scholarly journals Evaluating pH in the Extracellular Tumor Microenvironment Using CEST MRI and Other Imaging Methods

2015 ◽  
Vol 2015 ◽  
pp. 1-25 ◽  
Author(s):  
Liu Qi Chen ◽  
Mark D. Pagel
Keyword(s):  
Tumor Microenvironment ◽  
Mr Spectroscopy ◽  
Chemical Exchange ◽  
Research Field ◽  
Chemical Exchange Saturation Transfer ◽  
Comprehensive Overview ◽  
Imaging Methods ◽  
Noninvasive Measurements ◽  
Cest Mri ◽  
Altered Metabolism

Tumor acidosis is a consequence of altered metabolism, which can lead to chemoresistance and can be a target of alkalinizing therapies. Noninvasive measurements of the extracellular pH (pHe) of the tumor microenvironment can improve diagnoses and treatment decisions. A variety of noninvasive imaging methods have been developed for measuring tumor pHe. This review provides a detailed description of the advantages and limitations of each method, providing many examples from previous research reports. A substantial emphasis is placed on methods that use MR spectroscopy and MR imaging, including recently developed methods that use chemical exchange saturation transfer MRI that combines some advantages of MR spectroscopy and imaging. Together, this review provides a comprehensive overview of methods for measuring tumor pHe, which may facilitate additional creative approaches in this research field.

scholarly journals A generalized ratiometric chemical exchange saturation transfer (CEST) MRI approach for mapping renal pH using iopamidol

2017 ◽  
Vol 79 (3) ◽  
pp. 1553-1558 ◽  
Author(s):  
Yin Wu ◽  
Iris Y. Zhou ◽  
Takahiro Igarashi ◽  
Dario L. Longo ◽  
Silvio Aime ◽  
...  
Keyword(s):  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Saturation Transfer ◽  
Cest Mri

scholarly journals Renal pH Imaging Using Chemical Exchange Saturation Transfer (CEST) MRI: Basic Concept

2021 ◽  
pp. 241-256
Author(s):  
Dario Livio Longo ◽  
Pietro Irrera ◽  
Lorena Consolino ◽  
Phillip Zhe Sun ◽  
Michael T. McMahon
Keyword(s):  
Chemical Exchange ◽  
Kidney Diseases ◽  
Chemical Exchange Saturation Transfer ◽  
Functional Information ◽  
Saturation Transfer ◽  
Ph Changes ◽  
Ph Imaging ◽  
Cest Mri ◽  
Magnetic Resonance Imaging Mri ◽  
Renal Mri

AbstractMagnetic Resonance Imaging (MRI) has been actively explored in the last several decades for assessing renal function by providing several physiological information, including glomerular filtration rate, renal plasma flow, tissue oxygenation and water diffusion. Within MRI, the developing field of chemical exchange saturation transfer (CEST) has potential to provide further functional information for diagnosing kidney diseases. Both endogenous produced molecules as well as exogenously administered CEST agents have been exploited for providing functional information related to kidney diseases in preclinical studies. In particular, CEST MRI has been exploited for assessing the acid-base homeostasis in the kidney and for monitoring pH changes in several disease models. This review summarizes several CEST MRI procedures for assessing kidney functionality and pH, for monitoring renal pH changes in different kidney injury models and for evaluating renal allograft rejection.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by 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. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.

scholarly journals 3D APT and NOE CEST-MRI of healthy volunteers and patients with non-enhancing glioma at 3 T

2022 ◽  
Author(s):  
Yulun Wu ◽  
Tobias Charles Wood ◽  
Fatemeh Arzanforoosh ◽  
Juan Antonio Hernandez-Tamames ◽  
Gareth John Barker ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Tumor Heterogeneity ◽  
Chemical Exchange ◽  
Magnetization Transfer ◽  
Chemical Exchange Saturation Transfer ◽  
Amide Proton ◽  
Magnetization Transfer Ratio ◽  
Normal Appearing White Matter ◽  
Saturation Power ◽  
Cest Mri

Abstract Objective Clinical application of chemical exchange saturation transfer (CEST) can be performed with investigation of amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) effects. Here, we investigated APT- and NOE-weighted imaging based on advanced CEST metrics to map tumor heterogeneity of non-enhancing glioma at 3 T. Materials and methods APT- and NOE-weighted maps based on Lorentzian difference (LD) and inverse magnetization transfer ratio (MTRREX) were acquired with a 3D snapshot CEST acquisition at 3 T. Saturation power was investigated first by varying B1 (0.5–2 µT) in 5 healthy volunteers then by applying B1 of 0.5 and 1.5 µT in 10 patients with non-enhancing glioma. Tissue contrast (TC) and contrast-to-noise ratios (CNR) were calculated between glioma and normal appearing white matter (NAWM) and grey matter, in APT- and NOE-weighted images. Volume percentages of the tumor showing hypo/hyperintensity (VPhypo/hyper,CEST) in APT/NOE-weighted images were calculated for each patient. Results LD APT resulting from using a B1 of 1.5 µT was found to provide significant positive TCtumor,NAWM and MTRREX NOE (B1 of 1.5 µT) provided significant negative TCtumor,NAWM in tissue differentiation. MTRREX-based NOE imaging under 1.5 µT provided significantly larger VPhypo,CEST than MTRREX APT under 1.5 µT. Conclusion This work showed that with a rapid CEST acquisition using a B1 saturation power of 1.5 µT and covering the whole tumor, analysis of both LD APT and MTRREX NOE allows for observing tumor heterogeneity, which will be beneficial in future studies using CEST-MRI to improve imaging diagnostics for non-enhancing glioma.

scholarly journals A method for accurate pH mapping with chemical exchange saturation transfer (CEST) MRI

2015 ◽  
Vol 11 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Phillip Zhe Sun ◽  
Gang Xiao ◽  
Iris Yuwen Zhou ◽  
Yingkun Guo ◽  
Renhua Wu
Keyword(s):  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Saturation Transfer ◽  
Cest Mri
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