Can susceptibility weighted imaging indicate the ischemic penumbra in patients with acute infarction in middle cerebral artery?

1.Purpose to evaluate the penumbra in acute ischemic stroke by quantitative mismatch between susceptibility weighted imaging(SWI) and diffusion weight imaging(DWI) in comparison with perfusion weighted imaging(PWI) and diffusion weight imaging(DWI) mismatch.

2.Method 85 eligible patients were enrolled with acute ischemic stroke who underwent MR scan including DWI, SWI and PWI before treatment within 12 hours after symptom onset. SWI-DWI mismatch was demarcated by the volume of asymmetrical prominent cortical veins（APCV）region in SWI MIP extending beyond the volume of infarct core segmentation of ADC maps. PWI-DWI mismatch was determined by using infarct core and perfusion deficits segmented from ADC and Tmax maps.

3.Result 41 cases have SWI-DWI mismatch，while 43 cases have PWI-DWI mismatch in totally 85 patients. 42 cases have neither SWI-DWI mismatch nor PWI-DWI mismatch. Only 2 cases have PWI-DWI mismatch without SWI-DWI mismatch. None has SWI-DWI mismatch without PWI-DWI mismatch. There is no a significant difference between SWI-DWI and PWI-DWI in showing mismatch with MCA stroke(P<0.01).The NIHSS of patients with SWI-DWI mismatch was statistically higher compared to the patients without SWI-DWI mismatch (t=-4.956, P<0.01). The NIHSS of patients was also statistically higher with PWI-DWI mismatch in comparison with none PWI-DWI mismatch（t=-4.481, P<0.01）.

4.Conclusion APCV in SWI might to be a good instrument to indicate the ischemic penumbra as well as PWI. SWI may be an alternative to PWI in some stroke cases.