Diffusion MRI: apparent diffusion coefficient (ADC) values in the normal brain and a classification of brain...

Area of Science:

• Neuroimaging
• Radiology
• Biophysics

Background:

• Diffusion-weighted imaging (DWI) is sensitive to water molecule motion, reflecting tissue integrity.
• Apparent diffusion coefficient (ADC) values quantify this diffusion, offering insights into tissue microstructure.
• Understanding ADC variations is crucial for diagnosing brain pathologies.

Purpose of the Study:

• To establish a classification system for brain disorders and imaging artifacts based on ADC values.
• To correlate ADC values with different types of brain lesions and normal brain parenchyma.
• To provide a framework for interpreting diffusion MRI findings.

Main Methods:

• Echo-planar diffusion MRI was employed in 310 cases.
• ADC values were measured in normal brain white matter and various lesions.
• Brain disorders and artifacts were categorized into five groups based on their ADC values relative to normal white matter.

Main Results:

• Normal white matter ADC values ranged from 0.60-1.05x10(-3)mm(2)/s (mean 0.84+/-0.11x10(-3)mm(2)/s).
• A five-category system was developed: ADC similar to, lower than, higher than normal white matter, similar to CSF, or markedly low/high.
• This classification successfully grouped diverse brain disorders and artifacts.

Conclusions:

• ADC value-based categorization provides a systematic approach to interpreting diffusion MRI.
• This framework aids in differentiating various brain pathologies and artifacts.
• Further research can refine these categories and include additional lesion types.