Related Experiment Video
Updated: May 30, 2026
06:54
MR Molecular Imaging of Prostate Cancer with a Small Molecular CLT1 Peptide Targeted Contrast Agent
Published on: September 3, 2013
A self-calibrating PARACEST MRI contrast agent that detects esterase enzyme activity
Yuguo Li1, Vipul R Sheth, Guanshu Liu
1Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85724-5024, USA.
Contrast Media & Molecular Imaging
|August 24, 2011
Summary
This study introduces a self-calibrating PARACEST MRI contrast agent for accurate biomarker detection. The ratiometric approach enhances specificity for esterase enzyme activity, overcoming limitations of single CEST effects.
Area of Science:
- Biomedical Imaging
- Chemical Biology
- Magnetic Resonance Imaging
Background:
- Chemical Exchange Saturation Transfer (CEST) MRI contrast agents' signals are affected by molecular biomarkers.
- Non-specific factors like other biomarkers or environmental conditions can alter CEST effects, limiting diagnostic accuracy.
- A dual-CEST approach using a ratiometric method can improve specificity by incorporating a control effect.
Purpose of the Study:
- To develop and evaluate a self-calibrating PARACEST MRI contrast agent with two distinct CEST effects.
- To assess the agent's ability to specifically detect esterase enzyme activity.
- To determine the agent's robustness against confounding factors like concentration, T(1) relaxation, temperature, and pH.
Main Methods:
- Development of a novel PARACEST MRI contrast agent with two CEST effects: one responsive to esterase activity and a control effect.
- Investigating the ratio of the two CEST effects to assess self-calibration properties.
- Evaluating the influence of concentration, T(1) relaxation, temperature, pH, and MR coalescence on the ratiometric signal.
Main Results:
- The developed agent exhibited a ratiometric signal independent of concentration and T(1) relaxation, indicating self-calibration for these factors.
- The ratiometric method showed temperature dependency and was influenced by MR coalescence at higher temperatures.
- The two CEST effects displayed different pH dependencies, indicating the agent was not self-calibrating for pH.
Conclusions:
- A self-calibrating PARACEST MRI contrast agent can enhance the accuracy of molecular biomarker detection, such as esterase enzyme activity.
- The ratiometric approach offers improved specificity but requires stable temperature and pH for reliable measurements.
- Further optimization is needed to address pH and temperature dependencies for broader in vivo applications.
Related Concept Videos
01:18Effects of EDTA on End-Point Detection Methods
Different methods, such as visual observance of metal-ion indicators, spectroscopic techniques, and potentiometric methods, can determine the endpoint of an EDTA titration.
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
01:33Enzyme-Linked Immunosorbent Assay
In 1971, Peter Perlman and Eva Engvall developed an Enzyme-linked immunosorbent assay (ELISA or EIA). ELISA differs from western blot in that the assays are conducted in microtiter plates or in vivo rather than on an absorbent membrane.
There are many different types of ELISAs, but they all involve an antibody molecule whose constant region binds an enzyme, leaving the variable region free to bind its specific antigen. Enzyme-substrate reaction allows the antigen to be visualized or quantified.
There are many different types of ELISAs, but they all involve an antibody molecule whose constant region binds an enzyme, leaving the variable region free to bind its specific antigen. Enzyme-substrate reaction allows the antigen to be visualized or quantified.
01:24Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI...