Brief Answer:
Read below.

Detailed Answer:
I read your question carefully and I understand your concern.

There are several findings in that CT scan. The first, the basal ganglia calcification is the least worrying one. Calcium depositions in the area of the brain called basal ganglia are a common finding in many scans and are considered an incidental finding, doesn't usually cause any symptoms. Their cause in most cases is unknown, especially found with increasing of the age. They have formed over the years and are not related to the accident. Usually no further testing is required unless it is the case of a young individual where it would be suspicious and would warrant more investigations for the cause.

The extra- axial fluid collection, extra axial refers to the finding being outside of the brain matter. That doesn't necessarily mean it doesn't affect the brain, as being inside the skull it can compress the brain. Now as to the nature of that fluid I can't judge since you give no more info (I assume the report goes in some more detail). It can be a collection of blood, like a subdural hematoma, a common complication of head injury due to rupture of veins on the surface of the brain. If sizable can compress the brain and need surgery. On the other hand it might be a harmless cyst which was already present before the trauma.

The next finding is acute cortical infarction. An infarction, otherwise called ischemic stroke, is damage of a brain area due to the blockage of a brain vessel supplying blood to the area. As a result infarction happens, the brain cells of that area die. Symptoms depend on the area in question about which you do not give any detail (again I assume the report has more details), most common one is paralysis, weakness of the limbs on the side opposite to the infarction.

The cerebral edema, means swelling of the brain, it can happen as a result of the infarction or traumatic injury to other areas of the brain.

The midline shift happens when as a result of the mass effect of the infarction, edema and/or the fluid collection the involved brain hemisphere is displaced, pushed to the other side, so it shifts beyond the midline (an imaginary line dividing the brain in half).

I remain at your disposal for further questions, possibly with the full report (you can write it or scan and upload as a report) which I am sure contains more information.

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