In this MEDICA-tradefair.com interview, Prof. Götz Thomalla talks about the use of thrombolysis to treat acute stroke, explains how two different MRI sequences can effectively improve the treatment and reveals what this means for the guidelines in acute treatment.
Prof. Thomalla, what was the reason behind the WAKE-UP study?
Prof. Götz Thomalla: Patients who have had a stroke with unknown time of onset – patients who go to sleep and awaken with stroke symptoms for example – have so far been excluded from acute thrombolytic treatment for stroke, that being a treatment that opens blocked blood vessels to dissolve a blood clot. Currently, thrombolysis is still the only approved and recommended treatment within 4.5 hours of stroke onset since it becomes less effective if carried out after this time window and it involves a slight risk of bleeding.
In the study, we researched whether these patients can be effectively and safely treated using MRI scans to detect and diagnose recent stroke, even if the actual time of symptom onset is unknown. This would subsequently also render an effective treatment option for this group of patients. After all, this would affect one in five stroke patients and could prevent long-term neurological complications or impairments.
What types of MRI exams did you perform on the patients?
Thomalla: The first exam is the diffusion-weighted imaging technique or DWI. It safely and very accurately indicates a probable stroke within a few minutes after the onset of restricted blood flow, so that we were able to clearly show that the patient has had a stroke and identify the location of the disturbance.
The second exam involves the "fluid-attenuated inversion recovery" (FLAIR) MRI sequence, which indicates edema in tissue, the accumulation of water. This edema does not appear until several hours after stroke onset.
The mismatch between the two sequences – when we see a definitive stroke via DWI, but no distinct changes in the FLAIR sequence yet – tells us that the stroke onset was less than four or five hours ago. This means the patient is very likely still within the treatment window where he/she can benefit from thrombolysis.