scholarly journals A combined analytical solution for chemical exchange saturation transfer and semi-solid magnetization transfer

2014 ◽  
Vol 28 (2) ◽  
pp. 217-230 ◽  
Author(s):  
Moritz Zaiss ◽  
Zhongliang Zu ◽  
Junzhong Xu ◽  
Patrick Schuenke ◽  
Daniel F. Gochberg ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Chemical Exchange ◽  
Magnetization Transfer ◽  
Chemical Exchange Saturation Transfer ◽  
Saturation Transfer ◽  
Semi Solid

Chemical exchange saturation transfer for detection of antiretroviral drugs in brain tissue

2021 ◽  
Author(s):  
Aditya N. Bade ◽  
Howard E. Gendelman ◽  
JoEllyn McMillan ◽  
Yutong Liu
Keyword(s):  
Chemical Exchange ◽  
Magnetization Transfer ◽  
Antiretroviral Drugs ◽  
Chemical Exchange Saturation Transfer ◽  
Magnetization Transfer Ratio ◽  
Saturation Transfer ◽  
Viral Reservoirs ◽  
Drug Concentrations ◽  
Imaging Results ◽  
Magnetic Resonance Imaging Mri

AbstractHuman immunodeficiency virus type-1 (HIV-1) antiretroviral drug (ARV) theranostics facilitates biodistribution and efficacy of therapies designed to target viral reservoirs. To this end, we have now deployed intrinsic drug chemical exchange saturation transfer (CEST) contrast to detect ARV distribution within the central nervous system (CNS).MethodsCEST effects for lamivudine (3TC) and emtricitabine (FTC) were measured by asymmetric magnetization transfer ratio analyses in solutions. CEST magnetic resonance imaging (MRI) was performed on 3TC-treated mice with analysis made by Lorentzian fitting.ResultsCEST effects of 3TC and FTC hydroxyl and amino protons linearly correlated to drug concentrations. 3TC was successfully detected in brain sub-regions by MRI. The imaging results were validated by measurements of CNS drug concentrations.ConclusionCEST contrasts can be used to detect ARVs using MRI. Such detection can be used to assess spatial-temporal drug biodistribution. This is most notable within the CNS where drug biodistribution may be more limited with the final goal of better understanding ARV-associated efficacy and potential toxicity.

scholarly journals Preliminary application of 3.0T magnetic resonance chemical exchange saturation transfer imaging in brain metastasis of lung cancer

2019 ◽  
Author(s):  
Yonggui Yang ◽  
Xiaobo QU ◽  
Yihui HUANG ◽  
Afsar Khan ◽  
Gen Yan ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Brain Metastases ◽  
Chemical Exchange ◽  
Magnetization Transfer ◽  
Metastatic Tumor ◽  
Chemical Exchange Saturation Transfer ◽  
Magnetization Transfer Ratio ◽  
Saturation Transfer ◽  
Tumor Group ◽  
Significant Difference

Abstract Background: Lung cancer brain metastases are very common and one of the common causes of treatment failure. We aimed to examine the clinical use of chemical exchange saturation transfer(CEST) technology in the evaluation of brain metastases for lung cancer diagnosis and prognosis. Methods: We included26 cases of lung cancer brain metastases, 15 cases of gliomas, and 20 cases with normal tests. The magnetization transfer ratio (MTR;3.5ppm) image from the GRE-EPI-CEST sequence was analyzed using the ASSET technique and APT technology. The MTR values were measured in the lesion-parenchymal, edema, and non-focus regions, and the MTR image was compared with the conventional MRI. ANOVA and t-test were used for statistical analysis. Results: The lesion-parenchymal, edema, and non-focus areas in the metastatic-tumor-group were red-yellow, yellow-green, and green-blue, and the MTR values were 3.29±1.14%,1.28±0.36%,and 1.26±0.31%, respectively. However, in the glioma-group, the corresponding areas were red, red-yellow, and green-blue, and the MTR values were 6.29±1.58%, 2.87±0.65%, and 1.03±0.30%, respectively. The MTR values of the corresponding areas in the normal-group were 1.07±0.22%,1.04±0.23%, and 1.06±0.24%, respectively. Traditional MR images are in black-white contrast and no metabolic information is displayed. The MTRvalues of the three regions were significantly different among the three groups. The values were also significantly different between the parenchymal and edema areas in the metastatic-tumor-group. There were significant differences in the MTR values between the non-lesion and edema regions, but there was no significant difference between the edema and non-focus areas. In the glioma-group, there were significant differences in the MTR values between the parenchymal and edema areas, between the parenchymal and non-focus areas, and between the edema and non-focus areas. Conclusions: CEST reflects the protein metabolism; therefore, early diagnosis of brain metastases and assessment of the prognosis can be achieved using molecular imaging.

scholarly journals Saturation transfer MRI is sensitive to neurochemical changes in the rat brain due to chronic unpredictable mild stress

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna Pankowska ◽  
Agata Chudzik ◽  
Tymoteusz Słowik ◽  
Artur Łazorczyk ◽  
Katarzyna Kochalska ◽  
...  
Keyword(s):  
Chemical Exchange ◽  
Nuclear Overhauser Effect ◽  
Magnetization Transfer ◽  
Brain Regions ◽  
Chemical Exchange Saturation Transfer ◽  
Magnetization Transfer Ratio ◽  
Mild Stress ◽  
Chronic Unpredictable Mild Stress ◽  
Saturation Transfer ◽  
Neurochemical Changes

AbstractChemical exchange saturation transfer (CEST) MRI was performed for the evaluation of cerebral metabolic changes in a rat model of depressive-like disease induced by chronic unpredictable mild stress (CUMS). CEST Z-spectra were acquired on a 7 T MRI with two saturation B1 amplitudes (0.5 and 0.75 µT) to measure the magnetization transfer ratio (MTR), CEST and relayed nuclear Overhauser effect (rNOE). Cerebral cortex and hippocampus were examined in two groups of animals: healthy control (n = 10) and stressed (n = 14), the latter of which was exposed to eight weeks of the CUMS protocol. The stressed group Z-spectrum parameters, primarily MTRs, were significantly lower than in controls, at all selected frequency offsets (3.5, 3.0, 2.0, − 3.2, − 3.6 ppm) in the cortex (the largest difference of ~ 3.5% at − 3.6 ppm, p = 0.0005) and the hippocampus (MTRs measured with a B1 = 0.5 µT). The hippocampal rNOE contributions decreased significantly in the stressed brains. Glutamate concentration (assessed using ELISA) and MTR at 3 ppm correlated positively in both brain regions. GABA concentration also correlated positively with CEST contributions in both cerebral areas, while such correlation with MTR was positive in hippocampus, and nonsignificant in cortex. Results indicate that CEST is sensitive to neurometabolic changes following chronic stress exposure.

scholarly journals Temporal Changes in In Vivo Glutamate Signal during Demyelination and Remyelination in the Corpus Callosum: A Glutamate-Weighted Chemical Exchange Saturation Transfer Imaging Study

2020 ◽  
Vol 21 (24) ◽  
pp. 9468
Author(s):  
Do-Wan Lee ◽  
Hwon Heo ◽  
Chul-Woong Woo ◽  
Dong-Cheol Woo ◽  
Jeong-Kon Kim ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Chemical Exchange ◽  
Magnetization Transfer ◽  
Imaging Study ◽  
Chemical Exchange Saturation Transfer ◽  
Cerebral White Matter ◽  
Magnetization Transfer Ratio ◽  
Saturation Transfer ◽  
Clinical Magnetic Resonance Imaging

Background: Glutamate-weighted chemical exchange saturation transfer (GluCEST) is a useful imaging tool that can be used to detect changes in glutamate levels in vivo and could also be helpful in the diagnosis of brain myelin changes. We investigated glutamate level changes in the cerebral white matter of a rat model of cuprizone-administered demyelination and remyelination using GluCEST. Method: We used a 7 T pre-clinical magnetic resonance imaging (MRI) system. The rats were divided into the normal control (CTRL), cuprizone-administered demyelination (CPZDM), and remyelination (CPZRM) groups. GluCEST data were analyzed using the conventional magnetization transfer ratio asymmetry in the corpus callosum. Immunohistochemistry and transmission electron microscopy analyses were also performed to investigate the myelinated axon changes in each group. Results: The quantified GluCEST signals differed significantly between the CPZDM and CTRL groups (−7.25 ± 1.42% vs. −2.84 ± 1.30%; p = 0.001). The increased GluCEST signals in the CPZDM group decreased after remyelination (−6.52 ± 1.95% in CPZRM) to levels that did not differ significantly from those in the CTRL group (p = 0.734). Conclusion: The apparent temporal signal changes in GluCEST imaging during demyelination and remyelination demonstrated the potential usefulness of GluCEST imaging as a tool to monitor the myelination process.

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