Infarction

1-Infarction is due to cutting of blood supply going to an area of the brain.

2-Signs of infarction:

-Infarction leads to death of the area which appears hypo dense on CT.

-This area should within territory of a cerebral vessel.

-Now the infarction appears black and edema surrounding it is also black, so how you can know that this infarction is surrounded by edema or not.

-This can be solved by mass effect, because infarction by itself cannot make a mass effect on the ventricle as it is not a space occupying lesion, so infarction which has a mass effect is due to edema and not due to infarction itself.

-Infarction which is accompanied by mass effect is the acute infarction.

-Infarction which accompanied by dilated epsilateral ventricle is the chronic infarction.

-Infarction which accompanied by normal sized epsilateral ventricle if compared to the contralateral one is the sub acute infarction.

-Chronic infarction shows a hypo dense area including grey white matter with evidence of loss of volume due to gliosis causing negative mass effect on the epsilateral ventricle and sulci.

-The end of the chronic infarction is by forming porencephaly in which liquefaction of brain tissue ended by opening  of the infarcted area with the epsilateral ventricle forming what is known as porencephalic cyst.

-Infarction in evolution(within first 72 hours).

Infarction that does not yet developed.

Subtle hypo density with subtle mass effect.

-Now diffusion MRI is used to evaluate such a condition.