Radiology Services

Newspaper Column

Question: My uncle went to the emergency room last week. They thought he might have had a “stroke”, and took him to Radiology where they did some tests. What is a “stroke” and what kind of tests did they do in Radiology?

Answer: The symptoms of a “stroke” can vary widely, and therefore requires an initial clinical examination before any tests are ordered.

Sometimes, a temporary weakness of the body, a part of the body, or difficulty in speech may indicate abnormal circulation to the brain. If that weakness is temporary, it may be a sign of “transient ischemia” which means a temporary loss of normal circulation to the brain. That can be the result of spasm of a blood vessel that supplies a part of the brain, or can be the result of a tiny particle that is flaked off of a deposit lining an artery that supplies the brain. Since those kinds of episodes are temporary, some patients ignore them. This is a real mistake, since a (TIA) “transient ischemic attack” may be the warning sign of a possible stroke that is a more permanent brain injury, or what is called a (CVA) “cerebral vascular accident”.

Cerebral vascular accidents are damaging events involving circulation to brain tissue. They may occur because of bleeding from one of the blood vessels in the brain, or because of blockage of one of the brain’s blood vessels.

To investigate symptoms of injury to the brain, the first step will often be a CT scan. This test has the patient lie on a couch that is positioned with the head in a large doughnut shaped scanner. An x-ray tube revolves around the patient’s head, producing data signals on a receiver on the opposite side of the scan gantry. A high-powered computer processes thousands of bits and bytes to form diagnostic images that can tell whether there has been any bleeding or hemorrhage in the brain. The CT images are very sensitive to any recent bleeding, and the blood looks like a bright white space in the brain. While blood from a brain hemorrhage shows up immediately, blockage of a blood vessel in the brain often shows no immediate CT change.

Blockage is sometimes treated with drugs to dissolve a clot in a vessel, or to prevent the clot from enlarging. Before any anticoagulants or “blood thinners” are given we want to make sure there is no bleeding present on the CT scan. Sometimes we do follow-up scans to make sure there is no delayed bleeding in patients who receive blood thinners.

Ultrasound scans of the blood vessels in the neck may be another test for “stroke” victims. We may find the vessels are partially occluded, or even find complete blockage on one side of the neck. In those cases, the brain must receive circulation from arteries on the other side of the neck, or from vessels that go to the brain from the spine. If the ultrasound shows an abnormality, there are other scans we can do in CT or MRI to give more detail. If the blockage is only partial, there may be a surgical procedure required to restore more normal flow.

Magnetic Resonance Imaging, or MRI can show us the amount and location of damaged brain tissue from a blockage of circulation. Brain damage from a permanent blockage is called an “infarct”. These infarcts have a wide range in size and location, and the MRI helps to predict the amount of recovery or the amount of disability that may be expected after convalescence.

So you can see there are a number of Radiology tests using CT, MRI and Ultrasound that may have been used to determine whether his symptoms meant he had transient ischemia, hemorrhage or infarct.

In any event, it is wise to check with your doctor if you have any symptoms of weakness or numbness of a part of your body, any alteration of consciousness, any difficulty in thinking or speaking or sudden visual disturbances. Even if these symptoms go away, they may have been a signal that you need to undergo examinations that can save your life, or keep you from having permanent disability.

A final comment: Smoking not only causes heart attacks and cancer, it causes crippling strokes by blocking the blood vessels to and in your brain. Quitting now would be a good idea.