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Updated: May 2, 2026
Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI
Published on: July 12, 2012
Dynamic MRI of rat brain following manganese administration through the internal carotid artery
Objective:
In this study, we investigated the dynamic distribution processes of Mn(2+) in rat brain using magnetic resonance imaging (MRI) after an intra-arterial (IA) injection of MnCl2 and following the breaking of the blood-brain barrier (BBB).
Methods:
Adult male Sprague-Dawley (SD) rats were employed in the study. After the rats were anesthetized with urethane, 25% mannitol was administrated into the right internal carotid artery (ICA) in order to disrupt the BBB, 50 mmol/l (10 mg/kg) of MnCl2 was then injected into ICA prior to the MRI assay. The MRI was performed at 7 T for a continuous 2 hours following the administration of MnCl2. Image reconstruction and analysis were performed using the Statistical Parametric Mapping (SPM) software.
Results:
As time progressed, the Mn(2+) enhanced signal intensity showed a gradual increase with a maximum increase at 10 minutes following MnCl2 administration, and began to decline after 10 minutes. From 30 minutes to 2 hours, the signal-enhanced region became more homogeneous, and the signal-enhanced range spread to the contralateral area up to 2 hours after MnCl2 administration.
Conclusion:
These results will help future research to select an appropriate time point to perform functional MRI for different types of activity-induced manganese (AIM) MRI research studies. These findings will allow researchers to discriminate intended, stimulation-specific enhanced signal from unintended, nonspecific enhanced signals.
Insights
This study tracked manganese (Mn2+) distribution in rat brains using MRI after breaking the blood-brain barrier (BBB). Findings reveal Mn2+ signal intensity peaks at 10 minutes and spreads contralaterally, aiding functional MRI research.
Area of Science:
- Neuroimaging
- Biomedical Engineering
- Pharmacokinetics
Background:
- The blood-brain barrier (BBB) restricts the passage of substances into the brain.
- Magnetic Resonance Imaging (MRI) is a powerful tool for visualizing brain structures and functions.
- Manganese (Mn2+) can serve as a contrast agent in MRI, but its dynamic distribution is complex.
Purpose of the Study:
- To investigate the dynamic distribution of Mn2+ in the rat brain following intra-arterial (IA) injection.
- To assess Mn2+ distribution after disrupting the blood-brain barrier (BBB).
- To establish optimal timing for functional MRI studies using Mn2+.
Main Methods:
- Intra-arterial (IA) injection of MnCl2 into Sprague-Dawley rats after BBB disruption with mannitol.
- High-field (7 Tesla) MRI scans acquired for 2 hours post-injection.
- Image analysis using Statistical Parametric Mapping (SPM) software to quantify signal changes.
Main Results:
- Mn2+ enhanced signal intensity increased, peaking around 10 minutes post-injection.
- Signal intensity began to decline after 10 minutes.
- The enhanced signal spread to the contralateral hemisphere and became more homogeneous between 30 minutes and 2 hours.
Conclusions:
- The study provides crucial temporal data on Mn2+ distribution in the brain.
- Findings aid in selecting appropriate time points for activity-induced manganese (AIM) MRI studies.
- This research helps differentiate specific, stimulation-induced signals from non-specific Mn2+ enhancement.
