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Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI
Published on: July 12, 2012
Early detection of neurodegeneration in brain ischemia by manganese-enhanced MRI
Kevin C Chan1, Ke-xia Cai, Huan-xing Su
1Laboratory of Biomedical Imaging and Signal Processing and the Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, China. kevin_ccw@hkuusa.hku.hk
Abstract:
This study aims to employ in vivo manganese-enhanced MRI (MEMRI) to detect neurodegenerative changes in two models of brain ischemia, photothrombotic cortical injury (PCI) and transient middle cerebral artery occlusion (MCAO) in rodents. After systemic Mn(2+) injection to both ischemic models, a close pattern of T1-weighted hyperintensity was observed throughout different brain regions in comparison to the distribution of GFAP, MnSOD and GS immunoreactivities, whereby conventional MRI could hardly detect such. In addition, the infarct volumes in the posterior parts of the brain had significantly reduced after Mn(2+) injection to the MCAO model. It is suggested that exogenous Mn(2+) injection may provide enhanced MEMRI detection of oxidative stress and gliosis early after brain ischemia. Manganese may also mediate infarctions at remote brain regions in transient focal cerebral ischemia before delayed secondary damage takes place.
Insights
Manganese-enhanced MRI (MEMRI) detects early neurodegeneration after brain ischemia in rodents. This technique shows promise for identifying oxidative stress and gliosis, potentially revealing remote infarctions before secondary damage occurs.
Area of Science:
- Neuroimaging
- Neuroscience
- Biomedical Engineering
Background:
- Brain ischemia, including photothrombotic cortical injury (PCI) and transient middle cerebral artery occlusion (MCAO), leads to neurodegeneration.
- Conventional MRI often fails to detect subtle, early-stage neurodegenerative changes.
- Manganese-enhanced MRI (MEMRI) offers potential for enhanced sensitivity in detecting these changes.
Purpose of the Study:
- To evaluate the efficacy of in vivo manganese-enhanced MRI (MEMRI) for detecting neurodegenerative alterations in rodent models of brain ischemia (PCI and MCAO).
- To investigate the correlation between MEMRI signal and markers of oxidative stress and gliosis (GFAP, MnSOD, GS).
- To explore the potential of manganese (Mn(2+)) to modulate infarct volume in ischemic brain regions.
Main Methods:
- Systemic administration of Mn(2+) in rodent models of photothrombotic cortical injury (PCI) and transient middle cerebral artery occlusion (MCAO).
- Acquisition of T1-weighted images to assess signal hyperintensity.
- Comparison of MEMRI findings with GFAP, MnSOD, and GS immunoreactivities.
- Measurement of infarct volumes in the MCAO model following Mn(2+) injection.
Main Results:
- T1-weighted hyperintensity was observed in various brain regions following systemic Mn(2+) injection, correlating with GFAP, MnSOD, and GS immunoreactivities.
- MEMRI detected changes not readily apparent with conventional MRI.
- A significant reduction in posterior infarct volumes was observed in the MCAO model after Mn(2+) injection.
Conclusions:
- Exogenous Mn(2+) injection enhances MEMRI for early detection of oxidative stress and gliosis in brain ischemia.
- Manganese may play a role in mediating remote infarctions in transient focal cerebral ischemia prior to secondary damage.
- MEMRI represents a promising tool for early diagnosis and understanding of ischemic brain injury progression.
