Analysis Protocol for the Quantification of Renal pH Using Chemical Exchange Saturation Transfer (CEST) MRI

Hahnsung Kim; Yin Wu; Daisy Villano; Dario Livio Longo; Michael T McMahon; Phillip Zhe Sun

doi:10.1007/978-1-0716-0978-1_40

Analysis Protocol for the Quantification of Renal pH Using Chemical Exchange Saturation Transfer (CEST) MRI

Methods Mol Biol. 2021:2216:667-688. doi: 10.1007/978-1-0716-0978-1_40.

Authors

Hahnsung Kim^{1

2}, Yin Wu^{3

4}, Daisy Villano⁵, Dario Livio Longo⁶, Michael T McMahon^{7

8}, Phillip Zhe Sun^{9

10

11}

Affiliations

¹ Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA.
² Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA.
³ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.
⁴ Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China.
⁵ Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.
⁶ Institute of Biostructures and Bioimaging (IBB), Italian National Research Council (CNR), Torino, Italy.
⁷ F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
⁸ The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
⁹ Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA. pzhesun@emory.edu.
¹⁰ Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA. pzhesun@emory.edu.
¹¹ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA. pzhesun@emory.edu.

Abstract

The kidney plays a major role in maintaining body pH homeostasis. Renal pH, in particular, changes immediately following injuries such as intoxication and ischemia, making pH an early biomarker for kidney injury before the symptom onset and complementary to well-established laboratory tests. Because of this, it is imperative to develop minimally invasive renal pH imaging exams and test pH as a new diagnostic biomarker in animal models of kidney injury before clinical translation. Briefly, iodinated contrast agents approved by the US Food and Drug Administration (FDA) for computed tomography (CT) have demonstrated promise as novel chemical exchange saturation transfer (CEST) MRI agents for pH-sensitive imaging. The generalized ratiometric iopamidol CEST MRI analysis enables concentration-independent pH measurement, which simplifies in vivo renal pH mapping. This chapter describes quantitative CEST MRI analysis for preclinical renal pH mapping, and their application in rodents, including normal conditions and acute kidney injury.This publication 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 analysis protocol chapter is complemented by two separate chapters describing the basic concepts and experimental procedure.

Keywords: Chemical exchange saturation transfer (CEST); Contrast agents; Iopamidol; Kidney; Magnetic resonance imaging (MRI); Mice; Rats; pH; pH imaging.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Contrast Media / chemistry*
Hydrogen-Ion Concentration
Image Processing, Computer-Assisted / methods*
Kidney / physiology*
Magnetic Resonance Imaging / methods*
Monitoring, Physiologic / methods*
Phantoms, Imaging*
Software

Substances

Contrast Media