Brain Imaging Modality before Systemic Thrombolysis for Ischemic Stroke within Three Hours

Abstract

Objective: In Japan, MRI-based thrombolysis after CT screening is the most common imaging strategy prior to intravenous thrombolysis (IVT) with tissue plasminogen activator (tPA) within 3 h after ischemic stroke. A choice of MRI with MR angiography (MRA) provides a higher diagnostic accuracy, but may delay an initiation of thrombolysis. Methods: In our neuro-unit, brain CT is the first screening image for suspected stroke. We retrospectively examined a delay to thrombolysis, imaging modality, diagnostic accuracy, and clinical outcomes at 3 months by the modified Rankin Scale in patients receiving IVT within 3 h. Results: Among 67 patients receiving IVT with tPA, brain imaging prior to IVT was solely CT in 10 (15%) patients and CT + MRI/MRA in 57 (85%) patients. Final diagnosis of brain ischemia was 100%. Patients receiving CT + MRI had significantly shorter pre-hospital delay (mean 54 vs. 83 min; p = 0.012), but longer door-to-needle time (mean 90 vs. 57 min; p = 0.019) than those receiving CT only. Finally, time from onset to thrombolysis was not different between the two groups and clinical outcomes were also comparable. The earlier patients arrived, the longer door-to-needle times were (p < 0.001). Conclusions: The imaging strategy of initial CT screening with optional MRI/MRA scans prior to IVT was feasible. However, it resulted in an additional 30 min in-hospital delay of tPA administration, which may affect clinical outcomes.