Dynamic visualization of brain pulsations using amplified MRI: methodology and applications.

Area of Science:

• Biomechanics
• Neuroimaging
• Physiology

Background:

• Brain pulsatility is crucial for understanding cerebral biomechanics, especially in mild traumatic brain injury (mTBI) and elevated intracranial pressure (ICP).
• Quantifying brain tissue motion dynamics can provide insights into neurological conditions.

Purpose of the Study:

• To quantify brain tissue pulsations using amplified MRI and analyze spatio-temporal motion dynamics with dynamic mode decomposition (DMD).
• To investigate changes in brain pulsatility across various physiological and pathological conditions, including heart rate changes, post-lumbar puncture, and post-brain injury.

Main Methods:

• Utilized amplified MRI to capture brain tissue pulsations.
• Applied dynamic mode decomposition (DMD) for spatio-temporal analysis of motion data.
• Examined four use cases: heart rate variations, pre- and post-lumbar puncture, baseline vs. post-brain injury, and test-retest.

Main Results:

• Brain tissue motion significantly varied across different conditions.
• DMD identified distinct modes and frequencies linked to physiological changes.
• Mild traumatic brain injury (mTBI) cases showed increased pulsatile motion post-injury.
• Elevated intracranial pressure (ICP) cases demonstrated altered pulsatility post-lumbar puncture, suggesting potential biomarker utility.

Conclusions:

• The dynamical analysis approach offers novel insights into physiological and pathological brain pulsatility.
• Altered brain pulsatility patterns may serve as biomarkers for mTBI and ICP.
• Larger cohorts are needed to validate findings, but the method shows promise for assessing intracranial dynamics in clinical diagnostics and research.