Hi, Ischemia - It is lack of blood to certain part of body. Ischemia is usually recoverable on its own or needs treatment. Previous ischaemic insult - There may be previous symptoms of mild stroke and recovery. It may be sudden loss in consciousness, paralysis or weak limbs, black outs, speech sluttering etc Large wedge shaped CSF density are - Usually blood vessels branches out, so when a blood vessel is blocked, it affects the area in wedge shape. CSF is cerebro spinal fluid. which gives boyuancy to brain (ie brain floats on it apart from many important functions). In case of injury CSF increases and cause ex-vacuo changes ( ie increase in empty space). So CSF increases ie bilateral periventricular white matter CSF density areas Whic also causes ex-vacuo changes. Importance of above changes are, it may compress brain tissue and produce symptoms. Here, the first line denotes it is a Old injury. identified now or causing symptoms now. Bye