To evaluate the accuracy of diagnosing the qualifying artery in patients with medium vessel occlusion stroke based on multimodal CT

Inclusion Criteria:

• Patients with acute ischemic stroke, without restrictions on gender
• Age ≥ 18 years old
• The time from onset to treatment is within 24 hours (the onset time is defined as the "last-well-time", and the treatment plan is determined according to the patient's wishes and local clinical experience)
• Before the treatment, CT, CTA and CTP examinations were conducted, and the relevant clinical data were complete.

Exclusion Criteria:

• Patients with acute intracranial hemorrhage
• Patients whose CTP original images cannot be processed by the CTP post-processing software
• Patients for whom the DICOM format image data of CT, CTP original images and MRI images cannot be obtained, or whose image quality is poor due to various reasons

According to previous literature reports, the prevalence of MeVO stroke accounts for 18% of ischemic stroke. It is estimated that the sensitivity of NCCT + CTA in diagnosing MeVO is 74%. Based on multimodal CT, the sensitivity for diagnosing moderate vascular occlusive stroke can be increased by 15%, reaching 89%. The test level is bilateral 0.05, and the confidence level 1 - β = 0.8. Then, at least 622 research subjects are required. Among them, the number of patients with MeVO, N1 = 622 * 0.18 = 112 cases.