Because the last 2 studies independently demonstrated benefit in the treated group, the role of additional imaging-based eligibility criteria is not well established and could lead to the exclusion of patients who would benefit from treatment and are therefore not indicated at this time. Further RCTs may be helpful to determine whether advanced imaging paradigms using CTP, CTA, and MRI perfusion and diffusion imaging, including measures of infarct core and penumbra, are beneficial for selecting patients for reperfusion therapy who are within 6 hours of symptom onset and have an ASPECTS <6. See Table XVII in online Data Supplement 1. 2.2.3. Mechanical Thrombectomy Eligibility Vessel Imaging (Continued) COR LOE New, Revised, or Unchanged Powers et al 2019 Guidelines for Management of AIS e359 2.3. Other Diagnostic Tests 2.3. Other Diagnostic Tests COR LOE New, Revised, or Unchanged Only the assessment of blood glucose must precede the initiation of IV alteplase in all patients. I B-NR Recommendation reworded for clarity from 2013 AIS Guidelines. COR unchanged. LOE amended to conform with ACC/AHA 2015 Recommendation Classification System. See Table XCV in online Data Supplement 1 for original wording. Recommendation was modified to clarify that it is only blood glucose that must be measured in all patients. Other tests, for example, international normalized ratio, activated partial thromboplastin time, and platelet count, may be necessary in some circumstances if there is suspicion of coagulopathy. Given the extremely low risk of unsuspected abnormal platelet counts or coagulation studies in a population, IV alteplase treatment should not be delayed while waiting for hematologic or coagulation testing if there is no reason to suspect an abnormal test. Baseline electrocardiographic assessment is recommended in patients presenting with AIS but should not delay initiation of IV alteplase. I B-NR Recommendation reworded for clarity from 2013 AIS Guidelines. COR unchanged. 