scholarly journals Preclinical MRI of the Kidney

2021 ◽  
Keyword(s):  
Preclinical Mri

scholarly journals Quantitative blood flow measurement in rat brain with multiphase arterial spin labelling magnetic resonance imaging

2018 ◽  
Vol 39 (8) ◽  
pp. 1557-1569 ◽  
Author(s):  
James R Larkin ◽  
Manon A Simard ◽  
Alexandre A Khrapitchev ◽  
James A Meakin ◽  
Thomas W Okell ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Measurement ◽  
Arterial Spin Labelling ◽  
Sprague Dawley ◽  
Functional Studies ◽  
Non Invasive ◽  
Disease States ◽  
Preclinical Mri ◽  
Invasive Measurement ◽  
Spin Labelling

Cerebral blood flow is an important parameter in many diseases and functional studies that can be accurately measured in humans using arterial spin labelling (ASL) MRI. However, although rat models are frequently used for preclinical studies of both human disease and brain function, rat CBF measurements show poor consistency between studies. This lack of reproducibility is due, partly, to the smaller size and differing head geometry of rats compared to humans, as well as the differing analysis methodologies employed and higher field strengths used for preclinical MRI. To address these issues, we have implemented, optimised and validated a multiphase pseudo-continuous ASL technique, which overcomes many of the limitations of rat CBF measurement. Three rat strains (Wistar, Sprague Dawley and Berlin Druckrey IX) were used, and CBF values validated against gold-standard autoradiography measurements. Label positioning was found to be optimal at 45°, while post-label delay was optimised to 0.55 s. Whole brain CBF measures were 109 ± 22, 111 ± 18 and 100 ± 15 mL/100 g/min by multiphase pCASL, and 108 ± 12, 116 ± 14 and 122 ± 16 mL/100 g/min by autoradiography in Wistar, SD and BDIX cohorts, respectively. Tumour model analysis shows that the developed methods also apply in disease states. Thus, optimised multiphase pCASL provides robust, reproducible and non-invasive measurement of CBF in rats.

scholarly journals Preclinical MRI: Studies of the irradiated brain

2018 ◽  
Vol 292 ◽  
pp. 73-81 ◽  
Author(s):  
Joel R. Garbow ◽  
Christina I. Tsien ◽  
Scott C. Beeman
Keyword(s):  
Mri Studies ◽  
Preclinical Mri

scholarly journals Contribution of preclinical MRI to responsible animal research: living up to the 3R principle

2021 ◽  
Author(s):  
Lydia Wachsmuth ◽  
Armand Mensen ◽  
Cristina Barca ◽  
Marlene Wiart ◽  
Catarina Tristão-Pereira ◽  
...  
Keyword(s):  
Animal Research ◽  
Preclinical Mri

scholarly journals Soma and Neurite Density MRI (SANDI) of the in-vivo mouse brain

2021 ◽  
Author(s):  
Andrada Ianus ◽  
Joana Carvalho ◽  
Francisca F Fernandes ◽  
Renata Cruz ◽  
Cristina Chavarrias ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Rank Correlation ◽  
Brain Atlas ◽  
Tissue Microstructure ◽  
Cellular Density ◽  
Neurite Density ◽  
Models Of Development ◽  
Preclinical Mri ◽  
Diffusion Kurtosis

Diffusion MRI (dMRI) provides unique insights into the neural tissue milieu by probing interaction of diffusing molecules and tissue microstructure. Most dMRI techniques focus on white matter tissues (WM) due to the relatively simpler modelling of diffusion in the more organized tracts; however, interest is growing in gray matter characterisations. The Soma and Neurite Density MRI (SANDI) methodology harnesses a model incorporating water diffusion in spherical objects (assumed to be associated with cell bodies) and in impermeable 'sticks' (representing neurites), which potentially enables the characterisation of cellular and neurite densities. Recognising the importance of rodents in animal models of development, aging, plasticity, and disease, we here sought to develop SANDI for preclinical imaging and provide a validation of the methodology by comparing its metrics with the Allen mouse brain atlas. SANDI was implemented on a 9.4T scanner equipped with a cryogenic coil, and experiments were carried out on N=6 mice. Pixelwise, ROI-based, and atlas comparisons were performed, and results were also compared to more standard Diffusion Kurtosis MRI (DKI) metrics. We further investigated effects of different pre-processing pipelines, specifically the comparison of magnitude and real-valued data, as well as different acceleration factors. Our findings reveal excellent reproducibility of the SANDI parameters, including the sphere and stick fraction as well as sphere size. More strikingly, we find a very good rank correlation between SANDI-driven soma fraction and Allen brain atlas contrast (which represents the cellular density in the mouse brain). Although some DKI parameters (FA, MD) correlated with some SANDI parameters in some ROIs, they did not correlate nearly as well as SANDI parameters with the Allen atlas, suggesting a much more specific nature of the SANDI parameters. We conclude that SANDI is a viable preclinical MRI technique that can greatly contribute to research on brain tissue microstructure.

scholarly journals Preparation of Ex Vivo Rodent Phantoms for Developing, Testing, and Training MR Imaging of the Kidney and Other Organs

2021 ◽  
pp. 75-85
Author(s):  
Jason M. Millward ◽  
João S. Periquito ◽  
Paula Ramos Delgado ◽  
Christian Prinz ◽  
Thoralf Niendorf ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Ex Vivo ◽  
In Vivo Studies ◽  
The European Union ◽  
Target Organs ◽  
Preclinical Mri ◽  
Renal Mri ◽  
And Training

AbstractHere we describe a simple and inexpensive protocol for preparing ex vivo rodent phantoms for use in MR imaging studies. The experimental animals are perfused and fixed with formaldehyde, and then wrapped with gauze and sealed with liquid latex. This yields a phantom that preserves all organs in situ, and which avoids the need to keep fixed animals and organs in containers that have dimensions very different from living animals. This is especially important for loading in MR detectors, and specifically the RF coils, they are usually used with. The phantom can be safely stored and conveniently reused, and can provide MR scientists with a realistic phantom with which to establish protocols in preparation for preclinical in vivo studies—for renal, brain, and body imaging. The phantom also serves as an ideal teaching tool, for trainees learning how to perform preclinical MRI investigations of the kidney and other target organs, while avoiding the need for handling living animals, and reducing the total number of animals required.This protocol chapter is part of the PARENCHIMA initiative “MRI Biomarkers for CKD” (CA16103), a community-driven Action of the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers.

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