diffusion-weighted imaging
An MRI technique measuring water molecule movement to differentiate tumor types and assess treatment response in brain tumors.
Full Definition
Diffusion-weighted imaging (DWI) is a specialized MRI technique that measures the random motion of water molecules (Brownian motion) within tissues. In neuro-oncology, DWI is particularly valuable for distinguishing between different types of brain lesions, monitoring treatment response, and detecting tumor recurrence. Areas of restricted diffusion appear bright on DWI sequences and correspond to regions of high cellularity, while areas of increased diffusion suggest cell death or necrosis. The apparent diffusion coefficient (ADC) provides quantitative measurements that help differentiate radiation necrosis from tumor recurrence, a critical distinction in post-treatment surveillance.
Usage
Usage note: Abbreviate as DWI after first mention; specify ADC values when quantitative analysis is performed.
In Context
- "Diffusion-weighted imaging showed restricted diffusion consistent with high-grade glioma." — radiology report
- "DWI sequences help distinguish tumor recurrence from treatment-related changes." — imaging protocol