A comparison of iopromide and iopamidol, two acidoCEST MRI contrast media that measure tumor extracellular pH

Brianna F. Moon, Kyle M. Jones, Liu Qi Chen, Peilu Liu, Edward A. Randtke, Christine M. Howison, Mark "Marty" Pagel

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

Acidosis within tumor and kidney tissues has previously been quantitatively measured using a molecular imaging technique known as acidoCEST MRI. The previous studies used iopromide and iopamidol, two iodinated contrast agents that are approved for clinical CT diagnoses and have been repurposed for acidoCEST MRI studies. We aimed to compare the performance of the two agents for measuring pH by optimizing image acquisition conditions, correlating pH with a ratio of CEST effects from an agent, and evaluating the effects of concentration, endogenous T1 relaxation time and temperature on the pH-CEST ratio correlation for each agent. These results showed that the two agents had similar performance characteristics, although iopromide produced a pH measurement with a higher dynamic range while iopamidol produced a more precise pH measurement. We then compared the performance of the two agents to measure in vivo extracellular pH (pHe) within xenograft tumor models of Raji lymphoma and MCF-7 breast cancer. Our results showed that the pHe values measured with each agent were not significantly different. Also, iopromide consistently measured a greater region of the tumor relative to iopamidol in both tumor models. Therefore, an iodinated contrast agent for acidoCEST MRI should be selected based on the measurement properties needed for a specific biomedical study and the pharmacokinetic properties of a specific tumor model.

Original languageEnglish (US)
Pages (from-to)446-455
Number of pages10
JournalContrast Media and Molecular Imaging
Volume10
Issue number6
DOIs
StatePublished - Nov 1 2015

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Keywords

  • CEST MRI
  • Iopamidol
  • Iopromide
  • Tumor acidosis

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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