Benign oligemia

Benign oligemia occurs when the brain's ability to autoregulate cerebral blood flow (CBF) by vasodilation is exceeded and cerebral blood flow begins to reduce. If this reduction is left unchecked, eventually neurological dysfunction and eventual infarction will occur.

There is, however, a window wherein brain tissue continues to function normally and can remain mildly hypoperfused indefinitely without progressing to infarction; this is termed benign oligemia.

Distinugishing between benign oligemia and ischemic penumbra is not trivial and is important is the true "at risk" penumbra volume is to be accurately characterized . Both overestimating and underestimating the region that represents benign oligemia is problematic as patients may be under or over treated.