perilesional edema
Fluid accumulation in brain tissue surrounding a lesion, appearing as increased signal on T2-weighted images.
Full Definition
Perilesional edema refers to the accumulation of fluid in brain tissue immediately adjacent to a pathological lesion. This edema appears as increased signal intensity on T2-weighted and FLAIR sequences and may demonstrate mass effect depending on severity. The extent of perilesional edema can provide diagnostic clues about the underlying pathology. Malignant lesions often produce more extensive edema relative to lesion size compared to benign processes. Vasogenic edema, which affects white matter preferentially, is the most common type seen around brain tumors, while cytotoxic edema may occur in inflammatory or infectious conditions.
Usage
Usage note: Describe the extent relative to lesion size for diagnostic context.
In Context
- "Extensive perilesional edema was noted surrounding the right frontal mass." — Brain tumor MRI
- "Minimal perilesional edema suggested a benign etiology for the lesion." — Radiological assessment