Susceptibility-Weighted Imaging in Predicting Ischemic Stroke Evolution: with Clinical NIHSS and Final Infarct Area on follow-up MRI

PURPOSE: The concept of ischemic penumbra is widely used in predicting stroke evolution and guiding therapy. Our recent experience indicated that susceptibility-weighted imaging (SWI) has a potential ability to reflect increased oxygen extraction of the penumbra area by presence of prominent hypointense vessels. The aim of this study is to evaluate the SWI in prediction of final infarct area and clinical outcome of acute stroke patient groups. MATERIALS AND METHODS: Seventeen acute stroke patients in the territory of middle cerebral artery were prospectively studied with MRI study including DWI, T2W, SWI, with follow up images in 7 days. Clinical NIHSS score was performed in acute stage < 24 hours and on the day follow-up MRI performed. Two experienced neuroradiologists interpreted the infarct territories on DWI, T2W and hypointense vessels on SWI and semi-quantified by Alberta Stroke Program Early CT Score (ASPECTS). Infarct growth was semi-quantified by modified ASPECTS, from 10 (no growth in 10 areas of ASPECTS) to 0 (growth in each area of 10 areas). RESULTS: Patients with more prominent hypointense vessels on the initial SWI had larger obvious infarct growth area on the follow-up MRI. A good correlation (r = 0.7589) was shown between 1st SWI ASPECTS and infarct growth score. Patients with more prominent hypointense vessels on the initial SWI also tended to have a progressively worse clinical outcome, with a fair correlation (r = -0.5785) between 1st SWI ASPECTS and NIHSS score difference. CONCLUSION: SWI can be feasible to predict stroke evolution with good correlation to final infarct area and clinical outcome, thereby potentially providing helpful tool guiding thrombolytic therapy.