A Rotational Cylindrical fMRI Phantom for Image Quality Control

Tovar, David A.; Zhan, Wang; Rajan, Sunder S.

doi:10.1371/journal.pone.0143172

Cited by 10 publications

(24 citation statements)

References 33 publications

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“…No shimming was performed in an attempt to mimic the variable B 0 environment of the in vivo situation. As has been previously proposed to quantify EPI distortions , the Jaccard self‐similarity index was computed to compare the spatial distribution of acquired proton and carbon images pre‐ and post‐correction. The Jaccard index represents the area of intersection over the area of union of two binary sets X i and X j , and is defined as

J_{i j} = \frac{| X_{i} \cap X_{j} |}{| X_{i} \cup X_{j} |}, J_{i j} \in [0, 1] .

…”

Section: Methodsmentioning

confidence: 99%

Susceptibility‐induced distortion correction in hyperpolarized echo planar imaging

Miller

Lau

Tyler

2017

Magnetic Resonance in Med

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PurposeEcho planar imaging is an attractive rapid imaging readout that can image hyperpolarized compounds in vivo. By alternating the sign of the phase encoding gradient waveform, spatial offsets arising from uncertain frequency shifts can be determined. We show here that blip‐reversed echo planar imaging can also be used to correct for susceptibility and B 0 inhomogeneity effects that would otherwise produce image‐domain distortion in the heart.MethodsPreviously acquired blip‐reversed cardiac 3D‐Spectral‐Spatial echo planar imaging volumetric timecourses of hyperpolarized [1‐13C]pyruvate were distortion corrected by a deformation field estimated by reconstructing signal‐to‐noise ratio (SNR)‐weighted progressively subsampled temporally summed images of each metabolite.ResultsReconstructing blip‐reversed data as proposed produced volumetric timecourses that overlaid with proton reference images more consistently than without such corrections.ConclusionThe method proposed may form an attractive method to correct for image‐domain distortions in hyperpolarized echo planar imaging experiments. Magn Reson Med 79:2135–2141, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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J_{i j} = \frac{| X_{i} \cap X_{j} |}{| X_{i} \cup X_{j} |}, J_{i j} \in [0, 1] .

…”

Section: Methodsmentioning

confidence: 99%

Susceptibility‐induced distortion correction in hyperpolarized echo planar imaging

Miller

Lau

Tyler

2017

Magnetic Resonance in Med

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“…The grey value in MRI, simply defined as poor image quality, is dependent on two factors: signal intensity and noise. 16 All images contain a level of background noise. Noise is always present and results from the electromagnetic noise caused by the movement of charged particles in the body, small anomalies in the measurement tools and other magnetic objects in the room.…”

Section: Introductionmentioning

confidence: 99%

“…Noise is always present and results from the electromagnetic noise caused by the movement of charged particles in the body, small anomalies in the measurement tools and other magnetic objects in the room. 16 Image quality depends on the homogeneity of the magnetic field and any metal introduced anywhere into the field distorts the static magnetic field, which may cause clip artefact (the enhancement and loss of signal). Even non-magnetic materials may cause artefacts by conducting current, which creates a new local magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Anaesthesia in the MRI suite

Swart

Rae

2018

Southern African Journal of Anaesthesia and Analgesia

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Anaesthesia in the magnetic resonance imaging (MRI) suite, or when performing surgery that requires MRI guidance, is becoming a more frequent and complex procedure for anaesthetists, as the study modality is increasing in application. MRI is not inert in its ability to do harm and may interfere with the anaesthetist's ability to assess the patient and intervene in the event of emergencies. Strong superconducting magnets can affect the physical environment and present unseen yet pertinent dangers, which may be avoided through awareness and vigilance. A culture of safety and collaboration in the radiology department, an area that is often remote from the usual milieu that anaesthetic providers are comfortable with, is essential to preventing serious injury or death to both patients and staff. It is therefore an important domain of knowledge and expertise for an anaesthetist. This article also describes some of the difficulties occasionally apparent only to the anaesthetic provider, which warrants anaesthetists' involvement in the planning and layout of MRI suites.

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“…change only accounts for a small fraction of the total signal (less than 5% for MRI systems with a magnetic field from 1.5 to 3 Tesla) (4,28), and extracting real BOLD signals from the total MR signal requires overcoming noise from various sources (28). To track the brain cognitive process, MR scanners need excellent temporal stability to acquire the BOLD signal over time (28).…”

mentioning

confidence: 99%

“…To track the brain cognitive process, MR scanners need excellent temporal stability to acquire the BOLD signal over time (28). Additionally, fMRI usually applies fast imaging sequences such as echo planar imaging (EPI), which require excellent time resolutions and temporal stability during fMRI (4)(5)(6)(7)(8)(9). EPI is sensitive to susceptibility effects (7).…”

mentioning

confidence: 99%

Quality assurance of human functional magnetic resonance imaging: a literature review

Dong

Cui

et al. 2019

Quant. Imaging Med. Surg

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Background Functional magnetic resonance imaging (fMRI) is one of the most popular methods to probe and understand the human brain, offering a noninvasive way for the in vivo investigation of brain function (1). fMRI accounts for the growth of neuroscience research with some 40,000 peerreviewed publications in the last two decades (2,3). The results of fMRI studies are largely determined by fMRI systems and informatics tools which process complex data generated from fMRI scan. fMRI quality assurance (QA) plays a critical role to guarantee high reliability of fMRI studies (4-11), since fMRI QA programs and methods can be used for calibrating fMRI scanner (10-13), testing the stability of fMRI system (14-17), assessing fMRI data quality (15,16,18-22) and evaluating informatics tools (4-9). Moreover, many QA-related metrics such as test-retest reliability and family-wise error rate (FWER) are applied to evaluate the reliability of fMRI studies (3,23,24). Many QA programs can test basic MRI system performances, such as resolution, signal contrast, geometric distortion, intensity uniformity, and ghosting artifacts (25-27). These programs are helpful but inadequate for fMRI study. The reasons are as follows: Scanner temporal stability The blood oxygenation level dependent (BOLD) signal

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A Rotational Cylindrical fMRI Phantom for Image Quality Control

Cited by 10 publications

References 33 publications

Susceptibility‐induced distortion correction in hyperpolarized echo planar imaging

Susceptibility‐induced distortion correction in hyperpolarized echo planar imaging

Anaesthesia in the MRI suite

Quality assurance of human functional magnetic resonance imaging: a literature review

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