Time is a primary factor in the treatment of acute strokes with thrombolysis. Therefore the so-called Door-Needle-Time for the patients is of great importance. A recent study carried out at Bispebjerg Hospital by PhD student Christine Krarup Hansen, compares the Door-Needle-Time for acute stroke patients examined with MRI and CT scanning respectively. The aim of this study was to compare Door-Needle-Times and perform a simulated prediction of the difference in long-term outcome between CT and MRI-examined acute stroke-patients.
No previous randomized trial has compared thrombolytic treatment-delay for CT versus MRI-examined acute stroke patients. The trial may contribute to making a more informed choice between CT and MRI as primary image modality prior to thrombolytic treatment; so far this has been at the discretion of local institutional preferences and not supported by scientific evidence.
The trial setup
The trial was based on four hundred and fourtyfour patients and was conducted in a well-established stroke-unit with 300 annual thrombolytic treatments. Consecutive acute stroke-patients admitted to an acute stroke-unit were quasi-randomized (dates) to CT or MRI-based assessment and received thrombolytic treatments, if eligible. Door-Decision-Time and DNT for CT versus MRI-examined patients were compared and predictors of treatment-delay identified.
CT is faster
The study showed that CT-based assessment prior to administration of intravenous thrombolysis in acute stroke patients is significantly faster compared with MRI-based assessment (CT 22 min. and MRI 30 min.). CT-based DNT are significantly shorter than MRI-based DNT and potentially translates into time-related superior long-term outcome. However, the clinical impact is not detectable.
Fast-track-setup saves time
This trial demonstrates that a well-organized fast-track setup combined with a dedicated stroke-team with standardized routines for admission, examination, imaging and thrombolysis administration secures the shortest possible Door-Needle-Time and overrules individual patient-related variations that potentially cause treatment-delays. The study further shows that MRI is a potential option in the acute stroke-setting— though significantly slower than CT. The study does not allow for assessment of the potential additional and clinically useful image-information gain when patients have MR.