Susceptibility–Diffusion Mismatch in Hyperacute Stroke: Correlation with Perfusion–Diffusion Mismatch and Clinical Outcome

Background A prominent vein (PV) on susceptibility-weighted imaging (SWI) was recently proposed to be a marker of the penumbra. We aimed to compare the utility of SWI and perfusion-weighted imaging (PWI) sequences for the evaluation of the penumbra in hyperacute middle cerebral artery (MCA) stroke, and to determine whether SWI–DWI mismatch is a neuroimaging marker of clinical outcome. Methods A total of 149 consecutive patients with MCA stroke were prospectively enrolled. Magnetic resonance imaging (MRI) was performed within 6 hours of the onset of stroke. The ASPECTS values on diffusion-weighted imaging (DWI), PWI (delayed mean transit time), and SWI (visualization of PVs) were calculated by 2 independent raters. Correlation between PWI-ASPECTS and SWI-ASPECTS was calculated with the Pearson coefficient. Reliability of the PV rating system was calculated by an intraclass correlation coefficient (ICC). Favorable outcome was defined as a modified Rankin Scale score of 0-2 at 3 months for the 88 patients who received thrombolytic therapy. Results The ASPECTS-SWI and ASPECTS-PWI scores showed a good correlation (Pearson coefficient of .69, P  .001). The reproducibility between the findings of the junior and the senior radiologists was excellent with an ICC of .89 (confidence interval of 95% (IC95): .85-.92, P  .001). However, neither SWI–DWI mismatch nor PWI-SWI mismatch was associated with clinical outcome. Conclusion SWI and PWI were complementary but not commutable for the assessment of the penumbra. Susceptibility–diffusion mismatch was not found in this study to have predictive value for stroke outcome.