MRI
Another imaging technique used for stroke patients is the magnetic resonance imaging or MRI scan. MRI uses magnetic fields to detect subtle changes in the content of brain tissue. One effect of stroke is the slowing of water movement, called diffusion, through the damaged brain tissue, and MRI can show this type of damage within the first hour after the stroke symptoms start.
The benefit of MRI over a CT scan is more accurate and earlier diagnosis of infarction, especially for smaller strokes. Also, MRI is more sensitive than CT for detecting other types of brain disease, such as brain tumor, that might mimic stroke. However, MRI cannot be performed in patients with certain types of metallic or electronic implants, such as pacemakers for the heart.
Although increasingly used in the emergency diagnosis of stroke, MRI is not immediately available at all hours in most hospitals, where CT is used for acute stroke diagnosis. Also, MRI takes longer to perform than CT, and may not be performed if it would significantly delay treatment.
Treatments
With stroke, treatment depends on the stage of the disease.
Medications
Medication or drug therapy is the most common treatment for stroke. The most popular kinds of drugs to prevent or treat stroke are antithrombotics -- which include antiplatelet agents and anticoagulants -- and thrombolytics.
In treating a stroke that has just occurred, every minute counts. Ischemic strokes -- the most common kind -- can be treated with thrombolytic drugs. These drugs halt the stroke by dissolving the blood clot that is blocking blood flow to the brain. But a person needs to be at the hospital as soon as possible after stroke symptoms start to be evaluated and receive treatment.
A thrombolytic drug known as t-PA can be effective if a person receives it intravenously within 3 hours after his or her stroke symptoms have started. Since thrombolytic drugs can increase bleeding,t-PA should be used only after the doctor is certain that the patient has suffered an ischemic and not a hemorrhagic stroke.
Antithrombotics prevent the formation of blood clots that can become stuck in an artery of the brain and cause strokes. Antiplatelet drugs prevent clotting by decreasing the activity of platelets, which are blood cells that help blood clot. By reducing the risk of blood clots, these drugs lower the risk of ischemic stroke.
In the case of stroke, doctors prescribe antiplatelet drugs mainly for prevention. The most widely known and used antiplatelet drug is aspirin. Other antiplatelet drugs include clopidogrel, ticlopidine, and dipyridamole.
Anticoagulants reduce the risk of stroke by reducing the clotting property of the blood. The most commonly used anticoagulants include warfarin, also known as Coumadin®, heparin, and enoxaparin, also known as Lovenox.
Neuroprotectants are medications that protect the brain from secondary injury caused by stroke. Although the Food and Drug Administration has not approved any neuroprotectants for use in stroke at this time, many are being tested in clinical trials.
There are several different types of neuroprotectants that show promise for future therapy, including glutamate antagonists, antioxidants, apoptosis inhibitors, and many others.