apparent diffusion coefficient
Also written as: ADC — Apparent Diffusion Coefficient
Quantitative measure of water molecule diffusion calculated from diffusion-weighted imaging, helpful in characterizing tissue pathology.
Full Definition
The apparent diffusion coefficient (ADC) is a quantitative parameter derived from diffusion-weighted imaging that measures the magnitude of water molecule diffusion in tissue. ADC values are calculated using multiple b-values and provide important diagnostic information beyond visual assessment of DWI images. Low ADC values indicate restricted diffusion, seen in acute stroke, dense cellularity tumors, and abscesses. High ADC values suggest increased diffusion, typical of vasogenic edema, necrotic tissue, or cystic lesions. ADC mapping is essential for accurate interpretation of diffusion imaging and helps distinguish various pathological processes.
Usage
Usage note: Include quantitative ADC values when available to support diagnostic impressions.
In Context
- "The lesion showed low ADC values consistent with restricted diffusion and high cellularity." — Brain tumor characterization
- "Apparent diffusion coefficient mapping confirmed the diagnosis of acute infarction in the right corona radiata." — Stroke imaging report