What difference is there between a cva and a tia?

Persistence. Tia = transient cerebral ischemia, meaning temporary insufficient blood flow to a brain area resulting in altered function with symptoms. Cva= cerebrovascular "accident" meaning permanent loss of brain tissue. Loss of brain function can be restored in stroke due a process known as plasticity, meaning brain remodeling.
Duration of symptoms. A TIA is a transient event where the brain is deprived of adequate blood flow. The time course is less than one hour, and there are no permanant effects. Lay people use the term mini-stroke, but it is an inappropriate term. A cva is ususally not an accident. A cause is found in most cases. Stroke symptoms last greater than an hour and have residual deficits. Mri/ct imaging + in stroke, negative tia.