To diagnose a stroke, it can involve some procedures and tests before your doctor and emergency team make a diagnosis. One of the common procedures is by using an imaging test called CT scan or also familiar known as CAT scan. This test can help doctors find the kind of stroke which is also very crucial in determining the most appropriate medication for best prognosis. But does a stroke always show up on CAT /CT scan?
Brain imaging test is often used to diagnose a stroke and determine what kind of stroke (whether it is ischemic or hemorrhage stroke). CT scan is one of popular choices of imaging test used to analyze the brain damage due to stroke.
Even it is often used for one of the first choices scheduled for a patient who has had stroke. In general, it is large device that uses a series of appropriate X-ray radiation to make a detailed picture of the brain.
With CT scan, doctor can analyze your brain’s anatomy through a series of thin slices of images that can show details of your brain.
Sometime the use of this test is also followed with the injection of contrast dye in order to provide more detailed pictures of your brain for clearly diagnosis.
The dye injection can help define tissues and blood vessels of the brain. The procedure of using CT scan with the injection of a contrast dye is medically called computerized tomography angiography.
In general, the working principle of CT scan is similar with how many regular X-rays work. The appropriate X-rays radiated by the device which then will be absorbed by the body.
The absorption can vary in each part of the body. Typically, water in the body absorbs little X-rays. Therefor it appears black on the image. On the other hand, the X-rays radiation is mostly absorbed by the bones. That’s why bones usually show up white.
How about with the brain? The brain usually appears grey on the image of test-result, because it has intermediate density in absorbing X-rays.
A part of the brain with hemorrhage usually appears white and denser than normal brain. And if there are ischemic strokes, they are usually darker and less dense than other parts of the brain.
Typically, the test can take about 20-60 minutes.
The device for CT-scan test is commonly available in emergency rooms. In general, this test is the standard procedure used to diagnose a stroke.
In many cases, the use of this test is helpful enough to show a brain damage due to stroke. But sometime due to certain reasons, stoke may not show up with this procedure.
It is also not effective to diagnose transient ischemic stroke (TIA) or often familiar called as an impending stroke. TIA usually doesn’t appear with CT or MRI scan test.
There are some reasons when this thing occurs. But many times, it usually occurs when the test is performed for the first several hours after you got a stroke attack.
Another reason is when the damage region in the brain is too small to get captured during CT-scan test. This is the reason for why TIA or mini-stroke usually doesn’t appear with this test, as noted before.
Furthermore, the location of damage also has an effect to the accuracy of test-result. For instance, when the damage occurs in small part of the brain (such as cerebellum or brain stem), it may not image well!
For these reasons, the diagnosis of stroke can involve numerous of different tests and procedures. Depending on the test-result, doctor can consider using additional testing for accurate diagnosis.
The test is not painful, instead it is painless. However, there are also few side effects that may occur. The radiation of X-rays during the test is safe because it uses very light x-ray radiation.
But if the test uses contrast dye, an allergic reaction may occur. Sometime the allergic reaction may become serious that requires appropriate treatment.
As mentioned before, the drawback of CT-scan is less accurate when the test is performed for the first several hours after the first stroke symptoms appear.