Strokes may not be seen on a CT scan for several reasons. It can sometimes take several hours for the brain to appear abnormal after the onset of stroke. The affected region may also be a part of the brain that CT scans do not image well, such as the cerebellum or the brainstem.
CT scans are excellent at detecting the bleeding in the brain that occurs in hemorrhagic stroke. However, ischemic stroke may be difficult or impossible to see in CT images, especially during the first few hours after the stroke occurs, which is the period when treatment decisions are most important.
You will likely have a head CT scan or brain MRI. A stroke may show changes on these tests, but TIAs will not.
The scans were independently interpreted by four experts, who had no other patient information. Based only on the MRI scans, experts accurately diagnosed acute strokes 83 percent of the time. Using the CT scans, however, they were right just 26 percent of the time.
CT scans are excellent at detecting a hemorrhagic stroke, and most general hospitals use CT to detect the fresh bleed. The lack of a hemorrhage in the presence of stroke symptoms can rule out a hemorrhagic stroke and reveal a possible ischemic stroke instead.
Strokes may not be seen on a CT scan for several reasons. It can sometimes take several hours for the brain to appear abnormal after the onset of stroke. The affected region may also be a part of the brain that CT scans do not image well, such as the cerebellum or the brainstem.
One of the most common stroke mimics is a seizure, which researchers believe account for as many as 20% of all stroke mimics. Other common stroke mimics include migraines, syncope, sepsis, brain tumor and metabolic derangement (low sodium or low blood sugar).
Weakness, numbness or paralysis in the face, arm or leg, typically on one side of the body. Slurred or garbled speech or difficulty understanding others. Blindness in one or both eyes or double vision. Vertigo or loss of balance or coordination.
Some of the most common stroke mimics are seizures, migraine, fainting, serious infections and functional neurological disorder (FND). Once the person is diagnosed, they can have treatment or support to manage their symptoms.
Call 9-1-1 immediately if any of these signs of stroke appear: Numbness or weakness in the face, arm, or leg; Confusion or trouble speaking or understanding speech; Trouble seeing in one or both eyes; Trouble walking, dizziness, or problems with balance; severe headache with no known cause.
Brain MRI with DWI has the most sensitivity and specificity and is the best option to diagnose acute stroke.
Results of the study show standard MRI is superior to standard CT in detecting acute stroke and particularly acute ischemic stroke. The four readers were unanimous in their agreement on the presence or absence of acute stroke in 80 percent of patients using MRI compared to 58 percent using non-contrast CT.
Brain scans and tests
You should have a brain scan soon after symptoms start, within an hour of arriving at hospital if possible. The scan can show whether the stroke is due to a clot or a bleed. There are two main types of scan used: A computed tomography or CT scan.
Other possible symptoms
sudden vision loss, blurred vision or double vision. vertigo. being sick.
People who have mild strokes may feel like they've dodged a bullet since physical symptoms—blurred vision, difficulty speaking and weakness or numbness on one side of the body—usually disappear in a few minutes. Remember, if you notice any signs of a stroke in anyone young or old, seek immediate medical attention.
A person experiencing a TIA might feel sudden weakness or numbness on one side of the body, have slurred speech, have trouble seeing or talking, and feel confused. The person may experience a combination of these symptoms at the same time.
These brief episodes are transient ischemic attacks (TIA), sometimes called “mini-strokes.” They still should be taken seriously, because they tend to be signs of underlying serious conditions that can lead to a full stroke, even possibly in the few days following a TIA event if not evaluated and treated for a TIA.
What does that mean? A. A silent stroke refers to a stroke that doesn't cause any noticeable symptoms. Most strokes are caused by a clot that blocks a blood vessel in the brain. The blockage prevents blood and oxygen from reaching that area, causing nearby brain cells to die.
Pre-strokes or mini strokes are the common terms used to describe a transient ischemic attack (TIA). Unlike a full blown stroke, a TIA only lasts a few minutes and does not cause permanent damage. Nevertheless it is a warning sign that a possible stroke may be coming in the future.
Some people will experience symptoms such as headache, numbness or tingling several days before they have a serious stroke. One study found that 43% of stroke patients experienced mini-stroke symptoms up to a week before they had a major stroke.
A person's life expectancy after a mini stroke reduces by around 4% in the first year following the attack in comparison to people who have not had one. In the following 9 years, life expectancy reduces by 20%. These statistics come from a 2019 review .
In fact, ischemic strokes unfold over a period of 10 hours. That means that with every second you wait for treatment, the brain damage gets worse. If a stroke is untreated for the full 10 hours, the brain ages up to 36 years! With every minute you wait, the brain loses two million brain cells.
The CT scan is the gold standard for identifying a stroke and differentiating between an ischemic stroke and a hemorrhagic stroke (Mink & Miller, 2011).