Spin-lock Imaging of Exogenous Exchange-based Contrast Agents to Assess Tissue PH

Overview

Journal Magn Reson Med

Publisher Wiley

Specialty Radiology

Date 2017 Mar 22

PMID 28321903

Citations 11

Authors

Zhongliang Zu

Hua Li

Xiaoyu Jiang

John C Gore

Affiliations

Soon will be listed here.

Abstract

Purpose: Some X-ray contrast agents contain exchangeable protons that give rise to exchange-based effects on MRI, including chemical exchange saturation transfer (CEST). However, CEST has poor specificity to explicit exchange parameters. Spin-lock sequences at high field are also sensitive to chemical exchange. Here, we evaluate whether spin-locking techniques can detect the contrast agent iohexol in vivo after intravenous administration, and their potential for measuring changes in tissue pH.

Methods: Two metrics of contrast based on R , the spin lattice relaxation rate in the rotating frame, were derived from the behavior of R at different locking fields. Solutions containing iohexol at different concentrations and pH were used to evaluate the ability of the two metrics to quantify exchange effects. Images were also acquired from rat brains bearing tumors before and after intravenous injections of iohexol to evaluate the potential of spin-lock techniques for detecting the agent and pH variations.

Results: The two metrics were found to depend separately on either agent concentration or pH. Spin-lock imaging may therefore provide specific quantification of iohexol concentration and the iohexol-water exchange rate, which reports on pH.

Conclusions: Spin-lock techniques may be used to assess the dynamics of intravenous contrast agents and detect extracellular acidification. Magn Reson Med 79:298-305, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Citing Articles

Correction of errors in estimates of T at low spin-lock amplitudes in the presence of B and B inhomogeneities.

Zu Z, Adelnia F, Harkins K, Wang F, Ostenson J, Gore J NMR Biomed. 2023; :e4951.

PMID: 37070215 PMC: 10619883. DOI: 10.1002/nbm.4951.

Spin-lock imaging of intrinsic susceptibility gradients in tumors.

Zu Z, Janve V, Gore J Magn Reson Med. 2019; 83(5):1587-1595.

PMID: 31883149 PMC: 7558740. DOI: 10.1002/mrm.28155.

Probing chemical exchange using quantitative spin-lock R asymmetry imaging with adiabatic RF pulses.

Jiang B, Jin T, Blu T, Chen W Magn Reson Med. 2019; 82(5):1767-1781.

PMID: 31237001 PMC: 6993944. DOI: 10.1002/mrm.27868.

AcidoCEST-UTE MRI for the Assessment of Extracellular pH of Joint Tissues at 3 T.

Ma Y, High R, Tang Q, Wan L, Jerban S, Du J Invest Radiol. 2019; 54(9):565-571.

PMID: 31107700 PMC: 6675630. DOI: 10.1097/RLI.0000000000000576.

Evaluation of the sensitivity of Rρ MRI to pH and macromolecular density.

Ali S, Fessas P, Kaggie J, Zaccagna F, Houston G, Reid S Magn Reson Imaging. 2019; 58:156-161.

PMID: 30771445 PMC: 6422633. DOI: 10.1016/j.mri.2019.02.004.

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