What is an MRI for a stroke?
MRI (magnetic resonance imaging) is a diagnostic procedure that uses magnetic fields and radio waves to create an image. With MRI, even small strokes can be visualized very well and, above all, much earlier than with CT (computed tomography). This article explains why the CT examination is nevertheless the most important examination in cases of suspected stroke. As with any procedure, there are disadvantages, such as the high costs or the more difficult monitoring options for seriously ill patients. Get basic information about:
- How to diagnose a stroke
Why do I have an MRI if I have a stroke?
The most important imaging requirement in general for acute ischemic (reduced blood flow) stroke is the exclusion of cerebral hemorrhage. Furthermore, the images are used to assess the degree and spatial extent of the stroke and thus the brain damage. Thus, the chances of success of the therapy can be assessed. Imaging is also important to exclude so-called stroke mimics (other causes that cause stroke-like symptoms). These include, for example
- Subacute encephalitis
- A space requirement
- An acutely symptomatic liquor circulation disorder
When do I get an MRI for a stroke?
There are different indications for an MRI. In acute situations it is used when the time window is unclear. This is particularly the case with wake-up strokes, when symptoms are noticed on awakening and the exact time of the onset of symptoms remains unclear.
MRI is also used as a basis for revascularizing therapy (improvement of the blood flow to less well supplied tissues) if the onset of symptoms is >4.5 hours. In the course of the treatment, MRI is used to exclude other possible diagnoses (differential diagnoses), so-called stroke mimics. In addition, the infarction pattern can be displayed very well in this way. MRI provides additional benefits in the following aspects:
- Early visualization of lesions
- Assessment of the tissue at risk (penumbra: this is brain tissue that is functionally disrupted in a stroke due to lack of oxygen, but which can be saved from cell death by revascularizing therapy).
- High sensitivity even with small infarcts