Rapid high resolution T1 mapping as a marker of brain development: Normative ranges in key regions of interest

Eminian, Sylvain; Hajdu, Steven D.; Meuli, Reto; Maeder, Philippe; Hagmann, Patric

doi:10.1371/journal.pone.0198250

Cited by 36 publications

(28 citation statements)

References 47 publications

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“…Phase‐based T 2 maps were reconstructed as described in the theory section. T 1 of 915 ms was assumed (midpoint between the T 1 of white matter and the putamen at the age of 20) . The reference T 2 map was reconstructed using least square error fitting to a single‐exponential model.…”

Section: Methodsmentioning

confidence: 99%

Phase‐based T₂mapping with gradient echo imaging

Wang

Hernando

Reeder

2019

Magnetic Resonance in Med

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Purpose: Transverse relaxation time (T 2 ) mapping with MRI has a plethora of clinical and research applications. Current T 2 mapping techniques are based primarily on spin-echo (SE) relaxometry strategies that rely on the signal magnitude, and often suffer from lengthy acquisition times. In this work, we propose a phase-based T 2 mapping technique where T 2 information is encoded into the signal phase of rapid gradient echo (GRE) acquisitions. Theory: Bloch equation simulations demonstrate that the phase of GRE acquisitions obtained with a very small inter-repetition RF phase increment has a strong monotonic dependence on T 2 , resulting from coherent transverse magnetization. This T 2 -dependent phase behavior forms the basis of the proposed T 2 mapping technique.To isolate T 2 -dependent phase from background phase, at least 2 data sets with different RF phase increments are acquired. The proposed method can also be combined with chemical shift encoded MRI to separate water and fat signals. Methods: The feasibility of the proposed technique was validated in a phantom experiment. In vivo feasibility was demonstrated in the brain, knee, abdomen, and pelvis. Comparisons were made with SE-based T 2 mapping, spectroscopy, and T 2 values from the literature. Results:The proposed method produced accurate T 2 maps compared with SE-based T 2 mapping in the phantom. Good qualitative agreement was observed in vivo between the proposed method and the reference. T 2 measured in various anatomies agreed well with values reported in the literature. Conclusion: A phase-based T 2 mapping technique was developed and its feasibility demonstrated in phantoms and in vivo. K E Y W O R D S gradient echo, magnetic resonance imaging, phase, quantitative imaging biomarker, relaxometry, RF spoiling, T 2 mapping 610 | WANG et Al.How to cite this article: Wang X, Hernando D, Reeder SB. Phase-based T 2 mapping with gradient echo imaging. Magn Reson Med. 2020;84:609-619.

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Section: Methodsmentioning

confidence: 99%

Phase‐based T₂mapping with gradient echo imaging

Wang

Hernando

Reeder

2019

Magnetic Resonance in Med

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“…Moreover, a comparison with the present data is precluded because no direct T1 values have been reported. Eminian et al [18] measured T1 relaxation times of gray and white matter in 42 children ages 1-20 years using MP2RAGE. Four regions matched those in our study: the nucleus caudatus, putamen, thalamus and frontal white matter.…”

Section: Discussionmentioning

confidence: 99%

“…overlap with pathologies such as inflammation and edema [5]. On the other hand, and despite these limitations, a diagnostic benefit of quantitative T1 mapping of the brain has been convincingly demonstrated for a number of conditions, including hepatic encephalopathy [6], multiple sclerosis [7][8][9], sickle cell anemia [10], epilepsy [11], heavy metal deposition [12], neurofibromatosis [13], brain tumor follow-up [14,15], infantile brain development [16][17][18] and aging [19]. The continuing desire for a viable quantitative MR sequence is also reflected in the multitude of recent faster mapping approaches, such as the MP2RAGE sequence [20], synthetic MRI [21] and MR fingerprinting [22].…”

Section: Introductionmentioning

confidence: 99%

Quantitative T1 mapping of the normal brain from early infancy to adulthood

Gräfe¹,

Frahm

Merkenschlager

et al. 2020

Pediatr Radiol

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Background Quantitative mapping of MRI relaxation times is expected to uncover pathological processes in the brain more subtly than standard MRI techniques with weighted contrasts. So far, however, most mapping techniques suffer from a long measuring time, low spatial resolution or even sensitivity to magnetic field inhomogeneity. Objective To obtain T1 relaxation times of the normal brain from early infancy to adulthood using a novel technique for fast and accurate T1 mapping at high spatial resolution. Materials and methods We performed whole-brain T1 mapping within less than 3 min in 100 patients between 2 months and 18 years of age with normal brain at a field strength of 3 T. We analyzed T1 relaxation times in several gray-matter nuclei and white matter. Subsequently, we derived regression equations for mean value and confidence interval. Results T1 relaxation times of the pediatric brain rapidly decrease in all regions within the first 3 years of age, followed by a significantly weaker decrease until adulthood. These characteristics are more pronounced in white matter than in deep gray matter. Conclusion Regardless of age, quantitative T1 mapping of the pediatric brain is feasible in clinical practice. Normal age-dependent values should contribute to improved discrimination of subtle intracerebral alterations.

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“…The use of quantitative imaging such as T1 mapping in MRI could provide considerable understanding of changing normal and pathologic conditions. MRI has been used to evaluate the development of the human brain, and myelination plays a key role in brain maturation with microarchitectural changes [17]. The T1 relaxation time is affected by myelin, water and iron concentrations in brain tissue, so demyelination increases the T1 value and increased iron accumulation shortens the T1 value [18,19].…”

Section: Discussionmentioning

confidence: 99%