Yves Berthezène1, Omer Eker2, Nikolaos Makris2, Maxime Bettan2, Adeline Mansuy2, Aurélie Chabrol2, Irene K Mikkelsenm3, Marc Hermier2, Laura Mechtouff2, Elodie Ong2, Laurent Derex2, Lise-Prune Berner2, Roxana Ameli2, Salvador Pedraza4, Gotz Thomalla5, Leif Østergaard3, Jean-Claude Baron6, Tae-Hee Cho2, Norbert Nighoghossian2. 1. Department of Stroke Medicine, Department of Neuroradiology, Université Lyon 1, CREATIS, CNRS UMR 5220-INSERM U1044, INSA-Lyon, Hospices Civils de Lyon, Lyon, France. Electronic address: yves.berthezene@chu-lyon.fr. 2. Department of Stroke Medicine, Department of Neuroradiology, Université Lyon 1, CREATIS, CNRS UMR 5220-INSERM U1044, INSA-Lyon, Hospices Civils de Lyon, Lyon, France. 3. Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark. 4. Department of Radiology (IDI), Girona Biomedical Research Institute (IDIBGI), Hospital Universitari de Girona Dr Josep Trueta, Girona, Spain. 5. Department of Neurology, Center for Clinical Neurosciences, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. 6. University of Cambridge, Department of Clinical Neurosciences, Cambridge, UK; Dept of Neurology, Hôpital Sainte-Anne, Université Paris Descartes, INSERM U894, Paris, France.
Abstract
OBJECTIVES: The aim of the present study was to assess the association between collateral status and DWI-FLAIR mismatch in patients with acute ischemic stroke within the 4.5 h time-window. METHODS: We analysed DWI, FLAIR, and PWI data in patients within 4.5 h after symptom onset from the I-KNOW European database. Collateral flow maps were graded by analyzing contrast 'staining' extent over the early, mid and late perfusion phases. ADC values, DWI lesion volume, and normalised perfusion parameters (CBV,Tmax) within DWI lesions were determined. Visibility of parenchymal hyperintensivty on FLAIR was evaluated ("FLAIR positive"), and DWI-FLAIR mismatch was assessed. Spontaneously reperfused regions were defined as voxels with Tmax <6 s within the DWI lesion. Final infarct size was assessed on day-30 FLAIR images. RESULTS: Of the 168 patients included in I-KNOW database, 87 were eligible for this study. DWI-FLAIR mismatch was present in 69 patients. There was no difference between poor and good collaterals status according to age, sex, baseline NIHSS score, time to MRI and DWI lesion volume. Collateral status was significantly better in the FLAIR positive group (p = .001). Patients with poor collaterals had significantly increased Tmax (p = .005). Baseline DWI lesion volume and final lesion volume were significantly smaller in patients with good collateral status (p < .001 and 0.01, respectively). CONCLUSIONS: We found that patients with early FLAIR lesion visibility have a better collateral status. This finding has implications for the management of stroke patients with unknown time-of-onset, and more widely should be considered in the current context of extending the therapeutic window.
OBJECTIVES: The aim of the present study was to assess the association between collateral status and DWI-FLAIR mismatch in patients with acute ischemic stroke within the 4.5 h time-window. METHODS: We analysed DWI, FLAIR, and PWI data in patients within 4.5 h after symptom onset from the I-KNOW European database. Collateral flow maps were graded by analyzing contrast 'staining' extent over the early, mid and late perfusion phases. ADC values, DWI lesion volume, and normalised perfusion parameters (CBV,Tmax) within DWI lesions were determined. Visibility of parenchymal hyperintensivty on FLAIR was evaluated ("FLAIR positive"), and DWI-FLAIR mismatch was assessed. Spontaneously reperfused regions were defined as voxels with Tmax <6 s within the DWI lesion. Final infarct size was assessed on day-30 FLAIR images. RESULTS: Of the 168 patients included in I-KNOW database, 87 were eligible for this study. DWI-FLAIR mismatch was present in 69 patients. There was no difference between poor and good collaterals status according to age, sex, baseline NIHSS score, time to MRI and DWI lesion volume. Collateral status was significantly better in the FLAIR positive group (p = .001). Patients with poor collaterals had significantly increased Tmax (p = .005). Baseline DWI lesion volume and final lesion volume were significantly smaller in patients with good collateral status (p < .001 and 0.01, respectively). CONCLUSIONS: We found that patients with early FLAIR lesion visibility have a better collateral status. This finding has implications for the management of strokepatients with unknown time-of-onset, and more widely should be considered in the current context of extending the therapeutic window.
Keywords:
Collateral; Fluid-Attenuated-Inversion-Recovery; Ischemic stroke; Magnetic Resonance Imaging; Perfusion-weighted-imaging; Time from symptom onset