Comparison of Susceptibility-Weighted Imaging and Perfusion-Weighted Imaging in the Estimation of the Amount of Reversible Ischemic Tissue (Penumbra)

MRI imaging is a method of choice for diagnosis of stroke and able to recognize the area of preventable infarct which selected for reperfusion therapy. Ischemic tissue could be reversed if perfusion is improved as the penumbra. Perfusion-diffusion mismatch was accepted as the standard tool for the evaluation of penumbra. We conducted a recent cross-sectional study to assess the accuracy of SWI-DWI mismatch as noninvasive and available alternative in the detection of penumbra. We determined ischemic tissue via diffusion-weighted images and detection of asymmetric hypointense vein (AHV) on ischemic region in the SWI sequences. After injection of contrast media, perfusion images were performed and finally we determined PWI-DWI and SWI-DWI mismatch values and evaluated the correlation between them. We also determined accuracy of SWI-DWI mismatch and cutoff values of SWI-DWI for detecting optimal PWI-DWI mismatch. Patients with ischemic stroke who were referred to our neuroimaging center and underwent an MRI within 48 h from the onset of symptoms are included in this study. Patients were imaged with stroke protocols including T1, T2 FLAIR, PWI, SWI, and DWI. AHVs were also determined for detection of ischemia in SWI sequences. A total of 30 cases are enrolled and 15 cases were excluded. There was a positive and significant correlation between SWI-DWI and PWI-DWI mismatch ratio (r = 0.34, p = 0.047). The sensitivity, specificity, and accuracy of SWI-DWI for detecting penumbra were 94%, 69%, and 76%. Our results indicated SWI-DWI mismatch is better alternative tool for detection of penumbra and predicting potentially viable brain tissue.