and Spin Echo PROPELLER-Diffusion Weighted Imaging for Orbital Tumors: A Comparative Study With Readout-Segmented Echo-Planar Imaging

Characterization of B0-field fluctuations in prostate MRI

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Characterization of B₀-field fluctuations in prostate MRI