MRI technique measuring tissue perfusion using susceptibility effects from gadolinium or BOLD contrast
Expansion
Perfusion-Weighted Imaging
Purpose
Assesses regional blood flow; used in acute stroke and brain tumour evaluation
Clinical Context
PWI can be gradient-echo (T2-star) or spin-echo (T2) based. Shows perfusion deficits (hypoperfusion) in stroke. PWI minus DWI mismatch defines ischaemic penumbra.
Related Terms
- Perfusion metrics
- Cerebral blood volume
Key Points
- PWI mismatch with DWI indicates penumbra (tissue at risk). Guides thrombolysis decisions