Idiopathic - Cause unknown.

Infarct - An area of tissue that dies due to a loss of blood supply.

Infarction - The formation of an infarct. see Infarct

Insulin - A hormone, produced by some of the pancreatic glands, which regulates the glucose metabolism.

Intracranial - Within the skull.

Ischemia - Local and temporary deficiency of blood supply due to an obstruction. Ischemia of the heart is commonly caused by coronary artery disease.