brain tumor symptoms from my point of view

I look back now and can see all the classic brain tumor symptoms of my dad.
It is sad that we did not know what to look for earlier, other wise we may have done a little more about investigating his symptoms.

His symptoms were typical of brain tumors, but were attributed to getting older.
shaking hand
dragging the left leg
slight vision imparment
maths or problem solving ability affected
he also said an odd thing or two.

etc.
the thing was he had a CT scan at a check up and it showed no problems. we later found out that he should have had a contrasting CT scan, and should have had a different doctor. the one we had was not qualified to read contrasting CT scans.

Maybe if we had known all this prior we we have invested more time into finding things out. my mother suspected problems for over a year, but the checkup came back OK. now we know we should have pushed for an MRI or a contrasting CT scan.