Clinical Application of Readout-Segmented− Echo-Planar Imaging for Diffusion-Weighted Imaging in Pediatric Brain

Holdsworth, Samantha J.; Yeom, Kristen W.; Skare, Stefan; Gentles, AJ; Barnes, P. D.; Bammer, Roland

doi:10.3174/ajnr.a2481

Cited by 67 publications

(58 citation statements)

References 10 publications

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“…This method provides images with less artefacts and higher resolution for the evaluation of brain, brain stem and the breast [11][12][13]. However, to the best of our knowledge, its effectiveness in the evaluation of middle-ear cholesteatoma has not been established, yet.…”

Section: Introductionmentioning

confidence: 99%

Detection of cholesteatoma: High-resolution DWI using RS-EPI and parallel imaging at 3 tesla

Algın

Aydın

Özmen

et al. 2017

Journal of Neuroradiology

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a b s t r a c tThe purpose of this study is to evaluate the impact of RS-EPI-DWI in the detection of cholesteatoma and to compare with single-shot echo-planar DWI (SS-EPI-DWI). Diffusion-weighted and apparent diffusioncoefficient (ADC) images were obtained using RS-EPI and SS-EPI techniques in 30 patients. Presence of cholesteatoma (3 point scale), amount of artefacts (4 point scale), visibility (4 point scale), and ADC values of the lesions were assessed. The results of both techniques were compared with each other and gold-standard (GS) test results. Lesion visibility and presence of artefact scores of RS-EPI-DWI group were significantly different from those of the SS-EPI group. RS-EPI-DWI images had fewer artefacts and higher visibility scores. The sensitivity, specificity, negative/positive-predictive, and overall-agreement values of RS-EPI-DWI technique were 100%, 78%, 100%, 74%, and 87%; respectively. These values for SS-EPI-DWI technique were 91%, 60%, 88%, 67%, and 75%; respectively. Also, these values were higher on axial plane than coronal plane images for ADC measurements. Based on gold-standard test findings, agreement values were good ( = 0.74) for RS-EPI-DWI and moderate for SS-EP-DWI ( = 0.50) techniques (P < 0.001 for both). The RS-EPI-DWI technique allows a higher spatial-resolution and this technique is less susceptible to artefacts when compared with SS-EPI technique.

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Section: Introductionmentioning

confidence: 99%

Detection of cholesteatoma: High-resolution DWI using RS-EPI and parallel imaging at 3 tesla

Algın

Aydın

Özmen

et al. 2017

Journal of Neuroradiology

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“…Segmented EPI (MS-DWI) techniques have been investigated primarily in brain imaging [18,19], although applicability in other organs has been studied as well [20–22]. Recently, Thian et al [23] studied the feasibility and image quality of MS-DWI in the pelvis in a mixed cohort of male and female patients.…”

Section: Introductionmentioning

confidence: 99%

Segmented diffusion-weighted imaging of the prostate: Application to transperineal in-bore 3T MR image-guided targeted biopsy

Fedorov

Tuncalı

Panych

et al. 2016

Magnetic Resonance Imaging

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Objective-To evaluate the applicability of using single-shot and multi-shot segmented diffusion-weighted imaging (DWI) techniques to support biopsy target localization in a cohort of targeted MRI-guided prostate biopsy patients.Materials and Methods-Single-shot echo-planar diffusion-weighted imaging (SS-DWI) and multi-shot segmented (MS-DWI) were performed intra-procedurally on a 3 Tesla system in a total of 35 men, who underwent in-bore prostate biopsy inside the scanner bore. Comparisons between SS-DWI and MS-DWI were performed with (in 16 men) and without (in 19 men) parallel coil acceleration (iPAT) for SS-DWI. Overall image quality and artifacts were scored by a radiologist and scores were compared with the Wilcoxon Mann-Whitney rank test. Correlation between the presence of air and image quality scores was evaluated with Spearman statistics. To quantify distortion, the anteroposterior prostate dimension was measured in SS and MS b=0 diffusion-and T 2 -weighted images. Signal-to-noise ratio was estimated in a phantom experiment. Agreement and accuracy of targeting based on retrospective localization of restricted diffusion areas in DWI was evaluated with respect to the targets identified using multiparametric MRI (mpMRI).Results-Compared to SS-DWI without iPAT, the average image quality score in MS-DWI improved from 2.0 to 3.3 (p<0.005) and the artifact score improved from 2.3 to 1.4 (p<0.005). When iPAT was used in SS-DWI, the average image quality score in MS-DWI improved from 2.6 to 3.3 (p<0.05) and the artifact score improved from 2.1 to 1.4 (p<0.01). Image quality (ρ=−0.74, p<0.0005) and artifact scores (ρ=0.77, p<0.0005) both showed strong correlation with the presence of air in the rectum for the SS-DWI sequence without iPAT. These correlations remained Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript significant when iPAT was enabled (ρ=−0.52, p<0.05 and ρ=0.64, p<0.01). For the comparison MS-DWI vs SS-DWI without iPAT, median differences between diffusion-and T 2 -weighted image gland measurements were 1.1 (0.03-10.4) mm and 4.4 (0.5-22.7) mm, respectively. In the SS-DWI-iPAT cohort, median gland dimension differences were 2.7 (0.4-5.9) mm and 4.2 (0.7-8.9) mm, respectively. Out of the total of 89 targets identified in mpMRI, 20 had corresponding restricted diffusion areas in SS-DWI and 28 in MS-DWI. No statistically significant difference was observed between the distances for the targets in the target-concordant SS-and MS-DWI restricted diffusion areas (5.5 mm in SS-DWI...

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“…At the same time, a left/right mirror image is formed along the frequency-encoding direction, but each echo has a different phase encode on the phase-encoding direction by phase-encoded blips. 2,[15][16][17] Interference RF signals occurring at the same frequency range symmetrically fill in the two sides of the centre frequency and form multiple parallel symmetrical linear stippled or dashed bands in the phaseencoding direction. Our study suggested that the gaps of RF artefacts were mainly affected by different BWs, and our results supported that RF artefact could be gradually moved away from the centre of the image by decreasing the BW within a suitable range.…”

Section: Discussionmentioning

confidence: 99%

Radiofrequency artefacts in echoplanar imaging induced by two 1.5 T MR scanners in close proximity

Cui²,

Sp³

et al. 2014

BJR

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Objective: The purpose of this study was to assess radio frequency (RF) artefacts in echoplanar imaging (EPI) induced by two 1.5T MR scanners in close proximity and to find an effective method to correct them. Methods: Based on the intact shielding of rooms, experiments were performed by two MR scanners with similar centre frequencies. Phantom A (PA) was scanned in one scanner by EPI at different bandwidths (BWs). Simultaneously, phantom B was scanned in a fixed sequence for scanning with the other scanner. RF artefact gaps of PA, scanning time and the image signal-noise ratio (SNR) were measured and recorded. Statistical analysis was performed with the repeatedmeasures analysis of variance test. Based on findings obtained from PA, three healthy volunteers were studied at a conventional BW and a lower BW to observe the artefact variance. Results: EPI RF artefacts were symmetrically situated in both sides of the image following the phase-encoding direction. The gap size of the artefact became larger and the SNR was significantly improved with a narrower BW. RF artefacts with a lower BW in volunteers presented the same characteristic as PA. Conclusion: For EPI RF artefacts produced by two 1.5 T MR scannerswithapproximatelysimilarcentrefrequencies,wecan reduce BWs in a suitable range to minimize the effect on MRI. Advances in knowledge: MR scanners with the same field strength installed in the same vicinity might produce RF artefacts in the sequence at larger BWs. Reducing BWs properly is effective to control the position of artefacts and improve the image quality.Owing to the limited space and inappropriate planning, two 1.5 T MR scanners in our hospital were installed with their apertures facing each other at the same level. Subsequently, artefacts appeared in MR images when they were used at the same time. Artefacts that severely impaired the quality of MR images were a band or zipper of intensity perpendicular to the frequency-encoding direction. They frequently appeared in many conventional sequences, so that the scanning could not work. We and the engineers studied the characteristics of the artefacts and considered them radiofrequency (RF) artefacts. We tried our best to search for the interference source, but we could not be sure what instrument it came from. After recording and analysing artefacts, we found an apparent law. Only when two scanners were used at the same time did the RF artefacts appear in many sequences. After closing the RF coil of one scanner, RF artefacts disappeared from the images of the other. Therefore, we considered that these artefacts were produced from the interaction between two scanners. Two MR scanners have the same field strength of 1.5 T and a similar approximate centre frequency (Avanto 5 63.680982 MHz; Symphony 5 63.685914 MHz). The difference of the centre frequencies between both scanners is 4932 Hz. As soon as half of the sampling rate of the sequence is .4932 Hz, RF of the opposite scanner will be received and fill in the k-space corresponding to the frequency range whe...

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Clinical Application of Readout-Segmented− Echo-Planar Imaging for Diffusion-Weighted Imaging in Pediatric Brain

Cited by 67 publications

References 10 publications

Detection of cholesteatoma: High-resolution DWI using RS-EPI and parallel imaging at 3 tesla

Detection of cholesteatoma: High-resolution DWI using RS-EPI and parallel imaging at 3 tesla

Segmented diffusion-weighted imaging of the prostate: Application to transperineal in-bore 3T MR image-guided targeted biopsy

Radiofrequency artefacts in echoplanar imaging induced by two 1.5 T MR scanners in close proximity

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