The robustness of <scp>T</scp><sub>2</sub> value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI

Lee, Dong‐Kyu; Song, Y.; Park, Bumwoo; Cho, Hwapyeong; Yeom, Jin S.; Cho, Gyunggoo; Cho, HyungJoon

doi:10.1002/mrm.27202

Cited by 2 publications

(2 citation statements)

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“…Ex vivo MRI data was exported for offline analysis in Matlab (The Mathworks, Natick, MA). Quantitative T1 and T2 maps were obtained by voxel-wise linear least squared error fits of the imaging data to established mono-exponential models for magnetic relaxation ( 23 , 25 , 26 ). The resultant fits were visually inspected to ensure linearity of the data.…”

Section: Methodsmentioning

confidence: 99%

Multi-parametric MRI of kidney disease progression for autosomal recessive polycystic kidney disease: mouse model and initial patient results

et al. 2020

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Background: Autosomal recessive polycystic kidney disease (ARPKD) is a rare but potentially lethal genetic disorder typically characterized by diffuse renal microcysts. Clinical trials for patients with ARPKD are not currently possible due to the absence of sensitive measures of ARPKD kidney disease progression and/or therapeutic efficacy. Methods: In this study, animal and human MRI scanners were used to obtain quantitative kidney T1 and T2 relaxation time maps for both excised kidneys from bpk and wild type (WT) mice as well as for a pediatric patient with ARPKD and a healthy adult volunteer. Results: Mean kidney T1 and T2 relaxation times showed significant increases with age (p<0.05) as well as significant increases in comparison to WT mice (p<2 × 10 −10 ). Significant or nearly significant linear correlations were observed for mean kidney T1 (p=0.030) and T2 (p=0.054) as a function of total kidney volume, respectively. Initial MRF assessments in a patient with ARPKD showed visible increases in both kidney T1 and T2 in comparison to the healthy volunteer. Conclusions: These preclinical and initial clinical MRI studies suggest that renal T1 and T2 relaxometry may provide an additional outcome measure to assess cystic kidney disease progression in patients with ARPKD.

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Section: Methodsmentioning

confidence: 99%

Multi-parametric MRI of kidney disease progression for autosomal recessive polycystic kidney disease: mouse model and initial patient results

et al. 2020

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“…Monte Carlo simulation was performed to optimize the dose of SPION and examine the feasibility of vessel size-related VSI and microvessel density-related Q and MVD by comparing them with input vascular size and vascular density in experimental MRI parameters, similar to the methods used in a previous study 21 . The simulation was implemented via in-house MATLAB (MathWorks, Natick, MA) scripts, which are based on the finite perturber method (FPM) 33 and analogous to previously described procedures 19,34,35 . Randomly oriented cylinders were generated in a 3-dimensional binary matrix (400 × 400 × 400) to represent microvessels in a tissue.…”

Section: Methodsmentioning

confidence: 99%

MRI Visualization of Whole Brain Macro- and Microvascular Remodeling in a Rat Model of Ischemic Stroke: A Pilot Study

Kang

Jin

Lee

et al. 2020

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Using superparamagnetic iron oxide nanoparticles (Spion) as a single contrast agent, we investigated dual contrast cerebrovascular magnetic resonance imaging (MRi) for simultaneously monitoring macro-and microvasculature and their association with ischemic edema status (via apparent diffusion coefficient [ADC]) in transient middle cerebral artery occlusion (tMCAO) rat models. High-resolution t 1 -contrast based ultra-short echo time MR angiography (Ute-MRA) visualized size remodeling of pial arteries and veins whose mutual association with cortical ischemic edema status is rarely reported. ΔR 2 -ΔR 2 * -MRi-derived vessel size index (VSi) and density indices (Q and MVD) mapped morphological changes of microvessels occurring in subcortical ischemic edema lesions. In cortical ischemic edema lesions, significantly dilated pial veins (p = 0.0051) and thinned pial arteries (p = 0.0096) of ipsilateral brains compared to those of contralateral brains were observed from UTE-MRAs. In subcortical regions, ischemic edema lesions had a significantly decreased Q and MVD values (p < 0.001), as well as increased VSi values (p < 0.001) than normal subcortical tissues in contralateral brains. This pilot study suggests that MR-based morphological vessel changes, including but not limited to venous blood vessels, are directly related to corresponding tissue edema status in ischemic stroke rat models.www.nature.com/scientificreports www.nature.com/scientificreports/ On the other hand, the spatial changes of MR signals can be measured with the administration of a blood-pool contrast agent, enabling morphological mapping of the macro-and microvasculature. To obtain morphological information regarding the entire macrovasculature, high-resolution 3-dimensional T 1 -contrast-based ultra-short echo time (UTE) MRA can be used 18,19 . To obtain morphological information about the microvasculature, vessel size index (VSI) and microvessel density indices (Q and MVD) can be measured. VSI, Q, and MVD values obtained through alteration of transverse relaxation rates (ΔR 2 and ΔR 2 * ) due to the administration of contrast agent 20-23 can be used to map morphological microvascular alterations after ischemic stroke [24][25][26][27][28][29][30] . As arteriogenesis and angiogenesis are likely to correlate with recovery after ischemic stroke, the association between vessel morphology and corresponding tissue ischemic edema status (via apparent diffusion coefficient [ADC]) can be verified by simultaneous assessment of total macro-and microvascular remodeling in the ischemic brain.In this pilot study, we performed dual contrast MRI using superparamagnetic iron oxide nanoparticles (SPION) as a single contrast agent 18,19 . We used Monte Carlo simulation to optimize the dose of SPION by correlating ΔR 2 and ΔR 2 * values at various vessel sizes/volumes at 7-T. High-resolution (59 μm 3 ) 3-dimensional UTE-MRA was combined with ΔR 2 -ΔR 2 * -MRI derived VSI/Q/MVD maps on tMCAO rat models. Such dual contrast MRI acquisition enabled simultaneous morphologica...

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The robustness of T₂ value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI

Abstract: T measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high-resolution 3D micro-MRI is difficult to obtain.

Cited by 2 publications

References 41 publications

Multi-parametric MRI of kidney disease progression for autosomal recessive polycystic kidney disease: mouse model and initial patient results

Multi-parametric MRI of kidney disease progression for autosomal recessive polycystic kidney disease: mouse model and initial patient results

MRI Visualization of Whole Brain Macro- and Microvascular Remodeling in a Rat Model of Ischemic Stroke: A Pilot Study

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The robustness of T2 value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI

Abstract: T measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high-resolution 3D micro-MRI is difficult to obtain.

Cited by 2 publications

References 41 publications

Multi-parametric MRI of kidney disease progression for autosomal recessive polycystic kidney disease: mouse model and initial patient results

Multi-parametric MRI of kidney disease progression for autosomal recessive polycystic kidney disease: mouse model and initial patient results

MRI Visualization of Whole Brain Macro- and Microvascular Remodeling in a Rat Model of Ischemic Stroke: A Pilot Study

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The robustness of T₂ value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI