MR-based Stroke Mechanism and Future Risk Score

To explore prediction model for outcome of patients with acute ischemic stroke using multimodal Magnetic Resonance(MR) imaging was a multicenter prospective observational study supported by National Natural Science Foundation of China. Imaging evaluation of hemodynamic status and antegrade flow were assessed. Patients were followed up to record radiological and clinical outcome. The study recruited patients from 11 centers located in 10 provinces or province-level municipalities across the northeast to the southeast of China mainland.

Patients:

Patients with cerebral ischemia sympton of onset in 24 hours were included. Baseline materials, NIH stroke scale score, modified Rankin Scale at admission, stroke causes, time from sympton onset to enrollment were recorded.

Imaging scan were conducted at admission, within 7 days after admission.

Imaging protocols:

MRI scan protocols: T2 weighted image, T1 weighted image, Diffusion weighted image(DWI), fluid-attenuated inversion recovery(FLAIR), Perfusion weighted image(PWI), arterial spin labeling(ASL) , susceptibility-weighted imaging(SWI).

Contrast agent:

Omniscan 2ml/kg, Inject rate：3ml/s

Digital subtraction angiography(DSA) protocols:

Selective angiography and imaging phase from arterial phase to late venous phase.

Imaging evaluation:

Antegrade flow assessment from ASL Cerebral blood flow(CBF) map. Collateral flow assessment from ASL CBF map, ASL subtraction CBF map, PWI postprocessing map, FLAIR hyperintensity vascular sign.

Initial infarct volume measurement form DWI. Final infarct volume measurement from FLAIR. DWI-ASPECTS. Stroke lesions pattern assessment identified on DWI. DSA antegrade and collateral grade using modified Thrombolysis in Cerebral Infarction(TICI) scale and The American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral grading system.

Treatment:

Intravenous recombinant tissue plasminogen activator(rtPA), endovascular therapy and conventional treatment including neuro protection, ante-platelet and statin.

Follow up:

within Seven days and a month after imaging follow up and clinical stroke event and modified Rankin Scale(mRS) record in 1 year.

Note:

The original trial from 2015 to 2018 recruited patients with acute and subacute ischemic stroke, and the trial plan was changed to recruit patients with acute cerebral ischemia sympton of onset within 24 h.The study has been upgraded from a single-center study to a multi-center study since 2018.

Eligibility Criteria:
Inclusion Criteria:

* age≥18
* Cerebral ischemic sympton with onset in 24 hours
* pre mRS\<2
* All MR examination performed according to study protocol
* Signed informed consent obtained from the patient or patient's legally authorized representative
* Having complete medical history and clinical follow up
* Imaging data can be processed

Exclusion Criteria:

* Intracranial hemorrhage
* Pregnancy and other contraindication to MRI scan
* Informed consent not obtained
* Pre-existing medical, neurological or psychiatric disease that would confound the neurological, functional, or imaging evaluations
* Known allergy to iodine previously refractory to pretreatment medications
* Renal Failure (serum creatinine \> 2.0 or Glomerular Filtration Rate \[GFR\] \< 30)
* History of sever kidney disease as an adult, including tumor or transplant surgery, or family history of kidney failure
* Severe cardiac insufficiency