penumbral imaging
Advanced neuroimaging techniques used to identify potentially salvageable brain tissue surrounding an ischemic core in acute stroke.
Full Definition
Penumbral imaging refers to specialized neuroimaging protocols designed to identify and quantify the ischemic penumbra—brain tissue that is functionally impaired but structurally intact and potentially salvageable with timely reperfusion therapy. These imaging techniques typically combine diffusion-weighted imaging (DWI) to identify the irreversibly damaged core with perfusion imaging (CT perfusion or MR perfusion) to map areas of reduced blood flow. The mismatch between the perfusion deficit and the DWI lesion represents the penumbra. Modern penumbral imaging protocols may also incorporate arterial spin labeling, FLAIR imaging, and advanced perfusion metrics such as time-to-peak maps. In neurocritical care, penumbral imaging guides treatment decisions for acute stroke patients, particularly those presenting beyond traditional time windows, and helps predict clinical outcomes and hemorrhagic transformation risk.
Usage
Usage note: Specify imaging modality (CT or MR) and mismatch criteria when documenting penumbral assessment.
In Context
- "Penumbral imaging revealed a large perfusion-diffusion mismatch favoring thrombectomy." — Stroke team consultation
- "The patient underwent penumbral imaging to assess tissue viability before late-window intervention." — Neuroradiology protocol