MRI Screening for Deficits of Patients With Minor Acute Ischemic Stroke

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A team of researchers sought to determine the IV tPA treatment rate of patients with minor acute ischemic stroke and compare the frequency of MRI targets by treatment stratification and clinical severity.

Researchers identified imaging targets by magnetic resonance image (MRI) screening among patients with minor acute ischemic stroke (mAIS) treated or untreated by intravenous tissue plasminogen activator (tPA), according to study results published in Neurology.

Patients (N=1989) who were evaluated by the National Institutes of Health (NIH) stroke team at MedStar Washington Hospital Center or Suburban Hospital between 2015 and 2017 were enrolled in this study. Study researchers stratified the patients to treated and untreated cohorts on the basis of MRI observations and diagnosis of ischemic stroke, then administered tPA within 4.5 hours for AIS.

They then assessed clinical outcomes through 90 days. A total of 21% (n=305) of patients were given tPA, and 46% (n=140) of treated patients had mAIS.

The patients who were treated and untreated differed by age (median, 68 vs 74; P =.008), perfusion-weighted imaging lesion (88% vs 53%; P <.001), gradient recalled echo thrombus (34% vs 10%; P <.001), fluid-attenuated inversion recovery (FLAIR)-positive lesion (16% vs 58%; P <.001), FLAIR hyperintense vessel sign (45% vs 20%; P <.001), preadmit modified Rankin Scale less than 2 (93% vs 77%; P =.001), perfusion- and diffusion-weighted imaging mismatch (62% vs 38%; P =.001), and identification of clearly disabling deficit at admission (25% vs 10%; P =.005), respectively.

Stratified by clearly disabling deficit, among all patients, those with a disabling deficit had higher NIH Stroke Scale score (median, 4 vs 2; P <.001) and anticoagulant use (10% vs 1%; P =.049).

Among only patients treated with tPA, those who had a clearly disabling deficit had higher NIH Stroke Scale score at 24 hours (median, 2 vs 1; P <.001), they stayed longer in the hospital (median, 5 vs 3 days; P =.001), and fewer were discharged home (53% vs 74%; P =.002), respectively.

The adverse events among the tPA cohort did not differ significantly on the basis of clearly disabling deficit.

This study was limited by the baseline difference among patients who were treated or not with tPA. Additional randomized trials are needed to assess its efficacy for the treatment of mAIS.

The study authors concluded MRI screening of patients with mAIS allowed for stratification of patients; however, it remains unclear whether intravenous tPA may be beneficial for patients with mAIS and no clearly disabling deficit.


Hsia AW, Luby ML, Leigh R, et al. Prevalence of imaging targets in patients with minor stroke selected for IV tPA treatment using MRI: the Treatment of Minor Stroke With MRI Evaluation Study (TIMES). Neurology. 2021;96(9):e1301-e1311. doi:10.1212/WNL.0000000000011527