Predicting stroke evolution: comparison of susceptibility-weighted MR imaging with MR perfusion.
OBJECTIVE
To investigate the ability of susceptibility-weighted imaging (SWI) to predict stroke evolution in comparison with perfusion-weighted imaging (PWI).


METHODS
In a retrospective analysis of 15 patients with non-lacunar ischaemic stroke studied no later than 24 h after symptom onset, we used the Alberta Stroke Program Early CT Score (ASPECTS) to compare lesions on initial diffusion-weighted images (DWI), SWI, PWI and follow-up studies obtained at least 5 days after symptom onset. The National Institutes of Health Stroke Scale scores at entry and stroke risk factors were documented. The clinical-DWI, SWI-DWI and PWI-DWI mismatches were calculated.


RESULTS
SWI-DWI and mean transit time (MTT)-DWI mismatches were significantly associated with higher incidence of infarct growth (P = 0.007 and 0.028) and had similar ability to predict stroke evolution (P = 1.0). ASPECTS values on initial DWI, SWI and PWI were significantly correlated with those on follow-up studies (P ≤ 0.026) but not associated with infarct growth. The SWI ASPECTS values were best correlated with MTT ones (ρ = 0.8, P < 0.001).


CONCLUSIONS
SWI is an alternative to PWI to assess penumbra and predict stroke evolution. Further prospective studies are needed to evaluate the role of SWI in guiding thrombolytic therapy.                                                     Key Points                                                  • SWI can provide perfusion information comparable to MTT                                                  • SWI-DWI mismatch can indicate ischaemic penumbra                                                  • SWI-DWI mismatch can be a predictor for stroke evolution.
Department of Radiological Sciences, University of California at Irvine Medical Center, 101 City Dr. South, Orange, Irvine, CA 92868, USA.
Hung-Wen
HW
Kao
Fong Y
FY
Tsai
Anton N
AN
Hasso
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications* / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000150:complications* / Q000473:pathology*