ADC value
Also written as: ADC — Apparent Diffusion Coefficient
A quantitative measurement from diffusion-weighted imaging that reflects tissue cellularity and membrane integrity.
Full Definition
The Apparent Diffusion Coefficient (ADC) value is a quantitative parameter derived from diffusion-weighted MRI sequences that measures the apparent mobility of water molecules within tissues. In oncologic radiology, ADC values help characterize tumor cellularity, differentiate benign from malignant lesions, and monitor treatment response. Lower ADC values typically indicate higher cellularity or restricted diffusion, often associated with malignancy, while higher values suggest less restricted diffusion. ADC measurements are particularly valuable in brain imaging, prostate cancer detection, and monitoring treatment response where cellular changes precede morphological changes visible on conventional imaging.
Usage
Usage note: Include units (×10⁻³ mm²/s) when reporting specific values; ADC maps are derived from DWI sequences.
In Context
- "The lesion demonstrated restricted diffusion with an ADC value of 0.65 × 10⁻³ mm²/s, suggesting malignancy." — Brain MRI report
- "Post-treatment ADC values increased, indicating successful tumor necrosis." — Treatment response assessment