title: Evolution of Volume and Signal Intensity on Fluid-attenuated Inversion Recovery MR Images after Endovascular Stroke Therapy.
abstract: Purpose To analyze both volume and signal evolution on magnetic resonance (MR) fluid-attenuated inversion recovery (FLAIR) images between the images after endovascular therapy and day 5 (which was the prespecified end point for infarct volume in the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution [DEFUSE 2] trial) in a subset of patients enrolled in the DEFUSE 2 study. Materials and Methods This study was approved by the local ethics committee at all participating sites. Informed written consent was obtained from all patients. In this post hoc analysis of the DEFUSE 2 study, 35 patients with FLAIR images acquired both after endovascular therapy (median time after symptom onset, 12 hours) and at day 5 were identified. Patients were separated into two groups based on the degree of reperfusion achieved on time to maximum greater than 6-second perfusion imaging (≥90% vs <90%). After coregistration and signal normalization, lesion volumes and signal intensity were assessed by using FLAIR imaging for the initial lesion (ie, visible after endovascular therapy) and the recruited lesion (the additional lesion visible on day 5, but not visible after endovascular therapy). Statistical significance was assessed by using Wilcoxon signed-rank, Mann-Whitney U, and Fisher exact tests. Results All 35 patients had FLAIR lesion growth between the after-revascularization examination and day 5. Median lesion growth was significantly larger in patients with <90% reperfusion (27.85 mL) compared with ≥90% (8.12 mL; P = .003). In the initial lesion, normalized signal did not change between after endovascular therapy (median, 1.60) and day 5 (median, 1.58) in the ≥90% reperfusion group (P = .97), but increased in the <90% reperfusion group (from 1.60 to 1.73; P = .01). In the recruited lesion, median normalized signal increased significantly in both groups between after endovascular therapy and day 5 (after endovascular therapy, from 1.19 to 1.56, P < .001; and day 5, from 1.18 to 1.63, P < .001). Conclusion Patients with ≥90% reperfusion after endovascular therapy have significantly less lesion growth on FLAIR images between after therapy and day 5 compared with patients who have <90% reperfusion. Therefore, the effect of reperfusion therapies on lesion volumes are likely more apparent at day 5 than after therapy. (©) RSNA, 2016.
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Christian
authors.initials: C
authors.lastname: Federau
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Michael
authors.initials: M
authors.lastname: Mlynash
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Soren
authors.initials: S
authors.lastname: Christensen
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Greg
authors.initials: G
authors.lastname: Zaharchuk
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Brannon
authors.initials: B
authors.lastname: Cha
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Maarten G
authors.initials: MG
authors.lastname: Lansberg
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Max
authors.initials: M
authors.lastname: Wintermark
authors.affiliation: From the Department of Radiology (C.F., G.Z., M.W.) and Stanford Stroke Center, Department of Neurology and Neurological Sciences (M.M., S.C., B.C., M.G.L., G.W.A.), Stanford University School of Medicine, 780 Welch Rd, Suite 350, Palo Alto, CA 94304.
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Albers
mesh_terms: D000368:Aged; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000601:surgery; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D017131:Thrombectomy / Q000379:methods*; D016896:Treatment Outcome