Functional cerebral imaging by susceptibility-contrast NMR.

Area of Science:

• Neuroimaging
• Biophysics
• Cardiovascular Physiology

Background:

• Cerebral physiology assessment is crucial for understanding brain function and disease.
• Dynamic contrast-enhanced (DCE) Magnetic Resonance Imaging (MRI) is a powerful tool for in vivo tissue characterization.
• Quantifying microvascular changes in the brain non-invasively remains a challenge.

Purpose of the Study:

• To demonstrate the in vivo measurement of cerebral physiology using dynamic contrast-enhanced Nuclear Magnetic Resonance (NMR).
• To establish a novel method for assessing brain blood volume based on magnetic susceptibility changes.
• To investigate the differential response of gray and white matter to microvascular stimuli.

Main Methods:

• Acquisition of time-resolved images of paramagnetic contrast agent transit in the brain.
• Utilized an ultrafast NMR imaging technique for rapid data acquisition.
• Employed a novel image contrast mechanism based on microscopic changes in tissue magnetic susceptibility.
• Induced global hypercapnia in dogs to create a controlled microvascular stimulus.

Main Results:

• Established a relationship between susceptibility-induced signal change and brain blood volume.
• Successfully measured the response of both gray and white matter to the induced hypercapnia.
• Demonstrated the feasibility of dynamic contrast-enhanced NMR for in vivo cerebral physiology assessment.

Conclusions:

• Dynamic contrast-enhanced NMR imaging provides a viable method for in vivo cerebral physiology measurement.
• The novel susceptibility-based contrast mechanism allows for quantitative assessment of brain blood volume.
• This technique offers insights into the microvascular behavior of different brain tissues.