scholarly journals Feasibility of Magnetic Resonance Fingerprinting on Aging MRI Hardware

Tomography ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 10-21
Author(s):  
Brendan Lee Eck ◽  
Kecheng Liu ◽  
Wei-ching Lo ◽  
Yun Jiang ◽  
Vikas Gulani ◽  
...  
Keyword(s):  
White Matter ◽  
Magnetic Resonance ◽  
Coefficient Of Variation ◽  
Strong Correlation ◽  
Advanced Imaging ◽  
Partial Explanation ◽  
In Vivo Experiments ◽  
Percent Difference ◽  
Relevant Range

The purpose of this work is to evaluate the feasibility of performing magnetic resonance fingerprinting (MRF) on older and lower-performance MRI hardware as a means to bring advanced imaging to the aging MRI install base. Phantom and in vivo experiments were performed on a 1.5T Siemens Aera (installed 2015) and 1.5T Siemens Symphony (installed 2002). A 2D spiral MRF sequence for simultaneous T1/T2/M0 mapping was implemented on both scanners with different gradient trajectories to accommodate system specifications. In phantom, for T1/T2 values in a physiologically relevant range (T1: 195–1539 ms; T2: 20–267 ms), scanners had strong correlation (R2 > 0.999) with average absolute percent difference of 8.1% and 10.1%, respectively. Comparison of the two trajectories on the newer scanner showed differences of 2.6% (T1) and 10.9% (T2), suggesting a partial explanation of the observed inter-scanner bias. Inter-scanner agreement was better when the same trajectory was used, with differences of 6.0% (T1) and 4.0% (T2). Intra-scanner coefficient of variation (CV) of T1 and T2 estimates in phantom were <2.0% and in vivo were ≤3.5%. In vivo inter-scanner white matter CV was 4.8% (T1) and 5.1% (T2). White matter measurements on the aging scanner after two months were consistent, with differences of 1.9% (T1) and 3.9% (T2). In conclusion, MRF is feasible on an aging MRI scanner and required only changes to the gradient trajectory.

In vivo gradients of thalamic damage in paediatric multiple sclerosis: a window into pathology

Brain ◽  
2020 ◽  
Author(s):  
Ermelinda De Meo ◽  
Loredana Storelli ◽  
Lucia Moiola ◽  
Angelo Ghezzi ◽  
Pierangelo Veggiotti ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Mean Diffusivity ◽  
White Matter Lesions ◽  
Healthy Controls ◽  
Paediatric Multiple Sclerosis ◽  
Multiple Sclerosis Patients

Abstract The thalamus represents one of the first structures affected by neurodegenerative processes in multiple sclerosis. A greater thalamic volume reduction over time, on its CSF side, has been described in paediatric multiple sclerosis patients. However, its determinants and the underlying pathological changes, likely occurring before this phenomenon becomes measurable, have never been explored. Using a multiparametric magnetic resonance approach, we quantified, in vivo, the different processes that can involve the thalamus in terms of focal lesions, microstructural damage and atrophy in paediatric multiple sclerosis patients and their distribution according to the distance from CSF/thalamus interface and thalamus/white matter interface. In 70 paediatric multiple sclerosis patients and 26 age- and sex-matched healthy controls, we tested for differences in thalamic volume and quantitative MRI metrics—including fractional anisotropy, mean diffusivity and T1/T2-weighted ratio—in the whole thalamus and in thalamic white matter, globally and within concentric bands originating from CSF/thalamus interface. In paediatric multiple sclerosis patients, the relationship of thalamic abnormalities with cortical thickness and white matter lesions was also investigated. Compared to healthy controls, patients had significantly increased fractional anisotropy in whole thalamus (f2 = 0.145; P = 0.03), reduced fractional anisotropy (f2 = 0.219; P = 0.006) and increased mean diffusivity (f2 = 0.178; P = 0.009) in thalamic white matter and a trend towards a reduced thalamic volume (f2 = 0.027; P = 0.058). By segmenting the whole thalamus and thalamic white matter into concentric bands, in paediatric multiple sclerosis we detected significant fractional anisotropy abnormalities in bands nearest to CSF (f2 = 0.208; P = 0.002) and in those closest to white matter (f2 range = 0.183–0.369; P range = 0.010–0.046), while we found significant mean diffusivity (f2 range = 0.101–0.369; P range = 0.018–0.042) and T1/T2-weighted ratio (f2 = 0.773; P = 0.001) abnormalities in thalamic bands closest to CSF. The increase in fractional anisotropy and decrease in mean diffusivity detected at the CSF/thalamus interface correlated with cortical thickness reduction (r range = −0.27–0.34; P range = 0.004–0.028), whereas the increase in fractional anisotropy detected at the thalamus/white matter interface correlated with white matter lesion volumes (r range = 0.24–0.27; P range = 0.006–0.050). Globally, our results support the hypothesis of heterogeneous pathological processes, including retrograde degeneration from white matter lesions and CSF-mediated damage, leading to thalamic microstructural abnormalities, likely preceding macroscopic tissue loss. Assessing thalamic microstructural changes using a multiparametric magnetic resonance approach may represent a target to monitor the efficacy of neuroprotective strategies early in the disease course.

Contrast magnetic resonance imaging for measurement of cartilage glycosaminoglycan content in dogs: A pilot study

2013 ◽  
Vol 26 (02) ◽  
pp. 100-104 ◽  
Author(s):  
M. C. Stewart ◽  
L. Ciobanu ◽  
P. D. Constable ◽  
J. F. Naughton
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Coefficient Of Variation ◽  
Signal Intensity ◽  
Linear Regression Analysis ◽  
Resonance Imaging ◽  
Post Contrast ◽  
Enhanced Mri ◽  
Over Time

SummaryObjective: To assess the ability of a contrast-enhanced magnetic resonance imaging (MRI) technique to quantitatively determine glycosaminoglycan content in canine articular cartilage.Methods: Fifty-four full-thickness cartilage discs were collected from the femorotibial and scapulohumeral joints of three adult dogs immediately following euthanasia. One set of discs from each dog was analysed for glycosaminoglycan content using a colourimetric laboratory assay. The remaining position-matched set of discs from contralateral limbs underwent pre- and post-contrast gadolinium-enhanced MRI, using repeated saturation recovery pulse sequences which were used to generate calculated T1 maps of the cartilage discs. Linear regression analysis was then performed relating delayed gadolinium-enhanced MRI T1 calculated signal intensity to the cartilage glycosaminoglycan content normalized to DNA content. Repeatability of triplicate measurements was estimated by calculating the coefficient of variation.Results: Mean coefficient of variation estimates for the gadolinium-enhanced MRI T1 signal intensity values for nine sampling sites from three dogs ranged from 5.9% to 7.5%. Gadolinium-enhanced MRI T1 signal intensity was significantly correlated (p <0.05) with normalized glycosaminoglycan content in two dogs (r = 0.79, p = 0.011; r = 0.78, p = 0.048), but not in the third dog (r = 0.53, p = 0.071).Clinical significance: Gadolinium-enhanced MRI assessment of cartilage may be predictive of glycosaminoglycan content and therefore offer an in vivo assessment of changes in cartilage characteristics over time. Additional studies appear indicated to determine the reliability and clinical applicability of gadolinium-enhanced MRI in detecting changes in cartilage over time.

scholarly journals Magnetic resonance techniques for the in vivo assessment of multiple sclerosis pathology: Consensus report of the white matter study group

2005 ◽  
Vol 21 (6) ◽  
pp. 669-675 ◽  
Author(s):  
Massimo Filippi ◽  
Andrea Falini ◽  
Douglas L. Arnold ◽  
Franz Fazekas ◽  
Oded Gonen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Magnetic Resonance ◽  
Study Group ◽  
Consensus Report ◽  
In Vivo Assessment

In vivo Measurement of Water Self Diffusion in the Human Brain by Magnetic Resonance Imaging

1987 ◽  
Vol 28 (3) ◽  
pp. 353-361 ◽  
Author(s):  
C. Thomsen ◽  
O. Henriksen ◽  
P. Ring
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Tissue Characterization ◽  
Pulse Sequence ◽  
Benign Intracranial Hypertension ◽  
Resonance Imaging ◽  
Self Diffusion ◽  
Brain Water

A new pulse sequence for in vivo diffusion measurements by magnetic resonance imaging (MRI) is introduced. The pulse sequence was tested on phantoms to evaluate the accuracy, reproducibility and inplane variations. The sensitivity of the sequence was tested by measuring the self diffusion coefficient of water with different temperatures. This phantom study showed that the water self diffusion could be measured accurately and that the inplane deviation was less than ±10 per cent. Seven healthy volunteers were studied with a 10 mm thick slice through the lateral ventricles, clear differences between grey and white matter as well as regional differences within the white matter were seen. In two patients with infarction, alternations in water self diffusion were seen in the region of the infarct. Likewise, pronounced changes in brain water self diffusion were observed in a patient with benign intracranial hypertension. The results indicate that brain water self diffusion can be measured in vivo with reasonable accuracy. The clinical examples suggest that diffusion measurements may be clinically useful adding further information about in vivo MR tissue characterization.

scholarly journals Investigating Sexual Dimorphism of Human White Matter in a Harmonized, Multisite Diffusion Magnetic Resonance Imaging Study

2020 ◽  
Vol 31 (1) ◽  
pp. 201-212 ◽  
Author(s):  
Johanna Seitz ◽  
Suheyla Cetin-Karayumak ◽  
Amanda Lyall ◽  
Ofer Pasternak ◽  
Madhura Baxi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Sex Differences ◽  
White Matter ◽  
Magnetic Resonance ◽  
Imaging Study ◽  
Resonance Imaging ◽  
Sexual Hormones ◽  
Specific Effects ◽  
Weighted Magnetic Resonance Imaging

Abstract Axonal myelination and repair, critical processes for brain development, maturation, and aging, remain controlled by sexual hormones. Whether this influence is reflected in structural brain differences between sexes, and whether it can be quantified by neuroimaging, remains controversial. Diffusion-weighted magnetic resonance imaging (dMRI) is an in vivo method that can track myelination changes throughout the lifespan. We utilize a large, multisite sample of harmonized dMRI data (n = 551, age = 9–65 years, 46% females/54% males) to investigate the influence of sex on white matter (WM) structure. We model lifespan trajectories of WM using the most common dMRI measure fractional anisotropy (FA). Next, we examine the influence of both age and sex on FA variability. We estimate the overlap between male and female FA and test whether it is possible to label individual brains as male or female. Our results demonstrate regionally and spatially specific effects of sex. Sex differences are limited to limbic structures and young ages. Additionally, not only do sex differences diminish with age, but tracts within each subject become more similar to one another. Last, we show the high overlap in FA between sexes, which implies that determining sex based on WM remains open.

P1-198: White matter damage in posterior cortical atrophy assessed in vivo using diffusion tensor magnetic resonance imaging

2012 ◽  
Vol 8 (4S_Part_5) ◽  
pp. P176-P177
Author(s):  
Shiva Keihaninejad ◽  
Hui Zhang ◽  
Tim Shakespeare ◽  
Natalie Ryan ◽  
Ian Malone ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Cortical Atrophy ◽  
Resonance Imaging ◽  
Posterior Cortical Atrophy ◽  
White Matter Damage
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