Short-term mechanisms influencing volumetric brain dynamics

Area of Science:

• Neuroimaging
• Brain Anatomy
• Physiology

Background:

• Magnetic Resonance Imaging (MRI) allows precise measurement of brain volume changes (approx. 0.5%).
• Beyond long-term neurodegeneration, short-term physiological and pathological mechanisms influencing brain volume are recognized.
• Understanding short-term brain volume dynamics is vital for accurate interpretation of longitudinal studies, particularly in neurodegenerative diseases.

Purpose of the Study:

• To review potential short-term mechanisms affecting brain volume.
• To establish a framework of MRI techniques and analysis tools for assessing volumetric changes.
• To differentiate between physiological and pathological causes of short-term brain volume fluctuations.

Main Methods:

• Utilizing 3D T1-weighted MRI sequences for optimal brain volume assessment.
• Employing analysis tools to quantify the degree of brain volume change.
• Reviewing existing literature on factors influencing brain volume.

Main Results:

• Factors decreasing brain volume include fluid restriction, evening MRI scans, corticosteroids, antipsychotics, and acute effects of Alzheimer's disease, hypertension, and Diabetes Mellitus Type II.
• Factors increasing brain volume include fluid intake, morning MRI scans, surgical revascularization, and potentially anti-inflammatory and anti-hypertensive medications.
• Exercise showed no short-term effect on brain volume, suggesting exercise-induced dehydration differs from fluid restriction.

Conclusions:

• Short-term brain volume changes are influenced by various physiological and pathological factors.
• Further research into physiological short-term changes is needed to better understand long-term pathological processes.
• This understanding may improve early detection of neurodegenerative diseases.