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Updated: Jun 26, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Investigation of relationships between transverse relaxation rate, diffusion coefficient, and labeled cell
Hemanthkumar Athiraman1, Quan Jiang, Guang Liang Ding
1Department of Neurology, Henry Ford Health System, Detroit, Michigan 48202, USA.
Abstract:
MRI has been used to evaluate labeled cell migration and distribution. However, quantitative determination of labeled cell concentration using MRI has not been systematically investigated. In the current study, we investigated the relationships between labeled cell concentration and MRI parameters of transverse relaxation rate, R(2), and apparent diffusion coefficient (ADC), in vitro in phantoms and in vivo in rats after stroke. Significant correlations were detected between iron concentration or labeled cell concentration and MRI measurements of R(2), ADC, and ADC x R(2) in vitro. In contrast, in vivo labeled cell concentration did not significantly correlate with R(2), ADC, and ADC x R(2). A major factor for the absence of a significant correlation between labeled cell concentration and MRI measurements in vivo may be attributed to background effects of ischemic tissue. By correcting the background effects caused by ischemic damage, DeltaR(2) (difference in R(2) values in the ischemic tissue with and without labeled cells) exhibited a significant correlation to labeled cell concentration. Our study suggests that MRI parameters have the potential to quantitatively determine labeled cell concentration in vivo.
Insights
Magnetic Resonance Imaging (MRI) can quantify cell concentration. Researchers found MRI parameters correlate with cell concentration in vitro, but not in vivo without background correction for stroke models.
Area of Science:
- Biomedical Imaging
- Cellular Biology
- Neuroscience
Background:
- Magnetic Resonance Imaging (MRI) is utilized for tracking labeled cells in vivo.
- Quantitative assessment of labeled cell concentration using MRI remains challenging.
- Understanding cell distribution is crucial for evaluating cell-based therapies.
Purpose of the Study:
- To investigate the relationship between labeled cell concentration and MRI parameters.
- To assess the feasibility of quantitative cell concentration determination using MRI in vitro and in vivo.
- To explore methods for overcoming challenges in in vivo MRI-based cell quantification.
Main Methods:
- Experiments were conducted using phantoms (in vitro) and rat stroke models (in vivo).
- MRI parameters including transverse relaxation rate (R(2)) and apparent diffusion coefficient (ADC) were measured.
- Correlations between labeled cell concentration and MRI parameters were analyzed, with and without background correction.
Main Results:
- In vitro, significant correlations were found between cell concentration and R(2), ADC, and ADC x R(2).
- In vivo, initial correlations between cell concentration and R(2), ADC, and ADC x R(2) were not significant.
- After correcting for ischemic tissue background effects, DeltaR(2) showed a significant correlation with in vivo cell concentration.
Conclusions:
- MRI parameters show potential for quantitative assessment of labeled cell concentration.
- Background effects from ischemic tissue impede accurate in vivo quantification.
- Correcting for background effects enables quantitative MRI-based cell concentration determination in vivo.
