Regarding the most recent ischemic stroke treatment guideline, American Heart Association 2018 (AHA 2018), the perfusion imaging has been recommended up to 24 hours after initial symptoms of brain infarction and patients with a significant amount of potential salvageable peri-infarct ischemia and without contraindication benefit from delay thrombolysis and intra-arterial thrombectomy. This approach causes more and more CT perfusion to be done in subacute phase of ischemic stroke. CT perfusion findings in this “subacute phase” are slightly different from “hyper acute” ischemic stroke. The interpreting radiologist must be confident to report the CT perfusion in urgent setting since these studies are under the umbrella of “code-stroke” and should be read in minutes. In addition, result of the CT perfusion has a critical effect on the patient’s outcome. Misinterpretation of stroke CT perfusion can be fatal. Underestimation of the salvageable ischemia excludes the patient from the potential effective treatment and increases the mortality and morbidity. Underestimation of infarct volume causes unnecessary thrombolysis/thrombectomy and potential fatal intracranial hemorrhage. In this review, I am trying to explain the challenges of sub- acute “code-stroke” CT perfusion.