Objective:

To evaluate the relationship between onset-to-needle time and the occurrence of negative diffusion-weighted imaging (DWI) findings following intravenous tissue plasminogen activator (IV tPA) treatment 

Background:

Timely administration of intravenous tissue plasminogen activator (IV tPA) remains critical for optimal outcomes in acute ischemic stroke. A subset of treated patients, however, exhibit no diffusion-weighted imaging (DWI) abnormalities on follow-up MRI. The relationship between time-to-treatment and negative MRI findings is not well characterized in community hospital settings, where imaging resources and workflows may differ from tertiary centers.

Design/Methods:

This retrospective study included adult patients who received IV tPA for suspected acute ischemic stroke between January and December 2024 at a community hospital. Clinical and imaging data were extracted from the institutional stroke registry, including demographics, onset-to-needle time (ONT), MRI findings within 72 hours, discharge diagnosis, and early neurological improvement (ENI). Patients were categorized as MRI-positive or MRI-negative based on DWI results. Group comparisons were performed using standard statistical methods.

Results:

Among 46 tPA-treated patients (mean age 69.1 ± 11.4 years; 48% male), 12 (26%) had no visible infarction on follow-up MRI. Median ONT was significantly shorter in the MRI-negative cohort (42 minutes [IQR 36–49]) compared with the MRI-positive cohort (58 minutes [IQR 42–78]; p < 0.01). MRI-negative patients were more often discharged with a diagnosis of transient ischemic attack or stroke mimic. No symptomatic intracerebral hemorrhages occurred in this group. ENI at 24 hours was observed in 61.5% of MRI-negative versus 44.3% of MRI-positive patients (p = 0.08).

Conclusions:

Shorter treatment times were associated with an increased likelihood of negative MRI findings following IV tPA administration. These results suggest that ultra-early reperfusion may prevent irreversible infarction or reflect treatment of TIAs or stroke mimics. Findings underscore the importance of rapid thrombolysis decision-making and support maintaining aggressive treatment timelines in community hospital settings.