Introduction:
In acute ischemic stroke (AIS), intravenous tissue plasminogen activator (IV TPA), if administered appropriately can be beneficial; however, with stroke misdiagnosis, it can expose patients to unnecessary bleeding risks. Thus, accurate diagnosis is critical. Brain Magnetic Resonance Imaging (MRI) is sensitive to detect AIS; however, a complete exam may consume 30-45 minutes. At the University of South Carolina Palmetto Health Richland Stroke Center, an ultra-rapid, 10 minute MRI called the Brain Attack Team MRI (BAT MRI) was designed to accurately and expeditiously diagnose AIS. Hypothesis: BAT MRI is a useful clinical tool to select or exclude patients for IV TPA who present acutely with stroke-like symptoms. Clinical correlates are not an effective substitution for BAT MRI to confirm AIS.
Methods:
In an ongoing study, conducted in 2010-11, 31 consecutive patients were identified who presented <4.5 hours from symptom onset and received a BAT MRI. They were 43-90 years in age; 48.4% White, 48.4% African American, and 3.2% unknown. BAT MRIs included diffusion weighted imaging, T2 gradient echo, T2 axial, and FLAIR sequences. The algorithm for BAT MRI use is shown in Figure 1. BAT MRIs were evaluated for ischemia, hemorrhage and other central nervous system (CNS) pathologies. Stroke risk factor correlates of abnormal BAT MRIs were assessed using t-test for continuous variables and Fisher's Exact Test for categorical variables.
Results:
Of the 31 BAT MRIs, 13 were read as abnormal (11-acute ischemia, 1-hemorrhage, 1-ischemia with hemorrhage). The hemorrhage was in the pons on BAT MRI and was not detected by CT. This finding excluded using IV TPA in this patient. Two cases where BAT MRI demonstrated AIS met NINDS/ECASS-III criteria and received IV TPA. Of the 18, in whom BAT MRI was read as normal, 9 had a discharge diagnosis of TIA, 2 MRI negative strokes, 3 conversion disorders, 1 CNS neoplasm, 1 respiratory failure and 1 peripheral vertigo. Stroke risk factor analysis yielded no significant correlation between BAT MRI findings and gender, race, prior stroke/TIA, coronary artery disease, diabetes, hyperlipidemia, hypertension, or smoking. Patients with AIS on BAT MRI were older (68.2 ± 17.5) than those without (58.6 ± 9.7); although, it bordered statistical significance (p=0.08). Atrial fibrillation correlated with AIS on BAT MRI (p=0.02).
Conclusion:
In patients with AIS-like symptoms, BAT MRI may be used to confirm AIS, exclude stroke mimics and assess candidacy for IV TPA. Atrial fibrillation correlated with AIS on BAT MRI; therefore, these patients may be more likely to be IV TPA candidates.
Effectiveness and Safety of Standard-Dose Nonvitamin K Antagonist Oral Anticoagulants and Warfarin Among Patients With Atrial Fibrillation With a Single Stroke Risk Factor
