Diagnosis

Imaging Techniques for TIAs. Several imaging techniques may identify small clots or other indicators of risk in the brain.

General Guidelines for Diagnosing a Major Stroke

Identifying a Stroke Quickly. To save a patient's life, a fast diagnosis of both the presence and type of stroke is critical. Health professionals have devised different tests to help emergency workers quickly identify a person with stroke even before they reach the hospital. For example, an assessment tool called the Face, Arm, Speech Test (FAST) is highly accurate. It involves watching for the following signs:

• Face: The face is not symmetrical. The mouth droops, and the patient is unable to show teeth when smiling.
• Arm: The patient is unable to lift an arm above shoulder level.
• Speech: The patient has trouble talking clearly and following simple instructions.

In one study, emergency workers who used this test accurately identified more people with stroke than either primary care or emergency room doctors.

Determining Ischemia Versus Hemorrhagic Stroke. Once a stroke has been identified, the next important step is to determine as quickly as possible whether it is hemorrhagic or ischemic. Clot-busting drug therapies can be life-saving for ischemic stroke patients, but they are effective only in the first 3 hours. In addition, they cause bleeding and can be lethal if the stroke is caused by a hemorrhage.

A computed tomography (CT) scan is essential for identifying or ruling out hemorrhagic strokes. The goal is to complete the CT examination and obtain and interpret the results within 45 minutes of arrival at the hospital. (An ultrasound technique called transcranial duplex sonography may be sensitive enough to differentiate between hemorrhagic and ischemic strokes if CT scans are not available.)

Certain factors suggest a hemorrhagic rather than ischemic stroke. They include specific symptoms (coma, vomiting, and severe headache), taking anticoagulants, very high systolic blood pressure, or high blood sugar levels in nondiabetics. However, such findings are not conclusive, and a CT scan or MRI is always needed.