Analytical corrections of banding artifacts in driven equilibrium single pulse observation of T2 (DESPOT2)

Jutras, Jean‐David; Wachowicz, Keith; Zanche, Nicola De

doi:10.1002/mrm.26074

Cited by 5 publications

(2 citation statements)

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“…The in vivo T 2 values show a significant underestimation when compared with other studies . However, this was not the case for the phantom experiment; in fact, failing to apply the T RF correction (8) for the phantom data resulted in an overestimation of the obtained T 2 values by 15 to 20% compared with the ones displayed in Figure .…”

Section: Discussionmentioning

confidence: 58%

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T₁ and T₂ estimation

Teixeira

Malik

Hajnal

2017

Magnetic Resonance in Med

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PurposeThis study aims to increase the precision of single‐compartment DESPOT relaxometry by two means: (i) a joint system relaxometry (JSR) approach that estimates parameters in a single step using all available data; and (ii) optimizing acquisition parameters by deploying a robust design tool based on the Crámer‐Rao lower bound (CRLB).MethodsFollowing the development of the analysis and design capabilities, phantom and four in vivo subject experiments were performed to compare directly the precision achieved with DESPOT and JSR estimation using published protocols and protocols designed using a proposed CRLB framework.ResultsExperimental data demonstrate JSR's ability to decrease relaxometry estimation variance. Phantom results show 72 to 77% improvement using the same data as conventional DESPOT. This is further improved to 81 to 87% using optimal parameters. Both experiments show systematic bias depending on the acquisition parameters used, which are shown to be highly reproducible and to vary with different magnetization transfer conditions.ConclusionsCompared with DESPOT, JSR produces reproducible relaxation maps with improved precision. Further improvement was achieved using CRLB as a protocol design tool. With this combined approach, it is possible to achieve submillimeter maps of ρ,T1,T2, and B0 in an 11‐min examination, making the approach appealing for potential clinical use. Magn Reson Med 79:234–245, 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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Section: Discussionmentioning

confidence: 58%

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T₁ and T₂ estimation

Teixeira

Malik

Hajnal

2017

Magnetic Resonance in Med

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“… 111 , 112 Similar to the discrepancy among T1 measurement methods, T2 measurement methods are known to show disagreement with each other. 113 Jutras et al 114 reported that the WM T2 of 70 and 50 milliseconds was measured by MET2 and DESPOT2, respectively, in the same subject, partly due to the different weighting of each tissue component by these methods.…”

Section: Magnetic Resonance Imagingmentioning

confidence: 99%

Variability and Standardization of Quantitative Imaging

et al. 2020

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Radiological images have been assessed qualitatively in most clinical settings by the expert eyes of radiologists and other clinicians. On the other hand, quantification of radiological images has the potential to detect early disease that may be difficult to detect with human eyes, complement or replace biopsy, and provide clear differentiation of disease stage. Further, objective assessment by quantification is a prerequisite of personalized/precision medicine. This review article aims to summarize and discuss how the variability of quantitative values derived from radiological images are induced by a number of factors and how these variabilities are mitigated and standardization of the quantitative values are achieved. We discuss the variabilities of specific biomarkers derived from magnetic resonance imaging and computed tomography, and focus on diffusion-weighted imaging, relaxometry, lung density evaluation, and computer-aided computed tomography volumetry. We also review the sources of variability and current efforts of standardization of the rapidly evolving techniques, which include radiomics and artificial intelligence.

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Whole‐brain T₂ mapping with radial sampling and retrospective motion correction at 3T

Corbin,

Trotier,

Anandra

et al. 2024

Magnetic Resonance in Med

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PurposeSeveral barriers prevent the use of whole‐brain T2 mapping in routine use despite increasing interest in this parameter. One of the main barriers is the long scan time resulting in patient discomfort and motion corrupted data. To address this challenge, a method for accurate whole‐brain T2 mapping with a limited acquisition time and motion correction capabilities is investigated.MethodsA 3D radial multi‐echo spin‐echo sequence was implemented with optimized sampling trajectory enabling the estimation of intra‐scan motion, subsequently used to correct the raw data. Motion corrected echo images are then reconstructed with linear subspace constrained reconstruction. Experiments were carried out on phantom and volunteers at 3T to evaluate the accuracy of the T2 estimation, the sensitivity to lesions and the efficiency of the correction on motion corrupted data.ResultsWhole‐brain T2 mapping acquired in less than 7 min enabled the depiction of lesions in the white matter with longer T2. Data retrospectively corrupted with typical motion traces of pediatric patients highly benefited from the motion correction by reducing the error in T2 estimates within the lesions. All datasets acquired on seven volunteers, with deliberate motion, also showed that motion corrupted T2 maps could be improved with the retrospective motion correction both at the voxel level and the structure level.ConclusionA whole‐brain T2 mapping sequence with retrospective intra‐scan motion correction and reasonable acquisition time is proposed. The method necessitates advanced iterative reconstruction strategies but no additional navigator, external device, or increased scan time is required.

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Analytical corrections of banding artifacts in driven equilibrium single pulse observation of T2 (DESPOT2)

Cited by 5 publications

References 40 publications

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T₁ and T₂ estimation

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T₁ and T₂ estimation

Variability and Standardization of Quantitative Imaging

Whole‐brain T₂ mapping with radial sampling and retrospective motion correction at 3T

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Analytical corrections of banding artifacts in driven equilibrium single pulse observation of T2 (DESPOT2)

Cited by 5 publications

References 40 publications

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T1 and T2 estimation

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T1 and T2 estimation

Variability and Standardization of Quantitative Imaging

Whole‐brain T2 mapping with radial sampling and retrospective motion correction at 3T

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Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T₁ and T₂ estimation

Joint system relaxometry (JSR) and Crámer‐Rao lower bound optimization of sequence parameters: A framework for enhanced precision of DESPOT T₁ and T₂ estimation

Whole‐brain T₂ mapping with radial sampling and retrospective motion correction at 3T