A biomarker-responsive T2ex MRI contrast agent

Iman Daryaei, Edward A. Randtke, Mark "Marty" Pagel

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Purpose: This study investigated a fundamentally new type of responsive MRI contrast agent for molecular imaging that alters T2 exchange (T2ex) properties after interacting with a molecular biomarker. Methods: The contrast agent Tm-DO3A-oAA was treated with nitric oxide (NO) and O2. The R1 and R2 relaxation rates of the reactant and product were measured with respect to concentration, temperature, and pH. Chemical exchange saturation transfer (CEST) spectra of the reactant and product were acquired using a 7 Tesla (T) MRI scanner and analyzed to estimate the chemical exchange rates and r2ex relaxivities. Results: The reaction of Tm-DO3A-oAA with NO and O2 caused a 6.4-fold increase in the r2 relaxivity of the agent, whereas r1 relaxivity remained unchanged, which demonstrated that Tm-DO3A-oAA is a responsive T2ex agent. The effects of pH and temperature on the r2 relaxivities of the reactant and product supported the conclusion that the product's benzimidazole ligand caused the agent to have a fast chemical exchange rate relative to the slow exchange rate of the reactant's ortho-aminoanilide ligand. Conclusions: T2ex MRI contrast agents are a new type of responsive agent that have good detection sensitivity and specificity for detecting a biomarker, which can serve as a new tool for molecular imaging.

Original languageEnglish (US)
JournalMagnetic Resonance in Medicine
DOIs
StateAccepted/In press - 2016

Fingerprint

Contrast Media
Molecular Imaging
Biomarkers
Nitric Oxide
Ligands
Temperature
Sensitivity and Specificity
benzimidazole

Keywords

  • Chemical exchange: molecular imaging
  • Nitric oxide
  • Responsive agent
  • T2ex MRI

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

A biomarker-responsive T2ex MRI contrast agent. / Daryaei, Iman; Randtke, Edward A.; Pagel, Mark "Marty".

In: Magnetic Resonance in Medicine, 2016.

Research output: Contribution to journalArticle

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